Water & Sanitation Africa Nov/Dec 2019

Water & Sanitation Africa

Complete water resource and wastewater management

George Diliyannis

Senior Technical Service and Development Engineer, Safripol

Industry Ins I ght

World-class plastic solutions

The advantages of PVC-O pipelines

Water S ecurity

Building resilience

Pla S tic P i P e S

Developments in PVC-O

Sanitation

Managing school toilets

Wa S te W ater

Changing reuse perceptions

Proce SS control The power of dashboarding

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Lightweight and requiring no specialised skills to install, sizabantu’s tom® 500 PVC- o is ideally suited for community projects in addition to providing longer-term savings for water utilities. P6

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The SBS Tanks® range has been designed, developed and engineered with expertise gained from over 20 years of experience within the international water storage industry. SBS Tanks® offers a broad product range of liquid storage tanks for multiple applications, from 12 kilolitres in capacity to the largest single storage solution of it’s kind, the impressive 3,3 megalitre capacity water storage tank. Manufactured from pre-fabricated Zincalume® steel panels, and fitted with an approved liner, SBS Tanks® are highly resistant to corrosion and proven to be an effective and reliable product offering.

As a company, SBS Tanks® operates on a shared set of corporate values and principles, with customer focus and ongoing investment in research and development being key elements. We as a corporate entity believe that, not only is it possible to achieve our objectives through positive business practice, but we can equally take positive steps toward framing our future simultaneously.

Editor Danielle Petterson

Danielle.Petterson@3smedia.co.za

Managing editor Alastair Currie

Head of design Beren Bauermeister

Designer Jaclyn Dollenberg

Chief sub-editor Tristan Snijders

Contributors Lester Goldman, Dr Michele Kruger, Mike Smart, Chanelle Mulopo, Herman Smit, Peter Townshend, Peter van der Merwe, Achim Wurster

Operations & production manager Antois-Leigh Botma

Production coordinator Jacqueline Modise

Distribution manager Nomsa Masina

Distribution coordinator Asha Pursotham

Group sales manager Chilomia Van Wijk

Financial manager Andrew Lobban

Bookkeeper Tonya Hebenton

Printers Novus Print KZN

Advertising sales Hanlie Fintelman t +27 (0)11 467 6223 | c +27 (0)82 338 2266 Hanlie.Fintelman@3smedia.co.za

Publisher Jacques Breytenbach

Novus Print (Pty) Ltd t/a 3S Media

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Tel: +27 (0)11 233 2600 Fax: +27 (0)11 234 7274/5 www.3smedia.co.za

ISSN: 1990 - 8857

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Copyright 2019. All rights reserved. All articles herein are copyright protected and may not be reproduced either in whole or in part without the prior written permission of the publishers. The views of contributors do not necessarily reflect those of the Water Institute of Southern Africa or the publishers.

WISA Contacts:

Head office

Tel: 086 111 9472(WISA) fax: +27 (0)11 315 1258

WISA’s Vision Inspiring passion for water

Physical address: 1st Floor, Building 5, Constantia Park, 546 16th Road, Randjiespark Ext 7, Midrand Website: www.wisa.org.za

BRANCHES

central Branch (Free State, Northern Cape, North West) chairperson: Dr Leana Esterhuizen company: Central University of Technology Tel: +27 (0)51 507 3850 email: lesterhu@cut.ac.za

eastern cape:

Branch contact: Dan Abrahams company: Aurecon Tel: +27 (0)41 503 3929 cell: +27 (0) 81 289 1624 email: Dan.Abraham@aurecongroup.com

Gauteng

Branch Lead: Zoe Gebhardt cell: +27 (0)82 3580876 email: zoe.gebhardt@gmail.com

KwaZulu-Natal chairperson: Lindelani Sibiya company: Umgeni Water cell: +27 (0)82 928 1081 email: lindelani.sibiya@umgeni.co.za

Limpopo chairperson: Mpho Chokolo company: Lepelle Northern Water cell: +27 (0)72 310 7576 email: mphoc@lepelle.co.za

Mpumalanga

Chairperson: Lihle Mbatha (Acting) Company: Inkomati-Usuthu Catchment Management Agency

Tel: +27 (0)13 753 9000

Email: mbathat@iucma.co.za

Western cape

chairperson: Natasia van Binsbergen company: AL Abbott & Associates

Tel: +27 (0)21 448 6340 cell: +27 (0)83 326 3887 email: natasia@alabbott.co.za

Namibia

Please contact the WISA Head Office on admin@wisa.org.za for more information

Are we flushing away our rivers? A

s we observe World Toilet Day on 19 November, it is worth giving some thought to the full sanitation value chain. While it is essential that we provide appropriate and dignified sanitation solutions for all members of society, it is equally important to ensure that our effluent is appropriately managed. Unfortunately, our rivers are paying the price for poor sanitation management. The recently released StateofRiversReport2017-2018 shows the ecological condition of our rivers based on data collected at 364 sites across the country. And the results are concerning.

State of rivers

The report categorises rivers into the following categories:

• A: unmodified/natural

• A/B: The system and its components are in a close to natural condition most of the time

• B: largely natural with few modifications

• B/C: close to largely natural most of the time

• C: moderately modified

• C/D: The system is in a close to moderately modified condition most of the time

• D: largely modified

• D/E: the system is in a close to largely modified condition most of the time

• E: seriously modified

• F: critically/extremely modified

Only 16% of sites, mostly located in the upper reaches of catchments, fell into the AB, B or BC categories. Approximately 50% are in a moderately modified (category C) condition and the Vaal River Water

Management Authority had no sites in a good condition (better than category C). Approximately 5% of the sites are in an unsustainable (DE to E) condition.

The report goes on to indicate that rivers in densely populated areas are in poor condition due to a lack of proper management and maintenance of wastewater treatment works and insufficient capacities of these works for the population served. Furthermore, many rural areas still lack proper sanitation, also leading to contamination of water resources.

Where to from here?

It is evident that a focus on sanitation should not only look at providing onsite solutions, but also at downstream management. Not only are we polluting our drinking water sources, but we are damaging the ecology of our rivers and dams.

Given the fact that drought conditions, high water use, and climate change are also impacting flow conditions, we must develop strategies to lessen our impacts, better manage land use and protect our water resources.

Poor sanitation, both urban and rural, is undoubtedly a threat to aquatic and human health, and is one of the largest contributors to the deterioration of our water resources.

This World Toilet Day, let’s focus on wellmanaged sanitation solutions from start to finish, ensuring we provide dignity while protecting our water resources.

Cover opportunity

In each issue, Water&Sanitation Africa offers companies the opportunity to get to the front of the line by placing a company, product or service on the front cover of the magazine. Buying this position will afford the advertiser the cover story and maximum exposure. For more information, contact Hanlie Fintelman on +27 (0)11 467 6223, or email Hanlie.Fintelman@3smedia.co.za

Sizabantu Piping Systems recently supplied the piping for the Driekoppies bulk water, Driekoppies reservoir and the Sibange bulk water pipeline projects for Ehlanzeni District Municipality and Nkomazi Local Municipality.

For all phases, a range of material options was assessed by Lubisi Consulting Engineers and GMH Tswelelo Consulting Engineers for the size and pressure classes required. Materials considered were steel, ductile iron and TOM 500 PVC-O. The design specification called for a pipeline at least 630 mm in diameter.

The decision was made to specify TOM 500 PVC-O as the most cost-effective option. TOM 500 PVC-O is supplied in

The advantages of PVC-O pipelines

Lightweight and requiring no specialised skills to install, TOM® 500 PVC-O is ideally suited for community projects in addition to providing longer-term savings for water utilities.

diameters up to 800 mm, so it comfortably met the varied scope requirements across the three projects.

“A key advantage of TOM 500 PVC-O piping systems is that they have between 15% and 40% greater hydraulic capacity compared to alternative material systems with the same external diameter,” explains Greg Loock, director, Sizabantu Piping Systems.

Sizabantu is the Southern African distributor for Spanish OEM Molecor, which is globally acknowledged as the pioneer of TOM 500 PVC-O, a major advancement on industry-standard PVC materials. This is because TOM 500 PVC-O’s molecular orientation reduces the thickness of the pipe wall, giving TOM 500 PVC-O pipes a greater internal diameter and flow section.

Additionally, the internal surface of TOM 500 PVO-O is extremely smooth, reducing load loss and making it more difficult for deposits to form on the inner walls.

Subsequently, TOM 500 PVC-O pipes carry more water which uses less energy than other material types, such as steel.

Thanks to their low density, TOM 500 PVC-O sections can be installed using a backhoe loader; smaller-diameter pipes can be installed by hand

“What’s more, they are arguably the most efficient in terms of the relationship between investment and available hydraulic capacity,” adds Loock.

A further advantage is that TOM 500 PVC-O is considerably lighter in weight than metallic options, measurably stronger and more flexible than standard PVC, and also does not require any special skills to install.

Materials lose their mechanical properties when they are subjected to strain over a long period of time. This characteristic, known as creep, appears to a far lesser extent in TOM 500 PVC-O than in conventional plastics, so providing better properties over the long term. TOM 500 PVC-O is also exceptionally resistant to fatigue and has a very good chemical resistance, much like conventional PVC.

Maintenance cost savings

Going the ductile iron or steel pipe route would have required the mandatory installation of cathodic protection. This prevents premature structural failure

LEFT The extreme smoothness of the inner wall of the TOM pipe minimises pressure loss, so the energy required for transport is lower

Energy consumed by pumping (kWh)

“Only 43% of TOM 500 PVC-O’s composition depends on oil. Therefore, the required consumption of this resource is lower than in other plastic solutions.”

caused by stray electricity currents, especially where pipelines are located near railway tracks or overhead power lines.

Although essential, the downside to cathodic protection is that it typically costs around 12% to 27% of the overall price of the pipeline. It also requires regular maintenance to be effective. That poses additional challenges for today’s cash-strapped municipalities, which also continue to experience shortages of technically skilled personnel.

Either way, failure to protect or maintain the pipe will result in immediate corrosion. This is evident in the continuous leaking of metallic pipelines across South Africa, which contributes to increased nonrevenue water losses and places a severe strain

on an already water-scarce environment.

“TOM 500 PVC-O is clearly a highly viable alternative,” points out Loock. “Providing a design life of at least 100 years, TOM 500 PVC-O systems don’t require coating or linings and require minimal maintenance.

TOM 500 PVC-O allowed the engineers to design a pipeline within budget.”

The reservoir phase was the largest of the three pipeline projects and consisted

6 100 m of TOM 500 PVC-O was specified for the Driekoppies reservoir pipeline project

Charts figures for DN 200250 mm PN16 bar pipes

of 6 100 m of TOM 500 PVC-O. Sizabantu supplied TOM 500 PVC-O PN 16 and PN 20 sections for Sibange, and TOM 355 PVC-O PN 16 for the Driekoppies bulk water component. On all phases, ease of installation has enabled the contractor to use local labourers to complete the project in the shortest time possible.

TOM 500 PVC-O complies with SANS 16422 and is manufactured locally by Molecor South Africa at the company’s state-of-the-art manufacturing facility in Richards Bay, KwaZulu-Natal. To date, Sizabantu has sold more than 4 000 000 m throughout Southern Africa.

“TOM500 PVC-O is undoubtedly a world-class product and has enabled municipalities and water authorities to extend the life of their bulk water pipelines,” Loock concludes.

www.sizabantupipingsystems.com

ABOVE TOM 500 PVC-O pipes do not require any specialised skills to install

Bringing dignity

While we acknowledge the excellent work done in the sanitation sector, it is worth considering our commitment - as the entire water sector - towards this SDG sub-goal. Do our water professionals see the sanitation challenge only as a means of saving water, or do they see this as providing real dignity to communities?

Most of us have never been without a flushing toilet, which can sometimes make it difficult to keep the ongoing quest for dignified sanitation top of mind. However, seeing the appreciation and light in someone’s eyes when they are able to use a newly installed flush toilet should motivate us to enhance this endeavour while also seeking to save water.

Let us try to use the next 10 years to make a meaningful improvement in attaining SGD 6.2.1, by discussing this in our boardrooms, research labs, offices and work corridors. Maybe then, collectively, we can bring dignity where it is needed.

WISA volunteers who have supported and built upon a wonderful legacy left by the old WISA MoI. Now, more than ever, we are looking to members to provide us with feedback in terms of the direction and vision for the future.

In November, we observe World Toilet Day. And as we fast approach 2030, we must review our progress towards SDG 6.2.1 –“Proportion of population using (a) safely managed sanitation services and (b) a hand-washing facility with soap and water.”

By Dr Lester Goldman

You may have participated in our WISA Think Tanks, completed our survey, or attended information sessions at IFAT, the Young Water Professionals Conference, etc. For this participation, we are grateful. As the saying goes, ‘we cannot be everything for everyone’, but we do want to try to satisfy the majority. Your feedback allows us to take a focused approach to serving our members and water community.

After what has been a trying year in many respects, with much change and many challenges, I hope that you will have a much-deserved December break spent with loved ones. I hope you find peace and look forward to 2020 with renewed vigour.

We are very excited about our WISA 2020 Biennial Conference, with planning already more than a year under way

The year in review

I cannot believe that this is the last issue of 2019, as time seems to have found

I would like to express our gratitude to our

We are very excited about our WISA 2020 Biennial Conference, with planning already more than a year under way. And please always let us know your thoughts on the sector via our dedicated email channel: thinktank@wisa.org.za.

Wishing you and yours a happy holiday. Keep safe and many blessings!

Dr Lester Goldman, CEO, WISA

WPotty training, Version 2.0

The Sustainable Development Goals (SDGs) call for universal access to adequate and equitable sanitation and hygiene by 2030. While this is something we all want to achieve, it is clear that we must change our approach to sanitation.

By Achim Wurster

ell-off members of society often berate government over newspaper headlines such as ‘Sewage crisis’, ‘Vaal River pollution’ or ‘Sewage spill into Apies’, while the same headlines hardly elicit a thought as the toilet is flushed. Less well-off members of society often still rely on open defecation, bucket systems or pit latrines, while their cries for safe sanitation are not heard or are written off as unreasonable service delivery protests.

Achim Wurster, chair, WISA

The reality is that all sectors of society are a source of pollution if sanitation is not managed appropriately. Is this situation acceptable? If not, who are we holding accountable?

The easy way out is to blame local government or the Department of Water and Sanitation (DWS). They rightly have to shoulder responsibility, at least for those aspects under their direct control. However, it is our toilet flushing that is the root of the problem so let us investigate a little deeper.

The challenges

Potable water is getting more expensive and periods of physical supply constraints are increasing, making potable water less suitable for waste disposal. Many formal sewage disposal systems - consisting of gravity sewers, pump stations and wastewater treatment works - are buckling under many years of inadequate maintenance and lack of treatment capacity expansion while inflows increase. At the same time, many informal settlements are springing up, leaving local government or the DWS playing catch-up with infrastructure provision, without any means to effectively recover costs in these areas. While the DWS and local government are doing a lot, many projects and schemes implemented to

address these challenges suffer from a myriad of problems, including corruption, poor design, poor project management (both technical and financial) and, lately, also work stoppages due to threats from the ‘construction mafia’. The result is a lot of money being spent, with inadequate or only moderate results.

The financial constraints that government currently faces mean that funding may be even less for the foreseeable future. This does not bode well if we want to achieve the sanitation aspect of SDG 6: access to adequate and equitable sanitation and hygiene for all.

The solutions

Clearly more of the same will not solve our problems. We need to accept that. Ultimately, we must change our approach to sanitation and set a new course. But turning this ship around and steering it in the right direct is going to take time. In the meantime, we need the following:

• an effective and fair regulator

• adequate funding to maintain and upgrade infrastructure at both national and local government level

• excellence in project planning, design and execution for new infrastructure

• excellence in operations and maintenance of existing infrastructure

• effective protection to safeguard existing infrastructure against theft and allow new projects to proceed without interference.

The above will keep the ship afloat for now but we are still heading towards being beached on a sand bank in a dried-out lake. What I saw at the recent Water Research Commission Symposium gives me hope that a prosperous course exists. There were many examples of new sanitation systems that reduce water demand or don’t require any water, with many already available commercially. However, for large-scale acceptance by society, we need more of the following:

• robust research to verify the safety and technical efficacy of new sanitation systems

• improved resource recovery from the collected waste streams of new sanitation systems in order to improve the economics, ultimately making them financially self-sustaining

• financial models that show the advantages of implementing new sanitation systems, to motivate financial support from savings gained in other areas, until they become self-sustaining

• regulations and by-laws at national and local government level that support the implementation of new sanitation systems, including technical and business model aspects

• standards, technical documentation and guidelines to assist industry to certify new sanitation systems and to implement them appropriately

• widespread public campaigns to promote the benefits and educate the public regarding new sanitation systems so that these become the preferred choice.

We all want a clean environment and cost-effective reliable water and sanitation services. To achieve this, we have to ‘potty train’ our minds to the changes in reality that will necessitate new sanitation solutions. I, therefore, ask you to consider how you can contribute to this goal in your work and personal spheres of influence. Effectively sailing our ship and charting a sustainable and financially viable course to new sanitation

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World-class plastic solutions

HDPE pipe has a proven history of high performance in water transportation. It offers the lowest failure rates of all traditional materials used for water systems, superb chemical resistance and low water absorption, and is easily processed and machined. Leading Southern African polymer producer Safripol supplies versatile, quality plastic material that is ISO compliant.

The plastic pipes industry is still seen as fairly new in South Africa but plastic materials are evolving at a rapid rate, so allowing plastic pipes to be engineered to last a remarkable 50 to 100 years.

“Although there isn’t too much awareness of, or education around, plastic material science, it’s an exceptionally competitive industry and one that can positively contribute to the environment and the residents it supports,” says George Diliyannis, senior technical service and development engineer, Safripol.

Safripol was established in South Africa in 1972, currently employing over 500 people in Johannesburg, Sasolburg and Durban. The company is the only local producer of high density polyethylene (HDPE) with technology licensed by LyondellBasell, and is also the only local producer of polyethylene terephthalate (PET) with technology sourced from Invista and Polymetrix. It also produces polypropylene (PP) with LyondellBasell licenced technology. Safripol supplies the

African and global markets with PET, HDPE and PP from its manufacturing operations in Sasolburg and Durban. Safripol has leveraged the best technologies and operational processes through global partnerships to design and provide unique, fit-for-purpose solutions that local customers have come to expect from the market leader.

iMPacT100

Safripol’s flagship HDPE PE100 pipe resin, branded as iMPACT100®, provides a single solution to both the water and wastewater transfer markets that conforms to the latest ISO standards.

iMPACT100 is a premium material and its high molecular mass grade offers good impact strength, abrasion, chemical and UV resistance. Compliant with the latest PE100 material requirements of ISO/SANS 4427, iMPACT100 is the preferred product for use in large-bore pipes up to 1.2 m in diameter.

According to Diliyannis, iMPACT100’s intrinsic properties – including resistance to cracking and longevity – make it

suitable for potable water, stormwater and sewerage pipes. “This versatile material is recognised globally for use in all of these functions and is more durable and sustainable than traditional pipe material,” he says.

Built on strong foundations

iMPACT100 is the result of Safripol’s strong international partnerships, which encourage the use of the very best pipe technology and operational and safety standards.

“Not only have we harnessed the global expertise of our partnerships with LyondellBasell and Qenos to comply with the highest industry standards, but we’ve also cultivated these relationships to allow us to develop a better understanding of the possibilities within the local market, and implement best global practice solutions relatively quickly,” explains Diliyannis. Safripol’s iMPACT100 was developed in collaboration with Qenos under a licence agreement that allows for informationsharing and gives Safripol’s Sasolburg plant

George Diliyannis Senior Technical Service and Development Engineer, Safripol

Safripol’S five core valueS underpin itS miSSion to become Southern africa’S preferred polymer partner:

access to future product developments in the HDPE pressure pipe industry.

With many years of experience in developing high-performance PE100 pipe grades for water supply and waste management in line with the latest ISO standards, Safripol considered Australian company Qenos as the partner of choice for pipe technology.

Meeting the standards

As part of the technical support offered through their exclusive partnership, Qenos’ ISO 17025 accredited laboratory assists with process verification testing, ensuring that Safripol’s iMPACT100 product meets compliance standards.

Safripol is currently in the process of becoming SANS/ISO 4427 certified, with third-party verification under way by the SABS.

“We stay on top of innovative technology through our collaborations and partnerships in the plastics industry, and SABS certification will ensure that iMPACT100 meets the global standard so that we can meet the market’s need for cost-effective, leak-free piping systems,” says Diliyannis.

Safripol also works with machine manufacturers to ensure its materials work with their machines and processes to facilitate the creation of fit-for-purpose piping products.

The Safripol advantage

“We have deep roots in South Africa, and we pride ourselves on bringing the very best technologies and products to the local market. We go to great lengths to ensure that our products and technology are globally competitive and that we serve the market demand,” says Diliyannis.

As a local supplier of raw materials, Safripol offers many advantages to customers, including a quicker supply chain response time, decreased inventory requirements, and easy access to product and technical support, as well as supporting local communities through job creation and economic growth.

global research project to determine the effects of using recycled materials in plastic pipes. “This forms part of our focus to produce long-lasting plastics sustainably. We strive to add value to the environment while using global expertise to improve local understanding. In this way, we work to ensure that Safripol remains Southern Africa’s preferred polymer partner.”

By ensuring it has the best local technical knowledge, Safripol is working to improve the industry through knowledge-sharing.

Diliyannis, together with some of Safripol’s partners, is currently undertaking a

www.safripol.com Neo

+27 (0)11 575 1031

nmekgoe@safripol.com

impact100 SupportS award-winning project

Safripol’s iMPACT100 was used to produce the 800 mm PN16 HDPE pipe used in the award-winning Temba Water Purification Plant upgrade in Hammanskraal.

The project, which won the Joop van Wamelen SASTT Award of Excellence, employed horizontal directional drilling (HDD) to ream out the existing 800 mm asbestos cement pipeline and replace it with a new 800 mm PN16 HDPE pipe supplied by Marley Pipe Systems. Specialist contractor Trenchless Technologies achieved a world first with this project: undertaking the pipereaming process and installation of the 800 mm HDPE pipe in a single pass.

In order to reduce the number of butt-welds required, the 800 mm PN16 HDPE pipe was delivered to site in 18 m lengths. These 18 m lengths were buttwelded into long continuous sections of approximately 150 m to be pulled into position in the reamed-out bore. This is the largest-diameter host pipe known to have been replaced by pipereaming technology.

The implications of inadequate WASH services on health in poorly resourced settings

Thought piece by Chanelle Mulopo, Communications Lead YWP

Water and sanitation are critical drivers of health. Although there has been much focus on, and investments in, the improvement and development of water and sanitation technology, little effort has been invested in WASH-related health outcomes.

Chanelle Mulopo

WASH-related diseases are among the leading causes of death among children below the age of five. Approximately 700 000 children die annually because of diarrhoeal diseases resulting from inadequate WASH services. Additionally, WASH is reported to have an impact on stunting and wasting in early childhood.

Studies show that the most vulnerable group affected by WASH-related diseases are children below the age of five. Furthermore, WASH plays an important role in combating neglected tropical diseases (NTDs) which cause about 543 000 deaths in sub-Saharan Africa. However, to date the WASH component of the strategy to combat NDTs has

received little attention. Schistosomiasis alone affects approximately 500 million people of which more than 90% of the infected population is in subSaharan Africa.

WASH-related diseases are common in poorly resourced settings such as rural areas and informal settings within the urban areas. Communities in these settings are characterised by limited access to improved water sources and inadequate sanitation.

Everyone understands that there is a link between WASH and health, however, both researchers and communities have a poor understanding of some of the transmission pathways of WASH-related diseases. Therefore, it is imperative for researchers to work hand in hand

with communities in order to understand the behaviours, which exacerbate the transmission of pathogens, as well as to identify transmission pathways.

Communities with limited WASH services are more likely to engage in practices that make them susceptible to WASH-related diseases. For example, if the community has inadequate sanitation facilities, some individuals may resort to practising open defecation.

As a young water professional pursing a PhD in public health, I believe that - in order to effect change - there is a definite need for collaboration between the water and sanitation sector and the Department of Health. Currently, these entities work in isolation. This collaboration is crucial because it will pave a way for the development of WASH technology and/or interventions that consider health outcomes.

To give a practical example, schistosomiasis is prevalent in some parts of South Africa. Various factors are responsible for the transmission and persistence of the disease. These include climate change, global warming and proximity to water bodies. Most villages where schistosomiasis is prevalent have limited access to water. In addition,

the villages are in close proximity to the rivers and other freshwater bodies. The combination of inadequate access to water supply and the proximity to the river has resulted in majority of these communities relying on rivers and dams as their main source of water. This has tremendously predisposed these communities to schistosomiasis.

As a public health specialist pursuing a career in the water and sanitation sector, I recommend that public health specialists should be involved in all water and sanitation interventions to ensure that communities have tangible health benefits. Public health specialists in the water and sanitation sector will also ensure appropriate measures are taken to ensure community engagement of all WASH projects.

In conclusion, stakeholder engagement is critical for successful WASH interventions. Collaborations between the water and sanitation sector, the Department of Health and the community are the future. This will ensure accelerated uptake of WASH technology, sustainability and improved health outcomes at the community level.

ForalistofreferencescontactChanelleMulopoon cmulopo@gmail.com.

YWPZA WC chapter welcomes new Lead

Anya Eilers has been appointed as the new Lead for the YWPZA Western Cape Chapter.

Eilers is a young water professional with a masters degree in hydrogeology from Stellenbosch University. She has worked in a range of different sectors in the water space and believes that a strong scientific understanding of water resources is becoming increasingly important for Africa’s fight against climate change.

Eilers recently returned to her home city of Cape Town to take up the role of a hydrologist at Aurecon. Prior to this, she worked in Addis Ababa for two years as an associate at the Global Green Growth Institute, where she managed water and climate change-related projects with the government of Ethiopia.

She still plans to pursue another masters degree in environmental economics as she believes that tackling climate change and promoting sustainable economic growth must go hand in hand. However, in the meantime she is happy to be home and is excited to become involved once again with the South African Young Water Professionals and other platforms that promote inter-disciplinary collaboration in the sciences and water space. Anya Eilers

KENyA

Water and sanitation in Africa

Kimwarer Dam cancelled President Uhuru Kenyatta of Kenya has cancelled the construction of the KSh22.2 billion (R3.14 billion) Kimwarer Dam.

This follows an investigation, which revealed that the dam project was technically and financially unfeasible. It is reported that no reliable feasibility study was conducted on the Kimwarer project before its construction.

A statement from State House reads, “The KSh22.2 billion Kimwarer Dam was found to have been overpriced and the project is neither technically nor financially viable. The water

R3.14 bilion

supply mechanism would involve pumping, an aspect the technical committee found to be unsustainable in terms of operations and maintenance costs.”

Kenyatta has, however, greenlit the commencement of the Arror Dam project, which was deemed economically viable by a technical committee.

However, since it was also found to be overpriced, new design components and a cost rationalisation plan have been developed. The changes will see the dam scaled down to 60 m from the original design height of 96 m, which was found to be unviable.

Kenyatta has since come under fire for cancelling the Kimwarer project and some leaders continue to push for the building of the multipurpose dam. A petition by two residents from Elgeyo Marakwet County has led to the Senate Standing Committee on Lands and Natural Resources being tasked to investigate the circumstances that led to the president’s cancellation of Kimwarer Dam and the downscaling of Arror Dam. There are also reports of major financial losses, with KSh19 billion (R2.69 billion) said to have been paid in advance in connection with the Kimwarer and Arror dams.

ETHIoPIA

First sustainable water to Serdo

USAID, together with DuPont Water Solutions and the Afar Regional State Government, has unveiled a state-of-the-art reverse osmosis (RO) water system in the Ethiopian community of Serdo.

The RO water system features a stand-alone cooling tower – the first of its kind in Afar. The facility is designed to safely treat salinity, filter out impurities and harmful bacteria, and reduce the high temperature of the local groundwater, making it safe to drink.

The system will provide the first-ever sustainable source of safe drinking water for more than 2 000 people in the area.

AFRICA

Marshall Plan for water During World Water Week in Stockholm, Sweden, African water ministers and several NGOs launched a proposal for a ‘Marshall Plan for Water in Africa’ for the next decade, to guarantee that all Africans have clean water and safe sanitation in 2030.

In nearly all African countries, more than 50% of the population does not have access to at least basic water and sanitation services. “If countries invest in this sector, economies start growing quickly. Inadequate water and sanitation services create 780 000 deaths worldwide per year from diarrhoea and cholera – more than deaths from flooding, droughts,

epidemics, earthquakes and conflicts combined,” said Wambui Gichuri, director: Water and Sanitation, African Development Bank.

Total investments are US$40 billion (R587 billion) per year. African governments and consumers will finance 50% of this, while the other half will be funded by donors, banks and private companies, including climate adaptation funds. This water plan fits in the broader ‘Marshall Plan with Africa’, proposed by German Federal Minister of Economic Development Gerd Müller to create jobs, economic growth and rule of law.

“Current global water and sanitation finance is $16 billion (R235 billion) per

year, but investments needed to realise the UN SDG 6 water goals for 2030, signed by 190 countries in 2015, are $114 billion (R1.67 trillion) –six times more; a huge finance gap,” said Gustavo Saltiel, global lead: Water Supply and Sanitation, World Bank.

According to a World Bank report, of the $114 billion overall cost estimates, subSaharan Africa accounts for 31% of the global costs of reaching the goals (over R520 billion per year). For Northern Africa, $4.2 billion (R61.7 billion) is needed, adding up to $40 billion for the Marshall Plan with Africa.

The Marshall Plan for Water was applauded by the global water community in Stockholm and it was proposed that AMCOW and the AU take the lead in drafting the Marshall Plan for Water, and to publish sector finance plans for the next decade by African governments, utilities and consumers – capitalising up to $20 billion (R294 billion) how other actors can contribute to financing

President Uhuru Kenyatta of Kenya has cancelled the construction of the KSh22.2 billion (R3.14 billion) Kimwarer Dam.

Word from around Africa – including the latest industry, project and development news.

LESoTHo

LHWP tunnels shut down for maintenance

Water transfers from Lesotho to the Vaal River System have been shut down from 1 October to 30 November 2019 for routine maintenance on the Lesotho Highlands Water Project (LHWP) assets.

The Lesotho Highlands Development Authority (LHDA), together with the Trans Caledon Tunnel Authority (TCTA), is conducting routine inspection and maintenance works on the water transfer and delivery tunnels. The current inspection and maintenance follow up

on the works undertaken in 2012. The focus is to ensure continued sustainable operations and service of the tunnels and all electromechanical components from the Katse intake tower, through Muela power station to the Ash River outfall.

The LHDA will also install new, state-of-the-art water flow meters at Ngoajane flow measuring station and replace the valve at the Muela hydropower station bypass.

The TCTA is undertaking routine inspection and maintenance work on the South African side.

ZIMbAbWE

Assessing cholera and typhoid readiness

The Zimbabwean Ministry of Health and Child Care, in partnership with the World Health Organization, has embarked on an exercise to assess the preparedness of health institutions to fight cholera and typhoid in the event of an outbreak.

The assessment, which was undertaken in all 10 provinces in the country, seeks to determine readiness to effectively implement the national cholera emergency plan, and to pave the way for the implementation of corrective measures.

A cholera outbreak and emergency preparedness

and response plan was developed in February 2019. The plan identified key activities, materials and supplies that would ensure effective coordination for cholera prevention and response activities, timely detection and investigation of any suspected cholera or typhoid case.

The upcoming rainy season puts Zimbabwe at an increased risk for cholera and typhoid outbreaks. Although Zimbabwe last recorded a cholera case in March this year. Last year around 50 people died from cholera in Harare and parts of the Midlands as a result of water challenges.

Because water transfer had to be stopped to allow workers access to the tunnels, Lesotho will not be generating its own electricity during this period but will rely on supply from Eskom in South Africa and the EDM in Mozambique. The first part of the operation (the repair work on the Katse intake) commenced on 19 September 2019 while water delivery and hydropower generation stopped at midnight on 30 September 2019. The electricity generation for Lesotho and the water delivery to South Africa will resume at midnight on 30 November 2019.

MoZAMbIquE

Deadline set to end water crisis

Mozambican Minister of Public Works Joao Machatine has announced that the problem of water shortages in the Greater Maputo area will be solved by August 2020. Since 2015, drought has led to Maputo’s main water source, the Pequenos Libombos Dam on the Umbeluzi River, reaching dangerously low levels, resulting in water supply restrictions.

The government has since constructed a 95 km pipeline from Corumana to the water distribution centre in the Matola neighbourhood of Machava, as well as a new water treatment

station on the Sabie River. Boreholes have also been drilled in outlying Maputo neighbourhoods and smallscale water systems repaired. Construction on a larger treatment station on the Sabie is under way and expected to be completed in August next year. This will double supply from Corumana to Maputo to 60 000 m3 a day.

This, together with other sources, is expected to deliver 350 000 m3 of water a day to Maputo, which Machatine believes will result in constant water supply to the Greater Maputo area.

95 km pipeline

The government has since constructed a 95 km pipeline from Corumana to the water distribution centre in the Matola neighbourhood of Machava, as well as a new water treatment station on the

Sabie River.

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World Toilet Day 2019 Leaving no one behind

Atoilet is not just a toilet, but a life-saver, dignity-protector and opportunity-maker.

World Toilet Day 2019 draws attention to those people being left behind without sanitation and the social, economic and environmental consequences of inaction.

Alarmingly, children under the age of five living in countries affected by protracted conflict are, on average,

nearly 20 times more likely to die from diarrhoeal diseases caused by a lack of safe water, sanitation and hygiene as opposed to direct violence.

Inspiring action is needed to tackle the global sanitation crisis and achieve Sustainable Development Goal (SDG) 6, which promises sanitation for all and an end to open defecation by 2030.

Sanitation is a human right. We must expand access to safe toilets and leave no one behind.

4.2 billion people

4.2 billion people live without safely managed sanitation – more than half the global population

673 million people 673

2

people

Making school sanitation work

Between 2014 and 2016, Partners in Development (PID) conducted a study evaluating rural school sanitation in the South African provinces of the Eastern Cape, KwaZulu-Natal and Limpopo. One key finding: infrastructure without a management system will fail.

Rural school sanitation in Sa

The Department of Basic Education (DBE) is responsible for implementing school infrastructure, including toilets. But once installation is complete, it becomes entirely the school’s responsibility to manage sanitation infrastructure. “If the school cannot do that, the toilets will fail,” says Jeanette Neethling, engineer, PID.

“Once infrastructure has failed, the schools often deem it completely unusable and wait years for the DBE to come back and build new toilets.

Many schools in South Africa have ‘toilet graveyards’, which can include two to four toilet systems that have at some point failed,” she explains.

“We’re giving all of that management responsibility to schools that don’t have the capacity or the skills to manage it. This is vital when we look at projects like the SAFE initiative, which seeks to roll out toilets to schools with inadequate sanitation. We need to safeguard that investment by investing in

capacity-building for management at the school level,” Neethling stresses.

This management is important for both dry and wet sanitation systems. Although many schools are under the impression that you cannot clean ventilated improved pit latrines (VIPs), there are many disease hot spots that need to be cleaned regularly to maintain dignity and health.

Management also includes monitoring, which is very important for VIP systems to ensure there are no further tragedies that lead to the deaths of children. Moreover, Neethling points out that flush toilets with blockages and leakages are far worse than a VIP toilet because they quickly become unusable to learners.

School sanitation management model

The previous study resulted in the creation of the SchoolSanitationManagement Handbook . This provides schools with a breakdown of what is required for managing sanitation, particularly:

• WHY toilets should be made a priority

• WHAT needs to be done to ensure decent toilets

• WHO has a responsibility for managing school toilets

• HOW you can meet the requirements effectively and sustainably.

This model was piloted at seven schools around Pietermaritzburg for seven months. The pilot project included the training of cleaners and management personnel, supply of materials, ongoing monitoring and support, and closing workshops to get

Despite government’s focus on the roll-out of sanitation at schools, research shows that the infrastructure is doomed to fail without proper management.

By Danielle Petterson

feedback from participants.

Support mainly involved monthly visits to each school to help them problem-solve and collect information on the use of supplies, cleaning protocols and how people were beginning to work together and share responsibilities.

“There is often not a clear division of responsibilities, so it all lands on one person or no one at all,” explains Neethling. However, there are six important stakeholders involved in managing school sanitation infrastructure:

1. Health and safety officer (HSO), e.g. school cleaner

2. Health and safety manager (HSM), e.g. staff member that acts as a bridge between the HSO and principal

3. Principal

4. School governing body (SGB)

5. DBE

6. Learners.

A successful school sanitation model will have multiple links between all stakeholders so that everyone feels

example: School 1

School 1 had a major problem: no HSO. The school cleaner, who was employed by the DBE, claimed that it was not in her job description (which the school did not have a copy of) to clean the toilets. This was made worse by behavioural issues among the learners.

The school had managed to hire a dedicated cleaner for the toilets, but could only finance this for a few months. However, the school’s private security company got involved in monitoring the toilets, leading to a decrease in behavioural issues. The HSM also got very involved with educating learners and encouraging the principal to resolve the HSO issues.

“Although this was one of our less successful schools, there was an increase in linkages between the stakeholders, and I have hope for this school,” says Neethling.

example: School 2

Although School 2’s sanitation management was in a better state, the cleaner was only cleaning the toilets once to twice per week. The cleaner also reported that the school regularly did not have enough cleaning materials, partly due to a failure of the SGB to make funds available.

By the end of the programme, the SGB was making funds available for cleaning materials, and the HSO was reporting directly to the principal about what cleaning materials he needed. The HSO also adjusted his cleaning protocol so that he was deep cleaning the toilets twice a week and cleaning disease hot spots daily.

example: School 3

The big problem at School 3 was learner behaviour. The HSO was also very timid and therefore often not inclined to report problems to the principal. In this case, the HSM got very involved and bridged the gap between the HSO and the principal, resulting in the three stakeholders working very well as a team to address any issues. The HSM also got learners involved in monitoring the toilets, leading to better learner behaviour.

“This example shows how the programme really empowered the HSO who, in the end, felt better equipped to do his job with support that he had not had before,” says Neethling.

supported on multiple levels.

“What is really great is that this model raises the profile of the school cleaner and gives them additional responsibilities. They’re not just a cleaner, they are also responsible for educating learners, monitoring and many other skills,” says Neethling.

Key take-aways

The pilot project has led to a partnership with Unilever and the DBE, and the sanitation management model has been updated based on the outcomes. Following this, the model was

infrastructure after we engaged with them.

Just putting sanitation on people’s radar gets them to realise how important it is,” says Neethling.

PID has also created a sample budget for managing school sanitation (Table1), which comes to R20 per learner per year – only 2% of the budget for the

Following engagement with the schools, it became clear that there are a number of key factors for good sanitation management at schools, particularly:

• training and empowering school cleaners (HSOs)

• availability of the right materials to do the job

• staff support for the HSO, including monitoring of learners.

Neethling stresses: “Everyone in this chain needs to be more proactive than reactive.”

poorer schools that get the most funding from government, which is roughly R1 000 per learner per year. “When we present these figures, it is very empowering to schools because it is manageable,” says Neethling.

“We believe this programme should be adopted by the DBE, especially where it is employing cleaners, and should be providing annual training for school cleaners and health and safety committees. There are also a lot of opportunities for school franchising, and entrepreneurial approaches to school sanitation management should be encouraged.”

Changing perceptions

removal of microorganisms and emerging contaminants

• to optimise the treatment train and configuration

Umgeni Water is in the process of establishing a 2 MLD fullscale recovery plant at its Darvill Wastewater Treatment Works. By

Danielle Petterson

Given South Africa’s increasing water stress, wastewater reuse is becoming a necessity; however, it is

problematic to implement due to public perception. In fact, without public buy-in, direct reuse projects are unlikely to get off the ground.

With water sustainability in mind, Umgeni Water is establishing a 2 MLD reuse demonstration plant at the Darvill Wastewater Treatment Works (WWTW), which is currently undergoing an upgrade from 65 MLD to 150 MLD.

The reclaimed water plant will be fed from the WWTW’s normal activated sludge process. The final effluent will then go through a conventional water treatment process, followed by an advanced treatment process. The advanced treatment process has a flexible configuration that will allow interchangeability between ultrafiltration and activated carbon filters, while undergoing an advanced oxidisation process using ozone and peroxide.

The final product will initially be used as process water but will be treated to potable water standards and subsequently monitored in line with the appropriate international reclaimed water standards.

Umgeni Water has four technical aims it hopes to achieve with the demonstration plant:

• to investigate the effectiveness of the treatment train for the

• to assess life-cycle costs and apply findings on a full scale

• to develop plans for operation, maintenance, monitoring and public engagement.

Winning over the public

Key to the success of the project is achieving public buy-in to reclaimed water for potable purposes. According to Megan Schalkwyk, process engineer, Umgeni Water, this requires improving public trust in the entity delivering the water, together with an education and awareness programme. “Studies show that our municipalities need to increase the consistency and quality of our service delivery so that people can start trusting us to deliver clean reclaimed water,” she says.

A US study found that there are seven key areas to address to successfully implement reclamation projects, namely:

1. Changing normative associations –associate water reuse with positive applications, focusing on the use of the reclaiming water and not the source.

2. Constructing normative networks – look at water quality and infrastructure.

3. Mimicry – make the reclaimed water mimic ‘normal’ water, such as that from surface sources.

4. Educating – educate people on the terminology and be transparent about results.

5. Valorising and demonising – popularise reclaimed water with, for example, celebrity endorsements.

6. Mythologising – show historic good performance.

7. Imagery – associate reclaimed water with positive images. These points have informed Umgeni Water’s strategy to address public perception around reuse.

Umgeni’s approach

“Previously, reuse plants in South Africa have been implemented during severe drought and people had two choices: drink it or go thirsty. Now that the drought has eased up, we need to look at other ways of getting public buy-in. Unfortunately, people have had an aversion to reclaimed water for years and reuse plants in other parts of the world have been canned as a result,” says Schalkwyk.

Umgeni Water’s education and awareness strategy will target children, tertiary students, nurses, medical practitioners, as well as municipal and government leaders. “These are the people that have the most influence on our communities. A study in Beaufort West found that children change the mindsets of their parents and influence communities, as do political leaders,” she explains.

In a bid to increase public interaction, a learning centre has already been constructed on site at the Darvill WWTW, where Umgeni Water will invite the public

to learn more about water recovery, look at the treatment works in process, and interact with the units. External stakeholder engagements will be held in November 2019, followed by a water recovery masterclass initiative, which will be introduced in 2020.

“Our demonstration plant is an opportunity to establish a learning platform, which - besides educationwill aid in the research that is needed – we still have a long way to go before we fully understand all the different aspects related to reclaimed water,” says Schalkwyk.

Umgeni Water will lead this initiative over the next five years in the hopes of creating a national learning platform in South Africa. Annual national forum sessions will be utilised for engaging all stakeholders and slowly desensitising people to various issues and explaining strategies that are in place by Umgeni Water and the research team. These forums will also help to collate national information to prevent silos for forming.

SA municipal wastewater reuse can learn from international trends

A report by Herman Smit* on the 34th Annual WateReuse Symposium in San Diego, California

*Herman Smit is the managing director of Quality Filtration Systems, based in Cape Town, South Africa – herman@ qualityfilters.co.za.

“Water and air, the two essential fluids on which all life depends, have become global garbage cans.” - Jacques Cousteau

South Africa is in a water crisis and wastewater reuse, desalination and potable water quality are top of the agenda. Where will our future water be sourced?

Different water sources become viable solutions for the drought with advanced treatment technologies used for the augmentation of conventional water sources with reuse and desalination. We need to plan how to use our water to its maximum potential, and follow the international trends in water reuse and change the paradigm of water and wastewater management, which aims

and accelerating the natural process of cleaning the water to make it suitable for its intended purpose, from irrigation to industrial uses to drinking. While the science is clear that recycling water is safe, misinformation has contributed to community resistance for water reuse projects,” stated Paul Jones, president of the WateReuse Association.

The WateReuse Symposium creates the ideal platform to engage with municipalities, service providers and technology suppliers to promote the acceptance of recycled municipal wastewater. Acceptance starts with education, which is shared through the

‘Decentralised Reuse: The future of distributed infrastructure’. Commercial buildings can capture and treat water generated from within or around a building for beneficial use on site.

The US has many pilot facilities that are researching the quality of different process trains for the reuse of municipal wastewater. A developed economy like the US is spending a tremendous amount of money on research in universities as well as on large-scale pilot plants at municipalities. South Africa can use these results beneficially and design a system based on the findings of the US institutions. Unfortunately, South Africa cannot rival

process was chosen for the full-scale facility with similar capital values but a reduced operational cost on a year-to-year basis.

Andrew Salveson from Carollo Engineers presented the ‘Demonstration Facility: Innovative Potable Reuse Technologies for Pismo Beach’. The droughts in California highlighted the vulnerabilities of the region’s water supply portfolio. Recycled water was identified as the most effective augmentation supply option (see Figure 2).

The benefits of a demonstration plant include promoting engagement with the public, demonstrating the technology and optimising engineering. A thorough 12-month test regime will help drive the design and provide new research for the potable reuse industry.

The process was operated without chloramines to determine if this process can reduce the formation of NDMA and improve economics. Using no chloramines nearly eliminates NDMA formation but maintains post-RO UVT. UF membrane fouling must be considered without a disinfectant dose before the UF membranes. Chemical enhanced backwashes might be considered with biological fouling. Microbial reduction after the UF membrane is an essential test for the success of the downstream process and showed a positive result during the trial operational period (see Table 1).

Toilet-to-tap – Get over it!

Patricia Tennyson from Katz & Associates

challenged the notion that we are too sensitive for the ‘yuck’ factor associated with wastewater reuse. Properly treated wastewater is a valuable source of water to augment traditional surface water. Considering that the reuse of wastewater could mitigate water scarcity in drought

water, advanced purified water, purified potable water, highly purified water and water purification project (Sources: OCWD, Pure Water Monterey, PureWater Soquel, Padre Dam, Pure Water San Diego, PureWater Colorado).

A strategy is required to change the misconceptions associated with wastewater reuse, which includes:

• prioritising understanding the community that will be using the water, which will also determine the terminology used

• forging partnerships in the community to communicate your positive message and education around water

• using expert endorsement for the process and safety of the final water

• making the facility accessible for tours and public visits

• reaching out to the public with community days, bottled water and presentations

• using images to your advantage and engaging the media early

• using social media as a marketing tool.

areas, we should make sure the public is educated and informed about the facts related to wastewater reuse.

Tennyson advocated that everyone in the water industry should help to stop the media from using terms and headlines that create negative perceptions around wastewater reuse.

A 2014 water research study in the US investigated a model to communicate plans for increasing awareness and fostering acceptance of potable reuse. Recommended nomenclature, deemed more acceptable, was purified water, drinking water, pure new water, renewed water and pure water.

Phrases already being successfully used in the US for current projects and pilots are advanced water purification, purified

What is happening in South africa?

It was valuable for QFS to get exposure to leading technologies and the studies on wastewater reuse in the US. We must learn from their in-depth studies to make sure of the safe production of final potable quality water from wastewater, making use of tried and tested process trains with state-of-theart technologies.

The good news is that plants installed in South Africa using the same technology referenced in the presentations have successfully been used in Beaufort West, Ballito and De Doorns Valley. A process train of screening, UF, RO and UV AOP has proven to be the most reliable solution in South Africa, and is confirmed by the US studies.

South Africa needs a robust and proven solution to make sure we build a reputation for successful water reuse, which will be part of the solution of providing water security to a drought-ridden South Africa. We are on the right track to establish wastewater reuse as a safe and viable augmentation solution for every town and city in South Africa.

FIGurE 1 The two process trains tested by the City of Jacksonville, Florida

FIGurE 2 Water recycling process for Pismo Beach, California

TABLE 1 Microbial reduction after UF membrane treatment at Pismo Beach, California

The cycle of solutions –water technology by KSB

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Powerful process technology

The mobile plant was equipped with an automatic self-cleaning TwistFlow Strainer as pre-filter, a 25 µm self-cleaning AutoFilt as main filter, with a 1 µm inline process depth filter as final polishing filter.

Upon receiving a request from the client, Hydac deployed this mobile plant on the Jukskei River near Lanseria, to test the suitability of its filtration technology for an upcoming project. Following a positive outcome after sampling, the client commenced with the feasibility study of a 250 m³/h water plant based

In 2014, Hydac Technology developed an 8 m³/h mobile water plant to demonstrate the effectiveness of the company’s OEM process technology equipment.

on the same set-up as the mobile plant for research and development (R&D) purposes.

Key performance indicators (KPIs) were a turbidity of 0.5 NTU and a filtrate throughput upwards of 96% of influent. In collaboration with the client, two dosing stations and a flocculation manifold were added to the design.

In 2018, Hydac was awarded the contract to design and build the R&D plant. Full operational wet FAT was conducted at Hydac’s Johannesburg works. The new R&D plant was installed adjacent to an operational traditional

multimedia filtration plant and the Hydac installation team followed through with successful commissioning on site. Water is now supplied to a disinfection station before distribution to the local community.

Features of the new R&D plant include automated system control and feedback via human-machine interface (HMI), monitoring of all parameters, trends and KPIs, real-time filter condition feedback, automated dosage control, bio-fouling indication, and auto bio-cleaning. The client monitors the plant via access from the HMI through off-site SCADA.

We focus on water, so you don’t have to.

Nafasi Water specialises in mine water treatment to aid in successful active mining, and mine closure requirements. formerly

Introducing Nafasi Water

Following its sale, established water treatment company Aveng Water will now be known as Nafasi Water.

Aveng Water was recently bought out of the Aveng Group by Infinity Partners, owned by Suzie Nkambule and E-Squared. Now in the process of rebranding to Nafasi Water, the company retains its expert capabilities and remains true to its goal of preserving sub-Saharan Africa’s water while ensuring access to alternative sources for potable and industrial use.

Building on strong foundations

With a focus on water reclamation and desalination technology for application in complex industrial and wastewater systems, Nafasi Water began a journey in 2003 to develop, implement and operate world-class industrial desalination projects.

As a 100% black-owned leading South African water technology and water utility service company, Nafasi Water partners with industry, government and local communities to provide sustainable solutions to broader water security challenges. Combining innovative technology with the funding and delivery of world-class water and wastewater treatment projects and services, the company aims to sustainably reclaim water affected by industrial and human activities. With considerable experience in the design, construction, commissioning and operation of complex water treatment plants, the company boasts three largescale water treatment plants under its O&M division. These include the eMalahleni and Middelburg Water Reclamation Plants, along with the flagship Erongo Sea Water

Desalination Plant in Namibia. Nafasi Water was also responsible for the construction and former operation of the Optimum Water Reclamation Plant.

expert capabilities

Nafasi Water provides consulting and contracting services for the mining, municipal and industrial water sectors, specialising in the design and engineering of treatment plants for:

• seawater desalination

• industrial effluent treatment and reuse

• municipal water and wastewater reuse

• water supply for power generation infrastructure.

For the treatment of mine water, Nafasi Water has developed a unique, internationally recognised product called HiPRO. With this, Nafasi has pioneered the application of reverse osmosis (RO) to treat mine water and achieve ultra-high water recoveries of 97% to 100%.

The HiPRO process achieves its high water recovery through the use of multiple stages of ultrafiltration and RO membrane systems, operating in series, and with interstage precipitation of low-solubility salts. This is applied without the expense of evaporators and crystallisers typically used in the final concentration step. The result is a very small brine stream that can be further treated or discharged into a lined evaporation dam.

Not only does HiPRO produce SANS-quality drinking water, it boasts lower capital and operating costs than other technologies and the recovery of potentially useful by-products.

operations and maintenance

Nafasi Water has the commercial experience and capability to offer project financing as build, own, operate (BOO) and build, own, operate, transfer (BOOT) contracts.

As leading providers of complete water treatment solutions, Nafasi Water offers a cost-effective water management service, which includes water analysis, utility management, audit and condition monitoring, routine maintenance and equipment renewal.

The company’s unique Sigma Ops monitoring and control system adds to its O&M capabilities, allowing Nafasi Water to extract the longest possible operational life from membranes, even with very difficult to treat feedwater.

Partner of choice

“Nafasi Water is a partner of choice for municipalities and organisations in search of full-scale water and wastewater treatment solutions,” says Suzie Nkambule, CEO, Nafasi Water.

“We partner closely with our clients to ensure we add value by developing local capacity through skills transfer. We are proud to be a business that contributes meaningfully to the sustainable development of the geographic markets in which we operate.”

info@nafasiwater.com

Nafasi Water has reclaimed over 160 billion litres of water affected by coal mining activities in Southern Africa

billion

AWater scarcity and pollution drive wastewater management

With global demand for quality water increasing at a rate inversely proportional to actual supply, the need for processes and systems that enable testing and purification becomes even more important.

world’s population will face severe water shortages, with ecosystems around the world under even greater strain.

lthough water makes up 70% of the planet, fresh water is incredibly rare. Only 3% of the world’s water is fresh water, and two-thirds of this are found in frozen glaciers or is unavailable for use or consumption by people.

Compounding this is inadequate sanitation. Some 2.4 billion people are exposed to waterborne diseases such as cholera and typhoid fever, with two million people (mostly children) dying each year from diarrhoeal diseases alone.

Many of the water systems that keep ecosystems thriving and feed a growing human population have become stressed. Rivers, lakes and aquifers are drying up or becoming too polluted to use. More than half the world’s wetlands have disappeared. Agriculture consumes more water than any other source and wastes much of that through inefficiencies. Climate change is altering weather and water patterns around the world, causing shortages and droughts in some areas and floods in others. By 2025, two-thirds of the

The widespread water quality degradation across the world is the most serious water problem, threatening human health and ecosystems’ integrity. It also represents a major concern for water resources sustainability. New water quality challenges, such as emerging pollutants and safe wastewater reuse, bring even greater concerns, calling for urgent attention.

Water quality, due to its serious human health and environmental impacts, represents a crucial but often neglected aspect of water resource management. Primary causes of water pollution are rapid urbanisation, increased agricultural activities, the use of fertilisers and pesticides, land degradation and

We look at the four biggest wastewater treatment problems and their solutions

deforestation, and the lack of adequate wastewater treatment and disposal. Poor water quality not only negatively affects

human health and ecosystems in multiple ways, but also makes water unfit for different uses and purposes so reducing the availability of water resources. As water treatment technologies are often expensive, wastewater management is inadequate or non-existent in most developing countries. Urgent action is needed to improve water quality and wastewater management.

We look at the four biggest wastewater treatment problems and their solutions below.

Problem 1: energy consumption

Energy consumption is one of the largest expenses in operating a wastewater treatment plant. Wastewater treatment consumes an estimated 2% to 3% of a developed nation’s electrical power, or approximately 60 terawatt hours (tWh) per year. In municipal wastewater treatment, the largest proportion of energy is used in biological treatment – generally 50% to 60% of plant usage.

Solution? Changes in biological treatment processes have the potential to significantly reduce a treatment plant’s energy demand, e.g. using fine screens in primary treatment, membrane technology for the aeration process, and the direct treatment of high-concentration return streams.

Problem 2: Staff requirements

Operators of wastewater treatment facilities must be adequately trained and certified. They are on call 24 hours a day and are responsible for overseeing everything from pipe leaks and valves to electrical and instrumentation equipment. This work becomes especially demanding during changes in influent and seasonal changes.

Solution? While there will always be a need for the physical presence of staff to be responsible for the overseeing of activities at treatment facilities, operator management can account for up to 30% of the operational costs of a wastewater treatment plant. Emerging technologies driven by reducing operational expenditure are utilising the benefits of automation, which reduces the requirement of operator engagement.

Problem 3: Sludge production

Sludge is the residue generated during physical, chemical and biological treatment. A major environmental challenge for wastewater treatment is disposing of the excess sludge that is

produced during the process.

Solution? Safe and long-term solutions for the destination of sludge produced by wastewater treatment plants are vital to a functional facility’s sustainability. The best solution for this is to recycle the sludge, which contains useful organic matter and nutrients, for use in agriculture. Some more modern treatment technologies are even able to reduce the burden of sludge, through lowering its production.

substantial land areas. Primary and secondary processes rely upon vast tracts of land for large and costly settling tanks and aeration basins. Due to continual population growth, municipal wastewater treatment plants also need to expand their capabilities.

Problem 4: footprint demand

Activated sludge treatment has many challenges, and one of the biggest is the footprint it demands. Activated sludge plants are costly to construct and occupy

Solution? Advanced technologies that use smaller process basins – by increasing the amount of biomass per unit volume via the addition of media for biofilm attachment or increasing the biomass concentration (such as MBR) – are leading the way in reducing site footprints. A smaller footprint means land cost savings, but also means reducing capex (less concrete, steel and equipment for construction).

How to perfect filter performance

Prompted by a baffling number of cases in which filter manufacturers are called upon to resolve filter problems that are easily prevented, industrial and municipal filtration specialist Superior Filtration conducted surveys among designers and end users of industrial plants.

Focusing on filtration system efficacy, the aim of the survey was to better understand the habits, needs and

The surprising results of a recent survey reveal the astonishing extent of easily prevented poor filter performance and filter failure.

frustrations of end users, as well as design engineers, project managers and consultants who provide industrial and municipal filtration solutions for water processing and industrial production environments.

Respondents used the full variety of filter types for inbound filtration to ensure clean

GrAPH 1 Have you ever found that a filter didn’t work as well as it might have – or even at all? What are the reasons?

2 Should design engineers or project managers consult widely with filtration experts or manufacturers to determine the correct filtration solution for each application before specifying a solution or provider?

water flowing into the plant, outbound filtration to ensure non-polluted water is returned to municipal systems or rivers, or for recycling and reuse inside the plant.

Shocking findings

The surveys revealed the astonishing extent of poor filter performance and the high level of filter failure across industries (see Graph 1).

These diagnostic or specification errors lead to excessive maintenance, unnecessary management oversight, and ultimately to more plant stoppages and higher costs.

Most, if not all, of these problems could be easily have been avoided if the correct diagnostic process had been carried out before the filtration type was decided upon and the specs drawn up.

a simple solution

Respondents further revealed the startlingly simple solution to prevent poor filter performance and filter failure: consulting more with experienced filtration specialists in the design stage regarding the variables specific to the filtration problems, as well as the specifications for filter types and sizes. Variables include, for example, variable quality water inputs, the required water quality output, the degree of automation, and the maintenance requirements.

In fact, 96% of end users and 94% of design engineers agreed that there should be consultation with original equipment manufacturers (OEMs) before filters are specified. But despite this, a surprising number admitted that OEM filter manufacturers are not consulted before they specify filters.

GrAPH

The significant difference between theory (Graph 2) and practice (Graph 3) certainly sheds light on a major possible contributor to poor filter performance and filter failure that exists, which could have been prevented easily.

The good news

The research results confirm the simple solution: a greater level of consultation between OEM filter manufacturers and the designers and end users of industrial filtration systems will result in the better diagnosis of requirements and accurate specification of filters. This in turn would eliminate excessive maintenance, management oversight and plant stoppages, while reducing risk, downtime and costs.

Respondents overwhelmingly indicated that they would engage with an experienced filtration specialist able to diagnose the cause of their filtration problems.

GrAPH 3 How often in your experience is consultation and advice from filter manufacturers for the latest information/advice taken into consideration before filters are specified?

BMG’s extensive range of industrial slurry valves, which are designed to cope efficiently in harsh conditions, include robust butterfly and knife gate valves as well as diaphragm and pinch valves.

These industrial slurry valves –which meet stringent quality and safety specifications – are highly efficient for controlling and isolating abrasive slurries in many industries, including power generation, chemical and petrochemical, cement handling, water treatment, mining, quarrying, pulp and paper,” says Willie Lamprecht, business unit manager: fluid technology low pressure, BMG.

Failure of a valve and subsequent leaking of corrosive media can have devastating effects on the safety of personnel and equipment, which leads to premature system failure and costly downtime. It is critical that the correct valve is selected for every application, for maximum safety, ongoing operation of the plant and minimum unscheduled maintenance.

“BMG’s highly skilled team has a thorough understanding of the processes where valves are installed and supports every component with a dependable solutions service to ensure optimum safety, efficiency and the extended service life of each system. The selection of the correct industrial slurry valve is based on factors that include the size and shape of particles, pressure, temperatures and chemical content,” says Lamprecht.

Holistic product offering Polyurethane-lined knife gate valves are available from BMG in standard sizes between DN 50 and DN 600, with manual, pneumatic and electric actuation. These knife gate valves have a wafer pattern and are manufactured from cast and ductile iron with stainless

Slurry valves for the toughest conditions

steel discs. These can withstand operating temperatures of between -20°C and +80°C as standard, with higher temperatures on request.

Polyurethane liner abrasion-resistant butterfly valves – in a wafer pattern or with a lugged design – are used for on-off and control of abrasive slurries. Butterfly valves are available from BMG in standard sizes between DN 50 and DN 400.

Locally manufactured KLEP BMG diaphragm valves – between DN 50 and DN 350, with manual or pneumatic actuation – are designed for abrasive slurry applications. These flanged diaphragm valves have a body pressure of PN 10 and can withstand temperatures between -10°C and +80°C. Long-lasting rubber and jumbo rubber linings are suited for full-bore diaphragm valves with a high flow capacity and an efficient sealing capability, which shuts off any flow and prevents leakage. Full bore diaphragm valves also have a low pressure drop because there is almost nothing obstructing the flow of the fluid when the valve is fully opened. This creates little resistance to flow, which makes

these valves suitable for fluids with abrasive particles.

Also included in the range are unlined diaphragm valves suitable for water treatment and general industrial applications.

FPV pinch valves, featuring a design where the sleeve is pinched to close mechanically or automatically by means of hand-wheel or actuator, are ideal for the control and isolation of abrasive slurries.

Open frame pinch valves are available from BMG with a short and long frame design, in sizes between DN 50 and DN 600.

The body is made from mild steel, but stainless steel is also available for specific applications. These valves, with soft rubber sleeves, have manual, hydraulic and pneumatic actuation and can withstand temperatures between -20°C and +80°C.

BMG’s extensive range of components for fluid technology systems and general industrial applications encompass valves, hydraulic hoses and fittings, accumulators, cylinders, heat exchangers, pneumatics, hydraulic motors and hydraulic plumbing, as well as pumps and reservoir accessories.

The company also offers a total process and lubrication management solution to meet exact market requirements.

Developing PVC-O pipes and fittings

The manufacture of PVC pipes began in about 1935 and one of the early installations was the water supply system in the 1936 Olympic Stadium area in Berlin. In the intervening 85 years, PVC has undergone significant technical development, culminating in PVC-O (oriented polyvinyl chloride), which itself has undergone five developmental improvements in its 40 years of existence.

Blue PVC-U (unplasticised PVC) pressure pipes dominate the potable water reticulation market, sand-coloured PVC-U pipes dominate the sewer and drain market, and white PVC-U pipes the soil, waste and vent market. However, this article will concern itself exclusively with water pressure pipes.

determining strength

All thermoplastic pipes (PVC, HDPE, PP, PB and PVDF) are manufactured from a polymeric raw material. Every polymer has a unique characteristic: the polymer’s CRRC (creep rupture regression curves) is its ‘fingerprint’, which is determined by conducting many thousands of tests over many

PVC-O pipes are well established in the potable water reticulation market. Now, PVC-O fittings are completing the solution, offering inherently superior hydraulic characteristics that are tried and tested.

By Mike Smart*

thousands of hours and plotting the results on a log/ log graph. The plot is configured with the abscissa – X-coordinate or X-axis, which is the time to rupture in hours – and

the ordinate – Y-coordinate or Y-axis, which is the stress at rupture. The polymer’s ‘family’ of curves for various temperatures is plotted.

The ISO protocol requires the strength of the polymer used to design the pipe – the allowable design stress (σ) – to be determined by dividing the minimum required strength (MRS) of the 20°C CRRC at 50 years (438 000 hours) by the applicable C (design coefficient); i.e. σ = MRS/C.

Graph1shows the blue CRRC for PVC-O 500 (Classification 500), the orange CRRC for PVC-U and PVC-M, and the grey CRRC for PE100, which highlights an interesting point.

The CRRC for PVC-U and PVC-M is precisely the same line, with exactly the same MRS. However, σ = 12.5 MPa (25/2) for PVC-U and σ = 18 MPa (25/1.4) for PVC-M. PVC-M’s reduced C value is justified on the basis it exhibits ‘tough’ characteristics by being modified

GrAPH 1 Creep rupture regression curves

by the addition of impact modifiers that enhance its impact strength – it ‘behaves tough’. For example, PE100 has a low C value (1.25) because it is tough and ductile.

The CRRC for PVC-O 500 (TOM 500®) gives an MRS of 55 MPa at 50 years. To be a classification 500 PVC-O, this value cannot be less than 50 MPa. Note the regression curve for TOM 500 is still above 50 MPa at 100 years (876 000 hours) – the service life demanded by end users.

Be careful not to confuse the term ‘class’, which refers to the pipe’s pressure class (bar), and ‘classification’, which refers to the polymer’s MRS. There are five PVC-O classifications – i.e. 315, 355, 400, 450 and 500 – specified in SANS 16422: ‘Pipes and joints made of oriented unplasticised poly (vinyl chloride) (PVC-O) for the conveyance of water under pressure – Specifications’. The classification number is simply 10 times the MRS of the polymer – a common nomenclature system for all polymers; note PVC-U is actually PVC-U 250. The strength of PVC-O has increased by nearly 75% during its existence. Other attributes have also improved as shown in Diagram1 , which compares the blue regular hexagon of PVC-U 250 with the irregular grey hexagon of PVC-O 500.

SANS 16422 Annex A ‘Establishment of the minimum required strength (MRS)’ specifies it must be proven in accordance with ISO 9080 ‘Determination of the long-term

hydrostatic strength of thermoplastics materials in pipe form by extrapolation’ and ISO 12162 ‘Classification and designation – Overall service (design) coefficient’.

SANS 16422 Annex B ‘Minimum depth of engagement of sockets’ also ensures the adequacy of the joint considering Poisson’s contraction, temperature contraction, angular deflection, chamfer length and safety allowance. Furthermore, the standard ensures, inter alia, the pipe’s impact strength, ring stiffness and tensile strength, and the joint’s negative and positive pressure strength and end-load-bearing leak tightness.

developing PVc-o fittings

Until recently, PVC-O pipes relied upon fittings made of other materials to complete the pipeline system. However, a range of fittings made from PVC-O pipe has been available since 2017 in sizes of 110 mm OD to 400 mm OD and PN16 pressure

class, including a range of bends – 11.25 degrees, 22.5 degrees and 45 degrees –reducers, couplers and sliding couplers. The fittings are rated 16 bar, although the wall thickness is 25 bar rated pipe, with improved hydraulics due to the increased dimensions and inherently superior hydraulic characteristics of PVC-O.

The development of PVC-O fittings took four years, from 2013 when the idea was first promulgated to product availability in 2017. The four stages of the design process were as follows:

1. Design criteria determination – from the working requirements

2. Critical stress analysis – FEM analysis of critical areas

3. Allowable stretch rates – determine safe hoop and axial stresses

4. Fitting performance evaluation –laboratory and field tests.

Diagram2 shows the hoop stretch (blue line), the axial % (red line), and the product of these two (green line) provides the control mechanism for the fitting production process.

DIAGrAM

A typical fitting’s axial tensile strength is about 55 MPa and the circumferential tensile strength is about 93 MPa –approximately 1.7 times greater. This is a fundamental objective of the production process because the circumferential, or hoop, strength is the primary strength requirement of a pressure pipeline component that must resist the hoop stress induced in a pressure pipeline application.

The fittings are subjected to a rigorous testing regimen, in accordance with the applicable standards including, among

others, ISO/SANS 16422, ISO 13844, ISO 13845 and ISO 1167-1, -2 and -3, which ensures it will deliver not less than its designed service life. Furthermore, the assembly of the fitting with the pipes is also tested to ensure the same. The current range of fittings has been

26

Nagington Road, Wadeville, Germiston 1400, South Africa

Tel +27 11 824 4810 / Fax +27 11 824 2770

E-mail info@apepumps.co.za / info@matherandplatt.com Website www.apepumps.co.za / www.matherandplatt.com

Split Case Pump

• Sugar and Paper Mills

• Refineries

• Petro Chemical

used on projects in the Eastern Cape, Free State, KwaZulu-Natal and Limpopo. In the first quarter of 2020, 90-degree bends will be available, and the fitting range will be extended beyond 400 mm OD.

*MikeSmartistheownerof GenesisConsulting.

DIAGrAM 2 Hoop and axial stretch rates

Optimising multistage performance

High-head pumps play a critical role in areas like bulk water delivery, which makes selecting the right product equally important.

AProudly South African company, Mather+Platt and its group company

APE Pumps are original equipment manufacturers (OEMs) with a product history in the local market dating back to 1952.

Mather+Platt manufactures horizontal multistage pumps designed for highpressure applications, and split-case pumps chiefly for high volumes. In turn, APE Pumps specialises in the design and manufacture of vertical industrial turbine pumps, split-case and end-suction pumps for most industries. APE Pumps and Mather+Platt also provide an installation and commissioning service. All products are designed, cast and assembled in South Africa.

What sets them apart is their ability to devise standard and custom-designed solutions across the entire fluid transfer spectrum. Within the public sector, this includes bulk water transfer systems for municipalities and utilities. Here, Mather+Platt leads with its PL/PJ range of multistage centrifugal pumps.

High-head

duties

These pumps, available either in horizontal or vertical configuration, are designed for a wide range of high-head duties at sustained highest efficiencies. This makes them particularly well suited for applications that include high-lift mine drainage duties, mainline water supply, and high-pressure boiler feed pumps operating at elevated temperatures. They feature a heavy-duty, ring-section design and robust fabrication.

Incorporating the latest hydraulic design principles, the materials used in their construction are selected to ensure the compatibility of rotating and stationary wearing parts, combined with high corrosion and erosion resistance. The end result is prolonged life, sustained efficiency and low maintenance costs.

High heads are achieved at standard direct coupled motor speeds of 1 480 rpm for PJ pumps and 2 960 rpm for PL units, both generated via a 50 Hz electrical supply. These pumps are also suitable for operation at other speeds, including those applying when directly coupled to 2- or 4-pole motors fed by a 60 Hz supply. A key benefit of these pumps is their relatively compact size and energy savings.

The PL/PJ system design further allows for direct drive from power recovery water turbines of the Pelton wheel type and for direct or indirect drive from virtually all other alternative forms of prime mover.

“Every project and installation has its unique requirements and we have the in-house design and

engineering expertise to devise the optimal pump and process match,” says John Montgomery, general manager, APE Pumps and Mather+Platt. “That includes the need for ease of access during routine maintenance.”

On these pumps, the bearing brackets and bearing bushes are designed with a horizontal split along the centre line. The main advantage is the ability to strip the bearing assembly without disturbing the alignment of the element, and without having to remove the pump, half coupling or driving unit. Additionally, the bearing brackets are supported at the top and bottom, thereby avoiding distortion of bearing bush/shaft alignment when the pump is under pressure.

The balance valve assembly is designed to enable the wearing parts to be replaced at minor cost. The stainless steel balance valve head will never have to be replaced, since it’s provided with a separate wear face.

“This is one of a series of examples of how how durability and practicality are built into our PL and PJ series,” Montgomery concludes.

www.matherandplatt.com

A Mather+Platt PJ250H five-stage horizontal pump

The PJ250AS vertical five-stage model manufactured by Mather+Platt

Plastic not all bad

Although the use of plastic packaging has come under harsh criticism by environmentalists and the public alike over the past year, it is important to recognise that not all plastic is bad for the environment. It is an extremely useful product that is used with great success in pipelines, appliances, cables, computers, etc. to reduce manufacturing costs, improve performance and reduce mankind’s impact on the environment,” Jan Venter, CEO, SAPPMA, told delegates at the recent PIPES XII Conference.

Benefits of plastic piping systems

- Corrosion resistance

- Excellent hydraulic properties throughout its lifespan, resulting in no increase in pumping energy over time

- Ease of transport and handling, due to lower mass

- Efficient jointing methods, enabling leak-free pipelines

- Available in long lengths, reducing the number of joints

- Flexibility, toughness and high impact resistance

- High resistance to abrasion

- 100-year service life

- Low embedded energy

- Thermoplastics and fully recyclable

Venter cited several positive properties associated with plastic, including a clean manufacturing process, being relatively light on the environment, and being recyclable.

The need for plastic pipes

As Venter pointed out, reliable pipelines form the backbone of a country’s infrastructure – a fact highlighted by South Africa’s recent scarcity of water and electricity. Dependable water and sanitation services are essential, and South Africa’s annual spend on each amounts to R42 billion and R13 billion, respectively. Moreover, the country requires an investment in water and sanitation infrastructure of R90 billion per annum over the next 10 years.

This offers huge potential to the plastic pipe market, which has captured more than 60% of the local market in water distribution and more than 90% in sewage disposal. According to Venter, plastic pipes offer many outstanding properties in this regard, including flexibility, toughness, corrosion resistance, ease of handling, suitability for trenchless applications, and long-term hydraulic properties.

The plastic pipe industry now enjoys a dominant footprint in most countries. In South Africa, the market grew by 22% over the past seven years in order to deliver the infrastructure needed to support a growing population.

Continuous research and development coupled with advances in polymer

Plastic has gotten a bad rap for being damaging to the environment; however, plastic is also an extremely versatile material that has an important role to play in the water space.

technology have made plastics an ideal choice for pipelines. “Yes, it’s plastic, but it’s in a totally different league,” said Venter. The global market for plastic pipes sits at US$30 billion (R444 billion), with strong growth in the demand for largediameter pipelines.

Quality assurance

Provided 100% virgin polymers from certified manufacturers are used, modern plastic pipes can achieve lifetimes of more than 100 years. However, even small percentages of post-consumer polymer in the raw material mix can have detrimental effects on the quality of pipe and severely reduce its life expectancy.

Not only is it very difficult to visually detect poor-quality pipe, but it is physically impossible for any inspection authority to scrutinise every metre of pipe going to market. However, SAPPMA offers quality assurance to the market by subjecting its members to considerably greater scrutiny. Strict standards must be met to achieve the SAPPMA mark of approval, which offers assurance to design engineers and customers.

Powerful pump set tested

With 1 350 kW of raw power produced by a massive V16 diesel motor, the SABS – in conjunction with KSB Pumps and Valves – has tested one of the most impressive pump sets to be assembled on South African soil in recent times.

The pump set – consisting of a heavyweight KSB a RDLO 400-935 A pump, V16 Quad-Turbo Mitsubishi motor and David Brown-manufactured gearbox – is part of Sasol’s Natref Hydrofluoric Acid Cloud Mitigation Project and is required to rapidly produce a spray water to ‘knock down’ any gas cloud that may form in an emergency spill situation. As a result, the pump set needs to be ultra-reliable and ready to spark into action in an instant, to pump approximately 770 litres of water per second at a head pressure of 13 bar.

Due to the critical nature of the application to suppress toxic gases in an emergency situation, engineers took the unusual step of pre-testing the complete pump set to ensure the unit performs precisely as required.

impressive scale

“The test is unusual as components are usually tested individually and again on commissioning. This time, however, the units were tested separately – the pump in Germany, before delivery to South Africa; the diesel engine by Mitsubishi, in France; and the gearbox by David Brown, here in Benoni. Due to the nature of the project, further tests were then required of the entire unit, including capacity, head, power, efficiency and net positive suction of the pump to ensure further conformity with specifications,” explains Norman Taylor, test field manager, KSB.

KSB usually performs these tests on its own standard equipment, but the size of the motor was a limiting factor and required the use of the SABS facility. Here, testing was done under the supervision of the customers, KSB and SABS personnel, and ran for four hours before being deemed to meet all specifications and requirements.

“These kinds of string tests are done to ensure the entire units work correctly, considering that the diesel motor must produce a staggering 1 015 kW of power just to handle the requisite absorb-power to produce the 2 800 m³ of water needed per hour. Also, the forces at play when you consider this power is generated at 1 500 rpm and reduced through a reduction gearbox to 1 000 rpm, which is the optimum range of the KSB a RDLO 400-935 A pump,” says Taylor.

Trusted type

“With the unit weighing in at an impressive 32 tonnes, it is particularly impressive that we have facilities in South Africa where our customers can witness the performance of the equipment they have purchased – in this instance by Worley, on behalf of Sasol,” adds Geoff Havenga, contract manager, KSB. This kind of pump is widely operated in high-volume applications in raw and potable water industries and is capable of reliably pumping high volumes on a continual basis. Well known for their reliable operation, they were deemed as the ideal pump for this critical operation.

Pressed Steel Sectional Water Tanks

Finding the right valve

Ultra Control Valves (UCV) was formed in 2010 by two industry veterans, with a combined experience of over 70 years. Although UCV has a complete range of valve products to service the water and mining industries, the emphasis has always been on control valves. This is the area least understood by users and where UCV fills a real need. The experience and products gained over the last 10 years have led UCV to offer solutions in a number of areas.

Water

hammer

The destructive phenomenon of water hammer is one of the areas where UCV has extensive experience and where it has the right products to solve most problems. The right selection of items such as control valves, check valves, air valves and surge tanks plays a crucial role in solving water hammer problems and a complete arsenal of such products is available.

Final solutions with guarantees can be provided with proper analysis, using suitable software programs. UCV has associate companies who are readily available to offer such assistance.

UCV has taken its water hammer solutions one step further by offering an ECSA-accredited course, entitled ‘Modern equipment options to reduce water hammer’, which offers 1 CPD point.

Since its inception, Ultra Control Valves has earned a substantial stake in both the water and mining industries, and now boasts a complete range of valves for both sectors.

Water saving

UCV provides a range of products in the field of pressure management:

• The Ultra ACV pilot-operated pressure-reducing valve (PRV) can be used with electronic controllers to operate as a ‘smart’ control valve to change pressures in networks in relation to demand. This normally results in significant water savings.

• The Ultra ratio-reducing valve reduces pressure in a ratio (between upstream and downstream pressure) and operates completely without pilots. This valve has captured the imagination of users and engineers as a truly African solution, due to its simplicity. It can be used as a simple two-stage PRV by the addition of a ratio-reducing valve upstream of a pilot-operated PRV.

In pressure management where pressures are set lower during nighttime, the addition of a ratio-reducing valve fitted with solenoid on the downstream side of a pilot-operated PRV can achieve this by simply activating the solenoid to bring the ratio-reducing valve into play at night

ultra pilot-operated PrV with solenoidactivated ratio-reducing valve

and to reduce the pressure to a lower setting. During the daytime, the solenoid is deactivated to ensure that the ratio-reducing valve is fully open. Ultra ratio-reducing valves have made an impact in high-rise buildings, where it is the only type of PRV that can be used in series without any instability

• The Maric flow control valve is an innovative Australian product, which is made in South Africa by UCV. It has many uses and also brings about water savings in various applications. Pilot projects are currently in progress in water networks and high-rise buildings.

UCV prides itself in supplying the right valve for the application and has a field service team with experience to solve most problems. Some of the team’s expertise is highlighted in a monthly newsletter, the content of which has received welcome attention and a growing database. You can join for free by subscribing on www.ultravalves.co.za under ‘Pete’s valves and hydraulics’ or by sending a request to peter@ultravalves.co.za.

ultra ACV control valve ArI air valve

ultra nozzle check valve H&H surge tank

4IR applications for wastewater treatment

Held under the theme of ‘Technology’, the 2019 FIDIC Conference provided an in-depth view into the changes ushered in by the Fourth Industrial Revolution. If embraced, these changes offer South Africa’s water professionals the ability to ensure sustainable water supply.

By Dr Michele Kruger*

The recent FIDIC Conference in Mexico City saw Stephen Brobst from Teradata in the US deliver the keynote address. Brobst was appointed to the US President's Council of Advisors on Science and Technology in the working group on Networking and Information Technology Research and Development during Barack Obama's first term as president.

As part of this work, Brobst co-authored a report entitled ‘Designing a Digital Future: Federally Funded Research and

Dr Michele Kruger Associate Director, CSVwater Consulting Engineers.

Development in Networking and Information Technology’, which was delivered to Obama and the US Congress. Delivered back in December 2010, this report recommended that all federal agencies should have a big data strategy and initiated government investment in this area.

The first thing that Brobst discussed at the conference was the fact that, as consulting engineers, we are generators/ perpetuators of huge amounts of data. And the ability to cope with big data will be key in coping with the Fourth Industrial Revolution (4IR). He went on to say that those consultants in denial about this may not survive in future.

The South african context

Being able to process large amounts of data is exactly the need I have seen emerging with South African water utilities. In a water-scarce country like ours, digitalisation will not only allow us to reduce water consumption and losses, but will fast-track sustainable and

resilient design of infrastructure. To measure is to know, and having online measurement of anything from flow data to chemical and energy usage, or anything at all really, will allow utilities to optimise the consumption of both energy and chemicals. Through understanding usage patterns, utilities can use predictive analytics (and artificial intelligence) to ensure no taps run dry while optimising opportunities to pump during cheaper Eskom timeslots.

Furthermore, it will enable predictive maintenance and massively reduce the cost that is currently associated with ‘run-to-failure’ maintenance caused by onerous procurement procedures experienced by some. It will also enhance confidence in the reliability of assets.

The power of dashboarding

Although this technology is nothing new to South Africa, business analytics comes into its own when in the control of wastewater treatment processes. Being able to process large amounts of data will enable business analytics to convert any data into helpful information via dashboarding. Thus, depending on what your role in the organisation is, you can view any volume of information in the form of dashboarding graphs, providing you with a big picture view of the health of all your wastewater treatment plants.

If you are your company’s Green Drop champion, you can dashboard both the flow and load entering multiple works compared with the capacity of the works and the water-use licence. You can track the requirements for your process controllers to improve their Process Controller classification. You can also load all required Green Drop information on your dashboard at your fingertips – no more looking for all those locked-away O&M manuals.

From a process point of view, you will be able to view, in real time, any changes in parameters with pre-set limits to alert you to problems. This means that instead of losing

your bugs in your biological nutrient removal reactor during an industrial dump event, an early detection system could alert you to divert the incoming flow, if possible.

You are also able to optimise your chemical addition to the changes in flow and load, ensuring that you do not dump too much disinfectant in the receiving water body, or use too much metal addition for orthophosphate reduction so reducing your options in terms of sludge beneficiation.

Taking wastewater treatment further into the future, by including wastewater reclamation and nutrient extraction factories, will reveal that it will not be a luxury but rather a necessity to ensure real-time, per-second data processing. This will protect consumers of reclaimed water and give customers the peace of mind that the water is safe to drink. Add to this the value of third-party verification with the use of blockchain, and an additional level of safety and transparency is added.

I am extremely excited about the future of water in South Africa. As the drought event in Cape Town showed us, we as South Africans have an unbelievable capacity to come together to do the right thing during times of need. We have all the skills, capacity and technology available right here to embrace 4IR. Every drought event will enhance the opportunities for reclamation/reuse and, coupled with digitalisation, it will ensure that we take better care of this valuable resource.

*drMicheleKrugerspecialises inwaterandwastewater treatmentdesignasan associatedirectorat CSVwaterConsulting Engineers.

Digitisation

saves costs

Trends such as the industrial internet of things (IIoT), cloud computing and ‘edge’ control are all emerging as technology engines that present cost-effective options for modernising operations.

“It is estimated in South Africa that almost 50% of existing wastewater treatment infrastructures are not functioning adequately and are in need of some form of intervention. As water systems’ physical assets age, the cost of maintenance rises exponentially, and instances of downtime increase in frequency. Maintenance is often performed in a reactive mode – only once equipment breaks down. During such instances, stress levels are high, productivity is lost and costs accelerate,” says Jacques Squire, segment leader: Water and Wastewater, Schneider Electric South Africa.

“These plants depend heavily on a pool of experienced workers to ensure that operations are run efficiently, safely and securely – generating high-quality output in a manner that adheres to regulations. Ageing facilities are not the only problem. A full 38% of utility employees will be eligible to retire within the next decade. The expertise they have nurtured over the years will disappear.”

In

an industry under increasing pressure, digitising key plant processes within water and wastewater operations offers the potential to generate 20% to 40% in cost savings.

Workforce considerations

The combination of an ageing workforce and ageing infrastructure, along with current cost control measures, means that these issues need to be addressed quickly. Squire argues that workers need to be supported with tools that enable them to make better operational decisions. New technologies such as IIoT and artificial intelligence (AI) present themselves as opportunities for the industry to reinvent itself. Proper implementation of digitised solutions can address both operational costs and some key workforce evolution issues.

“These technologies will both enhance knowledge retention and provide more flexibility when managing a changing workforce. This is another crucial part of the modernisation puzzle, which requires careful consideration. Digital technologies will be key in attracting and training new workers now and into the future. Such tools also enhance the ability of the plant to capture the knowledge of more experienced workers so that it can be shared with the new generation of incoming workers,” he says.

Reducing capex

Very few municipalities have the funds to engineer wholesale infrastructure improvements. Fortunately, many of these new technologies are designed to

operate within open architectures, which allows for easy ‘snap-on’ upgrades to existing infrastructure, explains Squire.

“This avoids the need to ‘rip and replace’ to achieve modernisation and corresponding operational benefits. Using fully integrated SCADA and telemetry systems, remote sites with limited internet signal can be connected reliably.”

An example is the UK’s Anglian Water company, which covers a geographical footprint of 16 100 km, 12 000 remote stations and 630 000 telemetry data points. The company also has 25 years of data from an old system installed in the 1970s. In order to complete its modernisation project successfully, it needed to migrate this data and integrate it with existing systems, while still maintaining operations. The result was a leakage rate of 4.97 m/3 km/day –one of the lowest levels in the UK.

Similarly, Australia’s Yarra Valley Water company saved 80% in external support costs, and reduced faults by 66% thanks in large part to its SCADA system and mobile data access. “Workforce mobility technologies that utilise mobile humanmachine interface technologies - such as smartphones, tablets, portable wireless devices and wearables - are also expanding capabilities and improving operator experience.”

informal area metering reduces nrW in KZn

Water losses have plagued South African municipalities for years. In KwaZulu-Natal, the eThekwini Municipality has embarked on an Informal Area Metering Project as part of its Non-revenue Water Master Plan.

Key strategies were identified to meet the targeted reduction of non-revenue water (NRW) in the eThekwini Municipality. This reduction was achieved by aiding water savings through the replacement of damaged pipes prone to extensive leaking, as well as the optimisation of existing bulk meters to measure flows of multiple water feeds into informal settlements. This has resulted in massive cost savings for the municipality as it eradicated the need for the installation of several meters.

SMEC South Africa’s Durban office was appointed to provide consulting services for the design and construction supervision of this plan and to programme-manage the key strategies. With a dedicated professional project team, the design and construction phases were carried out using efficient and effective methods that considered the best interests of the environment at all times, as land was restored and installations located in areas that did not affect indigenous plants and trees. The meters were sited in areas that facilitated quicker and easier meter reading.

Through the Contract Participation Goal programme, skills were transferred to developing contractors, thereby stimulating local business growth. Having installed 391 manifolds with meter sizes ranging from 15 mm to 80 mm in diameter, local enterprises had benefited immensely as a result of specified participation goals, including the employment of semi- and unskilled labourers from within the informal settlements.

Overall, the project – which was nominated as a finalist in the 2019 KwaZulu-Natal Regional SAICE Awards – set a stable foundation for future planning and reduced the imbalance of the unbilled, unmetered components. “SMEC South Africa acknowledges the project, as it exposed young professionals to many challenges that were dealt with as a team,” states Jashmer Rajcoomar, function manager: Management Services, SMEC. “This inspired some to consider the field of water engineering as a career and thus make a difference.”

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Building resilience

With its first year behind it, the USAID Resilient Waters Program is making headway in building water security and resilience in Southern Africa.

By Danielle Petterson

The five-year USAID Resilient Waters Program commenced in June 2018, providing US$32 million (R473 million) in funding to build resilience and water security in Southern Africa. Focusing on the Limpopo and Okavango river basins, the project has four key objectives:

• to improve transboundary water security and resource management

• to increase access to safe, sustainable drinking water and sanitation services

• to strengthen the ability of communities and key institutions to adapt to change – particularly the impacts of climate change

• to conserve biodiversity and ecosystem services.

According to Nandipha Kunaka, communications specialist: Southern Africa, USAID Resilient Waters Program, the funding is earmarked for biodiversity, drinking water supply, sanitation and hygiene, specifically at the intersection of people, institutions, biodiversity and water.

improved transboundary management

The programme supports the two river basin organisations – namely the Limpopo Watercourse Commission (Limcom) and the Permanent Okavango River Basin Water Commission (Okacom) – to deliver on their mandate of transboundary water governance. The Limpopo river basin is home to 18 million people living in parts of South Africa, Botswana, Zimbabwe and Mozambique, while a further 1 million people in parts on Angola, Namibia and Botswana live around the Okavango river basin.

People in these regions face increasing water shortages and floods, as well as declines in crop yields as climate shocks add further stresses to the already water-scarce region. Transboundary cooperation and adaptive management of river ecosystems are, therefore, crucial in securing the region’s fragile biodiversity and ecosystem services – key elements needed to support livelihoods.

The Resilient Waters Program is supporting Limcom and Okacom to reach their objectives in water resources management through capacity building and technical assistance.

“We need to strengthen the ability of these institutions to deliver on their mandate at the transboundary level; therefore, we have embedded key strategic resources to help with the delivery,” explains Kunaka.

a focus on WaSH

One of the core components of the Resilient Waters Program is

strengthening institutional and governance capacities to create an enabling environment for improved water, sanitation and hygiene (WASH) conditions and to ensure the sustainability of the proposed resilience and WASH mechanisms.

People living in the Okavango and Limpopo basins are often the poorest, most remote and least economically active in their respective countries. As a result, there are high levels of open defecation and a significant lack of access to water and sanitation services.

Led by JG Afrika, the Resilient Waters approach to WASH is to work with WASH sector monitoring mechanisms such as the Global Analysis and Assessment of Sanitation and Drinking Water (Glaas) of the World Health Organization (WHO), in close cooperation with national WASH institutions, to improve the enabling environment for WASH at a national level.

This engagement is taking place in six countries within the footprint area, namely Angola, Botswana, Mozambique, Namibia, South Africa, and Zimbabwe.

The aim is to achieve:

• strengthened capacity for WASH service delivery among responsible stakeholders and institutions

• increased access to safe, affordable, and appropriate drinking water supply and sanitation services

• improved quality of services or hygiene promotion

• increased municipal or local water service provider capacity to plan, finance, execute, and monitor appropriate water and wastewater infrastructure

• improved policy, regulatory, and institutional environment for mobilising investment in drinking water and sanitation services.

The Glaas survey

The Glaas survey was developed by the WHO as a mechanism to monitor progress in WASH against the SDG 6 targets. The survey is a UN-Water initiative implemented by the WHO, which seeks to provide policy- and decision-makers at all levels with a reliable, easily accessible, comprehensive and global analysis of the investments and enabling environment to make informed decisions for sanitation, drinking water and hygiene.

Kunaka explains that the Resilient Waters approach was to assist countries in their submission of the Glaas survey through data collection and verification processes, and to develop a gap analysis tool that allowed the team to analyse the data contained in the survey to identify highlevel national bottlenecks to WASH implementation. Through this approach, the team was able to reduce the turnaround time between gap analysis and implementation, prioritising areas that required immediate attention. The biggest impact of this was seen in Botswana.

Botswana success story

The USAID Resilient Waters project facilitated the data collection and verification workshops for Botswana in the submission of their Glaas 2018/19 Survey. Botswana was the second country in the world to submit their final survey for the Glaas 2018/19 cycle. The

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improving the coordination and performance of WASH in the country. Through the workshop engagements, Resilient Waters was able to identify the primary gaps in Botswana’s water and sanitation sector in terms of policies, plans, resources and finance, and initiated discussions around support to the government to address the gaps identified. Some of the gaps relate to the absence of programmes, strategies and policies to address hygiene, and a lack of monitoring mechanisms. During the workshop engagements, open

defecation quickly emerged as an area that needed attention. Within the first nine months of the programme becoming operational, Resilient Waters was able to support the beginning of a community-led sanitation programme in Eretsha Village, Botswana.

The USAID project team also supported the development of a National Sanitation Roadmap for the country within the first six months of the programme becoming operational. “This is an amazing accomplishment for the country, with the potential for changing the way Botswana does sanitation,” says Kunaka. Roughly

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40% of Botswana’s population does not have access to basic sanitation services, and poor waste and sanitation management are a threat to the sustainability of major settlements.

f uture trajectory

“We are confident we are ramping up in the right direction. Our capacity- and institution-building specialists can help focus on where technical assistance is needed and we are using tools and strategies to focus interventions in the right areas. We want to build resilience and water security in Southern Africa – and we are ensuring that we drive change to that level.”

Reducing water costs for food and beverage

Food is becoming increasingly expensive to produce. But there is one area where agri-food industries can make large inroads into reducing food production costs: the role of water.

An estimated 14% more water will be required for agriculture and food production by 2030. With water scarcity becoming a more regular issue across large parts of Africa, avoiding a water crisis in the near future requires a smarter, holistic approach to water management across the value-adding chain of food production.

“Optimising the costs of water in food production will be critical in ensuring overall costs of producing food remain in line with what consumers can afford,” explains Chris Braybrooke, GM: Marketing, Veolia Water Technologies.

For agri-food companies, the primary water objectives are to ensure safe, hygienic water quality and to reduce consumption, wastewater and energy footprint. The efficiency, cost-effectiveness and reliability of water and wastewater treatment facilities, therefore, play a vital role in overall business performance.

“As companies look to improve their financial performance and get more from

their assets, the optimal utilisation and management of their existing assets are becoming obvious economic priorities,” says Braybrooke.

They are achieving this by reaping the rewards that digital technologies have brought to the plant floor: historical, real-time and predictive process data; intelligent condition monitoring; remote plant visibility; and more automated supply chain management.

Veolia’s Aquavista™ suite brings these capabilities to water treatment in the food and beverage industry.

The aquavista suite of services

“Aquavista is a complete and customisable suite of digital services that can help monitor, manage and optimise water treatment processes. Equally suited to both existing and new water treatment facilities, Aquavista aggregates and enriches plant data through a variety of applications and algorithms to provide a greater, detailed layer of plant intelligence for managers, operations and

maintenance teams,” Braybrooke explains. Aquavista consists of four different modules that can be flexibly deployed to a plant according to overall optimisation and operations requirements. In doing so, it enables companies to:

• optimise energy and chemical consumption

• improve operating efficiency and stability

• minimise maintenance and prevent costly downtime

• reduce non-compliance incidents and lower environmental impact

• enhance equipment monitoring

• gain a complete view of operating status, historically and in real time.

“It is clear that to ensure water security for the food and beverage industry in the future, we need to look past conventional freshwater sources to supply our water needs. Instead, by optimising the internal water cycle of food production, we will be able to ensure we can meet the needs of food producers as we look towards 2030 and beyond,” Braybrooke concludes.

BULK WATER S TORAGE SOLUTIONS

Dams in urban areas can either be an asset for recreation or a liability if polluted. Measures like automatic scour and crest gates are highly effective in countering flotsam and sediment build-up while retaining optimum storage capacity.

By Peter Townshend*

Dams such as Emmarentia Dam in Johannesburg or the lakes in Benoni are attractive water features and enhance the quality of life for the community, especially where fishing and boating occur. These dams have catchments that are predominantly developed residential areas where the run-off has low pollution and litter loads.

Keeping urban dams clean and safe

have caused considerable problems and are then liabilities for the local authority.

unpleasant odours. Further litter and debris, emanating from urban area, were strewn along the watercourse and in the lake.

An effective litter trap upstream of the dam offers an advantage in reducing the eyesore view of litter strewn along the banks and the biodegradable material in the dam

the high-density areas of Hillbrow and Berea in Johannesburg. Initially, it was a big attraction with prestigious office blocks, shops and restaurants on the waterfront; however, over the years, it became highly

A combination of scour and crest gates works well on low spillway heights of up to 12 m to keep the dam relatively free of sediment and pollution

However, dams on watercourses that drain from high-density city areas or developing sites with informal settlements can and

polluted and an environmental hazard. The standing polluted water with high E.colicounts became anaerobic, releasing

on the Hennops River, also resulting in its eventual drainage and closure.

countermeasures

Given rising pollution trends, there’s a fair chance that similar problems are currently developing or occurring at other water features and dams in urban areas or municipal boundaries across South Africa. The good news is that there are ways to improve the functioning of such dams. Automatic scour gates can be fitted to the base of the dam spillway or embankment; these open automatically when the water level rises in the event of a heavy rainstorm in the catchment. A considerable amount of sediment

emanates from disturbed development and building sites, which accumulates in the dam. This can soon render the dam ineffective, which was the case with Rattray’s Weir on the Braamfontein spruit in Randburg. It was once a pleasure resort

in the early 1900s, with boating and fishing, but is now totally silted up.

The scour gates will open automatically in heavy flows to pass the sediment through the dam or weir while the sediment is still in suspension or rolling on the river bed. The gates will then close automatically to retain the full supply level.

It is possible to allow the scour gates to draw down the water level in the dam slightly below the full level and then close so that the dam fills with relatively clean antecedent run-off. The gates can also be opened manually to drain the water feature, if necessary, to clean it out occasionally.

Scour and crest gates

and the biodegradable material in the dam. Automatic spillway gates can also be used to increase the storage capacity of urban dams, especially those that have extractions for water treatment works or urban irrigation. Again, these gates will open automatically to pass floods and

Automatic gates fitted to the crest of the spillway will also open automatically in floods to decant the debris and flotsam-laden surface water from the dam. They also close automatically after the flood has passed to retain the full water level.

A combination of scour and crest gates works well on low spillway heights of up to 12 m, to keep the dam relatively free of sediment and pollution. An effective litter trap upstream of the dam offers an advantage in reducing the eyesore view of litter strewn along the banks

close again to retain the full supply level. By using these gates, small dams have had their capacity doubled following a water rise increase of as little as 600 mm. Larger regional dams would benefit with larger gates, which can increase storage capacity by about 50% depending on the dam characteristics.

With droughts more common now as a result of global warming, additional storage in regional supply dams is important. These gates can be fitted within a few months and meet dam safety requirements. For further details, visit www.amanziflow.com.

*PeterTownshend,PrEng,isthe managingdirectorofAmanziflowProjects.

An automatic scour gate discharging sediment-laden water from a river weir

2 m high crest gates

An automatic spillway gate opens to pass flood waters

Hydropedology – a growing focus

Growing awareness around the importance of wetlands is leading the Department of Human Settlements, Water and Sanitation (DHSWS) to request specialist hydropedological studies from companies applying for water-use licences under certain conditions.

Hydropedology – the study of the interaction between soils and water – provides insights into interflow processes in the subsurface area between surface water and groundwater. The field helps to understand the flow drivers contributing to wetlands and water courses that may be impacted by the activities of the water licence holder.

“By understanding the flow drivers, developers can make better decisions about which mitigation measures need to be in place for a project, highlighting which areas need to be protected to preserve the main feeder flows, and which areas can be developed,” explains Christie Terrell, senior scientist: Water Resources, SRK Consulting.

The DHSWS may request hydropedological studies in accordance with their guidelines in terms of sections 21(c) and 21(i) of the National Water Act (No. 36 of 1998). These sections refer to the two water uses most commonly linked to wetlands.

Roanne Sutcliffe, Bioresource Engineer, SRK Consulting adds that, “Any development or operation within a 500 m buffer zone of a wetland will fall within the ambit of these sections, and will trigger the

requirement for a hydropedological study.”

Terrell highlights that, whenever a surface water or groundwater study is required, companies also need to consider whether a hydropedological study may be required in their context. Such a study will investigate features like hill slopes and soil properties around a wetland or water source, and how these features interact with hydrological elements.

Understanding inflows

“A hydropedological study will include an exploration of how water will flow through the soil on a hill slope,” she says. “Traditionally, a wetland study will focus on the wetland itself and its buffer zones – but not really on how those wetlands are being sustained, including the hill slopes and flows in the area that affect how they are fed.”

Terrell notes that a better understanding of interflows is important, not just in terms of environmental impact mitigation and rehabilitation, but in terms of how subsurface water could directly endanger a construction or mining project.

“If a development is planned on a hill slope that has a significant interflow component, the client may be dealing with a lot more water than originally

anticipated,” said Terrell. Project planning needs to be informed by how soils will react. Different soils will have different flow components, so they will respond differently to water flowing through the subsurface area.

Local expertise

Fortunately, South Africa has been involved in numerous research projects regarding hillslope hydrology and the discipline of hydropedology has evolved globally over the past two decades, with South African researchers providing valuable direction in the development of the discipline.

The local academic community includes a number of specialists in this field, including Dr Simon Lorentz, a principal hydrologist at SRK, and an honorary associate professor at the School of Bio-Resources Engineering and Environmental Hydrology at the University of KwaZulu-Natal.

“While there has been pioneering research conducted in the field of hydropedology in South Africa, it has only recently started being applied by industry,” says Sutcliffe. “The new focus by the DHSWS on hydropedological studies will see this application increasing sharply.”

Open channel flow measurement and monitoring

Demystifying primary devices

Increasing legislation and continuing public interest in conservation and environmental matters have emphasised the importance of flow measurement, but effective and accurate flow measurement of an open channel can be challenging. By Peter van der Merwe*

Flumes are the primary measuring device in open channel flow, while the secondary device is the electronic monitor and a visual staff gauge.

The advantages of flumes for open channel flow measurement include minimal head loss, adaptability to a variety of channel shapes, and the ability to measure wide ranges of flow with custom-designed structures manufactured within the constraints of laboratory calibrations and relevant international standards. All flume ratings depend on laboratory calibration.

Flow measurement methods are continually being upgraded and new concepts exploited, offering the promise of ever-increasing convenience and improved economics for water control and management. The implementation of these developments confront the difficult problems associated with measuring open channel flows and can provide water resource managers with vital operational data in locations not deemed measurable.

A common way to gauge flow through an open channel is to measure the height of fluid as it passes through the primary device (flume or weir) in the channel. The flow height is the indicator of the flow volume and therefore provides an established measurement of the flow rate (by laboratory calibrations and the international standards) to the secondary device (ultrasonic, etc.).

The primary device is necessary to convert channel flow to a cross section of the channel for repeatable head

production and accuracy. The carefully constructed geometry of the primary device with a calibrated staff gauge verifies the monitoring of the flow by the secondary device.

difficULTieS eNcoUNTeRed

estimating open channel flows

Manning’s Formula:

The difficulty is determining the ‘n’ roughness coefficient.

The ‘n’ values can vary greatly along a given stretch of channel and over time, due to encrustation and deterioration of the channel. The formula is acceptable for the engineering design of a channel, but not for continual monitoring, as the results would not be expected to provide better than 30% accuracy in field conditions.

Velocity Area Method: (ASTM D3858-95)

To quote from this Standard (Item 11.1): “Determination of the precision and bias for this test method is not possible… due to the high instability of open channel flow.”

“Resultsindicatethatwhenusing area-velocitymetersincontrolled environmentserrorsinexcessof±10% indischargearepossible,” states the US Department of the Interior, Bureau of Reclamation Hydraulic Laboratory Report HL-2012-03. Slope Area Method: (ISO 1070) (Item 1 Scope)

This method is subject to the large uncertainties of the Manning’s roughness coefficient and is even less accurate than the Velocity Area Method. Slop Area Method is used for determining

Peter van der Merwe, Pr Tech Eng, (MSAICE, MPET, MCET, MWISA) is an independent consultant

the extreme high-stage end of rating curves in cases of floods.

The measuring/monitoring point

Measuring point within the flume:

ISO 9826: ISO Parshall

ASTM 1941-9: US Parshall

ASTM D5390-93: Palmer-Bowlus

ISO 4359: U-throat and trapezoidal USDA-NRCS: Hybrid

Measuring point <M> before the flume:

ISO 4359: Rectangular long-throat (M = 3-4 maximum head)

Khafagi (M = width of channel)

Minimum length of channel before the flume for modular flow

10 x maximum head (ISO 4359: rectangular, trapezoidal, U-throat and Khafagi flumes)

5-10 x channel width (ISO 9826: ISO Parshall flumes)

10-20 throat width (ASTM 1941-91: US Parshall flumes)

THe MoST coMMoN fLUMe ModeLS

The British Standard flume

The BS 3680: Part 4A:1981 standard has

Rectangular long-throat flume

been superseded by BS ISO 4359:1983 and subsequently ISO 4359:2013. These flumes are individually designed to the ISO standard for specific channels. The ISO 4359 standard also covers the trapezoidal and U-throat flumes. The condition for these flumes is that the flow in the approach channel is reasonably uniform and steady. With reference to the relevant current ISO 4359 standard, the expression ‘Venturi’ is not applicable to open channel flumes. A Venturi meter is used within a closed conduit system

and relies upon gauging the head at two locations and the application of Bernoulli’s energy equation.

The Parshall flume

The Parshall flume was developed by Dr Ralph Parshall of the US Soil Conservation Service, primarily to measure irrigation water flow. It is now used in industrial and municipal sewers, and in sewage treatment works on condition that the flow in the approach channel is

ISO and ASTM Parshall flumes compared

Parshall flume

reasonably uniform and steady. The original Parshall flumes are specified by ASTM D1941-91 (ASTM International, formerly known as the American Standard for the Testing of Materials). Caution is needed when obtaining dimensions from the many sources on the internet. Only the ASTM dimensions are required to obtain a true and accurate rating of the flume.

The US Parshall flumes are specified by their throat width, with the sizes ranging from 1 inch to 300 inches (25 ft).

ISO 9826 specifies a range of Parshall flumes by a model number, from 1 to 21.

The two ranges of Parshall flumes (US and ISO) are not similar geometrically or in rating. The misunderstanding of the two types occurs when a bill of quantities indicates the ISO standard and the drawings indicate the US standard.

Every Parshall flume is an empirical device, hydraulically and individually calibrated, and no intermediate sizes are standardised by either ISO or ASTM. Parshall flumes are not scale models of each other.

developed specifically for sewage flows and has been designed according to:

• DerVenturikanalby Anwar Khafagi

• Delft Hydraulic Laboratory

• Endress+Hauser’s ‘Canal Khafagi-Venturi QV’

• Endress+Hauser’s ‘Wastewater Measurement and Automation’.

The Palmer-Bowlus flume

The Khafagi flume

Matching the shape of the channel to the streamline curvature of the Khafagi flume achieves a 4% higher flow than would be available with the same water depth. The average divergence between theoretical calculations and practical measurements is not more than 1%. The condition is that the approach flow is reasonably uniform and steady. The Khafagi flume was

When utilising a Palmer-Bowlus flume, the diameter of the flume is not necessarily the primary factor to suit an incoming pipeline of the same diameter. According to the ASTM D5390-93 standard for this flume, the maximum head is recommended to be restricted to half the throat length – i.e. 0.5D. This means that only if the incoming pipeline maximum flow is half pipe that a same-diameter

Palmer-Bowlus may be suitable. A more suitable flume is the ISO 4359 U-throat. With reference to ISO 8368, these flumes are well suited for measurement of flows in conduits running partly full.

The hybrid flume

H (hybrid) flumes were designed in the mid-1930s by the Soil Conservation Service of the US Department of Agriculture. They are capable of monitoring flows that vary over wide ranges with a high degree of accuracy, as their design allows for a relatively accurate estimation of both low and high flow.

An H flume is the result of a combination of the physical and mechanical characteristics of a weir and flume. Its shape resembles a triangular weir more than a flume. From a mechanical perspective, the H flume is capable of passing run-off that contains a heavy sediment load, solids and floating debris. The H flume was developed to measure the flow of irrigation water from small catchment areas and surface water. Today, it is generally used to measure the flow of irrigation water, slow-flowing watercourses and water in sewer and industrial systems.

In free-flow conditions, the precision of an H flume is comparable to that of other flumes. To obtain this type of precision, these flumes need to be manufactured with close attention to detail in compliance with the standard dimensions. This is a very versatile flume, as it is a combination of the best features of both the weir and flume. It has the accuracy of

Khafagi flume

Palmer-Bowlus flume

Hybrid flume

low flows of weirs, the high flows of flumes with the advantage of through-flow of a flat-bottomed flume. This flume performs well under perturbed flow conditions and the length of the approach channel at twice the maximum depth is sufficient.

facToRS To Be TaKeN iNTo accoUNT foR a fLUMe

The channel:

• Shape – rectangular, circular, trapezoidal or earth channel

• Dimensions – length between screens/ sluice gates and exit, depth and width

• Condition – existing, under construction or in the design process

• Construction material – concrete, metal

• Flow – maximum and minimum

• Gradient.

The medium:

• Water condition – clean or carrying silt, vegetation, detritus, solids

• Water toxicity – neutral or carrying acids, alkalines.

caLiBRaTed STaff GaUGeS

Materials

Stainless steel staff gauges should have deep engraved calibrations indicating litres per second for clear, direct readings. Calibrated and engraved heavy-duty laminated acrylic material is suitable for the curved surface of the Palmer-Bowlus and U-throat. These durable materials are able to cope with alternating wet and dry conditions, resisting the accretion of both vegetable and mineral matter and the markings are resistant to wear and fading.

INDEX

Below are extracts from ISO 4373 Hydrometry – Water Level Measuring Devices:

Item A.1.1.3 Strengths

Staff gauges are an inexpensive, simple, robust and absolute method of determining water flow through a flume or weir. They can be utilised, without the use of rating charts, by relatively unskilled staff. Item A.1.1.4 Weaknesses

Staff gauges can only be used for spot measurements. It is difficult to obtain readings in the field with a true resolution higher than ±5 mm. Some staff gauge locations are such that the gauges require regular cleaning.

Calibration Certificates for Staff Gauges

These certificates should be calculated from the relevant calibrated rating chart and stage-discharge curve with reference to the International Standard. The reliability of the trend and accuracy of the forecast of calculating the calibration should be made with the coefficient of determination (R squared) and additionally with the average deviation (mm).

*PetervanderMerwe,PrTechEng, (MSAICE,MPET,MCET,MWISA)isan independentconsultantwho,inaprivate professionalcapacity,advisesonhydraulic mattersrelatingtoopenchannelflow monitoring.Hehassevenyears’extensive experienceinthedesign,manufacturea ndsupplyofawiderangeofflumesand weirs,andhasconsultedandsupplied productstoover150clientsfromSouth Africaandinternationally. Contact:flumesandweirs@gmail.com.

TO ADVERTISERS

inteRnational

stanDaRDs foR flUmes anD WeiRs

ISO – International Organization for Standardization

ISo 772 Hydrometry – Vocabulary and Symbols

ISo 1070 Slope-Area Method

ISo 1438 Thin Plate Weirs

ISo 3846 Rectangular broad-Crested Weirs

ISo 4359 Rectangular, Trapezoidal and u-Shaped Flumes

ISo 4360 Triangular Profile Weirs

ISo 4373 Hydrometry – Water Level

Measuring Devices

ISo 8368 Hydrometric Determinations

ISo 9826 Parshall and SANIIRI Flumes

ASTM International, formerly known as American Society for Testing and Materials

ASTM D1941-91 Parshall Flume

ASTM D3858-95 Velocity-Area Method

ASTM D5242-92 Thin-Plate Weirs

ASTM D5390-93 Palmer-bowlus Flumes

ASTM D5614-94 broad-Crested Weirs

ASTM D5640-95 Standard Guide for Selection of Weirs and Flumes

BS – British Standard produced by BSI – British Standards Institution bS 3680: Part 4A:1965 (Superseded by bSI bS 3680) Thin Plate Weirs

bSI bS 3680: Part 4A:1981 (Superseded by ISo 1438) Thin Plate Weirs

bSI bS 3680: Part 4b:1986 (Superseded by ISo 4360) Triangular Profile Weirs

bSI bS 3680: Part 4C:1981 (Superseded by ISo 4359) Flumes

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