IMIESA July 2022

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IMESA The official magazine of the Institute of Municipal Engineering of Southern Africa

INFRASTRUCTURE DEVELOPMENT • SERVICE DELIVERY • ROADS • BUILDING • MAINTENANCE • ENERGY

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WHY CHOOSE A PREFILLED SOLUTION OVER A TRADITIONAL ONE? OVER 70% STONE SAVINGS VS RIP-RAP

LESS MATERIAL, MORE ACCURACY

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RenoMac Plus and CubiMac do not need to be filled on-site but they can be moved to the construction site ready for installation. With prefilled solutions the laying process is more accurate, avoiding unnecessary waste of time and resources, and the whole installation process becomes more sustainable.

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VOLUME 47 NO. 07 JULY 2022

INSIDE

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22 Regulars

www.infrastructurenews.co.za

IMESA The official magazine of the Institute of Municipal Engineering of Southern Africa

INFRASTRUCTURE DEVELOPMENT • SERVICE DELIVERY • ROADS • BUILDING • MAINTENANCE • ENERGY

Roads & Bridges The Pothole Patrol

GLS CONSULTING

Women in Construction

Editor’s comment

3

President’s comment

5

Index to advertisers

48

No smart water utility without making a start

6

Infrastructure news from around the continent Energy Hydropower on the Ash River

10

A new standard for RCC innovation

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Energy

ON THE COVER

At the grid edge

12

Water & Wastewater

The power of waste

14

Establishing a hydraulic model is the start to leveraging smart technologies in the age of the Fourth Industrial Revolution, which is spawning concepts like digital infrastructure twins, the internet of things, artificial intelligence, cloud processing and real-time data transfer from electronic metering devices and sensors. P6

Green hydrogen in South Africa

16

Key project to boost Gauteng water supply

18

Dams, Reservoirs & Storage

POWER STATIONS

40

Keynotes to share global perspective at road conference

41

21

Neckartal Dam sets a new standard for RCC innovation

22

Year 2: An update on the NatSilt Programme

24

Avoid crusher downtime

Polihali Dam and tunnel programme update

27

Cement & Concrete

Municipal Focus: Nelson Mandela Bay

18

28

NELSON MANDELA BAY

38

The Pothole Patrol

Rainwater harvesting should not be a luxury

Groundwater has the muscle to push back ‘Day Zero’ – but are we protecting it?

37

Roads & Bridges

Power Stations Hydropower on the Ash River

34

Pumps & Valves Energy-efficient treatment processes

Dams, Reservoirs and Storage

32

Environmental Engineering Gabions and riverbank protection

Africa Roundup

31

Pipelines Quality control starts with adherence to material standards

Cover Story No smart water utility without making a start

2022 cidb awards programme celebrates women in construction

Fleet Management Save fuel with Ctrack Crystal

42

Vehicles & Equipment 43

Fibres can add significant strength to concrete

44

Reinstating an old floor

45

Precast solutions for a residential estate 47 28

Composite cements lead in sustainability drive

34

48

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EDITOR’S COMMENT MANAGING EDITOR Alastair Currie SENIOR JOURNALIST Kirsten Kelly JOURNALIST Nombulelo Manyana EDITORIAL COORDINATOR Ziyanda Majodina HEAD OF DESIGN Beren Bauermeister CHIEF SUB-EDITOR Tristan Snijders CONTRIBUTORS Lesego Gaegane, Bhavna Soni PRODUCTION & CLIENT LIAISON MANAGER Antois-Leigh Nepgen GROUP SALES MANAGER Chilomia Van Wijk BOOKKEEPER Tonya Hebenton DISTRIBUTION MANAGER Nomsa Masina DISTRIBUTION COORDINATOR Asha Pursotham SUBSCRIPTIONS subs@3smedia.co.za PRINTERS Novus Print Montague Gardens ___________________________________________________ ADVERTISING SALES KEY ACCOUNT MANAGER Joanne Lawrie Tel: +27 (0)11 233 2600 / +27 (0)82 346 5338 Email: joanne@3smedia.co.za ___________________________________________________

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The energy to change things for the best outcome

A

ccording to World Bank data, some 84.4% of South Africans had access to electricity in 2020.

In 1996, that figure was 57.6%, so there has been a marked improvement thanks to sustained public sector investment, particularly in terms of municipal electrification projects, which deliver the final product.

However, keeping pace with demand is becoming increasingly challenging, given significant population growth, urban migration, and our unique and complex socio-economic history. This has been compounded by continued and unscheduled breakdowns within the Eskom power station fleet.

Towns and cities are further faced with the need to upgrade their distribution networks. Across the board, electrification infrastructure is aged and straining. Moving forward, addressing this will require a collective intervention effort from business, government and the community.

This was the essential message during President Cyril Ramaphosa’s energy action plan address on 25 July 2022. Broadcast to the nation, the plan acknowledges the extent of the electricity crisis and the immediate steps needed to prevent the undermining of South Africa’s socio-economic objectives. The primary short-term goal is power security, alongside a progressive transition away from coal-fired to green energy.

A renewed call for private participation In parallel with additional funding support for critical maintenance at Eskom power stations, the action plan embraces full-scale participation by the private sector. That ranges from households and general businesses with rooftop solar, to specialist independent power producers (IPPs).

To fast-track the process, the unlicensed threshold – previously capped at 100 MW for IPP embedded generation projects – is being scrapped. Projects will still need to be registered with and meet the National Energy Regulator of

South Africa’s requirements. However, the fact that the sky’s now the limit is a major milestone.

Red tape and renewables Historically, one of the key obstacles to infrastructure implementation has been the public procurement process. This is now also being addressed to speed up the phased execution of South Africa’s Renewable Energy Independent Power Producer Procurement Programme (REIPPPP), which commenced with Bid Window 1 in 2012.

In the latest round, Bid Window 5 projects are due to achieve commercial operation from early 2024, adding a further 2 600 MW to the grid. Given the long lead times for completion, government has committed to ensuring that Bid Window 5 projects commence construction as scheduled.

Affordability and climate change As we focus on keeping the lights on, IPPs, municipalities and government must factor in the social cost. Power must be an enabler that sustains our communities, environment and economy. It must therefore be efficiently supplied, equitably shared and priced at competitive levels that are affordable.

The Just Energy Transition Partnership (JETP) is a key step along the way. Concluded between South Africa and the governments of France, Germany, the UK, USA and EU – following the 26th UN Climate Change Conference (COP26) – it paves the way for exciting development opportunities. In terms of the JETP, around US$8.5 billion (R144 billion) has been committed in the first phase to support South Africa’s shift to renewables.

As this starts to bear fruit, South Africa’s future will be a bright one.

Alastair To our avid readers, check out what we are talking about on our website, Facebook page or follow us on Twitter and have your say.

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IMIESA July 2022

3

PRESIDENT’S COMMENT

IMESA

The value of SHARED EXPERIENCES

Between 22 and 24 June 2022, associations from around the world gathered in Rome, Italy, for the International Federation of Municipal Engineering (IFME) Annual Convention.

This included IFME’s first of two board meetings for the year. The second will be held in South Africa, coinciding with IMESA’s 85th Annual Conference in November 2022.

A

s the president of IMESA, I had the honour of representing South Africa at the 2022 IFME Convention, sharing key infrastructure challenges with municipal engineering counterparts from Asia, Europe, North America and the Middle East.

Presentations focused on ways to achieve a sustainable green transition within the urban context.

Key topics covered included the reimagining of sustainable urban spaces, smart mobility and asset management. The latter topic is especially important in managing and progressively upgrading ageing infrastructure, particularly water and sewer pipelines.

Stemming non-revenue water losses remains a global concern, from both environmental and financial perspectives, so this is an area where a great deal of IFME knowledge-sharing takes place.

South Africa’s urban landscape has also been strongly influenced and affected by apartheid spatial planning. The result is that there are disconnects, with poorer communities often housed at significant distances from economic opportunities.

In line with international trends, South Africa has witnessed a major migration from rural to urban areas as job seekers enter cities look for work. As many are unemployed, they end up joining rapidly expanding informal settlements, placing additional strain on resources and existing infrastructure services.

People-centric infrastructure Across the board, a key takeaway from the rigorous Covid-19 lockdowns imposed worldwide has been the need to create liveable spaces that place people at the centre of city planning.

Social housing, for example, isn’t there purely to provide accommodation. It must enhance the living experience.

Sustainable strategies Universally, IFME members acknowledge that climate change is the biggest single threat to our future. However, the way in which individual countries respond will be influenced by their unique socio-economic history and culture.

From an energy perspective, for example, South Africa’s shift from coal-fired to renewable power stations will be more gradual than in Europe, where the clean energy transition is already well advanced. Key reasons for this locally include funding availability, the current policy environment, plus the fact that many South African communities depend on coal mining for their livelihoods.

hugely beneficial in helping to preserve scarce water sources. Communities not connected to conventional sanitation can also be serviced with alternative, cost-effective solutions that aren’t high-tech.

An example I shared with IFME delegates is a pilot project under way in eThekwini Municipality in partnership with the Pollution Research Group. This entails the trialling of a modular Decentralised Wastewater Treatment System (DEWATS) plant for on-site waterborne sanitation.

Designed to treat wastewater from some 86 households, the potential for reuse in an irrigation application is also being investigated, fostering SMME opportunities for vegetable farmers.

The fact is that greenhouse gas emissions know no boundaries, and the world shares a common responsibility in achieving the UN Sustainable Development Goals. How countries individually and collectively achieve this depends on collaboration. Our role as IMESA – in conjunction with IFME – is to facilitate this process within the municipal arena.

Game changers As municipal engineers, we have a key role to play in influencing next-generation service delivery from a design and build perspective. And not every solution has to be state of the art to be innovative.

This is certainly underscored by the ancient legacy of Italy’s Roman infrastructure – from the Colosseum to still functional aqueducts and roads. These icons remind us of what is possible with the technology available at the time, and what works best in practice.

From an environmental viewpoint, simple interventions like rainwater harvesting tanks are

Bhavna Soni, president, IMESA

IMIESA July 2022

5

COVER STORY

INNOVATIONS IN HYDRAULIC MODELLING

NO SMART WATER UTILITY WITHOUT MAKING A START Establishing a hydraulic model is the start to leveraging smart technologies in the age of the Fourth Industrial Revolution (4IR), which is spawning concepts like digital infrastructure twins, the internet of things (IoT), artificial intelligence, cloud processing and real-time data transfer from electronic metering devices and sensors.

O

ver the past 30 years, GLS Consulting has established hydraulic models of real world, physical water distribution systems for 62 of the 144 municipal water services authorities in South Africa.

The total length of water pipelines modelled is 91 059 km with a total water consumption of just over six billion litres per day (6 000 Mℓ/day). The population in these 62 municipalities amounts to 30.2 million Establishment of a digital model of the infrastructure

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people, which represents half of the South African population.

Within smaller municipalities and large rural ones, it is often found that the information required to support the establishment of hydraulic models is wholly inadequate.

However, through close collaboration – and with engineering adaptation and innovation – new and exciting (often disruptive) approaches to modelling have been developed by GLS for municipalities and water boards to solve these challenges.

Establishment of a water consumption database (spatial)

FIGURE 1 Establishment of a hydraulic model

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IMIESA July 2022

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Hydraulic model (start of a digital twin)

The complete modelling process entails building a digital or computer model of the infrastructure, and then developing a water consumption database. Applying the consumption database to the infrastructure model results in the creation of a hydraulic model. These steps are shown in Figure 1.

The journey to establish a hydraulic model (about a year), embrace technology and become a smart water service provider is less daunting when viewed as an incremental process. Each step in the journey adds value to municipal engineers and managers by offering increased access to data, which leads to more knowledge and better decision-making. The foundation that this journey is built on is a wellestablished, geospatially accurate hydraulic model that reflects real-world assets and system operations, as feasibly as possible.

ESTABLISHMENT OF A SMART DIGITAL INFRASTRUCTURE MODEL Data collection All existing sources of information pertaining to the water distribution system need to be collected and assimilated in the hydraulic modelling software. These sources can

COVER STORY

vary from as-built drawings – both physical paper drawings and computer-aided design (CAD) files – GIS databases, technical project completion reports and operational staff knowledge. Separate from municipal information, additional pipe catalogue and unit costing information can be collected and set up in a database file that is imported into the modelling software.

Building the model of the infrastructure From the information collected, all infrastructure assets are imported and captured in the model software GIS environment, and network connectivity rules are enforced. Leveraging GIS capabilities (e.g., spatial correlation) allows for data transfer from various information sources to occur at a rapid rate. If up-to-date aerial imagery is not available, then the use of online maps from either publicly accessible or licensed sources can be used for the verification of asset location, especially reservoirs, or pipe routes.

Infrastructure components that are not required for the operation of a basic hydraulic model (e.g. a hydrant, air valve or shut-off valve) should still be imported or captured if data is available to expand the asset register and may be required if more advanced analyses are considered in future.

Pipe and other asset Information The already established and imported pipe catalogue can be used to fill in relevant fields in the model database table, such as material, internal and external pipe diameter and friction coefficients, through a system of dropdown selections. This reduces manual data entry requirements and ensures consistency. The pipe catalogue can be used while capturing individual pipes or to update information of a larger selection of pipes at once.

Age information is captured by providing the construction or refurbishment year and, in combination with the material, provides knowledge on the expected useful life (EUL) and the remaining useful life (RUL) of the asset.

With the use of the unit cost file imported into the model software, the construction or replacement value of the assets can be calculated based on physical attributes and location. The location of buried infrastructure plays a vital role in replacement or refurbishment costs when excavation and backfilling is considered. Intangibles like traffic control are also affected, especially when the asset is buried under a major roadway or residential street, and different

FIGURE 2A A high-level view of Drakenstein Municipality’s water infrastructure model

costings will apply to assets located in a servitude or open space.

Verification of model integrity Various software routines exist to verify the integrity of the established model. This includes a ‘traversal function’ (e.g. a routine to determine all pipes connected to one selected pipe) to confirm zone isolation and the connection of nodes to sources of water, such as reservoirs. During initial assessments, the location of reservoirs and their associated viable reservoir zones remain critical to assess initial static pressure requirements at consumers. It is here that the knowledge of operational staff can be invaluable.

Finally, the computer or software hydraulic solver will report problematic issues to the user on network connectivity – e.g. zones

that are without a source of water but have demand, or the connection of links and nodes in a way that is illegal for the solver, or the connection of pressure-reducing valves directly to reservoirs.

Challenges in building the infrastructure model The quality of data remains the single biggest challenge. Often, as-built plans are simply missing, and parts of the network will have to be estimated. The concept of dummy pipes or provisional pipes in the model can be useful but must be clearly identified for follow-up and on-site inspection at a later stage when budget allows.

Pipe roughness values – important for the hydraulic model to accurately calculate flow and velocities in links and pressure

IMIESA July 2022

7

COVER STORY

FIGURE 2B Digital representation of a water infrastructure model of the Drakenstein Municipality with line colours representing pipe diameters

head at nodes – remains a challenge when the internal size of pipes and even their existence is uncertain. An iterative approach is recommended, where the data integrity is clearly marked as ‘estimated’ or ‘provisional’ and later refinement is planned.

Figures 2A and 2B show the results of data collection and model building to provide a digital representation of Drakenstein Municipality’s water infrastructure model, at two different zoom levels, with different line colours representing different pipe diameters.

ESTABLISHMENT OF A SPATIALLY ACCURATE WATER CONSUMPTION DATABASE Cadastral and municipal billing data After a model of the real-world water distribution system has been built, the water demand or so-called output for the model nodes is required to perform hydraulic analysis. Cadastral information outlining the stand/property/ erf/village layout is of vital importance to determine theoretical water demand in the absence of reliable (or any) consumer metering data. However, first prize is a utility that provides a data extract from the treasury billing Cadastral layout

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Consumer meter readings and land use/zoning codes

system, and the modeller would add value by processing the data and later returning the processed data to the municipality.

Further billing information on land use, zoning and tariff codes can be beneficial and allows for a more relevant assignment of theoretical demands to the model based on design guidelines.

If consumer metering data is available, the readings can be extracted, entered on the model, and the average annual daily demand (AADD) calculated for each meter in question.

Algorithms can be implemented to determine if the reading values are actual readings or more likely to be estimated values.

Furthermore, if the consumer meters have associated spatial/coordinate information, each meter and its water demand can be assigned to each cadastral stand/property/ erf/village. In some cases, the consumer street address (rather than a meter coordinate) is available and can be used to locate the corresponding cadastral polygon.

Consumer demands are the best reflection of the real-world operation of a network system and are preferred in the journey to becoming smart. In an ideal smart world, these demands

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Determination of a water consumption spatial database compare

FIGURE 3 Process to establish a water consumption database and determine NRW

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IMIESA July 2022

Bulk water meter readings in a spatial database

are available for all consumers at a high frequency – e.g. every 15 minutes.

If bulk water meter readings are available, then the system-wide non-revenue water (NRW) can be calculated. Various resources are available from the International Water Association (IWA) to assist with the calculation of NRW, such as the Infrastructure Leaking Index (ILA).

Summary reports per suburb can be generated from the software indicating the water demand per land use per suburb. Or a global average can be determined in cases where no meters exist – e.g. in rural villages.

Figure 4 shows a map of the AADD per stand from a subset of the Drakenstein Municipality’s billing database. The one selected stand shows an AADD of 0.27 Kℓ/day, which is efficient for a 1 000 m2 stand.

To create a digital representation of the realworld system, the water consumption database must be loaded on to the model representing the infrastructure. This is achieved by extracting demands per stand and combining them with the spatial data from the cadastral layout. This spatial linking results in a more accurate model.

With the infrastructure model populated with water demands, water consumption per reservoir distribution zone can be established.

These digital zone demands can be compared to physical zones where water usage can be tracked using bulk water meters.

THE HYDRAULIC MODEL AND DIGITAL TWIN Once the water demands have been loaded on to the infrastructure model, the hydraulic software mathematically simulates the flows and pressures in the entire system. Once again, these digital results can be compared to physical results in the field, should level, flow and pressure sensors or loggers be available at strategic locations.

The digital simulation will make apparent all pipes that have high flows and low pressures that fall outside the parameters of design guidelines. The hydraulic modeller then redesigns the network by digitally reinforcing pipes to understand adjustments required in the physical system to improve flows and pressures.

EXTRACTING FURTHER VALUE NRW

Master planning With a well-established existing system representation, the hydraulic model can be expanded and modified to perform planning for future requirements of 10 to 20 years or more.

For example, the information obtained from

COVER STORY

FIGURE 4 Map indicating the AADD per stand taken from Drakenstein Municipality’s consumer database

the Municipal Spatial Development Framework (MSDF) can be used to compile GIS shapefiles of the future development areas of town growth with a database of expected land use and development density.

From this information, the number of units that will be developed, and their combined water demand, can be determined. Thereafter, schematic future distribution networks can be added to the model and the future demands allocated.

The master plan or future model consists of the existing system model, which is merged with the pipes required for the future development areas, and then reinforced where required so that the design criteria are met.

Additional reservoirs can also form part of the future model. Individual pipe and system upgrades can be identified, and an associated cost calculated for each item. The expected or proposed implementation year can also be assigned to the item.

Projects are created, which may contain several items, and can span over several years e.g. – a new reservoir and main outflow pipe to a new township or a rezoning project after a new reservoir has been completed.

Multi-year capital programme summaries can be produced from the master plan projects and their selected implementation year. Inversely, in cases where access to funding is constrained, the available funds for each financial year can be used to impose phasing on the most critical projects.

Asset register Detailed model summary reports by suburb, pipe sizes, total length, age, pipe material, RUL, replacement values and more can be generated, forming a solid basis for an asset register.

Plan books and valve closure programmes for operational staff Plan books can be generated that show the detail of the existing system, including the location of valves and hydrants for operational and field staff.

The digital water model network that mirrors the physical system and known valve locations allows for the determination of valve closure programmes in the event of pipe bursts or other maintenance activities to isolate sections of the system. Furthermore, if the model has been linked to a consumer database, the affected stands may be reported and, by embracing innovative technology, an automated notification system can send mobile notifications to the affected users when unplanned maintenance activities occur.

Sensitivity analysis What-if scenarios can be run using methods such as sensitivity analyses. This allows various combinations of growth or water restriction demand patterns to be investigated to ensure the system will be able to cater for changes. This might include consequences of potential rezoning or the densification of an existing zone.

Pipe replacement programmes A pipe replacement prioritisation (PRP) study can be performed to identify the pipes with the highest comparative risk of failure or greatest criticality grade should failure occur. This clears the way to proactively budget for annual pipe replacement programmes, replacing pipes that cause maintenance headaches due to age and other factors.

Fire risk compliance study Fire risk compliance analyses can be performed

to ensure that the entire system is compliant with regulations by being able to provide the 20 ℓ/s, 50 ℓ/s or 100 ℓ/s at specified locations for firefighting purposes, or to which extent there is a shortfall. A level of compliance in terms of firefighting ‘readiness’ can be attributed to every stand, and the network capability to deliver the required flow tested.

Display of models on online platforms All model data can be exported and spatially viewed on online platforms that allow quick and easy access to view-only system information for managers, designers and operational staff whenever and wherever needed. Of particular interest is also viewing the integrity of information collected (e.g. estimated pipe sizes) to plan data collection improvements projects.

CONCLUSION Overcoming the first hurdles to becoming a smart water municipality or utility starts with establishing a hydraulic model from infrastructure information and billing data. Once a water utility has made a start with a hydraulic model, the downstream benefits – such as being able to develop a master plan and establish accurate multi-year capital and PRP programme budgets, plus many more – are fairly easily achieved.

www.gls.co.za

IMIESA July 2022

9

INFRASTRUCTURE NEWS

FROM AROUND THE CONTINENT

RWANDA Update: Nyabarongo II Hydropower Plan The construction of the 43 MW Nyabarongo II Hydropower Plant will begin this year. It is expected to be operational between September 2025 and January 2026. The Export-Import Bank has funded US$214 million (R3.6 billion) towards the project.

Nyabarongo II is a concrete gravity dam built on the Nyabarongo River between the districts of Gakenke and Kamonyi in south-western Rwanda. The dam will be bordered by a 48 m high wall with a crest length of 228 m and have a storage capacity of 55 million m3. The dam is envisaged to supply water for domestic use, irrigation and livestock.

At the foot of the dam, Chinese company Sinohydro will build a hydropower plant. The water released from the reservoir will turn the turbines to produce 43.5 MW of electricity. The project also includes the construction of a substation, as well as the creation of a 110 kV transmission line over a distance of 19.2 km to connect the plant to the Rulindo substation.

The project will directly employ about 700 Rwandans and create income streams for local distributors by sourcing building resources such as sand, stone, timber and cement from them. Reportedly, only electrical and electromechanical equipment will be imported.

TANZANIA Private sector to manage plastic waste Eight brewing companies are joining forces to form the Polyethylene Terephthalate Recycle Company (PETCO) to boost plastic collection and recycling. The companies include A-One Products & Bottles Ltd (MeTL), Coca Cola Kwanza Ltd, SBC Tanzania Ltd (Pepsi), Nyanza Bottling Co. Ltd, Bonite Bottlers Ltd, Sayona Drink, Cool Blue Pure Drinking Water and Silafrica Ltd. The founding members have injected over US$100 000 (R1.7 million) towards the project, which will be used for ongoing consumer and public education, awareness activities to

promote environmental responsibility, and encourage PET collection and recycling.

Apar t from cleaning the environment, this will also create an estimated 5 000 job oppor tunities for the youth and attract investors, boosting the countr y’s revenue. The process will involve raw material producers, conver ters, brand owners, retailers, consumers and recyclers, with PETCO fulfilling the PET industr y’s role of driving extended producer responsibility (EPR), which encourages the incorporation of environmental costs associated with PET products throughout their life cycles into product market costs and shifts

responsibility for used containers from government to private industr y.

Tanzania’s Minister of State in charge of Union Affairs and the Environment, Selemani Jafo, called on other corporates to join the body.

“The founding par tners are responsible corporates; the government fully suppor ts the initiative and will work closely with PETCO to ensure this programme is well executed for the wellbeing of our environment.”

This will fast-track Tanzania's ongoing effor ts to attain the 12th goal of the UN’s Sustainable Development Goals – responsible consumption and production. Tanzania produces 14 800 tonnes of waste per day, 48% of which is plastic.

TRENCHLESS TECHNOLOGY | SEWER REHABILITATION

EGYPT Completion of Cairo Metro Line 3

ZIMBABWE New transformer signals end to constant power outages Phase II of the Emergency Power Infrastructure Rehabilitation Project (EPIRP) has reached the last leg of implementation with the delivery of a 175 MVA transformer to the Sherwood Substation. Over 1.2 million people from the Midlands, as well as Mashonaland East and West provinces of Zimbabwe will now have relief from persistent power outages.

ZimFund (of which African Development Bank is a major partner) provided US$22.74 million (R388 million) towards Phase II of the EPIRP. The Sherwoord Substation is currently equipped with three 90 MVA, 330/88/11 kV transformers, giving a total substation installed capacity of 270 MVA against a substation demand of 350 MVA. The new transformer will replace the old equipment, which is beyond repair, causing numerous power interruptions that have impacted negatively on households, industry, human capital institutions, and essential basic service delivery.

“Delivery of the transformer was a key milestone since it is the largest key equipment included in the project scope. The project faced delays exacerbated by the Covid-19 pandemic, especially on the production and shipping lines. We would like to thank Zimbabwe Electricity Distribution Company and the people of Zimbabwe for their patience throughout this project,” says Dinesh Buldoo, MD: Power, WSP. The African Development Bank-managed EPIRP Phase II is designed to improve the availability of electricity supply through the rehabilitation of generation, transmission and distribution facilities. The project target areas are Kwekwe, Gweru, Bulawayo, Mutare, Harare and Hwange, with a combined target population of 5 million people.

ZimFund has been one of the most instrumental programmes in the country in terms of restoring Zimbabwe’s critical infrastructure for power, water supply and sanitation, especially in the targeted areas. The $145.8 million (R2.49 billion) fund’s donors include Australia, Denmark, Germany, Norway, Sweden, Switzerland and the UK.

The recent inauguration of the Cairo Metro Line 3 was celebrated, among others, by the European Investment Bank, the largest international public bank, which provided €600 million (R10.4 billion) for its the construction.

It is the largest single transpor t project backed by the financier in Africa. The project is also backed by €300 million (R5.2 billion) in financing from Agence Française de Développement and €3 million (R52 million) grant suppor t from the EU. Cairo Metro Line 3 will improve urban mobility and reduce traffic congestion for the more than 20 million people living in Cairo. Improving Cairo’s transpor t network will contribute to more sustainable and green economic growth and urban development in Egypt.

“We are proud to celebrate the completion of Cairo Metro Line 3, a crucial project to transform sustainable transport and deliver climate action in Egypt. It will transform transport for millions of people every day, provide a faster and more sustainable transport alternative, and help to alleviate traffic congestion in the Egyptian capital. Line 3 is a model for sustainable transport in global cities that will improve access to jobs and education, cut pollution and reduce carbon emissions,” stated Gelsomina Vigliotti, vice president of the European Investment Bank.

IMIESA July 2022

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ENERGY

AT THE GRID EDGE

The increasing influence of digitalisation creates new possibilities for the energy sector as power generation becomes increasingly decentralised and automated. Sabine Dall’Omo, CEO, Siemens Southern and East Africa, speaks to IMIESA about trends shaping the future.

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Sabine Dall’Omo, CEO, Siemens Southern and East Africa

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t the 26th UN Climate Change Conference (COP26) held in 2021, member countries reaffirmed their commitment to greenhouse gas emissions reductions and a net-zero carbon future. Since this requires major shifts away from fossil fuel reliance, the so-called Just Energy Transition (JET) movement presents an argument for a progressive change that balances the environment with socio-economic realities.

To this end, COP26 mapped out funding and investment programmes that help developed and developing nations achieve an equitable transition. South Africa, which relies heavily on coal for its energy, is a prime candidate and will receive ongoing support in terms of the Just Energy Transition Partnership (JETP) concluded in 2021 with the governments of France, Germany, the UK, USA, and EU.

As a technology provider, Siemens is well placed to lead the transition to reduce carbon emissions across industries.

Siemens Xcelerator Further innovation will now be supported by the recent launch of Siemens Xcelerator.

“An open digital business platform, Siemens Xcelerator is designed to assist customers in their digital transformation journey,” Dall’Omo explains.

Xcelerator offerings include Building X – an end-to-end data and analytics suite for key categories like energy management, security and building maintenance. An allied solution, known as Industrial Operations X, will bridge the virtual and physical world in similar ways in optimising processes for specific industries.

“These and other developments within Siemens drive our understanding of how we’ll generate electricity in the future, use it and consume it,” Dall’Omo continues. “Examples include the evolution of domestic and industrial

ENERGY solar installations and the opportunities for independent power producers (IPPs) to wheel their electricity surplus back into the grid. What this means in practice is that we’ll need a far more intelligent grid to maintain constant baseloads.”

Connected and intelligent Siemens refers to the new digital frontier as the ‘grid edge’, where smart infrastructure and energy intelligence come together.

Here, connected technologies create the interface between the energy supply side (grid) and the energy demand side from industry, municipalities, buildings and general consumers.

Digital intelligence is the key to management, monitoring and control, with artificial intelligence there to interpret and process the massive data communication traffic produced in the 5G environment. Examples from within Siemens include PowerLink for secure and efficient communication, and SIPROTEC and SICAM for energy automation and protection, as well as power quality analytics.

“The boundaries between consumers, producers and distributors will become increasingly blurred as grids become more localised at the source of current and future demand within towns and cities. South African municipalities will also lead the change,” Dall’Omo explains.

Renewable energy Wind and solar are the preferred solutions for Africa and other developing countries, as they provide the lowest cost of energy.

Other alternative options like carbon fuels, in many countries, come at an additional foreign-currency-dependent cost, whereas the sun and wind are free, but of course there are still expensive battery storage requirements. Inevitably, some type of hybrid approach is needed.

To date, South Africa’s Renewable Energy Independent Power Producer Procurement Programme has been a great success since the initial launch of Bid Window 1 in 2012. More recently, the preferred bidders for Window 5 were announced in 2021, with Window 6 now open. Each project has crowded in much-needed local and foreign investment, empowered communities, and taken South Africa further down the JET road.

Without exception, the offtake agreements so far have been concluded with Eskom.

Going forward, that framework is destined to shift into new territory as an increasing number of IPPs enter the market with the intention of going direct to municipalities and industries.

Energy balance “For a sustainable energy transition to be possible in South Africa, we need to create the right balance so that there’s benefit for both advantaged and disadvantaged communities,” says Dall’Omo. “Part of that process includes using this energy to create new opportunities within segments, like agriculture, that help communities dependent on the mining sector find new career paths as coal-fired power stations progressively shut down.”

An example is a research project currently under way at North-West University’s Potchefstroom campus. Here, an experimental project is studying the potential of using solar power for growing commercial-scale vegetables in greenhouses, with drip irrigation regulated automatically via digitalisation.

A joint effort As COP26 has highlighted, achieving measurable targets requires cooperation and teamwork. “In South Africa, industry and government need to come up with

ideas that haven’t been tested yet in other countries as the JETP gains traction, so that creates exciting opportunities,” Dall’Omo continues.

Siemens globally has set a goal of being net-zero by 2030. Many of its customers also have the same or similar objectives, namely to decarbonise their full value chain. This means that their suppliers and logistics solutions providers also need to be carbon neutral.

Ecolabels on products are becoming increasingly common, confirming that goods and services comply with strict environmental criteria. This has implications for all counties where ‘green’ multinational companies operate and, increasingly, digitalisation will be used to evaluate and refine every process, and to provide a clear audit trail of compliance.

“Those governments or companies that try to greenwash will be caught out,” Dall’Omo stresses.

Clean energy “Now and in the future, every element of industry and society will be influenced by clean energy. It’s the only way to deliver carbon-neutral solutions. We’re already seeing this change in the electric car industry globally, with demand now outstripping supply, and it will be interesting to see how this trend plays out in South Africa.

“The important point to emphasise is that there are no quick fixes and there are always going to be events that place a bump in the JET road,” she adds.

“However, collectively, we remain on the right and only path if we want to halt and reverse climate change before it’s too late. Investment in green technologies is the future and we must embrace it,” Dall’Omo concludes.

Digital intelligence is the key to management, monitoring and control, with artificial intelligence there to interpret and process the massive data communication traffic produced in the 5G environment

IMIESA July 2022

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ENERGY

At its facility in Germiston, Interwaste specialises in producing refuse-derived fuel materials. The final processed material is close to A-grade coal quality in terms of its calorific value

THE POWER OF WASTE As populations increase, so too do waste streams, placing increasing pressure on their safe disposal.

For waste that cannot be recycled, there are other alternatives, like energy generation, says Kate Stubbs, group marketing director at Inter waste. By Alastair Currie

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Kate Stubbs, group marketing director at Interwaste

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IMIESA July 2022

South African company with a 33-year track record for innovation, Inter waste forms part of French multinational waste management specialist Séché Environnement, which operates in 15 countries across Europe, South America and Africa.

Locally, Interwaste’s integrated solutions cover the full spectrum of general and hazardous waste, with the company operating its own licensed Class B waste landfill in Delmas, Mpumalanga. Allied operational focuses encompass waste-to-energy, waste recovery and complex hazardous waste treatment solutions.

“The strategic advantage of being part of the Séché Environnement group is that Interwaste can draw on best-in-class technological solutions that support our offering within the Southern African region,” says Stubbs.

A prime example is the development of a new leachate and industrial effluent

treatment plant at its Delmas site. The first of its kind in South Africa, the plant is currently under construction and scheduled for commercial operation by the end of the first quarter of 2023.

“In line with current and future legislation, Interwaste’s strategy is to provide clients with expert advice on how best to manage and implement processes that optimise their waste streams, both from a sustainability and operating cost perspective,” Stubbs explains.

Waste as a resource Handled correctly, waste can be a valuable resource that promotes reuse, growth in the circular economy, and a zero waste-to-landfill methodology. “The reality is that South Africa is fast running out of landfill airspace, and constructing new facilities is not the only answer from an environmental standpoint.

Therefore, we need to find solutions urgently, drawing from international best practice,” she continues.

For waste that cannot be recycled, one highly viable option is to reprocess this as an alternative fuel source. In parallel are renewable waste-to-energy opportunities derived from landfill gas, organics, as well as wastewater treatment plants.

In developed countries, waste-to-energy is a common practice and receiving increasing focus. Within France, for example, Séché

ENERGY

Environnement operates various large-scale plants. These include its project in Laval, France, where landfill gas is converted into energy, alongside the production of a refusederived fuel (RDF), both of which provide the town with its power requirements.

Another example is Séché Environnement’s operation in Lyon, France, where hazardous waste from a local chemical plant is processed and converted into energy using thermal destruction technology. In terms of its agreement with the client, the electricity generated is wheeled back to power the plant.

South African opportunities “There are major opportunities for South Africa to harness the value of waste-to-energy as we transition away from fossil fuels. Plus, it’s very evident that – on top of our growing waste crisis – South Africa has a power crisis that needs urgent interventions,” says Stubbs.

Within the renewable energy space, solar and wind are the most logical options for clean, net-zero power. However, Stubbs points out that waste-to-energy plants serve the added benefit that they can also safely dispose of toxic and hazardous materials that cannot be reused, alongside more renewable biogas options.

Based on studies, wind and solar typically cost less than R1/kWh to produce, and waste-to-energy around R1.50/kWh. However, the added cost is outweighed by the environmental gains.

“There is a general perception that waste-to-energy pollutes. In fact, thanks to technological advances, the emissions from these processes are often cleaner than the air around us,” says Stubbs.

Assessing commercial viability As for any recycling initiative, the crucial starting point for a waste-to-energy project is commercial viability. “Of foremost importance is understanding your feedstock – what type of waste you have, its quality, quantity and consistency. This will determine the technology to employ, which must be appropriate for the South African market. Equally important is a guarantee of constant, 24/7 waste streams to feed the plant to ensure a sustained energy baseload, plus a secure independent power producer agreement so that the commercial model works in practice,” Stubbs explains.

A working example is Bio2Watt, based in Bronkhorstspruit, which operates a 4 MW anaerobic digestion plant that supplies

electricity to an automotive manufacturer in Rosslyn in terms of an offtake agreement.

Interwaste supplies Bio2Watt with some of its feedstock requirements.

Essentially, anaerobic digestion produces natural, methane-rich gas during the decomposition process, which is then converted into electricity.

Organics ban In terms of South African legislation, a national ban will be imposed on the disposal of organic waste to landfill by 23 August 2027. As a proactive measure, the Western Cape Provincial Government took the decision to start the process early and, in 2022, has set a 50% landfill reduction target for organics.

Organics in landfills create methane gas, which is far more toxic than carbon dioxide.

Additionally, methane creates leachate, which poses a risk in terms of groundwater contamination. For existing sites, part of the environmental solution is to install biogas plants that can convert this methane to usable energy.

“There’s no doubt that the opportunities for anaerobic digestion and biogas plant operators are favourable going forward,” says Stubbs.

RDF Within the mix, RDF is another waste-toenergy platform gaining traction. The latter is created from solid, dry, non-recyclable waste typically found in industrial and municipal waste streams. A prime candidate is the multilayered material used in the FMCG

There are major opportunities for South Africa to harness the value of waste-toenergy as we transition away from fossil fuels.” sector, such as foil plastic packaging, which can be especially challenging to recycle.

At its facility in Germiston, Interwaste specialises in producing RDF materials. The final processed material is close to A-grade coal quality in terms of its calorific value.

It can be used as a fuel source for firing cement kilns as a supplement or alternative to coal.

Hazardous liquid wastes (such as hydrocarbon sludges), oils and greases with a calorific value – but not pure enough to be converted into more direct fuels – can also be processed for thermal energy. For this purpose, Interwaste uses a blending platform at its Germiston operation that employs a special formula to create an alternative liquid fuel suitable for co-combustion with traditional fuels.

Interwaste’s research and development teams continue to explore solutions suited to the South African market that can process waste of any complexity.

“There has to be a shift in our thinking towards waste. It’s happening, but there needs to be far more public and private sector collaboration, and funding support for waste infrastructure. Within this context, wasteto-energy projects make environmental and commercial sense, and need to become a permanent feature of South Africa’s power mix,” Stubbs concludes.

IMIESA July 2022

15

ENERGY Hydrogen filling station

GREEN HYDROGEN IN SOUTH AFRICA Green hydrogen presents a wealth of oppor tunities to assist with South Africa’s economic recover y and the countr y’s ability to transition to a low-carbon, climateresilient future. Ziyanda Majodina speaks to Fahmida Smith, market development principal at Anglo American and vice chairperson of the African Hydrogen Par tnership, about the impor tance of green hydrogen locally.

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reen hydrogen uses renewable energy to split water by electrolysis into hydrogen and oxygen. It can also be transformed into ammonia, synthetic fuels and used in hydrogen fuel cells within mobility, stationar y and backup power solutions – offering alternatives to decarbonise the transportation, petrochemical, mining and shipping industries.

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IMIESA July 2022

Green hydrogen is produced from renewables such as solar/PV and wind, while grey hydrogen can be created from natural gas or coal. Hydrogen can be mixed with natural gas to heat up homes and be stored through liquid organic hydrogen carriers.

Advantages of green hydrogen Hydrogen is a clean, sustainable and versatile form of energy. It can be used

in hydrogen fuel cells and deliver energy where it is needed. It can also be utilised in a variety of applications, from transport to baseload or backup power generation.

The benefit of green hydrogen is that it is found abundantly. Green hydrogen can be produced locally and manufactured near end-use stations. “From a decarbonisation perspective in relation to diesel trucks, buses or plant and equipment on mines, we have found that hydrogen provides zero-emissions solutions to diesel-fuelled systems and in terms of refuelling infrastructure – the speed it takes to refuel hydrogen vehicles in comparison to a diesel system is almost equal,” says Smith.

“Green hydrogen also offers various options when it comes to decarbonisation solutions. For instance, the introduction of hydrogen in hard-to-abate sectors like steel manufacturing enables the production of green steel. In addition, carbon-neutral

INDUSTRY INSIGHT ENERGY

feedstock such as green ammonia and methanol can also be created,” she explains.

Due to its advantageous storage ability, green hydrogen offers greater resilience.

“Renewable energy put directly into the grid only exists when there’s the availability of wind or sunshine. Hydrogen, on the other hand, only requires obtainability, which guarantees an abundance of power,” Smith notes.

Projects Anglo American recently launched the world’s largest hydrogen-powered mine haul truck, which will operate daily at the Mogalakwena platinum mine in Limpopo, as a part of Anglo America’s nuGen™ Zero Emission Haulage Solution.

The hydrogen-batter y hybrid truck generates 2 MW of power and can carr y 290 tonnes of payload. The green hydrogen is generated at the mine site. nuGen has a fully integrated green hydrogen system that consists of production, fuelling and haulage.

Smith expands: “The project was done in conjunction with our partners Engie, who were responsible for the production of the green hydrogen and the hydrogen refuelling infrastructure on-site. Our team at Anglo America took responsibility for the development of the truck.”

Fahmida Smith, market development principal at Anglo American

The truck incorporates 800 kW of fuel cell system together with a 1.2 MW batter y. It has a total power generating potential of 2 MW. The project is expected to be fully implemented by 2026 and is a first step in making eight of the company’s mines carbon-neutral by 2030.

The Hydrogen Valley Feasibility Study Report states that the Department of Science and Innovation (DSI) and the South African National Energy Development Institute – in partnership with Anglo American, Bambili Energy and Engie – continue to explore opportunities to create a ‘Hydrogen Valley’.

“The report was a private-public partnership initiative that provides insight into what impact a hydrogen economy could have in South Africa. The study shows what the generation of green hydrogen and the uptake would be in the valley, which is around a 835 km distance between Mokopane in Limpopo extending through the industrial and commercial corridor to Johannesburg and leading to Durban,” states Smith.

According to the feasibility study, the creation of a hydrogen economy could generate approximately US$3.9 billion (R62.75 billion) and $8.8 billion (R141.68 billion), with associated taxes of $900 million (R14.3 billion), for South Africa’s GDP by 2050 and create about 14 000 and 30 000 jobs annually.

“There could be an enormous benefit for us as a countr y when we start talking about the hydrogen economy. Another benefit to a valley or corridor is that it can be easily replicated in other regions within the countr y and globally,” Smith adds.

Approximately nine catalytic projects within the transport, construction and industrial sectors have been identified across these hubs.

The cost of green hydrogen “Presently, utilising hydrogen in fuel cells is more expensive than diesel. However, by 2030, when doing a total cost of ownership between hydrogen and diesel systems (with economies of scale), we

predict price parity or for hydrogen to be a cheaper option,” Smith says.

Anglo American aims to reduce hydrogen costs by exploring investment in the hydrogen ecosystem, which will facilitate a competitive advantage on a global scale.

Smith explains, “We focus on how to reduce the delivered price of green hydrogen through our investment in AP Ventures.

One such example is the investment in Hydrogenious LOHC Technologies, which aims to decrease the price of energy storage and transportation.”

Challenges •C

ost and demand aggregation: Ensuring the right partnerships for the improvement and the resilience around the technology allows for larger uptake and economies of scale. Hydrogen needs to be competitively priced. This can be achieved through the creation of new business opportunities aimed at reducing pain points within the hydrogen value chain.

• Governmental approach in structuring policies: The DSI’s announcement of the Hydrogen Society Roadmap launch will encourage the production and uptake of the technology. There needs to be alignment between different governments in Africa to ensure largescale deployment and attract additional cohesive concessional, grant and developmental funding.

• Incentives: There should be a repurposing of existing incentives for the availability and application of hydrogen and fuel cell technologies.

Anglo American recognises green hydrogen’s role in transitioning to greener and cleaner energy and transport. “Our platinum group metals are used in key technologies along the hydrogen value chain from production through electrolyser technologies to hydrogen storage such as liquid organic hydrogen carriers (LOHC) and end uses like fuel cells. Therefore, from a market development perspective, we see hydrogen as a key opportunity for us in terms of our metal uptake. The second lens we use to look at hydrogen is through our own decarbonisation ambitions like our hydrogen mine haul truck. The third lens is in support of the Just Energy Transition and is aligned with our efforts on the Hydrogen Valley initiative,” Smith concludes.

IMIESA July 2022

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POWER STATIONS | HYDROPOWER

Hydropower on the Ash River A downstream bird’seye view of the Middle Kruisvallei facility

Middle Kruisvallei abstraction works

The Lower Kruisvallei powerhouse

Completed in March 2021, the construction of the Kruisvallei Hydropower Scheme showcases exceptional innovation as well as multidisciplinar y engineering and construction management teamwork in delivering a worldclass clean energy solution.

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ocated on the Ash River approximately 13 km north-west of Clarens and 17 km south of Bethlehem in the Free State, the scheme consists of two small run-ofriver hydropower plants – Middle and Lower – generating a combined output up to 4 MW, which cost approximately R260 million to construct within a tight 18-month programme.

The project formed part of Round 4 of South Africa’s Renewable Energy Independent Power Producer Programme (REIPPP), with the power purchase agreement (PPA) awarded to Zevobuzz (RF) as the IPP. Zevobuzz (RF) is majority owned by Red Rocket, with H1 Holdings as a shareholder. Red Rocket is a pan-African IPP with previous experience in wind and solar projects. This is Red Rocket’s first hydropower investment.

Team dynamics Zevobuzz employed Red Rocket as the EPC

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PROJECT TEAM Client/Independent Power Producer: Zevobuzz (RF) Civils, Structural & Hydraulic Design Engineers: Zutari EPC Contractor: Red Rocket Civil & Mechanical Contractor: Eigenbau Hydroelectrical Contractor: Scotta SpA Interconnection Contractor: Tractionel Enterprise

(engineering, procurement and construction) contractor, with Eigenbau appointed as the main design and build contractor, and Scotta appointed as the turbine supply contractor (water to wire). Zutari was, in turn, appointed

by Eigenbau as the design engineer. Designs were developed in close cooperation with the contractors, with a strong emphasis on constructability.

The Zutari team was responsible for the detail design of all civil and structural works.

Another team from Zutari formed part of the management and supervision team of Red Rocket during construction. Zutari also undertook all necessary grid code and network compliance studies, and was responsible for witnessing the factory acceptance tests of electromechanical equipment. Zutari also managed the critical commissioning activities for the EPC. The project included the fabrication and installation of large radial gates and large

active spillway gates, as well as automatic trash rack cleaning machines and switchyards, together with the 13 km transmission line and upgrading an existing Eskom substation to enable the power to be exported to the national grid.

Revisiting the original design proposal A design proposal had been undertaken for each site at a feasibility level over 10 years before the project was realised, with Zutari appointed to conduct a more detailed technical feasibility study. The results of that study indicated the preferred option for project implementation required single turbines at each site of approximately 2.25 MW and 1.55 MW housed in power stations constructed along the Ash River.

Each of the two standalone, run-of-river systems has an offtake canal tying into the river above the existing Department of Water

POWER STATIONS | HYDROPOWER

Geocell construction of a headrace canal

and Sanitation (DWS) weirs at each site. The approach channels run through the intake works, consisting of a coarse screen and radial gate. The water is then transferred via a concrete-lined headrace canal to each power station.

Perfect location The Ash River is utilised to transfer water from the Lesotho Highlands Water Project (LHWP) to South Africa and provides a reliable, year-round flow, varying between 14 m3/s and 32 m3/s.

This was a key consideration for the optimal location of the two power stations. Their location also considers the future completion of Phase 2 of the LHWP, which will increase the flow to approximately 45 m3/s.

Powerhouse construction under way at Middle Kruisvallei

The intake works at Middle Kruisvallei include coarse screens and radial gates

main turbine hall. This houses the turbine, generator, gearbox and hydraulic equipment, a chamber housing the dewatering and sump pumps, control and switchgear rooms, a loading bay for assembly, installation and maintenance work, and the structural steel frame building incorporating an overhead crane.

Specifying a vertical Kaplan turbine required a significantly deeper excavation than for a horizontal turbine, but resulted in a more efficient scheme overall. In addition, the turbine is fitted with a step-up gearbox, significantly reducing the size, weight and costs of the generator. This solution further minimised the size of the gantry crane and the supporting superstructure.

In turn, the hydromechanical equipment design was optimised from a cost and operational flexibility perspective. Instead of the traditional stoplogs at the up- and downstream ends of the waterways, radial gates are employed. Additionally, Active Spillway gates are used to control flow into the bypass channels in the event of an unplanned shutdown.

Extensive computational fluid dynamics analyses were undertaken to optimise waterway designs and to ensure uniform, turbulence-free flow entering the turbines. The use of concrete-lined canals, as opposed to riprap (rock lining), significantly reduced the head losses through the system.

Being a low-head scheme, every centimetre of head loss has an associated value.

Consequently, it was imperative to design the scheme to minimise hydraulic losses through the water conveyance.

Optimisation of costs versus returns achieved a maximum hydraulic loss of 0.5 m and 0.7 m respectively at the Middle and Lower Kruisvallei power station sites. The measured Canal design and rated flow hydraulic loss was evidently Further efficiencies were less than the allowed Kaplan turbine assembly in achieved in terms of the canal losses through careful progress within the Middle designs, which are key to the design and construction.

Kruisvallei powerhouse overall success of the plant The bypass canals were operations. Here, geocell liners designed to discharge were utilised as a flexible and into the tailrace permeable concrete liner. canals rather than The use of a concrete liner directly back to the significantly decreases the river, where energy friction losses in the canals dissipation structures (compared to an unlined would have been canal), aiding the hydraulic required, allowing for a efficiency of the scheme. The plastic more compact site. layers between the square interlocked Farmhouse theme concrete cells act as a bond breaker, allowing The main powerhouse structure is reminiscent the slow release of hydrostatic pressure of a typical farm barn, an intentional aesthetic when the canal is emptied, and eliminating element that blends in well with the surrounding the need for a subsurface drainage system. agricultural landscape. These buildings also The two separate power stations are each house the control, switchgear and storage able to operate with a rated flow of 37 m3/s.

The existing DWS weirs provide the available rooms, which are painted to match the outside head – specifically 7.2 m and 4.9 m for of the main structure, therefore maintaining a Middle and Lower Kruisvallei, respectively clean and subtle appearance.

– to ensure sustained downstream Stone, taken locally from the excavation power delivery. works, was used as riprap along the banks of After passing all necessary tests to be the canal. While having obvious engineering able to connect to the Eskom network, the benefits by stabilising the exposed slopes, it project achieved commercial operation at the has also been used to afford a natural look as end of February 2021. Now, over the term of far as possible and to provide natural surfaces the 20-year PPA, the generating capacity will for fauna and flora. provide electricity to some 2 000 households Powerhouse configuration and the comforting assurance of having The powerhouse at each site comprises the power on demand.

IMIESA July 2022

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PIPES XIII CONFERENCE The versatility of Plastic Pipe 6 – 7 SEPTEMBER 2022

EMPERORS PALACE, GAUTENG

SPEAKER LINE-UP

The Southern African Plastic Pipe Manufacturers Association (SAPPMA) has released an exciting line-up of local and international speakers who will be presenting at the PIPES XIII Conference that will be taking place on 6 &7 September 2022 at Emperors Palace in Gauteng, in collaboration with the Plastic Pipes Conference Association.

Jan Venter, Chief Executive Officer of SAPPMA says they are looking forward to the hybrid conference after a two-year absence owing to the COVID-19 pandemic. Whilst SAPPMA encourages as many people as possible to attend in person, there will also be the opportunity for delegates to log-in virtually.

The theme of PIPES XIII is “The Versatility of Plastic Pipe”. Local industry experts will share the stage with some of the best international papers that were presented at the PPCA’s PIPES XX conference in Amsterdam last year.

“We are very fortunate that our event will take place in collaboration with the Plastic Pipe Conference Association (PPCA) - hosts of the biggest international pipe conference that takes place every second year either in Europe or the USA. A spin-off conference is organised every alternate year and this year it is coming to South Africa!” Jan says.

“Each year, our PIPES conference attracts people from a wide range of different ages, backgrounds and industries who benefit from this valuable learning opportunity. The event is a must for students and academics, engineers, industry representatives, local government, parastatals, pipe fittings and extrusion equipment manufacturers, raw material suppliers and consultants who need to remain at the top of their game. For two days, they will not only have the privilege of being exposed to the latest industry research and best practice, but there will also be ample networking opportunities with fellow professionals,” Jan concluded.

The opening keynote speaker for the event will be popular economist Roelof Botha, followed by various local and international speakers who will be covering all elements relating to pipeline design and installation, standards, testing and certification, extrusion technology, addressing water problems in Southern Africa, infrastructure, raw materials and the rehabilitation of old pipelines.

PRESENTERS INCLUDE: Dr Mike Troughton (TWI LTD), George Diliyannis (Safripol), Dolores Herran (Molecor), Dominique Gueugnaut (GRTgaz), Kirtida Bhana (Plastics SA), Beverley Manikum (Sasol), Antonio Rodolfo Jr (Braskem S/A, Vinyls), Sylvie Famelart (European Council of Vinyl Manufacturers), Albert Vaartjes (Rollepaal), Christian Schalich (SIKORA AG, Corporate Communications), Joerg Wermelinger (Georg Fischer Piping Systems Inc., TEC), Ilija Radeljic (Pipelife Norway), Gunter Dreiling (Borouge Pte. Ltd., Innovation Centre), Peter Sejersen (TEPPFA), Mario Messiha (Polymer Competence Center Leoben GmbH), Prashant D.Nikhade (Borouge Pte Ltd), Sjoerd Jansma (Kiwa Technology), Gregory Vigellis (Union Pipes Industry LLC), Norbert Jansen (PE100+), Lennert Bakker (Suloforce), Simon Thomas (Simon Thomas Consulting), Moshodo Motebele (Department of Water & Sanitation), Jacques van Eck (Avesco), Mike Smart (Genesis Consulting), Alaster Goyns (Pipes CC), Victor Pinedo (Georg Fischer Piping Systems Inc., TEC), Ian Venter (SAPPMA), Bruce Hollands (Uni-Bell PVC Pipe Association), Ricardo Pascual Galan (Aenor) and Kate Kleingeld (Plastic & Chemical Trading).

EXHIBITORS In addition to listening to this line-up of world-renowned speakers, delegates will also be able to visit exhibitions by leading plastic pipe manufacturers, suppliers and industry partners such as Aenor, Alprene, BSI Group, MacNeil, Molecor, Pipeflo, Plastiweld, Pipestar Africa, SAVA, Zerma etc.

SPONSORS We would not be able to host this event without the financial support of our sponsors. In particular, we wish to thank Molecor, who has come onboard as a Gold sponsor and Plastic & Chemical Trading, our silver sponsor.

REGISTRATION FEE:

GOLD SPONSOR

SILVER SPONSOR

• • • •

R4 300 or 300 Euro (excluding VAT) R3 400 SAPPMA members (excluding VAT) R3 000 for 5 or more in group (excluding VAT) R2 200 virtual attendance (excluding VAT)

For more information or to register for PIPES XIII, visit the Events Page on www.sappma.co.za or contact Enrike Albasini via email at admin@sappma.co.za.

DAMS, RESERVOIRS & STORAGE

RAINWATER HARVESTING SHOULD NOT BE A LUXURY Rainwater harvesting and management is nothing new. This technique has been used for thousands of years – from Mesopotamia to Ancient Rome, India and China. Today, growing water scarcity, climate change, rapid urbanisation and ‘Day Zero’ are making this ancient technology a viable option for cities.

W

ater scarcity is becoming one of the most critical risks threatening social and economic development throughout the world. Access to appropriate quality and quantities of water can either impede or enable economic growth. Rainwater har vesting can reduce water consumption, alleviate the damage caused by excessive amounts of stormwater run-off, and provide usable water. For cities and communities to become truly water-wise, adapting to use alternative water sources, such as rainwater, is key,” explains Chester Foster, GM, SBS Group.

Specialist manufacturer SBS Tanks, which is part of the SBS Group, provides rainwater har vesting solutions for the manufacturing, commercial property

development, mining, agricultural, residential estate development, fixed fire protection, desalination and municipal sectors.

Due to their modular nature, SBS Tanks are easy to retrofit, requiring minimal site preparation and no heavy-duty machiner y, and are made of steel that is hotdipped and coated with a molten alloy, Zincalume®. This, along with the internal water liner, makes SBS Tanks more resistant to corrosion, alleviating hidden maintenance costs. Systems designed by SBS can store from 7 000 to 4.4 million litres of water, and can maximise either vertical or horizontal space usage.

Considerations for different rainwater systems “A rainwater har vesting system generally

SBS Tanks at the Buthelezi Museum

Due to their modular nature, SBS Tanks are easy to retrofit, requiring minimal site preparation and no heavyduty machinery

Chester Foster, GM, SBS Group

starts off with a catchment area, where water is brought from that area into a tank. A rainwater system off a building roof will usually include gutters and piping,” explains Foster. “First flush diverters will be required to help remove sediment and leaves that may have built up on a roof. If the har vested water is used as drinking water, additional processing will be required. SBS works with a network of experts to develop the per fect system for each site.”

The water tanks can be located above the ground or even inside a built structure.

When the tanks are above the ground, rainwater should not have contact with sunlight, as this could lead to the growth of algae in the tank. Smooth sur faces on the inside of the tank, a potable water liner and a roof preventing sun exposure inhibit algal growth.

When designing a rainwater har vesting system, potential over flow needs to be considered. SBS Tanks can be fitted with water level control valves to regulate the water levels and various inlets, outlets, dump drains or scours. Excess water as a result of a heavy or continual downpour will typically be drained into additional water storage tanks, or diverted safely into stormwater systems; however, municipal bylaws always need to be considered. When designing a system, SBS engineers will work closely with a client’s engineers to ensure that all regulations are obser ved.

“Rainwater har vesting is highly sustainable and ever y building, public or private, should have a rainwater har vesting system. Water scarcity will always be with us, which means that current consumer and business behaviour will need to adapt to ensure sustainability of this precious resource. Ever y drop we can store, and reuse, will have a positive ripple effect,” concludes Foster.

IMIESA July 2022

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DAMS, RESERVOIRS & STORAGE

Neckartal Dam sets a new standard for RCC innovation The early stages of construction. The full supply level of the dam was fixed at RL 787.5 masl, with the mean foundation level in the spillway area at RL 718 masl. Some parts of the dam foundation needed to be lower, at RL 714 masl

Strategically positioned to support socio-economic growth, and specifically farming, Namibia’s Neckartal Dam is one of the most significant concrete structures built in the last decade within Southern Africa. Engineered by Knight Piésold Consulting, it ranks as the region’s eighth largest dam by storage volume.

N

eckartal Dam is located on the Fish River, a major tributary of the Orange River, with the primary objective of supplying bulk water to a planned 5 000 ha irrigation scheme located 40 km south-west of Keetmanshoop. This is a region much in need of water. Daytime temperatures often exceed 40°C during the summer, with a mean annual precipitation of less than 150 mm.

Based on factors that include the local geology and remote location within Namibia’s Karas region, Neckartal was designed and constructed as a roller compacted concrete (RCC) dam. It measures 78.5 m in height,

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IMIESA July 2022

with a crest length of 518 m and a gross storage capacity of 857 million m3, extending over a 40 km2 surface area at its full supply level.

“The curved layout of the dam improves the structural stability, increases the length of the spillway, and enhances the dam aesthetics,” explains David Stables, principal project leader at Knight Piésold Consulting, and project manager for the dam’s development.

Some 844 000 m3 of RCC and approximately 110 000 m3 of conventional concrete was used to build the dam. Three different types of RCC were used, namely a higher cementitious content of RCC to

create an impermeable upstream face, and two lower cementitious RCC mixes for the body of the dam.

Construction started in September 2013 on behalf of the Namibian Ministry of Agriculture, Water and Forestry, which subsequently became the Ministry of Agriculture, Water and Land Reform in 2020. The contractor was Salini, which became Salini Impregilo in 2014 and, later, Webuild in 2020.

Material challenges One of the construction options presented in the past was a rockfill dam; however, there are no substantial clay sources available in the vicinity of the dam location. To construct a rockfill dam successfully would have required a reinforced concrete face, or an asphaltic core to provide a watertight structure, which was not practically achievable. The best approach was therefore a concrete gravity dam, more specifically an RCC structure.

“Based on the engineered design, approximately 116 000 tonnes of cement were

DAMS, RESERVOIRS & STORAGE required for the dam’s construction; however, the key logistical challenge was supplying this material,” says Stables.

That’s because the dam site is situated approximately 1 000 km from the nearest cement factory, located at Otavi in northern Namibia, and 1 200 km from the closest fly ash sources in South Africa’s highveld region.

With high transport costs and large quantities of cement involved, an innovative approach to the RCC mix designs was needed. “A key objective was to reduce the cementitious content and in turn the overall project cost. This was achieved using the latest developments in RCC technology and factoring in the arid temperature conditions,” says Stables.

From an aggregates perspective, an intensive geotechnical investigation identified a suitable source of dolerite approximately 10 km from the dam site, which further supported the preference for an RCC gravity dam.

The dam wall curves along a 500 m radius. The river section is very wide, and the left bank is much steeper than the right. The substantial spillway requirement was provided over the RCC structure by using an ogee spillway and a stepped downstream spillway with an apron for energy dissipation The dam outlets release water, via an intricate design of pipework, through two Francis turbines, to an abstraction weir and pumping station located 13 km downstream to provide water for future irrigation

Perfecting the mix design The mixes and the aggregate specifications were carefully developed with the aid of an internationally recognised RCC expert to ensure an economic solution. The low cementitious mixes, containing only 85 kg and 110 kg of cementitious materials, impressively achieved a compressive strength of 26 MPa at 365 days and a density of 2 650 kg/m3.

Placement temperature Thermal analyses conducted during the early phase of the design indicated that the maximum RCC placement temperature should not exceed 28°C to avoid thermal cracking in the dam structure, with a maximum joint spacing of 20 m. This was 5°C higher than the maximum temperature usually specified for RCC by the Department of Water and Sanitation in South Africa.

To achieve this, the contractor imported and constructed a 3 MW cooling plant capable of cooling both the coarse aggregate and the mixing water. The cooling plant consisted of two chiller units, four air blast units and four insulated aggregate silos through which the cold air was blown. During the course of the project, the average temperature for placed RCC was 22°C.

Condition monitoring Following

an

extensive

construction

With the ambient temperature over 30°C almost every day in summer and quite regularly over 40°C, the contractor had to run a 3 MW cooling plant continuously in summer to meet the specified placing temperature. The average temperature for placed RCC was 22°C

programme, the completed works saw the Neckartal Dam filling rapidly for the first time in January 2021. To date, the structure is performing well with minimal leakage along the construction joints.

Going forward, the dam’s performance will be monitored by nearly 300 electronic instruments to measure the behaviour of the structure. There are 52 long-base strain gauges to monitor the induced joint openings, and 100 piezometers in the foundation to monitor the hydrostatic pressure under the dam. In addition, there are temperature gauges, multiple head extensometers, tilt meters, 3D joint movement gauges, survey targets, V-notch gauges and water level recorders.

“Instrument readings are recorded every few minutes and all are downloaded to a dedicated computer, which can be accessed remotely over the internet. Consequently, the employer and the design team can continuously monitor the dam,” adds Stables.

Once the 5 000 ha of land have been put under irrigation, approximately 4 000 direct and indirect jobs are expected to be created.

Farmers in the region will be able to take advantage of the unique climatic conditions to produce table grapes, dates and lucerne, in the process positively contributing to Namibia’s micro- and macro-economic growth.

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DAMS, RESERVOIRS & STORAGE

YEAR 2: AN UPDATE ON THE NATSILT PROGRAMME

Executed by the Water Research Commission and funded by the Depar tment of Water and Sanitation, the National Dam Siltation (NatSilt) Programme aims to reduce the risk of siltation in dams.

By Lesego Gaegane, senior project manager, NatSilt Programme

T

he programme addresses siltation at the source (catchment area) and identifies pragmatic inter ventions in minimising the transportation and transfer of siltation into the river system, and managing siltation in the sink zone (dam).

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IMIESA July 2022

The NatSilt Programme is implemented over three phases, with the first phase completed in March this year. Phase 1 developed a Dam Operations Model that can be used for the planning and designing of new dams where siltation management inter ventions are incorporated into the design phase of dams. This will allow funds that are made available to design and construct a dam to be utilised further to implement catchment management inter ventions and thus extend the lifespan of the dam. The focus of the model is on improved and sustainable storage capacity of dams, through catchment and engineering inter ventions with a focus on maximising the yield of water resources and their economic benefits.

This Dam Operations Model is also used to prioritise siltation management activities and inter ventions on existing

The uMkhomazi River

dams through a cost-benefit analysis. It identifies inter ventions in the three zones – the catchment, the river system and the dam – where users of the model can see which inter ventions are more feasible for implementation. Upstream inter ventions can be more easily justified by making the socio-economic benefits associated with a longer life of a dam quantifiable.

Smithfield Dam Currently, the Dam Operations Model is implemented at three existing dams to improve their storage capacities and enhance their sustainability. It will also be used for a dam earmarked for construction – the Smithfield Dam. Located in the upper uMkhomazi river catchment in the southern part of

DAMS, RESERVOIRS & STORAGE

The release of large volumes of muddy water can inundate riverbeds and drastically affect downstream ecosystems if not properly planned

KwaZulu-Natal, the proposed Smithfield Dam project will have both built and ecological infrastructure. Ecological infrastructure and its conditions in the area will be mapped and used as a baseline for the development of a catchment and ecological infrastructure management plan for interventions. The

goal is to create a healthy catchment that will limit siltation. The integration of ecological infrastructure into the Smithfield Dam design will operationalise siltation management at a catchment scale and will enable the improvement of water security through improved water storage capacity of the proposed dam, but will also improve livelihoods and increase the climate resilience of communities in the catchment.

The uMkhomazi catchment area forms part of the Southern Drakensberg Strategic Water Source Area, with a number of industries and farmers. It is therefore important to ensure that ecosystems within this catchment are functioning well to maintain the sustainable water requirements of all users.

One of the components of this project will entail the co-development of certain aspects of the catchment and ecological

infrastructure management plans with the communities and stakeholders within the catchment to ensure the long-term sustainability of siltation management inter ventions. The stakeholders will include traditional authorities, subsistence farmers, working groups and catchment management forums. Knowledge transfer to the communities is crucial to enable capacity development and the maintenance of ecological infrastructure inter ventions.

A primar y goal of the NatSilt Programme is to see the incorporation of siltation management in the operations of dam activities to ensure that siltation management is embedded in ever y aspect of dam management. Through this project, proactive mitigator y measures against soil erosion, sediment transfer to the reser voir, and siltation of the reser voir will be incorporated into the dam design, catchment and ecological infrastructure management plan, as well as the dam operations and maintenance manual.

We hope this will inform enhanced dam planning operations and new ways of dam design going for ward.

sustainable & long term

WATER STORAGE

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Manufactured in SOUTH AFRICA

EVENT: 85 TH IMESA Conference DATES: 2-4 November 2022 EARLY BIRD REGISTRATION

STANDARD REGISTRATION

Register and pay BEFORE 31 July 2022

Register and pay AFTER 1 August 2022

• Members: R6 700 • Non-members : R8 000

• Members : R7 500 • Non-members : R8 900

Hotel rates are noncommissionable if delegates book through travel agents.

Bookings to be done directly with Hotel. Reference to be used is IMESA CONFERENCE. Rooms are subject to availability.

BOOK YOUR accommodation NOW www.birchwoodhotel.co.za BED & BREAKFAST

Birchwood Single: R1 000 Birchwood Sharing: R1 200 Silverbirch Single: R1 100 Silverbirch Sharing: R1 300

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Silverbirch Single: R1 350 Silverbirch Sharing: R1 800 CONFERENCE ENDORSED BY

t: +27 (031)266 3263 e: conference@imesa.org.za marketing@imesa.org.za www.imesa.org.za

IMESA ORGANISER

THE INSTITUTE OF MUNICIPAL ENGINEERING OF SOUTHERN AFRICA (IMESA)

DAMS, RESERVOIRS & STORAGE

The Polihali Dam will create a reservoir with a surface area of 5 053 hectares (Credit: Matla a Metsi JV)

POLIHALI DAM AND TUNNEL PROGRAMME UPDATE

O

nce completed, the Polihali Dam will add approximately 2 325 million cubic metres in storage capacity to the Lesotho Highlands Water Project (LHWP) in Phase II of the programme. This will increase the project’s current annual supply rate capacity from 780 to 1 270 million cubic metres – a welcome addition towards meeting South Africa’s rising water needs.

Simultaneously, the additional flow of water from Polihali will increase the volume of hydropower generated within Lesotho by approximately 40% and is another step towards meeting the country’s domestic electricity needs and reducing its dependence on imported power.

The dam site is located approximately 130 km north-east of Lesotho’s capital, Maseru, 20 km west of the highlands town of Mokhotlong, and just a kilometre downstream of the confluence of the Khubelu and Senqu (Orange) rivers.

Key elements The Polihali works include:

Dam

and

appurtenant

-1 66 m high concrete faced rockfill dam (CFRD) forming the main dam on the Senqu River - 48 m high CFRD saddle dam - 98 m long spillway with 40 m wide concrete chute and flip bucket discharging into an excavated plunge pool in rock - access bridges - compensation outlet system with intake tower and a compensation outlet pipe - outlet house with hydropower station - river gauging stations in the upper reaches of the Khubelu, Senqu, Moremoholo, Mokhotlong and Sehonghong Rivers with associated access roads.

The construction programme is focused on the impoundment date and for this reason both the rockfill embankment and concrete face slab of the Polihali Dam will be staged.

The Polihali Dam will create a reser voir with a sur face area of 5 053 hectares.

Its waters will be conveyed by gravity through the Polihali transfer tunnel – the second main works feature of the Phase II water transfer component – to the Katse reser voir.

TRANSFER TUNNEL - 38 km long - 5 m nominal bore - Links Polihali reservoir to Katse Dam - Transfers water by gravity - Construction commences in 2022

Milestones Construction procurement is advanced for both the Polihali Dam and the Polihali transfer tunnel, with construction expected to commence this year. Anticipated milestones according to the current Phase II master programme are: - Impoundment (first stage): 2025 - Dam complete (civil works): 2027 - Dam complete (including final wet testing): 2028 - Tunnel complete: 2027 - Water deliver y: 2027/28.

In December 2021, the Lesotho government confirmed the Oxbow Hydropower Scheme as the preferred option for Phase II. The procurement of a ser vice provider for the detail design and super vision is under way.

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MUNICIPAL FOCUS: NELSON MANDELA BAY

GROUNDWATER HAS THE MUSCLE TO PUSH BACK ‘DAY ZERO’ – BUT ARE WE PROTECTING IT? Groundwater is being used in the fight against the worst drought in Nelson Mandela Bay’s recorded history. To stop the taps from running dry, businesses, citizens and NGOs are drilling boreholes in Gqeberha. But, among the panic and desperation, is enough care being taken to protect this precious resource? By Kirsten Kelly Neville Paxton, chairman: Eastern Cape Branch, Ground Water Division (GWD)

C

A successful water strike; groundwater rises to the surface under its own pressure (Photo credit: Stefanutti Stocks)

overing 1 959 km2, Nelson Mandela Bay (NMB) is major seaport and automotive manufacturing centre. With below-average rainfall being experienced in catchment areas, dam levels have continued to decline rapidly. The combined storage levels have not been above 25% since February 2020. As dam levels continue to decline, it is groundwater that is augmenting water supply in the region.

“Depending on its quality, groundwater is generally more affordable than water reuse or desalination. It is a ‘sleeping giant’ and has huge potential in improving the region’s water security. Groundwater flows a lot

slower than surface water and can provide water when the surface water sources are stressed. Then, when rainfall levels improve, and the rivers start flowing again, the groundwater can be recharged, while the surface water sources again become the primary water source. Groundwater can buffer the impacts of drought,” says Neville Paxton, chairman: Eastern Cape Branch, Ground Water Division (GWD).

NMB has a complex, favourable geology for good-quality groundwater with relatively high yield. It mostly comprises sedimentary rocks that have undergone tectonic stress, resulting in the mountainous landscapes and large faults that are subsequently overlain with

aeolian and alluvial material. There have been highly successful groundwater development projects in and around the city for the municipal, industrial and private sectors.

When the big water users become completely, or partially, dependent on groundwater, that volume is freed up for other end-users.

Nelson Mandela Bay Municipality Nelson Mandela Bay Municipality (NMBM) conducted groundwater investigations during the 2010/11 Eastern Cape drought, and it was found that some properties owned by NMBM had a high groundwater potential.

Subsequently, over 200 boreholes were drilled to locate suitable sites (Table 1).

TABLE 1 Sites identified with high groundwater potential

Location Coegakop St. George’s Park Glendinning Fort Nottingham Fairview Bushy Park Total Churchill (design phase)

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IMIESA July 2022

Anticipated completion month (2022) September September July July July September

Low yield (Mℓ/day) Medium yield (Mℓ/day) 6 10 1.4 2.1 1.6 2.3 0.8 1.0 0.9 1.5 7.0 10.2 17.7 27.1 1.7 3

High yield (Mℓ/day) 12.6 3.6 2.9 1.8 2.2 13.3 36.3 4.3

MUNICIPAL FOCUS: NELSON MANDELA BAY

Establishing a production borehole at Coegakop (Photo credit: Stefanutti Stocks)

• Glendenning – three production boreholes with an estimated yield of 2.2 Mℓ/day.

• Fairview – four production boreholes with an estimated yield of 0.96 Mℓ/day.

Bushy Park Wellfield: To date, 18 boreholes have been drilled, of which 10 are marked for production. Groundwater from these boreholes will be disinfected and blended into the Churchill pipeline situated near the wellfield and will supplement the water supply to the western side of NMB, which will reduce the severe pressure of the water demand required from the sources through the western water supply system. It is estimated that an additional 10.5-13.7 Mℓ/day should be available on completion of this scheme.

The contract is currently under construction with an estimated completion date in August 2022.

Churchill Wellfield (Future): 73 boreholes were drilled on municipal property around Churchill Dam, 19 of which were identified for production purposes. Groundwater from these boreholes will augment the

NMBM then developed a plan where it is anticipated that a sustainable yield of around 35 Mℓ/day can be abstracted through groundwater sources. The plan entails: Coegakop Wellfield and Water Treatment Works (WTW): The drilling of five production boreholes is finished and the WTW should reach completion in the next few months. It is estimated that an additional 12.5 Mℓ/day should be available at the end of the project.

St. George’s Park Wellfield: High-potential groundwater sites were identified at St. George’s Park, which also falls along the Moregrove Fault. To date, nine boreholes have been drilled – four of which were identified for production purposes. The four production boreholes have been drilled with an estimated yield of 2.1-3.6 Mℓ/day. Water from the boreholes will be filtered, disinfected and blended into the existing water supply system. The contract is currently under construction with an estimated completion date in August.

Moregrove Fault Wellfield: These wellfields are completed and comprise boreholes at: • Fort Nottingham – three production boreholes with an estimated yield of 1 Mℓ/day.

raw water supply from Churchill Dam and water will be treated at the existing WTW. Conceptual designs have been completed and commencement is dependent on the provision of funding.

It is estimated that an additional 3-4.3 Mℓ/ day should be available on completion of this scheme. An additional 26 boreholes could see an increase of between 5.6-8.9 Mℓ/day.

Non-potable groundwater use at municipal facilities: NMBM has drilled 27 boreholes at selected municipal pools, parks, stadiums and sports fields. Of these, seven provided suitable water quality and sufficient sustainable yield to take the respective facilities off-grid. All seven boreholes were equipped in June 2019 and have cumulatively saved NMBM 19 000 kℓ of potable water to date.

Word of caution Paxton cautions all potential users against choosing the cheapest groundwater solution.

“Groundwater development can be a costly investment. However, the worst approach is to take the cheapest route. Currently, there is a lot of panic and a rush to drill boreholes in

Covering 1 959 km2, Nelson Mandela Bay is a major seaport and automotive manufacturing centre

IMIESA July 2022

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MUNICIPAL FOCUS: NELSON MANDELA BAY

NMB and people are choosing inexperienced and unqualified people to do the job. From the start, get a registered professional scientist who is a member of the GWD to guide you – from locating the best position to drill, sourcing reputable drillers, managing the drill process, yield and quality testing, to helping you find the correct pumps and registering or licensing the borehole.”

Each rock type has different characteristics and in NMB, there is a lot of sand and loose particles, hard rock and clay, as well as rock layers that yield highly saline groundwater. A hydrogeologist therefore needs to work with drillers to design a borehole. By doing this, one can avoid disappointment and needless expenditure in the long run.

“I cannot emphasise enough how important it is to get a qualified hydrogeologist to manage the whole groundwater development process. South Africa has some of the best fractured aquifer hydrogeologists in the

world. Do your due diligence. There has been an influx of ‘one-stop shops’ and self-proclaimed ‘hydrogeologists’ with zero quality control. And because groundwater is shrouded in folklore and mystery, they find it easy to evade responsibility when something goes wrong,” he continues.

A common misconception is that groundwater does not require maintenance; however, if a hydrogeologist is working with a suitable driller, the borehole will be designed appropriately for the geology, and the required maintenance will be less frequent. Huge maintenance costs will arise when untested groundwater that contains certain mineral elements is connected to an irrigation or plumbing system, causing damage to pipes and pumps over time.

This can be averted or mitigated at the very beginning. Regularly inspecting the pump and borehole integrity will also improve the longevity of both.

As an unseen and often forgotten resource, Paxton feels that there is a dire need for education around groundwater. “I often see water cycle diagrams that do not include groundwater. Everyone needs to be aware of its value and potential.”

Policy and regulation While South Africa has top-notch groundwater policies, the implementation of these policies is the challenge. However, the goal of all policies and regulation is to protect groundwater for the use of all South Africans.

It is mandatory to register a borehole with NMBM. “Unfortunately, the current application process for registering and or licensing boreholes is tedious, unnecessarily rigid with a box-ticking approach that is often non-sitespecific. This dissuades end-users from even starting the process. Regulatory bodies need to create an enabling environment rather than take a punitive role. But this is a challenge, as they are understaffed,” adds Paxton.

Registering boreholes creates invaluable data for the municipality, where the levels of groundwater abstraction from the aquifer can be understood and accurate water supply strategies can be formulated.

He suggests that there is a need for groundwater user associations (similar to water user associations) where private stakeholders manage their own groundwater in a sustainable manner together with guidance from government. “Monitoring groundwater use with a flow meter and levels with a sensor will ensure that a borehole is used sustainably and is a legal requirement by the Department of Water and Sanitation.

It protects the end-user with surety of supply but also helps immensely in the licensing process. As a user of a borehole, it is important to understand how an aquifer is reacting to groundwater abstraction.”

Advice for municipalities

Two boreholes at the Coegakop Wellfied of 88 ℓ/s and 24 ℓ/s artesian flow rates respectively (Photo credit: Dr Ricky Murray, Groundwater Africa)

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IMIESA July 2022

While groundwater should not be a standalone solution in pushing back Day Zero, it is an integral part of the solution. “All municipalities should make use of groundwater now, even if there is a good rain season and no threat of drought. Do not wait for a crisis. Furthermore, make use of experienced and qualified hydrogeologists to manage groundwater.

When projects are put together to go out for tender, they need to be designed and implemented by hydrogeologists – not drillers or NGOs. This will promote quality control and long-term supply,” concludes Paxton.

WOMEN IN CONSTRUCTION

PROMOTING THE GENDER AGENDA

Category winners at the 2021 ERWIC Awards

2022 CIDB AWARDS PROGRAMME CELEBRATES WOMEN IN CONSTRUCTION With the aim of celebrating and encouraging women in the construction industry, the Construction Industry Development Board (cidb) will once again be celebrating the outstanding achievements of women making their mark in the construction industry, through the Empowerment & Recognition of Women in Construction Awards (ERWIC Awards) event taking place in Johannesburg on 24 August 2022.

L

aunched in 2020, the ERWIC Awards recognise and reward women in all areas of the construction industry. Award entrants include the young business owners, the mentors, the outstanding projects and the organisations ensuring transformation.

Over the 12 different categories, the top achievers are awarded.

Traditionally a male-dominated space, the construction industry has seen a great evolution over the past few years. The cidb has identified women as a critical target for development and proudly hosts the ERWIC Awards for the third year.

The aim of the awards is to encourage excellence among women and commitment among stakeholders to support women in their professional growth and development.

Through the ERWIC Awards, the cidb also aims to promote role models for women in lower-grade construction categories and motivate women in the higher grades.

Award categories The 2022 awards categories are as follows: Category 1: Project Delivery Excellence of the Year – Woman-owned Construction Entity Category 2: Rural Project of the Year Category 3: Mentoring Entity of the Year Category 4: Transformation Entity of the Year Category 5: Innovative Entity of the Year Category 6: Business Resilience of the Year (Covid-19) Category 7: Youth-owned Woman Construction Entity of the Year Category 8: Woman-owned Construction Entity of the Year Category 9: Woman Mentor of the Year Category 10: Women with Disability Contractor of the Year Category 11: Exceptional Woman in Construction Contributor of the Year Category 12: The Chairman’s Award Finalists are organisations or individuals from the private or public sector who are actively registered with the cidb, where

appropriate. Depending on the description and criteria of the category, the finalists may nominate themselves or be nominated by a third party. Entered projects must have been completed in the Southern African regions between 1 January 2021 and 31 December 2021 to be eligible for the 2022 Awards.

The Awards process enjoys an esteemed panel of judges, made of industry specialists and participants, to independently adjudicate the entries. Finalists and winners are awarded at the ERWIC Awards gala dinner – to take place on 24 August 2022 at the Sandton Hilton Hotel.

For more information, visit www.erwicawards-cidb.co.za

IMIESA July 2022

31

PIPELINES

Jan Venter, CEO, SAPPMA

The safe delivery of essential infrastructure services is non-negotiable and needs to be backed by strict quality assurance programmes, says Jan Venter, CEO of SAPPMA, which represents more than 80% of South Africa’s plastic pipe manufacturers.

U

nderscoring the key role played by the plastic pipes industry, South Africa currently produces approximately 78 000 t of PVC pipe annually – 72% of which is used in highpressure markets and 28% in non-pressure markets. Added to these statistics is the 48 000 t of high-density polyethylene

SAPPMA prohibits members from using recycled content, ensuring that only original polymer materials are used

QUALITY CONTROL STARTS WITH ADHERENCE TO MATERIAL STANDARDS (HDPE) pipe produced each year, 84% of which is used in the pressure-pipes market, 4% in the non-pressure market, and 12% in telecommunications.

As for most industry sectors, the plastic pipes industry faces rising material cost pressures.

“During the past two years in particular, global events such as the outbreak of the pandemic, shipping and supply chain constraints, natural

and man-made disasters have all contributed to the price of polymers skyrocketing to reach a 30-year high,” says Venter.

“Owing to the fact that polymers make up more than 75% of the total cost of finished pipes, it’s easy for unscrupulous operators to try to reduce costs and increase their profits by including substandard polymers or recycled content into the mix. SAPPMA and its members continue to push against the natural inclination to choosing the path of least resistance by maintaining our standards and the benchmarks that are stipulated in our Code of Conduct and Memorandum of Incorporation,” Venter explains.

The SAPPMA audit To ensure that members meet the strict national and international product standards for HDPE and PVC pipes, they commit to frequent, unannounced audits, which are carried out by an independent auditor. Pipe samples are selected at random and sent to accredited certification authorities for lab tests. Only members who pass these inspections are allowed to display the SAPPMA (Southern African Plastic Pipe Manufacturers Association) logo on their pipes – a mark of quality that helps to preserve and promote plastic piping systems.

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IMIESA July 2022

PIPELINES

Strict pipe manufacturing rules “In order for us to ensure unquestionable quality, a key focus area of our manifesto relates to the use of recycled content. Other than a small percentage that is created in the same factory, manufacturers are prohibited from including recycled materials or regrind in their products,” Venter explains.

Explaining the reason for taking such a tough stance at a time when virtually every other industry is pushing to include recycled content, Venter explains that plastic pipes are measured with respect to time.

A good-quality plastic pipe is designed and manufactured to have a minimum lifespan of 50 years (with 100 years being a realistic possibility) thanks to the long-term strength of the polymer.

The minimum required strength for plastic pipes is 50 years (or 436 000 hours) from the creep rupture regression curves for the polymer, as also specified by the International Standards Organisation (ISO). However, Venter says customers are demanding a service life of no less than 100 years for their investment in infrastructural assets.

The home of Infrastructure development, building, maintenance, service delivery

If the strength of the polymer is compromised in any way, for example, due to manufacturers using a non-conforming polymer, or due to the inclusion of recycled material, these requirements will not be achieved. “Although inferior-quality pipes might look the same at face value, nonconformance will soon become apparent – often still within the contractual maintenance period,” Venter explains.

Consumer safety Another reason why SAPPMA prohibits the use of recycled content is to protect the health and safety of the end-users. Pipe manufacturers who do not belong to SAPPMA might purchase scrap plastic pipe from secondary markets without knowing where it was used previously.

It might have been employed in a sewage application or exposed to chemical contamination, for example. This potential downstream risk for potable water users is a major concern for SAPPMA since no provision has been made for the chemical testing of pipes and the onus for responsible manufacturing rests with the industry.

“For this reason, we are unrelenting in our efforts to communicate and educate design engineers, contractors and all users of plastic pipe about the critical importance of getting the highest quality of polymers in the products they specify or procure. Our appeal to them is to ensure that their tender documents and subsequent contracts are perfectly clear on the fact that recycled material is not allowed at all,” Venter implores.

Producing high-quality, durable plastic pipes is not a cheap exercise. “It is therefore crucial to have high standards of quality in place to discourage manufacturers from taking shortcuts and producing substandard pipes that will not be able to do the work expected of them, or that will have to be replaced soon after installation,” adds Venter.

Without industry and product standards – and having a watchdog organisation there to enforce these standards – chaos would erupt in the market. Thanks to SAPPMA’s ongoing efforts, plastic pipes that are manufactured in South Africa, and bearing the SAPPMA logo, are bought and sold with confidence throughout the country and meet – or even exceed – international quality standards.

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ENVIRONMENTAL ENGINEERING

Gabions and riverbank protection The versatility, permeability and resilience of gabion systems make their application well suited for a range of interventions within riverine and wetland environments. However, every site has its own unique requirements that need to be factored into the design, says Louis Cheyne, managing director of Gabion Baskets. By Alastair Currie

T

he recent floods that have swept across South Africa have highlighted the need for riverbank protection, particularly in urban areas where the speed of stormwater run-off on hard surfaces exacerbates erosion.

“Mass gravity river walls are among the most common applications for gabion systems when it comes to erosion protection and maximising the structural stability of embankments, which are frequently bordered by roads and buildings.

There are many different configuration options to choose from to suit the hydrological conditions and terrain,” Cheyne explains.

“A key factor in the design is determining the maximum expected scour depth to protect the toe of the submerged structure from soil loss and potential undermining. That’s often not fully understood by designers and installers, resulting in premature failure and wall collapse over time, especially following major storm events.”

A gabion stilling basin weir installed within a Gauteng wetland

Allowable water velocities

Gabions versus mattresses The two main systems are box gabions and gabion mattresses. The latter are flat structures extensively used in river courses over flat or sloped areas in need of protection against soil loss or scour.

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Weir construction in progress

Depending on the circumstances, gabion walls can be founded directly on the riverbed, resting on a geotextile sheet. “We’ve also seen walls founded on a loose stone platform in the river or resting on sausage gabions designed to follow the contours of the riverbed. Where a mattress foundation is employed, this should extend out from the front face to the point where maximum scour is anticipated,” Cheyne explains.

Depending on the site, these walls can either have a stepped-back design or a vertical front face, and in both cases the base width is typically 55% to 60% of the height of the structure. Gabion Baskets manufactures a complete range of gabion products and supports its solutions with integrated systems that include geotextiles and biodegradable blankets. The latter serve a key role on backfilled slopes forming part of the overall retaining system.

“In cases of severe erosion, large sections of the original riverbank might have been washed away. The only solution then is to import material to reshape the embankment that the gabion wall is designed to support. This is a cost-effective approach, since the backfill

ENVIRONMENTAL ENGINEERING ENERGY

reduces the overall volume of gabions required.

Placing biodegradable blankets together with planted seedlings on these slopes also greatly reduces soil loss and future erosion,” Cheyne explains.

Examples of riverbank protection structures. Every design will be influenced by factors such as the terrain, riverbed contours and water velocities Structure with deep foundation

Wired by design For riverine environments, the most suitable approach is to employ Class A galvanised doubletwisted hexagonal woven steel wire mesh to manufacture gabion box and mattress systems. In more corrosive conditions, a higher-specification Galfan wire coating is recommended, with the added protection of a 0.5 mm PVC sleeve to provide a design life exceeding 50 years.

Woven mesh, in various diameters and aperture specifications, has a high tensile as well as compressive strength when filled with suitable non-weathered rock. There’s also a degree of flex, which is an important feature within rivers to cope with varying flow velocities and flotsam impacts.

A thicker-diameter wire is recommended in fasterflowing river conditions.

Depending on the rock fill, gabions typically have a 35% void ratio. This has the advantage of achieving a degree of permeability, which is controlled by the geotextile layers behind, below and within the gabions and mattresses themselves.

Packing gabions correctly is essential, as is selecting the right rock size for the river conditions.

Without geotextile layers, and where the rocks are too small, the water flow will progressively result in gabions and mattresses losing materials and becoming structurally compromised. It’s also not uncommon for mattresses to lose their covering lid where the lacing wire selected is too thin and therefore unsuitable. Using non-galvanised wire is certain to cause this, as corrosion rapidly sets in and weakens its integrity.

The correct rock specification is equally important.

Softer materials like sandstone, for example, will break down in the water.

Gabion Baskets supplies two main mattress aperture/wire diameter configurations to meet standard and more heavy-duty applications. The standard offering has a 60 mm x 80 mm aperture and a 2.2 mm diameter wire specification, with the more robust version measuring 80 mm x 100 mm and manufactured using 2.7 mm diameter wire.

Before construction begins on any site, an expert hydrological study should be undertaken. The findings will have a direct bearing on how thick the river mattress needs to be.

Gabion structure built on apron

Sturcture built on loose stones

Sturcture built on cylindrical gabions

Importance of weirs “Equally important is the installation of weirs at strategic points in the river to control longitudinal velocities, and here again box gabions and mattresses are perfectly matched to build these structures,” Cheyne continues, adding that

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ENVIRONMENTAL ENGINEERING A longitudinal cross section of a typical gabion weir design

well-positioned weirs can reduce the length of a river wall, passing on cost savings.

“What some designers forget though are the gabion wingwall extensions required to prevent the river outflanking the weir during floods. A 100 mm concrete cap on the upstream weir notch is also required to protect the gabions from debris.”

Another popular weir application is the installation of catch walls forming part of a gully rehabilitation programme where severe erosion has occurred. Mattresses are also ideal for slowing down stormwater flows on the downstream ends of culverts.

As Cheyne points out, where the hydraulic jump is greater than 0.5 m, a concrete capping layer should be placed on top of the mattress at the point of impact to protect it from damage.

Correct installation crucial Even with a first-class design, structures can

A completed stilling basin structure with wing wall extensions to reduce the risk of outflanking during floods

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A river embankment wall constructed to make way for a housing development

still fail due to poor installation technique. In this respect, Gabion Baskets provides training and project management services, passing on decades of experience.

A classic example is a weir system installed for a wetland project completed in Brakpan, Gauteng. The contractor on-site had constructed a series of weirs with stilling basins without factoring in the natural flow of the water course. They ended up facing in the wrong angle.

Gabion Baskets was approached to provide design and installation advice. The company also sent one of its trainers to assist with the reconstruction. Since all the materials were in situ, it was simply a case of unpacking and repacking the gabions in their correct position.

“In expert hands, gabion systems can be used to construct just about any retaining system, from mining tip walls to bridge abutments supporting old-school Bailey bridges,” adds Cheyne.

“Within rivers and wetlands, they’re the most natural and perfect choice for combatting erosion and preserving these environments in a way that is unrivalled by alternatives like concrete structures,” Cheyne concludes.

PUMPS &ENERGY VALVES

ENERGY-EFFICIENT TREATMENT PROCESSES

S

piralling electricity costs are placing increasing pressure on municipalities to reduce consumption. This is particularly the case for water and wastewater plants, which tend to be among the heaviest users, says Hugo du Plessis, senior project engineer at KSB Pumps and Valves.

This view is supported by Sustainable Energy Africa’s 2017 report entitled Sustainable energy solutions for South African local government: a practical guide.

An extract from the report states, “The indications are that, on average, water and wastewater accounts for some 17% of energy consumption in a South African metro. In terms of electricity consumption alone (i.e. excluding liquid fuel use for vehicles), the proportion is far higher – often representing as much as 25% of the entire municipality’s electricity bill.”

Du Plessis says that aeration is one of the stages that consumes a lot of

energy, as it requires large pump systems.

“Municipalities may not always pay attention to this aspect and may neglect to overhaul due to the expensive nature of more energy-efficient systems. However, what is important to remember is that although the expense may be high at the start, the benefits of cost saving in the long run will be worth it,” he explains, adding that KSB’s

energy-efficiency audits assist in improving process performance.

“Reliable, energy-efficient pump systems will not only result in energy and cost savings, but there are also other benefits for the municipality, which include no spillages, a reliable uptime, decline in downtime, as well as better water quality,” Du Plessis concludes.

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WATER & WASTEWATER

Station 5A has the option to use slaked lime and silica or slaked lime and organic coagulant

KEY PROJECT TO BOOST GAUTENG WATER SUPPLY Zuikerbosch Station 5A is a water purification plant under construction, located within the Rand Water Zuikerbosch Water Treatment Plant in Vereeniging. By Kirsten Kelly

FAST FACTS: Scheduled for completion in 2024 Value: R3.9 billion project Will purify an additional 600 Mℓ/day Will augment the Zuikerbosch water supply capacity to the Palmiet and Mapleton booster stations

High water demand and inefficient water systems in Gauteng remain a concern in a country that receives approximately half the global average of rainfall. By increasing Rand Water’s supply capacity, Station 5A improves Rand Water’s network resilience and Gauteng’s water security,”

ZERO EFFLUENT DISCHARGE PROCESS As one of the oldest pump stations within the Rand Water distribution network, Zuikerbosch follows a zero effluent discharge process. This is an engineering approach to water treatment where all water is recovered; the process water is recycled back to the intake works of the plant and the contaminants are reduced to solid waste at the water residue disposal site.

The project is split into subcontracts, the following of which have either reached practical completion or are within their respective stages of plant commissioning: • raw water pipeline from the Zuikerbosch forebay/ buffer dam and all other secondary pipeline works Desludging bridges

Sipho Mosai, chief executive, Rand Water • lime slaking and dosing plant, and lime loading bay • polyelectrolyte dosing plant • activated silica dosing plant • flocculation, sedimentation and sludge pump plant •m edium-voltage power supply and reticulation of Station 5A and all the associated infrastructure.

The following contracts are either under construction or still need to be procured: • filter house plant (design and construction phase) • r eservoir and engine room (design and construction phase) • disinfection plant (scoping phase) • landscaping and permanent roads (scoping phase).

High levels of groundwater were a challenge on-site

WATER & WASTEWATER

CHEMICAL DOSING Station 5A has the option to use slaked lime and silica, or slaked lime and organic coagulant, depending on the quality of raw water and availability of chemicals.

The sedimentation tanks stretch over 30 000 m2, comprising a total of 60 floor panels, measuring 25 m by 25 m. The 160 walls, each 25 m long, were then constructed on the floor panels. They have a capacity of 720 Mℓ/day, providing an additional 120 Mℓ/day – should the plant size be expanded in the future. The sedimentation tanks are rectangular in shape.

PIPELINES

RESERVOIR

SEDIMENTATION TANKS Concrete

3 213 m³

Formwork

534 m²

Reinforcing

8 491 t

Rock anchors

91 nr

ENGINE ROOM Concrete

5 798 m³

Formwork

19 604 m²

Reinforcing Rock anchors

1 229 t 70 nr

Murray & Dickson Construction (M&D) was awarded the R234 million pipeline contract.

QUANTITIES OF PIPELINE WORK • Total pipeline length: 2 600 m • Clear and grub: 2 600 m • Trench excavation: 44 000 m3 • Removal of hard rock: 10 000 m3 • River sand bedding: 21 000 m3 • Installing of pipe: 3 600 m3 • Concrete works: 7 000 m3 • Manholes and structures: 12 • Valves: 45 • Hot tap connections: 4

Among the great achievements of this project was the completion of four big hot taps by a specialist contractor overseen by M&D. There were two 1.4 m connections to a 3 028 ND pipeline (7 000 kPa) near Pump Station 4 and two 1.5 m connections to a 2.1 m diameter pipeline. This was the largest hot tapping works on a water line in South Africa.

Hot tapping (under pressure cutting) is the method of making a connection to existing piping without interrupting the line. Once the T-piece is welded, a valve is connected and specialised drilling equipment is connected on to the valve. The valve is opened, a pressure test is done and the equipment cuts a portion out of the pipe. The valve is closed and equipment is removed, completing the tie-in.

ENGINE ROOM AND RESERVOIR Termed the ‘heart of the water treatment plant’, the engine room (as well as the reservoir) is constructed by King Civil Engineering Contractors. While 600 Mℓ/day of water will go through the pump station, it is designed to handle an impressive 1 000 Mℓ/day of water – creating 400 Mℓ redundancy.

The pump station is designed for six pumpsets, five of which have been supplied by Rand Water. They will all be electronically controlled by a programmable logic controller.

The pipe work in the engine room will eventually be connected to feed into the Rand Water distribution network.

With the high water table, buoyancy of the structure was an important design consideration. Part of the engine room is 12 m below the ground. The original design of the structure was extremely heavy to prevent buoyancy. After further geotechnical investigations, the decision was made to use a less costly design and build a lighter structure with ground anchors to counter the weight.

Rand Water had to strike a balance between cost of ownership and mitigating the risk of reduced supply from unexpected machinery failure and scheduled maintenance, as well as operational efficiencies.

While Station 5A is a gravity-fed system, water still needs to be pumped 50 km to the Palmiet and Mapleton booster stations. Therefore, large pumps are required. Additional pump capacity has been supplied and suitable valve configurations are provided to facilitate the removal of pumps and motors for planned and unplanned maintenance.

Furthermore, standby power is provided for the intricate dosing, electromechanical and automation systems. Capacity was also added to the flocculators, sedimentation tanks and filters. This means that cleaning and inspection can occur on a rotational basis with little impact on operational duties and no impact on water quality.

IMIESA July 2022

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ROADS & BRIDGES

The

POTHOLE PATROL

received in-depth training by the bitumen and equipment suppliers specified for the project, in conjunction with the JRA, to ensure adherence to quality control standards. Each patch repair completed by the Pothole Patrol is recorded and will be monitored in terms of its performance. While pothole repairs are not a permanent solution, the goal is to protect the riding surface for as long as possible, with a two-year warranty provided on repairs carried out by the Pothole Patrol.

“In terms of our joint venture agreement, an independent company is employed to carry out random samples of the list of repairs completed by the Pothole Patrol teams. We then receive a comprehensive report each month on what is and isn’t working, so we can refine the materials and application techniques,” Ossip explains.

From the onset, the joint venture set a target of repairing 50 000 to 70 000 potholes annually.

During the Pothole Patrol’s first year, that target was significantly exceeded, with over 100 000 repairs successfully completed.

Reporting potholes

In par tnership with Dialdirect Insurance and the Johannesburg Roads Agency (JRA), Discover y Insure launched the Pothole Patrol in May 2021 to help tackle the wear and tear on the city’s roads.

Alastair Currie talks to Anton Ossip, CEO, Discover y Insure, about this proactive initiative.

W

hen potholes routinely occur, they pose a general hazard to road users and result in substantial costs in terms of accidents, tyre damage and disrupted traffic flows. Combatting the problem is a global challenge and the worldwide Covid19 lockdowns have exacerbated the issue by creating major maintenance backlogs. In South Africa’s case, this situation has been worsened by some of the heaviest rainfalls experienced in recent years.

“As insurers, Dialdirect and Discovery decided to engage with the JRA to explore how we could make a difference within one of the country’s most heavily trafficked metropolitan zones,” says Ossip. “The positive response from the JRA has been fantastic, with Discovery and Dialdirect backing the Pothole Patrol venture on a 50/50 basis. It’s a public-private partnership that is working out really well.”

Currently, there are eight fully equipped Pothole Patrol vans in operation, with approximately

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IMIESA July 2022

40 people employed. Work is coordinated and executed by an approved contractor managed by the Discovery and Dialdirect joint venture.

Training and monitoring The Pothole Patrol crews, several of whom were previously unemployed, have all

A Pothole Patrol demonstration in progress

As Ossip points out, no one knows for certain how many potholes there are out there across Johannesburg’s extensive road network. As part of mapping out their extent, Dialdirect and Discovery launched a Pothole Patrol app, which anyone can download and then proactively report potholes in their area.

The data produced is being merged with Discovery Insure’s telematics driving data to see what type of correlation exists. This will further refine the science of statistically estimating the full extent of the pothole pandemic, and then quantifying this from a maintenance budgeting perspective.

“As corporate citizens, and as insurers, we are invested in our policyholders’ well-being, and that extends to the city’s infrastructure.

We’re pleased to report that the response from all sides has been overwhelmingly positive,” Ossip concludes.

ROADS & BRIDGES

Keynote speakers to share global perspective at international road conference

Four prominent keynote speakers have been confirmed for the October 2022 gathering of the 7th Regional Conference for Africa, hosted by the South African Road Federation (SARF) in collaboration with the International Road Federation (IRF) and the World Road Association (PIARC).

T

he event takes place from 18 to 20 October at the Cape Town International Convention Centre under the theme ‘Connecting Africa through Smart, Safe and Resilient Roads: Stimulating Growth and Trade on the Continent’.

“Our conference this year truly reflects an international perspective. We are bringing together best practice from across the world,” says Basil Jonsson, operations director, SARF. This international focus has enabled the organisers to secure keynote speakers such as Anouar Benazzouz, the first African president to stand at the helm of the IRF. He is also the director-general of Moroccan Highways.

Nazir Alli, president of PIARC, is also a keynote. A World Bank consultant and civil engineer, he is well known to the South African industry, having been the founding CEO of Sanral.

Renowned local speakers also join the international keynotes, notably Professor André Roux, head: Futures Studies Programme, University of Stellenbosch Business School; and Dr Pierre Voges, CEO of the Atlantis Special Economic Zone Company and former CEO of the Mandela Bay Development Agency.

The enormous international interest in the event is also reflected in the high volume of papers submitted from all four corners of the world – not only from those countries that usually participate, but also from a number of countries attending for the first time. The event is anticipated to draw more than 420 delegates, and ECSA accreditation

has been secured by SARF with 1 CPD Point in Category 1 for each of the three days of the conference.

“Our Regional Conference has become a pivotal ‘space’ in which road specialists and decision-makers come together to collaborate and discuss ways to expand and improve our road network, specifically in Africa, but then, in addition, to take the lessons learnt here further abroad,” says Jonsson.

KEYNOTE SPEAKERS

Anouar Benazzouz, directorgeneral of Moroccan Highways and first African president of the International Road Federation

Specialist seminars The conference will also host two specialist seminars, the first focusing on ‘Safe and efficient transport by road’ and the second on ‘The role of low-volume roads in rural connectivity’ – two topics of vital concern around road networks throughout the continent. This seminar will be presented jointly by PIARC. Other topics on the three-day programme include: - Determination of roads needs and financing mechanisms - Preserving Africa’s road assets - Innovative practices to optimise road networks - Roads and the environment - Capacity development in the roads sector.

With delegate registration now in full swing, those wishing to participate are encouraged to sign up as soon as possible and take advantage of the earlybird registration, open until 9 September.

Special accommodation rates for out-oftown delegates have also been secured at various Southern Sun hotels close to the conference venue.

For more information contact SBS Conferences & Exhibitions on +27 (0)71 348 1780, email info@sbs.co.za or visit sbs.co.za/sarf2022

Nazir Alli, president, World Road Association

Dr Pierre Voges, CEO, Atlantis Special Economic Zone Company

Professor André Roux, head: Futures Studies Programme, University of Stellenbosch Business School

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FLEET MANAGEMENT

SAVE FUEL WITH CTRACK CRYSTAL

The ever-increasing fuel price continues to put pressure on motorists and businesses.

Unfor tunately, as consumers, we are at the mercy of government and global oil prices.

F

or many businesses that operate fleets, driving less is not an option. The most apparent solution is finding ways to use vehicles more efficiently.

In response, Ctrack recently launched Crystal, a fully customisable platform that combines all the existing functionality and a variety of novel features into a new cloudbased platform. Easy to use, it allows fleet managers to react more effectively.

A new driver app launched alongside Ctrack Crystal features a comprehensive host of intuitive functionality, including the ability to easily monitor fuel usage and efficient driving.

“The way vehicles are used can have a significant impact on the running costs of a business, and Ctrack is able to equip customers with the tools to easily and efficiently monitor a variety of factors that have a direct impact on fuel consumption,” says Hein Jordt, CEO of Ctrack Africa.

positively impacting fleet and driver safety, and reducing fuel consumption significantly.

Further measures can be implemented by adding speed limiters that can prevent drivers from speeding entirely or according to pre-determined geozones.

Adopting a smooth driving technique is the most economical way to drive, as is maintaining a constant speed on the open road and sticking to the speed limit.

Through monitoring and reporting, drivers can be coached on factors such as avoiding speeding up between intersections and excessively revving a vehicle.

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IMIESA July 2022

Enhanced communication and driver engagement This all-new app gives fleet managers enhanced communication features such as voice commands, two-way messaging, job listing, navigation and post-trip coaching, which can be shared with drivers to encourage efficient driving.

The app also allows drivers to manage themselves and see their own scores. Drivers who continually achieve good scores can be incentivised and rewarded, fostering a culture of good, efficient driving.

Correct tyre inflation Underinflated tyres are a huge contributor to unnecessary fuel consumption.

Tyres should be checked regularly and inflated according to the manufacturer’s specifications for the load being carried.

This practice can be included in the pre-trip inspection functionality that forms part of the new Ctrack Crystal driver app.

Speed monitoring and control The most significant contributor to inflated fuel usage is excessive speed. With Ctrack hardware and the Crystal platform, managers and business owners can monitor speed and reduce speed violations,

that vehicles are always travelling on the optimal route, while incorporating multiple stops in the most efficient manner.

While the time of day that vehicles travel might be unavoidable in many cases, planning routes around peak hours will mean spending less time in traffic, shorter travelling time and less fuel used.

Ctrack Crystal allows fleet managers to easily populate reports on various parameters according to their needs. This reporting can be used to upskill drivers by highlighting where they need to improve.

Fleet managers can further support positive driving behaviour by monitoring driver skills, driver training, and applying scoring models that result in a reduction of the cost per kilometre.

Plan the route One of the best ways to save fuel is to drive less, and this can be done by better route planning. The driver app includes a builtin navigation system, which will ensure

Efficient service scheduling and administration Vehicle maintenance can also have a substantial effect on fuel consumption.

Crystal’s improved asset control allows fleet managers to stay ahead of service and maintenance schedules, licensing and vehicle usage.

“Cost and inflationary pressure remains top of mind for any business; at Ctrack, we create solutions for fleet managers and business owners to be more productive, efficient and ultimately to save costs,” Jordt concludes.

VEHICLES & EQUIPMENT

Avoid crusher downtime During routine mobile crushing operations, short-term or prolonged overload situations can occur, interrupting production. To help counter this, Kleemann’s latest-generation Mobicat MC 110(i) EVO2 and MCO 90(i) EVO2 units come equipped with revolutionary overload mitigation features to help keep crushed materials flowing.

The active overload system on the Mobicat MC 110(i) EVO2 jaw crusher

T

he multistage overload system on Kleemann’s Mobicat MC 110(i) EVO2 jaw crusher improves efficiency and safety. If, for example, metal enters the crushing process, the crushing gap (CSS) opens automatically in up to two seconds over the complete gap range. When the overload situation is corrected, the system moves back to the original crushing gap and the crushing process is continued.

Tramp Release and Ringbounce Detection The Mobicone MCO 90(i) EVO2 cone crusher has two different overload systems installed, namely Tramp Release and Ringbounce Detection.

Tramp Release protects the crusher against uncrushable material such as wood or metal. During this process, the bowl – including the bowl liner – lifts automatically to allow uncrushable material to fall through.

In turn, the Ringbounce Detection system reacts to an excessively high share of fines in the feed material and

prevents ‘briquetting’ – i.e. the clogging of the crusher or the sticking together of the material. The crusher’s hydraulic pressure is monitored continuously, and the system reacts as required to prevent latent overloads. Depending on the machine application, Ringbounce Detection can be oriented via the control system to Mixture Mode (output) or Precise Mode (product quality).

By preventing machine damage and production bottlenecks, Kleemann’s overload systems guarantee increased operational reliability.

Kleemann’s intelligent Ringbounce Detection system automatically reacts to an excessively large share of fines in the feed material to prevent clogging

The power- and load-dependent fan drive ensures low noise and economical operation

IMIESA July 2022

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Glass fibres in concrete

Fibres can add significant strength to concrete Including stiff natural or synthetic fibres in the concrete mix can significantly augment the strength of concrete, says Br yan Perrie, CEO of Cement & Concrete South Africa (CCSA).

P

errie says concrete made with Portland cement is relatively strong in compression, but weak in tension, which can be overcome not

only by the usual insertion of conventional rod reinforcement, but also by the inclusion of enough stiff fibres in the mix. The fibres alter the behaviour of the fibre-matrix composite after it has cracked, thereby improving its toughness.

Perrie advises the following for the effective use of fibres in hardened concrete: - fibres must be significantly stiffer than the matrix - fibre content must be adequate - there must be a good fibrematrix bond - fibres must have a high aspect ratio – i.e. their length must be in the correct relation to their diameter.

There are natural and Steel fibres in concrete

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IMIESA July 2022

Bryan Perrie, CEO of Cement & Concrete South Africa

synthetic types of fibre. Steel and glass versions are the most commonly used.

Steel Steel fibres have been used in concrete since the early 1900s. The early fibres were round and smooth, and the wire was cut or chopped to the required lengths. The use of straight, smooth fibres has largely disappeared, and modern fibres have either rough sur faces, hooked ends or are crimped or undulated through their length.

Modern commercially available steel fibres are manufactured from drawn steel wire, from slit sheet steel or by the meltextraction process, which produces fibres with a crescent-shaped cross section.

CEMENT & CONCRETE

“Typically, steel fibres have equivalent diameters (based on cross-sectional area) of from 0.15 mm to 2 mm and lengths from 7 mm to 75 mm,” Perrie states. “Carbon steels are most commonly used to produce fibres, but fibres made from corrosion-resistant alloys are available. Stainless steel fibres have been used for high-temperature applications.”

Some fibres are collated into bundles using water-soluble glue to facilitate handling and mixing. Steel fibres have high tensile strength (0.5-2 GPa) and modulus of elasticity (200 GPa), a ductile/plastic stress-strain characteristic, and low creep.

Applications Steel fibres have been used in conventional concrete mixes, shotcrete and slurr y-infiltrated fibre concrete. Typically, content of steel fibre ranges from 0.25% to 2% by volume. “Fibre contents over 2% by volume generally result in poor workability and fibre distribution but can be used successfully where the paste content of the mix is increased and the size of coarse aggregate is not larger than about 10 mm,” Perrie explains.

Steel fibre-reinforced concrete containing up to 1.5% fibre by volume has been pumped successfully using pipelines of 125 mm to 150 mm diameter. Steel fibre contents up to 2% by volume have also been used in shotcrete applications using both the wet and dr y processes.

“Steel fibre contents of up to 25% by volume have been obtained in slurr y-infiltrated fibre concrete. Concretes containing steel fibre have been shown to substantially improve resistance to impact and show greater ductility of failure in compression, flexure and torsion. The elastic modulus in compression and modulus of rigidity in torsion are no different before cracking when compared with plain concrete tested under similar conditions,” Perrie continues.

Steel fibre-reinforced concrete could, because of its improved ductility, find applications where impact resistance is important. Fatigue resistance of the concrete is reported to be increased by up to 70%.

“The inclusion of steel fibre as supplementar y reinforcement in concrete could also assist in the reduction of spalling due to thermal shock and thermal gradients. However, the lack of corrosion resistance of normal steel fibres could be a disadvantage in exposed concrete situations where spalling and sur face staining are likely to occur,” Perrie adds.

Reinstating an old floor

T

he recent refurbishment of the damaged concrete flooring within Klein Constantia Winery’s production area has provided a functional and aesthetic solution for this world-renowned wine estate. CCRS was the main contractor on-site, with Apex Construction Consultants appointed as the project managers.

Following an assessment of the floor’s condition, the bad substrates were removed and reprofiled with SikaCem-810 – a one-component, modified SBR (styrene-butadiene rubber) polymer additive. This was mixed in with the floor screed to correctly shape the floor falls. Once complete, it was left to cure for 21 days.

In preparation for the next phase, the floors were prepared with a light grind and then termination slots were cut into them. These slots facilitate the holding and gripping of the new floor, thus increasing its lifespan.

The final stage entailed the application of Sikafloor-20 PurCem. This hybrid flooring screed is designed to withstand high impact, is slip resistant and allows for steam cleaning.

The specialist applicator used a hand trowel to apply the Sikafloor-20 PurCem at a 6 mm thickness, which was then left to cure for five to seven days. The result is a first-class finish.

The old and damaged flooring within the winery’s production area

Glass In the form first used, glass fibres were found to be alkali reactive, and the products in which they were used deteriorated rapidly. However, alkali-resistant glass containing zirconia was successfully formulated in the 1960s and was soon in commercial production. Alkali-resistant glass fibre is used in the manufacture of glass-reinforced cement (GRC) products, which have a wide range of applications.

“Glass fibre is available in continuous or chopped lengths.

Fibre lengths of up to 35 mm are used in spray applications and 25 mm lengths are used in premix applications. GRC products are used extensively in agriculture, for architectural cladding and components, and for small containers,” Perrie concludes.

The newly refurbished floor surfaced with the Sikafloor-20 PurCem hybrid flooring screed

IMIESA July 2022

45

IMESA MESA

IMESA AFFILIATE MEMBERS PROFESSIONAL AFFILIATES

CEMENT & CONCRETE AECOM siphokuhle.dlamini@aecom.com AFI Consult banie@afri-infra.com Alake Consulting Engineers lunga@alakeconsulting.com ARRB Systems info@arrbsystemssa.com Asla Construction (Pty) Ltd johanv@asla.co.za BMK Group brian@bmkgroup.co.za Bosch Projects (Pty) Ltd mail@boschprojects.co.za BVI Consulting Engineers marketing@bviho.co.za CCG puhumudzo@ccgsytems.co.za / info@ccgsystems.co.za Corrosion Institute of Southern Africa secretary@corrosioninstitute.org.za Dlamindlovu Consulting Engineers & Project Managers info@dlami-ndlovu.co.za EFG Engineers eric@efgeng.co.za Elster Kent Metering Mark.Shamley@Honeywell.com EMS Solutions paul@emssolutions.co.za ERWAT mail@erwat.co.za GIBB marketing@gibb.co.za GIGSA secretary@gigsa.org GLS Consulting nicky@gls.co.za Gorman Rupp Cordeiro@gormanrupp.co.za Gudunkomo Investments & Consulting info@gudunkomo.co.za Hatch Africa (Pty) Ltd info@hatch.co.za HB Glass Filter Media info@hardybulkinglass.com Herrenknecht schiewe.helene@herrenknecht.de Huber Technology cs@hubersa.com Hydro-comp Enterprises info@edams.co.za Infrachamps Consulting info@infrachamps.co.za INFRATEC info@infratec.co.za IQHINA Consulting Engineers & Project Managers info@iqhina.co.za iX engineers (Pty) Ltd hans.k@ixengineers.co.za JBFE Consulting (Pty) Ltd issie@jbfe.co.za JG Afrika DennyC@jgafrika.com KABE Consulting Engineers info@kabe.co.za Kago Consulting Engineers kagocon@kago.co.za Kantey & Templer (K&T) Consulting Engineers ccherry@ct.kanteys.co.za Kitso Botlhale Consulting Engineers info@kitsobce.co.za KSB Pumps and Valves (Pty) Ltd salesza@ksb.com KUREMA Engineering (Pty) Ltd info@kurema.co.za Lektratek Water general@lwt.co.za Makhaotse Narasimulu & Associates mmakhaotse@mna-sa.co.za Mariswe (Pty) Ltd neshniec@mariswe.com Martin & East gbyron@martin-east.co.za M & C Consulting Engineers (Pty) Ltd info@mcconsulting.co.za Mhiduve adminpotch@mhiduve.co.za MPAMOT (PTY) LTD mpumem@mpamot.com Mvubu Consulting & Project Managers miranda@mvubu.net Nyeleti Consulting naidoot@nyeleti.co.za Odour Engineering Systems mathewc@oes.co.za Prociv Consulting & Projects Management amarunga@prociv.co.za Rainbow Reservoirs quin@rainbowres.com Re-Solve Consulting (Pty) Ltd maura@re-solve.co.za Ribicon Consulting Group (Pty) Ltd info@ribicon.co.za Royal HaskoningDHV francisg@rhdv.com SABITA info@sabita.co.za SAFRIPOL mberry@safripol.com SAGI annette@sagi.co.za SALGA info@salga.org.za SAPPMA admin@sappma.co.za / willem@sappma.co.za SARF administrator@sarf.org.za.co.za SBS Water Systems marketing@sbstanks.co.za Silulumanzi Antoinette.Diphoko@silulumanzi.com SiVEST SA info@sivest.co.za Sizabantu Piping Systems (Pty) Ltd gregl@sizabantupipingsystems.com Siza Water (RF) Pty Ltd PA@sizawater.com Sky High Consulting Engineers (Pty) Ltd info@shconsultong.co.za SKYV Consulting Engineers (Pty) Ltd kamesh@skyv.co.za Smartlock jp.alkema@smartlock.net SMEC capetown@smec.com Southern African Society for Trenchless Technology director@sasst.org.za SRK Consulting jomar@srk.co.za Star Of Life Emergency Trading CC admin@staroflife.co.za TPA Consulting roger@tpa.co.za V3 Consulting Engineers (Pty) Ltd info@v3consulting.co.za VIP Consulting Engineers esme@vipconsulting.co.za VNA info@vnac.co.za Water Institute of Southern Africa wisa@wisa.org.za Wam Technology CC support@wamsys.co.za Wilo South Africa marketingsa@wilo.co.za WRCON ben@wrcon.co.za WRP ronniem@wrp.co.za Zutari Rashree.Maharaj@Zutari.com

Precast solutions for a residential estate

T

Technicrete’s DZZ 60 mm slatecoloured interlocking pavers provide a durable and aesthetic finish at the Eye of Africa development

he infrastructure network for the Eye of Africa Golf and Residential Estate development south of Johannesburg is now well advanced, with Down to Earth Civils moving on to Phase II from mid-2022.

Down To Earth Civils selected Technicrete and Rocla for the supply of paving, manholes and stormwater pipes for Phase I of the project.

This included the 25 000 m2 of main roadways throughout the estate that been paved with Technicrete’s DZZ 60 mm interlocking pavers.

Technicrete will be supplying a further 18 900 m2 of DZZ 60 mm pavers for Phase II.

Stormwater To meet the estate’s stormwater requirements, Rocla supplied 675 m of interlocking joint (IJ) pipes. The IJ pipes are specifically designed and manufactured for stormwater applications. The male/female type joint is formed inside the wall of the pipe. The joint itself is used for centering the pipe during laying operations, thus making the process easier.

“Although the IJ pipe is primarily designed for use in a non-watertight pipeline, rubber collars can be supplied to facilitate a measure of water-tightness. These can be used where the ingress of groundwater needs to be avoided, and the more expensive rubber ring joint pipe is not necessary,” explains Grant Fourie, sales consultant at Technicrete Olifantsfontein. (Technicrete and Rocla form part of the Infrastructure Specialist Group of companies).

“The pipes are manufactured in 2.44 m and 1.22 m sections, but can be manufactured in special lengths to meet specified customer requirements. The standard strength classes for these pipes are 50D, 75D and 100D (refer to SABS 677),” he adds.

“Special intermediate strengths or heavier loading requirements can be designed and manufactured.

These are subject to various material constraints but will be evaluated by our engineers on an ad hoc basis,” Fourie concludes.

Rocla also supplied 142 manhole units measuring 1 000 mm in diameter

IMIESA July 2022

47

CEMENT & CONCRETE

Composite cements lead in sustainability drive AfriSam has become a trailblazer in cutting carbon emissions in one of the economy’s most energy-intensive sectors.

H

annes Meyer, cementitious executive at AfriSam, highlights that the energy consumed in producing ordinary Portland cement can be 20% to 25% higher than a composite cement of the same strength class.

“This results from the added cost of producing a higher-percentage clinker at high temperatures used per tonne of composite cement manufactured,” says Meyer.

“Extenders like fly ash or ground granulated blast furnace slag can be blended into the mix, reducing the amount of clinker milling required per tonne of cement.”

This has more recently become a focus for other players in the market – even those who had previously not embraced the concept of composite cement, he notes. AfriSam has in the meantime become the benchmark for these cement innovations, along with a range of sustainability initiatives to monitor and reduce carbon emissions.

“A vital aspect of our use of extenders has been our ability to activate these materials for

greater reactivity,” he says. “Through evolving our chemical and mechanical activation methods, we achieve a more reactive product – allowing us to progressively replace more and more clinker while retaining high cementitious quality and strength performance.”

Meyer points out that cement blending companies have already recognised the high reactivity of AfriSam cement, with many of them preferring AfriSam’s products as they ‘go further’ in a blending application.

Grinding aids “We have also had great success in the use of grinding aids in our milling processes, collaborating closely with specialist firms to address our exacting requirements,” says Meyer.

“These grinding aids are specific to the extenders we use, helping to improve reactivity and, in some instances, adding 10% to 15% early strength enhancement,” he continues.

The result is that less clinker needs to be produced per tonne of final product, leading to less carbon dioxide being generated.

Hannes Meyer, cementitious executive, AfriSam

Energy gains AfriSam has also become more efficient in the use of thermal and electrical energy in its processes. While electricity used to be a minor cost in cement plants, it is now a major factor in cement manufacture. In this context, AfriSam has explored alternative fuels, which has also become a major focus for many cement producers globally.

“We have made progress with responsibly disposing of waste products in our energy generation strategies, and we hope that government will take the necessary steps to allow us to expand these initiatives,” Meyer continues. These include the combustion of waste tyres and industrial carbon sludge, using high-efficiency multichannel burners that reduce hazardous emissions.

“The employment of increasingly sophisticated process control technology is also part of the ‘AfriSam Way’ towards a sustainable planet,” Meyer concludes.

INDEX TO ADVERTISERS CIDB Corestruc Ctrack DMG Exhibition Management Services

48

IMIESA July 2022

31

GLS Consulting

IBC OBC 37

IMESA Maccaferri SA

OFC 2, 26 & 46 IFC

SAPPMA

20

Structa Group

25

Vukani Communications

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