46 minute read
Water Quality
WATER QUALITY REGULATION UNDER LOCKDOWN
The Drinking Water Quality Regulator for Scotland (DWQR) is open for business, although as with all of us – under very different conditions than we were used to.
Advertisement
by Moira Malcolm
Drinking Water Specialist, DWQR
DWQR is the title of the Regulator herself: Sue Petch, who is independent of Scottish Ministers and is responsible for the scrutiny of the water company in Scotland, Scottish Water, with respect to drinking water quality; and the supervision of local authorities in their regulation of private water supplies.
There are ten of us in the Drinking Water Quality team authorised to work for Sue; covering operations, policy and support functions (we also use the term ‘DWQR’ to apply to the whole of Sue’s team). The Operations Team are primarily involved with the regulation of Scottish Water, and assisting with the supervision of local authorities who regulate private water supplies. The Regulatory Team are responsible for developing and implementing legislation, guidance and other policies with respect to drinking water quality in Scotland, as well as managing all of our data. Lately we have been setting up and leading a steering group to advance and overhaul private water supplies legislation; and are also trying to make sense of the recast Drinking Water Directive.
To achieve all of this we are usually busy attending meetings with a variety of stakeholders; visiting water treatment works for investment sign-off, audits and incident investigation; contributing to training and conferences; and researching innovation. We are rarely all in the office at the same time and each week is different and brings its own challenges.
However at time of writing we are under lockdown in Scotland, and we anticipate that even when restrictions are eased things will not return to ‘normal’ for some time to come – either for us in DWQR or Scottish Water.
Over the last few months we have developed and adapted our working practices to accommodate the necessary changes required by our current circumstances so we can continue to provide the necessary direction to Scottish Water and local authorities in a fastchanging situation.
The backbone to regulation is the sampling and analysis of drinking water from consumers’ taps at a frequency set by legislation. Back in February we could see the potential for Covid-19 to make a significant change to the practices of regulatory sampling if it became an issue in Scotland, so after discussion with Scottish Water we developed and issued alternative sampling guidance so that samplers did not have to cold call consumers and to take account of potential staff absence. We were also aware that the households sampled were often elderly as these people were more likely to be at home during the day (pre-lockdown), and both Scottish Water and DWQR did not wish to risk their
health or unnecessarily cause concern.
Around the same time Scottish Water samplers started to experience some pushback on doorsteps from consumers who were wary at allowing access to their homes. We formalised the guidance in Information Letter 1/2020 and initiated regular virtual meetings with Scottish Water’s scientific services and public health team to keep communication open and monitor the situation. The Information Letter allowed Scottish Water to cease sampling from consumers’ taps and instead take zonal samples from storage point outlets and final water sample points, with the exception of plumbing metals which are to be caught up when restrictions are lifted. The overall aim is to ensure that public health is safeguarded at all times.
Meanwhile in DWQR HQ we postponed conferences in Edinburgh and Inverness organised with Scotland’s local authorities on private water supplies and cancelled non-essential visits to Scottish Water sites.
The week before lockdown was officially announced we held our annual business planning meeting under the cloud of realisation that this was probably the last time we would be in each other’s company for the foreseeable future. This was especially poignant for our colleague Hollie, who is now on maternity leave and very busy with preparations of her own!
We confirmed the changes to Scottish Water’s operations for sampling and analysis and kept in regular contact about these as everyone adapted to the ’new normal’. Specific challenges for Scottish Water have included the transport of samples from the Scottish islands with restricted flights and ferries, which has resulted in subcontracting microbiology samples to a local UKAS accredited lab in Shetland. When bottle necks in analysis formed, the analysis of colony counts was temporarily suspended for a short time. Cryptosporidium sampling and analysis was scaled back to the regulatory minimum. These measures were done with full consultation and agreement of DWQR, and analysis restarted as soon as resource was available. The rigour demonstrated by the company has meant that DWQR has a high level of trust in their intentions and actions to only reduce their service when absolutely essential.
FEATURE: WATER QUALITY
Fortunately the Scottish Government has always supported working from home, and we were able to transfer all our internal meetings to videoconferencing without too much difficulty. The software and internet has (mostly) held up under the strain – and we have all become a bit more tech savvy. Our meetings with external stakeholders are all online now too: with Scottish Water and also DEFRA and DWI, local authorities and other regulators. We even hold regular team ‘cake’ meetings online (as we have to provide our own cake, it’s an excuse to show off our new baking skills).
So at the moment we are in a new ‘business as usual’ phase. We continue to regulate from a distance: scrutinising data and events; examining paperwork and asking for photo/video evidence and auditing by videoconference. Our regular meetings with Scottish Water continue. DWQR may still visit Scottish Water sites when required for urgent regulatory purposes, taking account of any reasonable precautions requested by the company. The whole team is involved in writing our Annual Report at the moment, which is something that lends itself to working from home. We’re also doing plenty of training online, and without travel to occupy our weeks, we are eventually getting to the bottom of our ‘to do’ lists.
Looking forward, we are working towards exit strategies – including protocols for physically distant site visits and audits, and preparing with Scottish Water for an eventual return to ‘normal’ regulatory sampling - with the constraints of physically distancing and the awareness that consumers may be very reluctant to welcome doorstep calls for some time. At the moment the discussion is around sampling from Scottish Water employee’s homes and from trade and public buildings where this is appropriate to get the correct spread of zonal samples. The DWQR team have also offered their kitchen taps as sample points.
Over the last few months DWQR has developed new ways of working that we are confident will ensure our scrutiny of Scottish Water and drinking water quality continues despite the constraints we are all enduring, and we look forward to the day we can do something as simple as attend a meeting where someone else brings the biscuits.
A NEW PHAGE FOR WATER SAFETY
What’s the deadliest killer on earth? Hippos, malaria, natural disaster? Well these may be some of the main offenders, but seldom do bacteriophage ever spring to mind.
by Austen Buck PhD CSci MIWater
Senior Water Scientist, Stantec
Bacteriophage (from the Greek “BacteriaEaters”), or phage, are a collection of virus families that exclusively infect and destroy bacterial cells in order to replicate. Phage are of no risk to humans but are a bacterial cells worst nightmare, destroying billions of bacteria each day. So how can they help us?
The limitations of current faecal indicator bacteria (FIB) such as E. coli, are well documented. Their inability to accurately predict the presence of viruses in water and that they are unrepresentative of virus removal through treatment are two key concerns. Therefore, phage (which share more similar characteristics to human viruses) have been proposed as more suitable target organisms to assess viral risk.
In addition to this, the proposed inclusion of somatic coliphage as a compliance parameter in the revised Drinking Water Directive (DWD) will also push the use of phage in the water sector into a new phase. Current treatment processes may not be able to remove somatic coliphage to the proposed target level (0 pfu/mL), depending on raw water challenge, so this requirement is of increasing interest.
There are three commonly used phage types for the assessment of waters. These are somatic coliphage and F-specific coliphage (which both infect E. coli and similar bacteria), and phage infecting Bacteroides spp. Figure 1 shows the common groups, linkages and examples. Each group has unique properties which determine their application which will be explored further.
So how can we use phage to ensure the continued provision of safe water for the communities we serve?
Raw source water characterisation
To ensure adequate disinfection, it is vital to understand source water risks associated with viruses. The presence of pathogenic viruses (causing illness in humans) in source water is closely linked to human faecal contamination either from leaking sewers, septic tanks, and effluent discharges.
Somatic coliphage, which originate from the gut of warm-blooded animals may not accurately represent risk of human viral pathogens in source waters. For instance, a source water with high levels of somatic coliphage but with no human faecal impact would pose a very low risk from human viruses. Therefore, specific phage have been identified that originate solely from the human gut and their presence in source water can more accurately predict the presence of human viruses. This ability to identify the source of faecal contamination is termed Microbial Source Tracking (MST). Phage infecting the bacterial genus Bacteroides (Figure 2) have been successfully isolated and used to identify and trace human faecal contamination in source waters to better understand virus risks and downstream treatment requirements (Ebdon et al., 2007).
Treatment performance and verification
Coliphage have been used successfully to demonstrate log removal values (LRV) for viruses through water and wastewater treatment, both in academic research (Purnell et al., 2015; Dias et al., 2017) and in practice.
F-specific coliphage are already used to validate wastewater disinfection processes in the UK, but the use of phage to verify the adequacy of potable water treatment in the UK is not common. Model viruses of each phage group (eg. PRD1, MS2, B1244) have been isolated and are used in a range of laboratory bench-scale studies, and full-scale spiking trials to ascertain LRVs across different treatment processes.
MS2, a type of F-specific coliphage is of key interest in treatment studies as its characteristics are closely related to human viruses, therefore it’s presence and removal through treatment closely models that of human viruses. Purnell et al., successfully used somatic and F-specific coliphage to assess microbial risk across a full-scale membrane bioreactor processes (MBR). Figure 3 shows two somatic coliphage of the Microviridae family identified post MBR during this study.
The presence of phage in treated waters could therefore be used to indicate inadequate treatment processes and a potential virus risk. Their presence in wastewater effluents may also indicate the presence of human viral pathogens and could present a risk to downstream shellfisheries and bathers.
Other applications
Phage have also been successfully used to: identify virus risk in sediments, bathing waters, and food including shellfish; and to model groundwater movement. One interesting use of phage away from the water sector is for the control of bacterial infections as an alternative to currently used antibiotics, this is termed “Bacteriophage Therapy”.
Current limitations
Whilst the use of phage in the water sector will help us: better predict risk in our source waters; better understand treatment requirements; and to verify
Figure 1. Common phage groups, linkages, and examples.
FEATURE: WATER QUALITY
the adequacy of water and wastewater treatment processes, they are not without their limitations. The sensitivity of the methods can be a key limiting factor, as current laboratory methods use 1 mL of sample, therefore there is a high frequency of negative results and the additional requirements for concentration of phage are necessary adding both complexity and cost to sampling and analysis. The current availability of methods may also limit their application and whilst somatic coliphage and F-specific coliphage tests are commercially available, tests for human-specific phage are less so, although this provides a great opportunity for university partnership.
Conclusion
With ever increasing emphasis on effective risk-based decision making processes through water safety planning and the potential future inclusion of somatic coliphage as a newly regulated parameter in the revised DWD, maybe now is the time to revisit our phage friends and utilise them to their maximum potential to ensure the continued public health protection of the communities we serve.
Figure 2. A TEM micrograph of a humanspecific phage (B124-4) that infects B. fragilis (GB124). This phage is from the Siphoviridae family (Courtesy of University of Brighton). Figure 3. A TEM micrograph of the somatic coliphage family (Microviridae) observed in MBR supernatant (adapted from Purnell et al., 2015).
References
Ebdon et al., (2007). Water Research, 41, pp. 3683-3690. Dias et al., (2018). Water Research, 129, pp. 172-179. Purnell et al., (2015). Water Research, 73, pp. 109-117.
ATI UK
SITEBOX SMART WATER QUALITY SYSTEMS DONATED TO NIGHTINGALE HOSPITALS
Cutting-edge, smart water quality systems have been donated to UK Nightingale Hospitals fighting COVID-19, helping to ensure the highest quality water to the emergency healthcare facilities.
ATi UK are playing a vital role in the safe running of these new, emergency sites by helping to ensure clean, reliable and safe water for critically ill coronavirus patients. The industry’s only portable, bespoke, water treatment control and policing system, SiteBox, has been delivered and installed, free of charge, into healthcare facilities in locations such as Bristol and Manchester, with other installations in the pipeline across the UK and Spain, to provide a higher level of water quality assurance during the pandemic, exceeding all compliance levels.
The first SiteBox was donated to Bristol’s Nightingale Hospital, within days of initial planning meetings, following concerns over the converted university building housing no onsite water storage. By working closely with Bristol Water, ATi UK were able to offer an innovative early warning solution with the use of a SiteBox, to help protect the hospital in the unlikely event that the water supply was lost.
Delivery to start up in minutes
This was closely followed by SiteBox and MetriNet installations at Manchester’s Nightingale clinical facility to safeguard the water security, for additional reassurance and compliance of the water supply. The systems were all installed onto the inlet and were generating live data in as little as 20 minutes, allowing the forward-thinking water companies to monitor, alarm and prevent events that could affect the water quality supply, minimising any disruption.
The live data is then transferred to a cloudbased platform, with water quality teams able to analyse the data in real-time, with alerts to any incidents. SiteBox is configured to alarm in the event of any water quality incidents, loss of supply or threats to compliance or security. The versatile ‘lift and shift’ systems were originally designed as event management tools, but the capabilities have now widened to emergency water quality management.
Bespoke, yet off-the-shelf
Each SiteBox was tailored to the customers’ needs, factory tested and installed within a week, allowing the water companies to lead the way with a more proactive, rather than reactive, approach.
SiteBox systems can be held by utilities for emergencies, capable of being deployed and working quickly, offering resilience of supply and mitigating against potential public health claims. This enables water companies to measure water quality immediately online, record real-time data for regulatory requirements, all whilst fixing the problem, saving the need for boil notices and customer compensation.
The modular nature enables users to tailor a bespoke monitoring system that fits individual site requirements, capable of measuring up to 20 different parameters. SiteBox can be used on its own as the input to a control system, or alternatively as an independent monitoring system that polices existing water quality monitors.
Versatile, Future-proof Technology
Its flexibility means that SiteBox can be used anywhere that water quality measurement and control is needed, from drinking water treatment and process water in the food industry, to large-scale event management and holiday parks.
Demonstrating its versatility, SiteBox can be used to extract deeper insights on pipeline networks to enhance operational efficiencies; assist in the cleaning and refurbishing of service reservoirs; is utilised by the world’s largest provider of water systems for global events; and is also set be used at the next Olympic Games in Tokyo in 2021.
Garry Tabor, ATi UK Executive Director, said: “ATi UK is proud to be working with our utilities partners to support the NHS Nightingale hospitals during the current pandemic. We are a values based company and are passionate about supporting communities, prioritising local communities in any way we can.
“SiteBox will ensure that these water companies are going above and beyond the usual guidelines to safeguard water quality for staff and patients during this difficult time. By continually measuring any of the 20 available parameters, the Nightingale Hospitals will have some of the best characterised and protected installations in the country and we are extremely proud to be part of these collaborations.”
Over the last 5 years Northumbrian Water has looked at how high performing corporations have been so successful. It has then adapted these principles to its own business.
The common thread has been to: provide targeted rich, accurate data to the right people at the right time train people on the interpretation of information so they can apply it in the real world create a culture of honesty and openness which recognises achievement and creates the desire to improve
It is very easy to get caught up in the data aspect of lean manufacturing, whilst this is an essential component it is merely an enabler to engage people to work toward the common goal of achieving a vision. It is also essential to engage the right people (those who will deliver the results and the stakeholders who will benefit from the results) at the earliest stage of strategy development and not to simply provide them with a set of KPI’s.
Our ambitious goal within our water supply team is for 100% of our customers to “choose tap water over bottled water”. This is challenging because there are many reasons why people would spend money on bottled water beyond just product taste and quality but it is useful because it clearly sets the scene for continuous improvement. There are many mechanisms for delivering continuous improvements, in Water Supply we chose a scrum type approach which consists of:
Daily Boardwalk where operators and site managers discuss performance against plan on a daily basis
Monthly Scorecard review where operators, stakeholders, support departments and leaders review the higher level key performance indicators against monthly improvement targets and modify plans to address areas of concern.
Our scorecard tracks 37 measures each month, these are split equally in the 5 categories of Safety, Quality, Cost, Delivery and People.
An example of one of the measures within our Quality section is “Drive Score” (Dynamic Risk and Intervention Effectiveness). This takes a specific basket of around 100 critical to quality leading and lagging measures at each of our water treatment works, we then calculate non-conformance based on the percentage of samples (or instrument readings) which fall outside stringent upper and lower control limits. We then apply an importance weighting to each measure and calculate a risk index score for each measure.
Our systems are designed to do this automatically and each day operators receive an email notification describing yesterday’s score for each measure, they respond by carrying out a root cause analyses (RCA) on these failures and propose actions to resolve these issues within the same system. These RCA’s are then used to inform improvement plans for each site which are formalised and shared with support departments and tracked as part of the monthly scorecard review process.
The other 36 measures are treated in a similar way and at the beginning of each year we develop steadily improving targets for each month supported by detailed action plans with clear accountabilities. Big improvement projects have their place in the water supply world but simple, often low cost structured incremental continuous improvement processes such as those described here play a vital role in achieving corporate goals, through employee engagement.
FEATURE: WATER QUALITY
INTRODUCING 2 NEW MECANA SYSTEMS IN THE UK
Eliquo Hydrok have added two new Mecana technologies to their existing Pile Cloth Media Filtration (PCMF) systems available for the UK Water and Wastewater markets.
PRIMARY & POST PRIMARY FILTRATION
Applications:
■ Primary Filtration ■ Post Primary Filtration ■ Stormwater ■ Sanitary Sewer Overflow (SSO) ■ Combined Sewer Overflow (CSO) ■ High Solids Applications (Municipal and Industrial)
The Pile Cloth Media Primary Filtration cloth media filtration system is designed as an economical and efficient solution for the treatment of primary wastewater and wet weather applications. This system utilises a disk configuration and the exclusive OptiFiber PF-14® pile cloth filtration media to effectively filter high Eliquo Hydrok have the UK distribution for the Mecana Pile Cloth Filter Media within their portfolio of Clean Water Treatment Processes, Drinking Water and Surface Water pre-filtration treatment utilising the Mecana Optifiber PES-14-DW® pile cloth media. Pile cloth media filtration can be used as a resilient pre-filtration solution to address the problems associated with algal blooms occurring in water extracted from surface water sources. Mecana PCMF systems can be used as an economical and an efficient pre-filtration stage in the treatment of surface water to produce drinking water or process water. The system utilises the disc configuration and the exclusive OptiFiber PES-14-DW® pile cloth filtration media, to effectively filter; a wide range of algae typically responsible for seasonal algal blooms, from diatoms and other unicellular algae in spring to filamentous types such as Melosira more common in the summer, solids waste streams without the use of chemicals. This technology is ideal for primary wastewater treatment as a primary filter, as an alternative to a conventional primary treatment; or it can also be used as a post primary filter in series after a conventional primary treatment, due to its proven removal efficiencies and high quality effluent, even under varying influent conditions.
The Primary Filtration system is designed to handle a wide range of flows in a fraction of space compared to conventional primary clarifiers. The system’s high solids removal in comparison to conventional treatment provides more energy and surface water particles and suspended solids without the use of chemicals. The pre-treatment of raw water is an important step in the multi-stage water treatment process, since it impacts crucially on the operating efficiency of the main treatment and after-treatment processes further downstream. Drinking water production with surface water from reservoirs or rivers is faced with a challenge of the removal of low density suspended solids and algae. In the context of climate change, droughts may impact reservoir water quality and result in more prolonged and severe algal challenges. An affordable chemical-free alternative to traditional processes such as sand filtration and DAF can be provided by pre-filtration with pile cloth media. Lewis O’Brien, Technical Director at Eliquo Hydrok said, “These two evolutions of the well proven Mecana Pile Cloth Media operational savings within the wastewater treatment plant due to reduced loads to the secondary process and the increase of organic solids for anaerobic digestion, producing more energy. Pile Cloth Media Primary Filtration contributes to the
DRINKING WATER & SURFACE WATER PRE-FILTRATION
positive energy balance of WwTP’s. Filtration technology not only provide exciting new opportunities to advance future water and wastewater treatment, but also stand as excellent examples of the commitment to research and development shared by both Eliquo and our core technology partners.”
For further information contact (Lewis O’Brien, lewis.obrien@eliquohydrok.co.uk, 01726 862000.
THERE’S NOTHING FUN ABOUT REG 31
Regulation 31 of the Water Supply (Water Quality) Regulations 2016 (as amended) (Reg 31) can be one the biggest regulatory headaches for most water companies.
by Dr Guy Franklin
Head of Water Quality and Compliance, Southern Water
Reg 31 requires input from departments, like procurement, which normally don’t have to deal with the DWI. Reg 31 has almost as much DWI published guidance as the rest of the Water Quality Regulations put together and guidance is very clear that the responsibility for ensuring compliance sits with the water company. Therefore it requires a robust paper trail across all aspects of asset design, build and operate to show compliance that often cannot be retrospectively assembled. Water companies have to take the requirements of Reg 31 seriously. Use of inappropriate products can present a public health risk that is hard to detect and lead to DWI prosecutions for noncompliance which have been the subject of ever increasing fines, ranging from a £1,000 back in 1995 to £80,000 in 2017 and £500,000 in 2019 (the most recent one leading to supply of water unfit for human consumption).
Regulation 31
The working of Regulation 31 starts out prohibiting the application of any product to water intended for customers. Which actually means it stops the use of any pipe, let alone treatment. It then proceeds to allow anything with an appropriate CE mark (there are no appropriate CE marks) or an appropriate British Standard (this only applies to treatment chemicals) to be used. Fortunately, it goes on to say that products can be used if approved by the Secretary of State (in reality DWI) and published on a list, the snappily titled List of Approved Products for use in Public Water Supply in the United Kingdom. It also allows for the use of a product if, in the opinion of the Secretary of State, it is unlikely to adversely affect the quality of water. This statement is used to allow small surface area products to be used without full approval. Finally it allows DWI to permit the use of products for testing and research purposes.
For both approved products and those which conform to a British Standard the Secretary of State can, and normally does, apply conditions. For approved products this almost always includes a requirement that it must be used and installed in accordance with the manufacturers instructions for use (IFU). For chemicals it can include maximum dose or impurity levels.
What the big deal about products in contact with water?
Materials used in products are often mixtures of chemicals and currently there are over 160 million known of these. These mixtures can include additives used as colorants, antioxidants, fillers, elasticity modifiers and a host of other functions that give us the wide array of useful materials currently on the market. If these chemical compounds stay in the materials then they aren’t going to create a water quality problem. Unfortunately all too often chemicals, particularly the lower molecular weight ones, can migrate through the material and find their way out into the surrounding water. It
would be a herculean task to analyse for even a small percentage of these additives at customers taps to check they aren’t leaching out.
There is one final complication, what goes into the material is not always what comes out. The chemicals are mixed in the material and react together or they can react with chlorine or oxygen or are otherwise degraded creating a whole research projects worth of further compounds, some of which have probably never been characterised. Then we have in situ cured materials where the chemical reaction to form the final material takes place on site. Without careful control of application and curing, this can result in compounds from side reactions with contaminants or the substrate creating yet more unexpected compounds.
There are a few compounds from organic materials that, for historic reasons, can be predicted to potentially be present in water supply systems. Degrading coal tar pitch internal coatings installed in the last century give rise to PAHs that we sample for as the only control for the public health risk without the replacement of vast swathes of mains.
Organic materials can also give rise to unacceptable smells and tastes, for example phenolic based antioxidants can break down, migrate out of the material and react with chlorine to produce “TCP” taste problems.
Materials can also act as a food source or habitat for microbes, allowing the gradual build up of complex biofilms, even in chlorinated water. The organisms present will then excrete waste products that can create taste and odour problems, release cells, for example legionella, or slough off lumps of biofilm into the water that find their way to customers’ taps.
To be able to adequately assess the risk from materials ideally we would know what is in them. However, material manufacturers are understandably reticent about publicly disclosing formulations of their materials as this knowhow gives them commercial advantage. In the absence of knowing what’s in the materials and not having the time, ability and resources to analyse for them all we must rely on disclosure to a third party followed by testing, assessment and approval. This allows the water company water quality team risk assessment to allow the use of the material although not fully understanding why.
Approvals
The UK, unlike most other countries, has two approvals systems for products used with drinking water that have developed, more or less, independently.
In 1975 the water industry started approving products for use in building plumbing systems. These requirements became BS 6920 and are used by the Water Regulations Advisory Scheme (WRAS) approval. This testing does not require the disclosure of the formulation (with a few exceptions) but is based on four tests of water which has been in contact with the material for taste and odour, appearance, toxicity and metals and a fifth test which measures the material’s ability to support microbial growth. Although this approval is not linked to Reg 31 the same BS6920 tests are also advised by DWI for companies assessment of materials with a small surface area.
Regulation 31 approval can trace its origins back to the Committee
FEATURE: WATER QUALITY
on Chemicals and Materials of Construction for Use in Public Water Supply and Swimming Pools which granted voluntary approvals to manufacturers. The use of approved products was made mandatory with the introduction of Regulation 25 of the Water Supply (Water Quality) Regulations in 1989. Although grandfather rights where allowed for products being used just before the regulations came into force to allow transition to the new requirements. Grandfather rights where whittled away until finally revoked when the regulation moved to its current numbering in the 2000 Regulations.
Regulation 31 approval requires manufacturers to carry out BS6920 testing and disclose the full chemical formulation and instructions for use documents to the DWI. Leaching tests are carried out for potentially harmful substances in the formulation and unexpected chemicals by GCMS full-scan analysis. The results are assessed before final approval may be granted. The whole process often takes over a year.
The UK is almost unique in having a government body rather than a private organisation body issuing Reg 31 approval. The advantage of this approach is the independence of DWI’s assessment and the powers in the regulations making it a criminal offence to provide false information as part of an application for approval.
However, the UK is not alone in having a requirement for approval. Art 10 of the 1998 Drinking Water Directive (DWD) requires member states to have due regard for the impact of products on water quality. The DWD is currently under review and there are big plans to change to a European wide approval, but that is a whole article in its own right.
SIMPLIFY PIPE REPAIRING
WINTER SEASON - PIPE DAMAGE CONTROL
Email: info@mvfh.co.uk • www.mvfh.co.uk
ADVANTAGES OF MODULAR WATER TREATMENT SYSTEMS
Complete temporary treatment works installed to enable Wessex Water site to take existing assets offline and refurbish
Modular water treatment systems have the potential to provide the industry with solutions to achieve a successful AMP7 outcome.
by Rich Matthews
MD at Siltbuster Process Solutions
Certainly, the water industry will face some significant pressures through the WINEP programme and the OFWAT efficiency targets. The good news is that modular water treatment systems can provide gains in flexibility and responsiveness that are vital to meeting these pressures. The use of such systems, in conjunction with existing treatment plants, ensures that asset life is optimised, and activity is sustained, without the need for excessive capital investment.
Beyond this, they allow the treatment capacity of existing treatment plants to flex at short notice to meet changing demands. This is particularly important given the fluctuating economic and environmental climate, which is creating additional compliance risk. This can be a combination of industrial (trader) activity, transient population, asset age, along with changes in seasonal demand presenting different demands on treatment needs. It is easy to see why now is the time for organisations to increase their water treatment capacities with modular packaged systems.
Resilient and Responsive
Packaged modular water treatment systems can be deployed rapidly. This is often seen when such systems are installed to assist with compliance during essential capital maintenance activities, such as biological filter refurbishments using package biological plants, bridge scraper refurbishment using mobile clarifiers or reed bed refurbishments using package tertiary plants.
The role of the modular plant in these applications provides both programme and consent reliability, removing constraints that may well have prevented proactive maintenance to take place in a timely manner to provide a more resilient asset. Further merits of responsive modular systems allow additional capacity to be provided when needed, offering asset efficiencies through not having to over size treatment capacities at the initial stages in the development of a site. The benefits of this can be seen for large new residential sites as the treatment capacity grows with the development.
If these principles for package plant solution provided flexibility and resilience then there is no reason why packaged plant solutions cannot be installed for wider capital programmes, allowing the development of asset investment in an incremental and sustainable way.
Principles developed outside the water industry can be drawn on and translated to provide further resilient wastewater delivery. Let’s consider, for instance, the construction of effluent treatment plants for the food, beverage and process sectors.
The integration of supplier packages, utilising different construction materials and design horizons, all contribute to the sector achieving best value without impacting on production/manufacturing processes.
There’s much talk about the programme savings associated with offsite manufacture such as DFMA. The practical application of modular construction techniques enables the water industry to realise such savings. For instance, using modular packaged plants allows for more focused build programmes; minimising onsite activities and therefore, site risks can be significantly reduced.
Designed for SMART Delivery
Furthermore, packaged plants embrace a ‘SMART’ delivery concept - Standard, Modular, Agile, Responsive, Treatment. As such, modular systems are well aligned to the ambition of the industry to drive for efficiencies and prove that AMP7 outcomes can be achieved in a sustainable manner.
The delivery of SMART solutions for wastewater requires increased engagement and collaboration with the supply chain. It will enable the water industry to draw on and benefit from experiences of other industries that are deploying responsive modular solutions.
As an example, the use of Dissolved Air Flotation in the food and beverage sector provides a SMART outcome, not just for FOG applications, but also highly loaded TSS; the use of a packaged plant in this manner is proven in reducing the load on existing processes. If this type of process is proven, flexible and readily deployable, then it has a place in the water sector’s SMART delivery chain. It can be coupled with other packaged plants and become a complete works solution.
FEATURE: WATER QUALITY
Water treatment solution for British Sugar
Treatment solution installed at a food factory to meet sewer consent as production increases as those in the future. This might mean
With the focus on environmental performance for the UK water industry, now is the time to evaluate resilience strategies to demonstrate the capabilities of the sector working together with the supply chain.
Summary
We need to be prepared to rethink where and how we invest our efforts and finances. The fact is, a modular outlook on things will bring rewards if applied in the right way. The need to adapt will not only prove how responsive the industry is to meeting the challenging targets, but will also be an opportunity to deliver resilient services to Process Solutions, visit
the customer in a more cost effective way.
The adoption of modular solutions doesn’t processes; it can involve simply thinking about things differently and thus using familiar technologies in smarter, more strategic ways. It is essential that any investment in water treatment is best placed to support current needs, as well building asset bases in an incremental manner or bolting on assets to optimise asset bases. The important thing is that it all adds up to achieving a more sustainable outcome for the industry and environment. With modular treatment solutions, we have the opportunity to deliver investment the SMART way.
To learn more about Siltbuster have to simply mean new technologies and
www.siltbusterprocesssolutions.com
SELWOOD
VICTORIA CLOUGH CULVERT REFURBISHMENT
The Lancashire town of Earby has been prone to devastating flooding in recent years - most notably on Boxing Day 2015, when homes and properties suffered significant water damage.
Since that date, the Environment Agency has worked in partnership with local authorities and Yorkshire Water to develop schemes to reduce the flood risk.
A significant contributor to the problem was the Victoria Clough Culvert, which carries water under the town. Part of the culvert, underneath a disused railway embankment, had collapsed.
In July 2018, a 13-week, £1million project began to replace the collapsed section and to re-line and replace a number of sections along the culvert to reduce the flood risk to 91 properties and 17 businesses. The scheme also included the installation of an improved trash screen at the inlet to the culvert, designed to be easier to clear and to reduce the likelihood of blockages.
The Environment Agency appointed JBA Bentley as contractors for the scheme. Selwood’s pumping solutions specialists were called upon by JBA Bentley to survey the overpumping of the culvert inlet while the trash screen was being upgraded.
The Challenge
While the trash screen works were being carried out, water needed to be overpumped away from the inlet and discharged into a manhole on a public street.
Selwood’s teams needed to move the water a distance of 450m, through woodland that needed to remain open to the public and through areas used by pedestrians, for the duration of the works.
Enabling pedestrians to safely cross the pipework and keeping access open at all times were challenges to be overcome.
The Solution
Because of the health and safety considerations and need for public access, the pumping setup needed to be as neat and tidy as possible. Two Selwood D150 Drainer pumps, connected together using a Y branch, were used to pump the water flow along the 450m distance.
One common line rather than two was used to minimise the amount of pipework involved, and at the point of discharge, the line was enlarged to reduce friction losses within the pipework. This was vital to ensuring the water could travel the distance required.
In the woodland areas, pedestrian bridges were used over the pipework to keep the footpath open. On the areas of public path, road ramps were used. These are wider than the bridges, with a more shallow ramp, helping the flow of pedestrians and providing an easier journey for those using wheelchairs or prams.
The Result
Selwood’s specialists were involved for seven of the 13 weeks of the project, successfully diverting the flow away from the culvert for the duration of the works without causing significant disruption to the public. The site manager reported satisfaction with the project and praised the expertise of Selwood’s team.
The project completed in late August 2019, with a new 40-metre length of culvert installed under the railway embankment and a further 60m relined. The project has been hailed as bringing significant flood risk benefits to homes and businesses in Earby.
The Recommendation
Selwood has signed a three-year deal to support JBA Bentley as a supplier of pump rental solutions. Andrew Ball, Plant Manager at JBA Bentley, said: “We are delighted to extend our long-standing partnership with Selwood. Selwood continues to demonstrate a proactive attitude to safety, an ongoing commitment to finding sustainable solutions that minimise operational carbon and total expenditure, and an unrivalled range of industry-leading assets backed up with exellent service.”
UNIVERSITY OF BATH
TURNING THE TIDE - MICROPLASTICS DETECTION IN WASTEWATER
Understanding the impact of microplastics on the environment and on human and animal health is a crucial challenge for the next century. However, before the true impact of microplastics can be calculated, first we must refine our methods of detecting and categorising microscopic and particle-sized plastics.
Bert Swart, Franciszek Bydalek, Professor John Chew and Dr Jannis Wenk from the University of Bath’s Water Innovation and Research Centre (WIRC) explain how they are approaching the issue and how the water industry can help.
The ecological impact of plastic on the environment has been well-reported: it causes both great ecological damage and is an eyesore. Larger plastic parts from consumer products and packaging can be found almost everywhere, for example in the oceans, at the most remote beaches, in rivers and on roadsides. But perhaps even more concerning that the plastics we can see are those we cannot. Microplastics are defined as plastic particles smaller than 5mm but they can often be microscopically small. Particles present in the environment originate from many sources, such as weathered or worn larger plastics and tyre wear from cars - but they can also be deposited through municipal wastewater. For example, ocean sediments sampled at a depth of several thousand metres have been found to contain almost 2 million microplastic particles per square metre.
The minute size of microplastics makes studying their environmental effects extremely difficult. Like larger plastic, microplastic is persistent in the environment and it presents significant risks. Microplastics can be ingested by small organisms such as krill, shellfish and juvenile fish, as well as larger filter feeders including whale sharks. In these smaller animals, microplastics may disrupt the digestive system with deadly consequences - as many small animals comprising the base of marine, coastal and river food webs and serve as food source for commercially important fish. Therefore, microplastic pollution may eventually affect fish populations, and human food security. Similarly harmful is the way in which plastic can attract pathogens and toxic chemicals known as endocrine disrupting compounds. These chemicals usually exist at very low concentration in water, but they can adhere to or inside plastic particles and become released once ingested. Via a process known as bioaccumulation these toxic chemical may further concentrate through the food web and slowly poison fish and humans that eat that fish.
Beyond a better understanding of the environmental effects of microplastics it is critical to minimise the release of microplastics into natural waters. Wastewater effluent can be a significant source of microplastics, specifically synthetic fibres from clothes and additives of cosmetics such as body scrubs and peeling products.
Most wastewater treatment plants are not designed to efficiently remove microplastics, while detailed inventories of microplastic fluxes through wastewater treatment plants are rarely available. Data collection is often hindered by the absence of fast and reliable microplastic detection methods. Therefore, in our research groups we work on better and more rapid microplastics detection methods to differentiate and quantify microplastics, and assess the severity of the issue in UK municipal wastewaters. Detection and identification of microplastics in wastewater presents various challenges. While particles larger than 0.5 mm are relatively straightforward to extract, smaller particles remain often undetected or may be destroyed during sample processing.
A huge variety of approaches and equipment can be used to detect and quantify microplastics - manual and semiautomated microscopic methods can be used to count particles, as well as materials characterisation via spectroscopy or spectrometry. The challenge is to have fast, less laborious but at the same time accurate, reliable and repeatable detection and characterisation methods for a wide ranging size distribution.
An automated computer-based high speed camera method for microplastics quantification is currently in development within WIRC at Bath.
A successful detection followed by identification of plastic type and shape requires first the removal of any organic and inorganic impurities such as biofilms, fats, proteins and sand. Cleaning methods include the use of strong surfactants and most importantly oxidation processes that remove non-plastic compounds selectively. Nevertheless, many detection methods suffer from 50% losses for particles smaller than 0.05 mm, which leads to a significant underestimation of the total amount of plastic particles.
Following sample preparation, both physical and chemical plastics characterization takes place. There are a variety of different methods available including microscopic techniques for shape analysis microscopic and advanced instrumentation for material analysis. Latter methods are also useful to look at effects of weathering and identify the source of microplastic particles.
In addition to using state-of the art microplastics detection and characterisation methods we have developed a setup that allows the observation and tracking of particles in solution by utilising automated image analysis. The solution is viewed through a transparent viewing slit using a high-resolution camera. Carrying out subsequent electronic image analysis allows easy identification of particle size within the micron range. The system is also being further developed and trained to
FEATURE: WATER QUALITY
Figure 1 Microscopic picture showing a partially weathered microplastic particle.
Figure 2 Image (3.4 x 4.3 mm) showing polyethylene microplastic particles in water. Figure 3 Investigating the fate of microplastics in wastewater treatment plants and constructed wetlands
distinguish different plastic types and non-plastic particles.
Parallel to the development of new the fate of microplastics in wastewater treatment plants and constructed wetlands.
However, we also observed the release of weathered and partially fragmented microplastics at our monitoring/ experimental site, attributed to intense physical and biological degradation processes.
Given the global scale of plastics pollution including microplastics, it seems inevitable that wastewater treatment plants may need to become better at cutting down the release of microplastics into the
detection methods, we are investigating environment.
Progress is already being made as some treatment setups including membrane bioreactor discs and rapid sand filtration or dissolved air flotation are currently reported to be capable of reaching over 95% removal of microplastics. Financial constraints might specifically encourage looking into the potential of existing facilities first, before making large investments. Our work helps to understand the fate of microplastics and can point towards ways for better removal of microplastic from wastewater streams.
We can help you reimagine your water R&D
Water Innovation & Research
Centre
Through the Water Innovation and Research Centre at the University of Bath our experts work with industry, academia, and other stakeholders to tackle the fundamental issues surrounding sustainable water. Through WISE, our Centre for Doctoral Training in Water Informatics: Science and Engineering, we work with collaborative partners to train the next generation of skilled water scientists and engineers.
To explore a partnership with water research experts and students at the University of Bath for your organisation, contact water-research@bath.ac.uk. go.bath.ac.uk/water-research
PUMP THAT SLUDGE – WITH OPTIMUM EFFICIENCY
Intensive techniques like thermohydrolysis produce sludges with higher dry solids content which are more difficult to pump. Image: Severn Trent.
Efficient sludge pumping has an important role to play as water companies gear up for zero carbon, says Mick Dawson, consultancy director, BHR Group, who urges designers and operators to better understand their sludge systems.
by Mick Dawson
More efficient pumping of sludge could help water companies in England reach their goal of net zero carbon emissions by 2030, along with meeting the regulator’s requirement to reduce capital expenditure and cut bills for customers. However, most utilities have not yet acted to reduce the carbon and financial cost of transporting sludge.
For decades the industry standard calculation technique for sludge pumping system pressure losses has been WRc’s TR 185 How to design sewage sludge pumping systems document, which dates back to 1983 and has served the industry well. It suited a pre-digital era when water companies could afford to build in a wide safety margin because energy was
consultancy director, BHR Group
less costly, carbon went unquantified and budgets were bigger.
Other recent factors impacting directly on sludge processing are population growth, which is increasing volumes, and legislation restricting disposal to land. This means utilities are using intensive techniques like thermohydrolysis, which result in sludges with higher dry solids content.
In summary, existing equipment now has to work harder, moving thicker, more concentrated sludges that are more difficult to pump. As with any application, accurate selection and sizing of pumps used for the transport of sewage sludge has important cost implications, along with operational risk management considerations.
Under-sizing can mean failure to achieve the required throughput, whilst oversizing leads to excessive capital cost and energy consumption. Utilities can no longer squander energy and emit unnecessary carbon and the cost challenge means they need to get to know their assets and process streams much better.
Data requirement
The need for leaner pump systems means more variables need to be taken into
account, which can be challenging where the data is not readily available. At the heart of making sludge transport and pumping more efficient is the need to better understand sludge rheology – how it flows.
Variables include pipe size, length, roughness, fittings and elevation as well as the viscosity and temperature of the sludge and the flow rate desired by the operator. To ensure efficient pumping systems, design engineers estimate total pressure losses across the range of variables at a given site. If these estimates are inaccurate this can result in oversized pumps and higher frictional losses, adding considerable capital and operational cost to any system.
The good news is that engineers can now predict sludge rheology and assess and interpret the impact and interaction of these variables through a sophisticated systems losses tool developed by BHR Group. SLOT 2.0, which was launched in January 2020, is a software program developed as part of a research programme originally funded by UK water companies and suppliers.
Operating efficiency
The software enables pump system operators to understand where each pump should be operating on its pump and efficiency curves, matching against the particular system pressure curve to find the operating point. This makes it possible to determine optimum pumpoperating points and identify the most effective pumps to use on a given system – selecting the optimal size, type, quantity and configuration, right down to the manufacturer. Potential blockages can also be identified by monitoring the actual versus the predicted pump performance.
The software shows what is actually happening in the network and can be used to generate scenarios in advance of anticipated changes to the system or the sludge rheology. This means it is now possible to specify pumps more precisely than ever before and the capital cost and optimum energy consumption can be calculated well ahead of installation.
Digital twinning
It is realistic to envision pump system designers using SLOT 2.0 to digitally twin the sludge pipe network. Being able to accurately compare pressure and flow in
FEATURE: WATER QUALITY
BHR’s SLOT 2.0 software helps pump system operators find the operating point of their equipment.
the real network with SLOT’s predictions, it is possible to see, for example, what would happen to pump operation in the event of a struvite blockage; or how the system would respond if a sludge stream was thickened by eight per cent.
For new-build sludge processing projects, SLOT 2.0 is the best tool available for accurate sizing of pumps and pipes. It is underpinned by BHR Group’s sludge rheology database, which is the largest in the world, and makes it much easier to characterise new sludge types that cannot be predicted using existing rheology data.
Future systems
Ultimately, SLOT 2.0 makes it possible for utilities to make investment decisions based on the most comprehensive assessment possible of both capital and whole-life cost of assets, bringing down the total expenditure (totex) required. The possibilities do not end there though. BHR is looking beyond the existing assets in the expectation that more sensors will be installed in sludge networks with the uptake of real-time monitoring.
Fifteen utility and contracting companies in the UK have already trialled sludge management operations with SLOT 2.0 and feedback to date has been very positive. Indications are that the value of being able to predict and manage sludge network performance at the desktop, before going going into AMP 7 – the regulatory asset BHR’s system losses tool SLOT 2.0 can be used to accurately size pumps and pipes used in sludge processing.
management period 2020-2025.
Meanwhile, BHR Group is continually improving SLOT, with further advancements out on site, will prove massively powerful
anticipated as users relay their experiences and requirements. The long-term outlook heralds greater capacity sludge systems with higher velocity throughput and solids content, which means the need for close attention to the whole performance envelope is only going to grow.
