Supply Chain - Water Treatment
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Case Studies
- Embsay WTW (2024)
- Durleigh WTC (2023)
Durleigh WTC (2023)In 2019, Wessex Water launched a £51 million project to upgrade the Durleigh Water Treatment Centre (WTC) in Somerset, which had reached the end of its operational life. This project was crucial in maintaining the delivery of high-quality drinking water to a population of 44,500 and was part of the company’s long-term water supply strategy for the region. Led by Wessex Water’s Engineering & Sustainable Delivery (ESD) department, this was the largest single-value scheme ever undertaken by the company. This case study focuses on the commissioning of the works and follows on from those published in 2020 and 2021:- 2020: Durleigh WTC: Wessex Water’s flagship clean water project
- 2021: Durleigh WTC: Project construction update
Introduction
Construction completed in autumn 2021 after which the 12 months planned period of commissioning began, during which all systems were rigorously tested to ensure that the upgraded water treatment centre met the necessary standards for quality and safety. In late summer 2022, water was supplied to the region and the project was completed within budget and ahead of schedule, providing a valuable additional water resource during the driest summer since 1976. This successful upgrade demonstrates Wessex Water’s commitment to providing reliable water supply of improved quality to its customers for years to come.Multi-barrier treatment for challenging source water
Durleigh Impounding Reservoir, which provides the raw water for Durleigh Water Treatment Centre, is fed by two sources; Durleigh Brook which runs through agricultural land from the Quantock Hills, and the Bridgwater to Taunton Canal via the Albert Street Pumping Station. The combination of these sources, however, introduces high levels of nutrients and several significant contaminants, leading to highly variable quality source water. Given this variability and the need to remove all potential contaminants, a multi-stage treatment process was required alongside the construction of a new wetland at the head of the reservoir. [caption id="" align="alignnone" width="1200"]
New Durleigh wetland - Courtesy of Wessex Water[/caption]
The wetlands have been designed to filter silt and coarse sediment and reduce levels of nutrients, helping to improve the raw water quality entering the reservoir as well as boosting biodiversity by becoming home to a diverse array of wildlife. An existing wet woodland also acts as a final screening process before the water reaches the reservoir.
The two new habitats, constructed to the west of the water treatment centre and reservoir, have brought about a near 75% reduction in the amount of ammonia present in the raw water, while phosphorus and sediments have dropped by around a third.
Treatment processes
The following treatment processes were then selected:- Pre-treatment with sulphuric acid and aluminium sulphate.
- Dissolved air filtration (3 x 10 Ml/d streams).
- pH adjustment (sodium hydroxide dosing).
- 6 (No.) dual media rapid gravity filters.
- Oxidation and pH adjustment (sodium hypochlorite and sodium hydroxide dosing).
- Re-lift pumping by 3 (No.) variable speed end suction pumps (duty/assist/stand-by).
- 6 (No.) manganese removal pressure filters.
- 9 (No.) pressurised granular activated carbon adsorbers.
- Orthophosphoric acid dosing (plumbosolvency control).
- Disinfection using chlorine and sulphur dioxide gases (super-chlorination and de-chlorination).
- pH adjustment (sodium hydroxide dosing).
- High lift pumping 3 (No.) variable speed end suction pumps (duty/assist/stand-by).
- Cryptosporidium inactivation using duty/assist UV treatment.
- Duty/duty lamella clarifiers for wastewater treatment.
Process flow - Courtesy of Project Support Systems[/caption]
Risk based approach to commissioning
The project team recognised that early consideration of the commissioning process would be critical to ensuring successful project delivery. To achieve this, a risk-based approach was adopted throughout the project starting with the design phase. In-house ESD commissioning staff were embedded in the design team and using the digital data available through the schemes BIM360 delivery mechanism undertook a detailed risk assessment of each commissioning activity to identify areas where the design could be revised to increase the efficiency of the commissioning process. By incorporating these changes into the final design, the team was able to expedite process commissioning and reduce testing time by implementing concurrent commissioning of parts of the treatment process. To ensure that the design of the control software met the company’s specifications and aligned with the delivery program, the project team took early ownership of this aspect of the project. The Functional Design Specification (FDS) was produced in-house by staff from the ESD Commissioning & Automation teams, as well as staff from Operations and the scheme designers AECOM. The FDS detailed the software requirements for normal and abnormal operation, setpoints, alarms, and interlocks. By constructing the control in a modular and standardised way, the team was able to achieve flexibility for future operations while reducing delivery and testing time through a simple logical code structure. [caption id="" align="alignnone" width="1200"]
Instillation of 14/25 sand media into manganese removal filters - Courtesy of Wessex Water[/caption]
The risk-based approach continued through the construction and commissioning phases of the project. Critical plant that had been identified during the design phase were subject to enhanced testing and inspection procedures to mitigate the risks and prevent any cost or time impacts. The risk-based approach also ensured that where specialist activities were required the appropriate contractors could be engaged in a timely manner to ensure the installation was delivered to their testing requirements.
By utilising this approach, early involvement in the commissioning process, and careful control design, the project team was able to achieve significant cost and program reductions, while also ensuring that the final design met all project requirements.
Collaboration in commissioning
Wessex Water recognises that project outcomes rely not only on technical expertise but also on effective collaboration between engineering and operations teams. Collaboration between the Engineering Department and Operations Team within Wessex Water has played a pivotal role in the delivery of the Durleigh WTC refurbishment project. Key areas where joint efforts have contributed to project success are:- Design specification collaboration: The engineering department and operations team within Wessex Water worked collaboratively from the project’s initiation to ensure that the design met both engineering standards and operational requirements. By leveraging their expertise, the teams combined engineering principles with operational insights to optimise the facility’s design for efficient water treatment processes.
- Ongoing involvement & secondment: To maintain a continuous exchange of knowledge and promote collaboration, members of the operations team were seconded into the engineering department throughout the project’s duration. This arrangement facilitated the sharing of operational insights and allowed the operations team to contribute valuable input during the project’s progress.
- On-site presence for commissioning: The operations team actively participated on-site several months prior to the completion date to observe and engage in commissioning activities. This early involvement enabled them to gain a comprehensive understanding of the plant’s operations, controls, and processes, ensuring a smooth transition from construction to operation.
Durleigh WTC main treatment building - Courtesy of Wessex Water[/caption]
- SCADA display optimisation: The operations team collaborated closely with the engineering department to optimise the Supervisory Control and Data Acquisition (SCADA) display. Leveraging their operational expertise, they worked together to customise the interface, aligning it with operational workflows and enhancing usability for the operators.
- Exposure to infrequent and abnormal operations: Through their presence during commissioning and early operation stages, the operations team had the opportunity to observe and gain experience with infrequent and abnormal operational scenarios. This exposure enabled them to develop strategies, protocols, and contingency plans to handle such situations effectively.
- Continuous training for operational excellence: Training was an ongoing process throughout the project, with formal training sessions scheduled after the operations team gained prior experience. This approach allowed operators to apply their knowledge and skills in practical settings, ensuring continual improvement and optimal performance.
(left) High lift pump hall and (right) air saturation test of DAF lane - Courtesy of Wessex Water[/caption]
Durleigh WTC: Supply chain - key participants
- Principal contractor: Wessex Water ESD
- Principal designer: AECOM
- Process design: Stantec UK
- CFD modelling: The Fluid Group
- Project and O&M documentation: Project Support Systems
- Temporary works & shoring: MGF Ltd
- End suction pumps: SPP Pumps Ltd
- Electrical installation: Field Systems Designs
- MDB/MCCs: GPS Group
- Lamella clarifier: Hydro International
- DAF saturation system: Quantum Engineering Developments Ltd
- Large bore pipework: Powerrun Pipe-Mech
- Large bore pipework: Berry & Escott
- Inlet screen air scour: Eliquo Hydrok Ltd
- UV treatment: Trojan Technologies
- Valves: AVK UK Ltd
- Air blowers: Aerzen Machines
- Polyelectrolyte dosing: Richard Alan Engineering
- Sodium hypochlorite dosing: WES Ltd
- Chemical dosing: DMS Engineering
- Chemical dosing: MBH Engineering
- Access steelwork: Dan’s Engineering
- Tank & vessel manufacturing: Vessco Engineering
- Desiccant drying systems: Aggreko
- Ice pigging: Suez Water Technologies
- WQ monitors: SWAN Analytical UK Ltd
- WQ monitors: Malvern Panalytical
- WQ monitors: Yokogawa UK Ltd
- WQ monitors: ATi UK
- WQ monitors: Metrohm
Durleigh WTC to Danesborough Service Reservoir Trunk Main
The recommissioning of the trunk main connecting Durleigh WTC to Danesborough Service Reservoir presented unique challenges, and required meticulous planning.- Assessing the condition & risks: The 1.7km long rising main, constructed from epoxy-lined ductile iron, served as the crucial link between Durleigh WTC and Danesborough Service Reservoir. However, the last 80m of the main were unlined and known to be a source of discolouration, with elevated levels of turbidity and iron. Although it had been flushed to a flow rate of 26 Ml/d prior to the old works’ removal from supply, it had been out of service for three years and it was essential to address the remaining risks and restore the main’s integrity.
- Ice pigging solution: Considering the limitations in delivering the required flow with Durleigh WTC still out of service, a decision was made to employ a technique known as ice pigging for the last 80m of the rising main. To execute this task, Wessex Water engaged the expertise of Suez Water Technologies, a specialist ice pigging team. The ice pigging involved the introduction of a 10m3 ice slug into the main, followed by a 90-minute flushing process.
- Effective turbidity reduction: The implementation of ice pigging, followed by flushing, proved highly effective in removing 21kg of solid material from within the last 80m of the rising main. This achievement was crucial in mitigating risks and guaranteeing the quality of the water to the Danesborough Service Reservoir.
Ice pigging flushing samples - Courtesy of Wessex Water[/caption]
- Comprehensive pressure testing & disinfection: To ensure the integrity and reliability of the entire rising main, Wessex Water’s in-house disinfection team carried out a comprehensive pressure testing and disinfection process. The main underwent rigorous testing over a 72-hour period, subjecting it to stringent protocols to confirm its ability to withstand operational demands and maintain water quality standards.
- Successful restoration & return to supply: Following clear sample results and meeting the required water quality standards, the recommissioning process was successfully completed, and the Durleigh WTC to Danesborough Service Reservoir rising main was returned to supply. This significant milestone was achieved in late September 2022, marking the successful completion of the project.
Conclusion
The successful completion of the Durleigh Water Treatment Centre upgrade project by Wessex Water represents a significant milestone in the company’s commitment to delivering high-quality drinking water to its customers. This ambitious project, the largest single-value scheme ever undertaken by Wessex Water, was executed with meticulous planning, collaboration, and a risk-based approach. Through the implementation of advanced treatment processes and a comprehensive control software design, the upgraded facility ensures the removal of potential contaminants, guaranteeing the provision of safe and reliable drinking water to its customers. [caption id="" align="alignnone" width="1200"]
Low lift pumping area - Courtesy of Wessex Water[/caption]
The project team’s focus on collaboration between the engineering department and operations team, along with their early involvement in the commissioning process, played a vital role in achieving remarkable results. By optimising the design specifications, streamlining the commissioning process, and fostering a culture of continuous learning, the team not only met project requirements but also set a new benchmark for water treatment engineering. This successful endeavour displays Wessex Water’s dedication to sustainable water management. - Hanningfield WTW - Washwater System (2023)
- Alderney WTW (2023)
Embsay WTW site layout render - Courtesy of Mott MacDonald Bentley[/caption]
(left) Final backfilling and reinstatement, (top right) main structures under construction and (bottom right) precast concrete contact tank construction - Courtesy of Mott MacDonald Bentley[/caption]
Backwash tank and pumping station construction - Courtesy of Mott MacDonald Bentley[/caption]
Synchro 4D Programming - Courtesy of Mott MacDonald Bentley[/caption]
New pumping station layout 3D model - Courtesy of TES Group[/caption]
Refurbished pumping station: (left) 3D model - Courtesy of TES Group and (right) pumping station layout - Courtesy of Essex & Suffolk Water[/caption]
3D model of the whole works - Courtesy of TES Group[/caption]
(left) Concrete pour for pumping station base and (right) the pumping station superstructure and tank bases construction - Courtesy of Farrans Construction[/caption]
Installed new pumps and gantry crane - Courtesy of Essex & Suffok Water[/caption]
New tanks during commissioning - Courtesy of Essex & Suffolk Water[/caption]
3D model inside the new Alderney WTW - Courtesy of South West Water[/caption]
Alderney WTW: Process flow diagram - Courtesy of South West Water[/caption]
3D model inside the new Alderney WTW - Courtesy of South West Water[/caption]
Outline/detailed design: ONGOING
Further progression of the detailed design well progressed to provide greater definition of the proposed works. This includes refinement of the process design to ensure an optimised whole life cost and carbon footprint, and development of the 3D model to finalise civils structures.
Engagement is also ongoing with various equipment manufacturers (for example, the chosen membrane supplier) to confirm plant layouts, control philosophy and power requirements.
Construction: ONGOING
Construction activities have been progressing on site over the last year. The enabling works have included ground clearance and demolition of old buildings over the construction area. Foundation/piling work is also now complete in preparation for the above-ground structures which will progress on site at the back end of 2023.
(top right) Final stage of demolition and the start of the large diameter pipework buried below the GAC contactors and process buildings and (left & bottom right) temporary works: installation of sheet piles prior to the excavation of the regen tank and chlorine contact tank - Courtesy of KIER[/caption]
Innovations
- SAM50 - Ultra-efficient Reverse Osmosis (2023)
SAM50 - Ultra-efficient Reverse Osmo...Reverse Osmosis (RO) will play an essential role in helping the water industry tackle the numerous environmental and sustainability challenges it faces. Global climate change is causing increased stress on water resources around the world, and this means more reliance on desalination of brackish and sea water sources to provide drinking water security. The technology of choice for these applications is RO. Nutrient pollution of waterways is another problem, and effective technologies are required for the removal of nitrogen and phosphorus from sewage works final effluent. In the industrial sector, RO can remove toxic elements and recover valuable minerals and metals from wastewater as well as providing opportunities for water reuse and recycling. With such a diverse range of applications, RO has the potential to ensure a cleaner, greener, and more water secure future. But traditional RO is energy intensive. SAM50, using ultra-efficient batch RO technology, significantly reduces the energy requirements, and provides the ideal solution for a growing demand far more sustainably. [caption id="" align="alignnone" width="1200"]
Benefits of the SAM50 batch RO system - Courtesy of Salinity Solutions[/caption]
Compact batch reverse osmosis technology
The SAM50 Batch RO system uses a pressure exchange vessel and valve control, both patented, to minimise the pressure in the system and therefore reduces energy requirements by 50% whilst purifying up to 98% of the water, producing 30% more clean water and generating 80% less waste than conventional RO systems. The compact system is containerised and easily transportable, and is the first batch RO product in the world to be manufactured commercially. SAM50 offers a sustainable, low energy water treatment solution that reduces both carbon footprint and operating costs. The technology, for which a European Patent Application has been granted, is suitable for desalination, wastewater treatment, water recovery, and industrial process and utility water treatment. Designed by Salinity Solutions the ultra-efficient batch RO system is manufactured by Te-Tech Process Solutions, part of Trant Engineering. The technology was co-developed over the past 10 years at the University of Birmingham and Aston University, by Tim Naughton, co-founder of Salinity Solutions, alongside Professor Philip Davies, Head of Water Technology Research, University of Birmingham.How it works
SAM50 is a fully automatic batch RO system. It consists of a high-pressure feed pump, a recirculation pump, industry standard RO modules and a free-piston pressure exchanger that operate in a cyclic manner using only three automatic valves as shown in the flow diagram: [caption id="" align="alignnone" width="1200"]
SAM50 pressurisation phase (left) and purge and refill phase (right) - Courtesy of Salinity Solutions[/caption]
In the first phase of the cycle, the pressurisation phase, the feed pump applies pressure to the feed side of the pressure exchanger, matching the minimum osmotic pressure of the water in the batch. This pressure is transferred to the batch of water that is being processed via the free moving piston. The batch then passes through the membrane module, producing permeate and a reject stream. The reject stream is then recirculated into the pressure exchanger via the recirculation pump. During this process no additional feed is added. This causes an increase in the concentration of the recirculation loop.
As the concentration inside the recirculation loop increases over time, the feed pump will generate a higher pressure to overcome the increasing osmotic pressure, causing the piston to slide to the right. This allows for the average pressure of the cycle to be lower than any competing RO technology, thus reducing the energy demand. When the piston reaches the end of its travel, the pressurisation phase ends, the automatic valves change position and the purge-and-refill phase begins. During this phase, concentrated reject brine is discharged to waste and the free piston moves to the left back to its original position.
This cyclic operation not only reduces energy consumption but also allows a much higher water recovery and, hence, reduced waste. In one recent customer field trial on brackish water application, the SAM50 achieved a 95% recovery rate and a concentrated brine with a 13 x concentration factor while producing a permeate quality of less than 10μS/cm, at a specific energy consumption of 0.5 kWh/m3.
Case Study 1: Mineral extraction - Cornish Lithium
A successful field trial, in collaboration with Cornish Lithium, helped reduce the high carbon footprint of lithium extraction from shallow well geothermal waters in Cornwall - a previously untapped resource. The SAM50 system helped achieve x 7 lithium concentration.Case Study 2: Nutrient removal - Wessex Water
Salinity Solutions, Te-Tech Process Solutions and Wessex Water have delivered a no-cost trial for Somerset Council to demonstrate the efficacy of their modular water treatment units for nitrogen and phosphate mitigation. A SAM50 system was placed at the Fivehead Water Recycling Centre near Taunton for two weeks allowing independent water sampling to be undertaken. The trial demonstrated the effective removal of dissolved nutrients, nitrogen, and phosphorus, which are otherwise discharged into rivers, causing environmental contamination. Early indications show promising results with the first verified laboratory results showing over 98% of phosphates and 88% of nitrates removed. [caption id="" align="alignnone" width="1200"]
Sarah Dyke, MP for Somerton and Frome, visiting the pilot trial at Fivehead Water Recycling Centre. Sarah’s visit follows Rebecca Pow’s ministerial visit, alongside representatives from various government departments - Courtesy of Salinity Solutions[/caption]
Key features & benefits
- High energy efficiency (>0.5 kWh/m3).
- Up to 98% water recovery.
- Produces 30% more clean water and 80% less waste water compared to conventional RO systems.
- Modular and scalable.
- Small footprint.
- Up to 50x brine concentration.
- ‘Plug & play’ installation.
- Engineered in the UK.
- Uses any standard 8” RO membrane.
Award winning technology
Salinity Solutions won the 2023 Water Industry (WIA) Energy in Water Award and were also highly commended in the category of Wastewater Innovation Project of the Year. They were also awarded Manufacturing StartUp of the Year in the StartUp Awards (Midlands). [caption id="" align="alignnone" width="1200"]
The containerised SAM50 unit arriving on site for the field trial at Cornish Lithium - Courtesy of Salinity Solutions[/caption]
References
- Park K et al Design, modelling and optimisation of a batch reverse osmosis (RO) desalination system using a free piston for brackish water treatment Desalination 494 (2020) 114625.
- Hosseinipour E et al A free-piston batch reverse osmosis (RO) system for brackish water desalination: Experimental study and model validation Desalination 527 (2022) 115524.
This paper was prepared by Te-Tech Process Solutions and Salinity Solutions.
For more information: Te-Tech Process Solutions Ltd | +44 (0)2382 351600 | www.te-tech.co.uk
- Detecting Hydrocarbon Contamination (2023)
Detecting Hydrocarbon Contamination ...A municipal wastewater treatment plant in Poland was struggling with a persistent issue; hydrocarbon contamination in the wastewater coming into the plant. The plant had not been designed to deal with high levels of hydrocarbon contamination, such as that coming from untreated industrial wastewater, which meant that every time there was a contamination event in the sewerage system, the WwTP performance was affected and, in the worst case, contamination was also released into the environment and regulations were broken. Moreover, the activated sludge performance was affected and, if the levels were high enough, this could lead to the process needing to be stopped altogether.The solution
In the spring of 2022, Multisensor Systems Ltd’s Polish distributor (GREMES) was contacted to review options and following preliminary discussions, engineers at GREMES proposed an MS1800 VOC gas analyser to be installed directly above the sewage line. The MS1800 is designed to monitor VOC concentration in the headspace above the wastewater and from this, calculate the hydrocarbon contamination within the wastewater. [caption id="" align="alignnone" width="1200"]
Installation diagram - Courtesy of Multisensor Systems Ltd[/caption]
The instrument was installed in a temperature controlled cabinet, ensuring that the analyser’s technical specifications were met in the open air. The system was linked to a remote control system to provide a live data feed and allow the user to generate reports and alarms.
The site selected for the installation is a wastewater pumping station, the last before the intake of the WwTP. This has made the installation more straightforward and, with a constant flow of wastewater, reduced the risk of H2S build-up that could be detrimental to the longevity of the system.
The data
The instrument was installed in July 2022 and, aside from a brief pause, has (at the time of writing - April 2023) been working non-stop ever since. The data below shows how the instrument has clearly identified several peaks over the course of several months. These peaks have been positively associated with contamination events and corroborated by analysis carried out by the WwTP. After several months of testing the client is extremely satisfied with the results and is in active discussions with GREMES to develop the next phase of the project that will consist in deploying a network of analysers across strategic points in the sewerage network. [caption id="" align="alignnone" width="1200"]
Graph showing hydrocarbon readings from September 1, 2022-March 1, 2023 (graph produced by independent software) - Courtesy of Multisensor Systems Ltd[/caption]
Uses
The MS1800 in this installation will be mainly used to identify contamination events and locate the source of pollution but also to protect the WwTP by diverting industrial wastewater for separate treatment.Strengths
This system allows the accurate on-line monitoring of hydrocarbon contamination in the sewage system, without touching the water, designing out of the equation words such as 'cleaning', 'maintenance' and 'filtering'.Conclusion
As can be seen from the data above, the MS1800 is an excellent solution for the monitoring of hydrocarbon contamination in any sewerage network. If your operations are suffering from unexpected hydrocarbon contamination at the raw wastewater intake of your WwTP, you can get in touch and discuss your case with our consultants.
This article was prepared by Multisensor Systems Ltd Alexandra Court | Carrs Road | Cheadle | SK8 2JY P: +44 (0)161 491 5600 | E: [email protected] | www.multisensor.co.uk
- Safe Return of Recovered Process Water (2023)
- Silicon Carbide Ceramic Membranes (2024)
Recovered process water recycling at WTWs - Courtesy of WSP[/caption]
Technology appraisal: long list of solid-liquid separation technologies - Courtesy of WSP[/caption]
Coagulation/flocculation and sedimentation process groups - schematics from (Gandiwa, 2020) (watertectonics.com, 2022) (van Djik, 2007)[/caption]
Among seven different types of depth filtration analysed in this study, the down-flow systems with continuous backwash showed the highest removal efficiency. Moreover, newly developed activated glass media was suggested to be more efficient at removing particles of 15 µm and smaller, compared to the conventional sand media. Therefore, upon more trials, these emerging media may be proven to be more suitable for the removal of viruses and Cryptosporidium from recovered process water streams.
Slow sand filtration has 20-50 times smaller flux than depth filtration, and thus it requires much larger footprint. Nevertheless, the free-gravitational operation of the system and no backwash requirements are among the key advantages of slow sand filters. These systems are not very efficient for total suspended solids (TSS)/turbidity removal (~90%), but highly effective for Cryptosporidium (up to 3 log) and viruses (1 – 4 log).
Surface filters offer higher efficiency than depth filtration with respect to TSS/turbidity. The backwash is also more efficient (2-5% of effluent) compared to depth filters (4-8% of effluent). However, sensitivity to influent quality (i.e. best at TSS< 20 mg/l) makes surface filters less suitable for recovered process water treatment compared to depth filters. Among different types of surface filtration methods analysed in this study, the bag filter offered the widest range of pore size (2-75 µm), and thus its design deemed to be easier to be tuned according to the specific contaminants in the recovered process water streams.
[caption id="" align="alignnone" width="1200"]
Depth filtration, slow sand filtration and surface filtration process groups – schematics from (Bielefeldt, 2011) (Metcalf & Eddy, 2014) (Eliquo Hydrok, 2020) (Rosedale Products, 2015) (mena-water.com, 2022)[/caption]
Sedimentation, slow sand filtration, depth and surface filtration were in the same order of magnitude in terms of both CAPEX and OPEX. Conventional sedimentation (i.e. horizontal flow) and slow sand filtration offer the lowest overall cost and the simplest operation. Nevertheless, where space is a major constraint, the addition of lamella plates to the conventional sedimentation tanks, and/or the use of higher rate depth or surface filtration, instead of slow sand filtration can offer footprint efficiency at a slightly higher CAPEX.
The OPEX of solid-liquid separation technologies would increase when they are paired with coagulation/flocculation processes. The addition of coagulation/flocculation can significantly boost the performance of some technologies (i.e. sedimentation, slow sand filtration, depth filtration and surface filtration), but is less beneficial for other technologies (i.e. MF/UF and microfluidic systems).
Microfiltration (MF) and ultrafiltration (UF) offer modular and high efficiency solutions for fine solids removal, specifically with regards to viruses (up to 7 log removal) and Cryptosporidium (up to 6 log removal). Still, their sensitivity to fouling, scaling and large solid blockage (i.e. pre-treatment requirements) and high TOTEX are among the main considerations of applying these technologies. Among the different types of MF and UF configurations reviewed, hollow fibres offer better flux to volume (i.e. economy of scale) due to their high surface to volume ratio. Spiral wound types are also compact, but their resistance to positive hydraulic pressure make them more suitable for nano filtration (NF) and reverse osmosis (RO). In terms of material, emerging metallic membranes have been shown to be mechanically robust and efficient for the removal of fine particles, such as Cryptosporidium (5.1-5.4 log removal). Yet, further trials are needed before adapting these membrane types in a large scale in the water industry.
The small footprint, modularity, and scalability of membrane technologies make them a suitable choice for small WTWs, where having a compact design is a priority. Moreover, MF/UF offer effective removal efficiencies (i.e. up to 7 log removal for viruses, up to 6 log removal for Cryptosporidium) for where a high degree of purification is necessary. Still, for larger WTWs and/or where lower ratio of recovered process water recycling is required, MF/UF membranes do not offer an economically feasible option. The high cost of membranes makes MF/UF technologies 10 – 15 times more expensive in terms of CAPEX than other technologies, while the high cost of pumping energy (0.2-0.3 kWh/m3) make the OPEX of MF/UF systems 2-15 times higher than other solid-liquid separation techniques, except microfluidic devices.
Activated carbon adsorption (GAC/PAC) is not an efficient method of solid separation. However, it can offer effective polishing (as post-treatment) for other technologies to minimise the taste and odour issues in the recycled recovered process water. Among different configurations, the up-flow GAC columns offer higher efficiencies as they promote a greater surface contact between the granules and the effluent. The disadvantage of the up-flow systems is the higher OPEX associated with pumping and the risk of media loss into the final effluent. The costs of GAC are very similar to that of depth filtration, unless considering the assets and energy required for media regeneration, which would make the costs 2-5 times higher than that of depth filtration.
Inertial focusing (IF) microfluidics are among the emerging and rapidly growing methods of solid removal from water systems, working based on the selective separation of microparticles through variously sized microchannels. Separation efficiencies up to 96% for Cryptosporidium and 99% for microplastics have been achieved in the lab-scale. Microfluidic separation is a chemical-free and easily scalable process, with an in-built ability of waste streams segregation and collection. However, sensitivity to blockage (i.e. requiring significant pre-treatment) and the low level of technology readiness (lab tested with drinking water and Cryptosporidium, scaled up for other applications), are some of the main challenges for the full adoption of this technology in the water industry.
[caption id="" align="alignnone" width="1200"]
MF/RO membrane separation, GAC/PAC adsorption, and microfluidic separation processes – Schematics from: (PCI Membranes, 2021) (Applied Membranes Inc, 2021) (reverseomosis4operators.com, 2021) (Balster, 2013) (ElgaLab, 2021) (Jimenez & Bridle, 2016) (Tang, 2020) (Miller, 2016)[/caption]
Cost estimations for inertial focusing microfluidics were provided by a UK-based vendor, extrapolating figures from previous smaller scale installations. The estimations suggest the lowest CAPEX among all processes (~3.4 £/m3), owing it to the significant advancements in the material and manufacturing methods (e.g. 3D printing, laser cutting, etc.) in the recent years. The OPEX however, is still the highest among all processes, about 2-10 times higher than MF/UF membranes, and 10-100 times higher than other separation processes. The high OPEX of microfluidics is due to the cost of pumping fluids through small micro channels. It is clear that significant reduction in pumping energy is necessary for microfluidic devices to be introduced as competitive solid-liquid separation technology in the water industry.
For the liquid waste (i.e. backwash from filtration and/or retentate/concentrate from the membrane systems) recycling to the head of the works, or mixing with the untreated process water, are key possibilities. However, further intermediary treatment (e.g. clarification) may be required depending on the quality of the liquid waste.
[caption id="" align="alignnone" width="1200"]
Treatment technology comparison overview - Courtesy of WSP[/caption]
Cost-quality model: In order to assist water companies in the UK and the Republic of Ireland to compare and select the most appropriate recovered process water treatment processes, based on the characteristics of the incoming recovered process water streams, as well the resilience state of the existing treatment processes on each particular site, a quantitative cost-quality model was developed. The model generates as an output the following key analytics:
Model output example: scenario-based treatment technology & configuration comparison - Courtesy of WSP[/caption]
Monitoring method selection: The main methods of detection and monitoring of microplastics, Cryptosporidium and viruses were grouped and reviewed under three main tiers, based on the methods ease of use/time to result, and the accuracy/quality of the results from each method.
[caption id="" align="alignnone" width="1200"]
Key methods of detection & monitoring - Courtesy of WSP[/caption]
Selection of monitoring methods should consider that recovered process water streams are likely to be relatively highly contaminated so any method should perform well under such conditions. Additionally, a review of particle counters noted that for particle counting there was good correlation between particle counts and oocyst numbers after coagulation/sedimentation treatments and slow sand filtration, but not after membrane filtration methods. Hence, it is important that the choice of monitoring method should consider the treatment methods used.
[caption id="" align="alignnone" width="1200"]
Detection and monitoring method selection - Courtesy of WSP[/caption]
Cembrane SiC membranes, modules, stacks & towers - Courtesy of Enpure Ltd[/caption]
Applications of Cembrane SiC membranes - Courtesy of Enpure Ltd[/caption]
(left) Installation of Cembrane SiC stack, (top right) Cembrane SiC stack from above, and (bottom right) SiC membranes have sprinkler cleaning option - Courtesy of Enpure Ltd[/caption]
Mini CS & Company News
- Hampton Loade WTW - LDPE Protectaflex
Hampton Loade WTW - LDPE Protectafle...- Customer: Ross-shire Engineering for South Staffs Water
- Application: Chemical dosing and transportation
- Chemicals: Including lime, poly, aluminium, PAC, hypo, caustic and bisulphite
- Transfer lines: Total length: 2940m | Material: LDPE Protectaflex dual contained hose : Sizes: 19mm and 25mm
FT Pipelines dual containment hose[/caption]
For more information: FT Water Treatment: +44 (0)1543 416024 | www.ftwatertreatment.co.uk
- Sandown WSW
Sandown WSWSouthern Water’s Sandown Water Supply Works is located on the south-east of the Isle of Wight and supplies drinking water to Sandown and Shanklin. The average winter demand of 7.7 Ml/d can almost double up to 13 Ml/d in the summer due to tourism. Southern Water’s Asset Strategy requires a reliable supply of 12 Ml/d of treated water from the works. A risk assessment to establish resilience of the works' infrastructure identified the ageing clear water tank and high lift pumping station as potential weaknesses which could affect supply. Southern Water awarded Trant Engineering a £10m design and construct contract, Phase 1 for the replacement of these assets. Phase 2 of the project works is for improvement of wash water discharge and flood resilience on site, and Phase 3 includes installation of new caustic soda offloading and storage facilities together with new dosing equipment installed in a new GRP kiosk.
The story so far
The new Phase 1 high lift pumping station will deliver up to 8 Ml/d to Shanklin Service Reservoir and up to 14 Ml/d to Brading Service Reservoir via existing ultraviolet reactors along with the power supply and motor control centre (MCC2). The contract also covers extensive pipework modifications and the installation of new supply flow meters, treated water aluminium monitoring and triple validated contact tank outlet chlorine residual monitoring. Prior to commencing on site, Trant undertook a series of surveys and investigations which identified a number of construction challenges. In addition to the requirement to keep the works in operation during the work, the site is located within an AONB, which required planning permission and environmental mitigations being satisfied for limited environmental impacts. Due to site space constraints and the need to cut down disruption to live treatment plant, Trant identified early on that the need to build the new equipment offline as far as possible and to provide a new incoming power supply, so that the new equipment could be powered up and tested independently of the existing works. [caption id="attachment_16889" align="alignnone" width="1200"]
The new glass-coated steel sectional clear water tanks - Courtesy of Trant Engineering[/caption]
Innovative design
To reduce excavation work, Trant proposed a design using two new glass-coated steel sectional clear water tanks, 6m diameter and 7m high, constructed above ground on a brownfield area of the site. The tanks feed two sets of five, vertical multistage pumps, one set for Brading and one for Shanklin, installed above ground mounted on concrete plinths, with a surrounding steel access platform with staircase at either end. Due to the level of the outlet of the contact tank being below ground, an intermediate 're-lift' pump station was introduced to feed the clear water tanks. The re-lift pumping station used a jacketed shaft construction method to avoid heavy temporary works. Southern Water’s Senior Project Manager, Kev Fausset said:“Trant was very pro-active in proposing innovative designs to minimise below-ground works and build off line for least disruption to live process works. That has helped to maintain supply and reduce the overall programme of works.”
[caption id="attachment_16888" align="alignnone" width="1200"]
Inside one of the new glass-coated steel sectional clear water tanks - Courtesy of Trant Engineering[/caption]
Looking forward
Trant started on site in September 2023 and the scheme has made a great start with significant progress on the civil construction works. However, a high volume of complex works remains to be delivered on the scheme within what is a challenging programme and site environment. Tony Jacobson, Trant’s Senior Project Manager said:“Success will be achieved through ongoing collaboration with our client, supply chain and the wider water industry. The new clearwater tanks will be installed during the summer and the new MCC and electrical work will be completed in time for the arrival of the new pumps in the last quarter of 2024. Simultaneously, we are progressing the mechanical and electrical works for Phases 2 and 3 so that the project delivers on all its objectives and provides an excellent standard of new and upgraded assets.”
For more information: Trant Engineering Ltd | +4423 8066 5544 | www.trant.co.uk |
- Seedy Mill WTW - LDPE PF Detect
Seedy Mill WTW - LDPE PF Detect
- Customer: IWS for South Staffs Water
- Application: Chemical dosing and transportation
- Chemicals: Sodium Hypochlorite 14%
- Transfer lines: Total length: 930m | Material: LDPE PF detect leak detectable dual contained hose | Sizes: 12.5mm & 25mm
FT Pipelines dual containment hose[/caption]
For more information: FT Water Treatment: +44 (0)1543 416024 | www.ftwatertreatment.co.uk
- P Removal
P RemovalProject Challenge
Although phosphorus is a necessary nutrient for plants and animals, excessive phosphorus in waterways can lead to the extreme growth of plants and algae. High levels of plants and algae in the water can have a detrimental impact on aquatic life and the quality of water, including low dissolved oxygen concentrations.Solution
Dutypoint successfully supplied, delivered and installed its weatherproof GRP kiosk, the QuadraTANK™, incorporated with a standardised wash-down package, ensuring it was efficiently operational and ready for use. The product was manufactured to the client’s project specifications and houses a water storage tank, controls, twin booster pump system for a network of wash-down points. To meet the client’s needs of removing phosphorus, the wash-down capabilities of the QuadraTANK™, combined with an additional hose reel component, provided a solution to significantly improve water quality by aiding in the removal of phosphorus, resulting in a very happy client. The wash-down additions are a valuable feature in hitting water regulations, including its CAT 5 protection capabilities. Our hose reel was a built-in check valve (one-way valve), which prevents the backflow of hazardous contaminated water into the water systems. [caption id="attachment_12307" align="alignnone" width="1200"]
QuadraTANK™ with Additional wash-down/Irrigation hose reel[/caption]
For more information about Dutypoint Ltd | 01452 300110 | www.dutypoint.com
For more information about QuadraTANK | 01452 300110 | QuadraTANK™
About Dutypoint Ltd
Since 1976, Dutypoint has become one of the leading players in fluid technology, trusted by clients in the UK and overseas. Integrity, transparency, accountability and clear communication are crucial to how we do business. We stand by what we say - today and every day. The Dutypoint range includes a variety of industry-leading products, including cold water booster sets and QuadraTANK™. - Hampton Loade WTW - LDPE PF Detect
Hampton Loade WTW - LDPE PF Detect- Customer: IWS for South StaffsWater
- Application: Chemical dosing and transportation
- Chemicals: Sodium hypochlorite 14%
- Transfer lines: Total length: 2420m | Material: LDPE PF Detect leak detectable dual contained hose | Sizes: 12.5mm & 25mm
FT Pipelines dual containment hose[/caption]
For more information: FT Water Treatment: +44 (0)1543 416024 | www.ftwatertreatment.co.uk
Jobs
- Senior Civil Engineer - Water (6286)
Senior Civil Engineer - Water (6286)The opportunity
Across the entire business, Stantec are building on top of what’s already been a highly successful period of growth. Our strategy within the Water division for 2023 and beyond is creating a number of new exciting opportunities across the business. We partner with the top water clients across the UK, work on some of the largest, most iconic water projects in the industry and we promise to design with community in mind by reducing environmental impacts and improving social impacts. We enable the delivery of sustainable development and infrastructure projects that adapt to and mitigate the effects of climate change. Our Civil Engineers work across the project lifecycle in asset planning / strategy, concept design, outline design and detailed design. We work in a variety of project areas within the water sector, including clean water treatment and networks, wastewater treatment, wastewater networks, flooding, and urban drainage. You can find out more about our work in the water sector here: Stantec H2O+U - UK. You’ll be responsible for the project’s civil engineering design, the leadership of civil engineering teams and will work alongside our overall project design leads to ensure successful project delivery and outcomes for our clients. You will also have access to Stantec’s world-class expertise to help you deliver cutting edge design.About You
You’ll have experience working as a Civil Engineer on projects within sectors such as the water, environment or other related infrastructure sectors. Ideally you will hold Chartered or Incorporated member status with a relevant professional body such as ICE or CIWEM. You’ll have a passion for the water and environment sector and supporting our developing civil engineers. You’ll also be experienced in successful project delivery and working collaboratively with project teams to develop innovative solutions. Finally, you will have experience of working in a client facing role, leading client engagement and collaboration on a regular basis.
About Stantec
The Stantec community unites more than 31,000 employees working in over 450 locations across 6 continents. We have been working with our clients and communities in the UK for over 150 years. We plan, design, deliver and manage the development and infrastructure needed to support the creation of sustainable, healthy and prosperous communities. Our teams provide effective and relevant solutions, translating our clients’ vision into valued consents, deliverable plans for projects and programmes, and efficient designs for delivery, based on technical excellence and deep market insights. We deal with today’s challenges, but also keep a fairer, better tomorrow in sight, looking at how we deliver clean growth, support radical changes in our economy and meet the needs of future communities. Stantec provides equal employment opportunities to all qualified employees and applicants for future and current employment and prohibit discrimination on the grounds of race, colour, religion, sex, national origin, age, marital status, genetic information, disability, sexual orientation, gender identity or gender expression. We prohibit discrimination in decisions concerning recruitment, hiring, referral, promotion, compensation, fringe benefits, job training, terminations or any other condition of employment. Stantec is in compliance with laws and regulations and ensures equitable opportunities in all aspects of employment. Building an inspired, inclusive work environment that attracts, supports, and develops world-class talent is a crucial key to our success. If you are excited by this role but worry that your experience doesn’t exactly align, we encourage you to apply. - Civil Engineer - Water (6331)
Civil Engineer - Water (6331)
The opportunity
Do you have a passion for Civil Engineering ? Are you driven to create solutions for the unprecedented climate, environmental, and efficiency challenges facing our clients and the wider community? Then make a real difference and join us at Stantec! We are excited to continue our growth journey in Ireland and Northern Ireland and we have exciting plans for expansion in 2025 and beyond. We look forward to continuing our work with Uisce Eireann on the Engineering Design Services Framework and in Northern Ireland, we are proud to have been appointed to Northern Ireland Water’s IF182 Professional Services Framework. Taoiseach Simon Harris recently opened our new Dublin office, and we have now also moved to a new city center office in Belfast. This exciting pipeline of work, coupled with the scale of opportunity across the AMP8 cycle in the UK means that we seeking Civil Engineers at all levels with experience in the water/wastewater industry to join us. We are flexible with location so the position can be based in Dublin, Belfast or elsewhere. You will have the opportunity to join a dynamic team spread across the UK and Ireland, supporting the delivery of a variety of projects as part of a major capital investment programme.You will play an important role in the team, developing technical solutions & providing advice to our clients. You will provide technical expertise to ensure projects are delivered to cost, schedule & quality standards and work collaboratively amongst multi-disciplinary teams to ensure first class delivery of our projects. You will work closely with external stakeholders & clients to develop long term relationships.About You
You will be Degree qualified (or equivalent) in Civil Engineering or other relevant subject and have some experience of working within the regulated water industry.You will have knowledge of water and wastewater infrastructure/networks and treatment. Due to the nature of upcoming projects, ideally, you will also have experience in areas such as Clean Water and Wastewater Treatment, Trunk Mains and Large Diameter Pipeline Design.Ideally, you’ll have previous consultancy experience in a design role.Most importantly, you’ll embody our values and ethos of client focus and service excellence and have a passion for making a difference in the Water sector.Why Join us?
- Our People Culture: We're a close knit team and very proud of our friendly and collaborative environment
- Growth: We're on an exciting growth journey in Ireland and Northern Ireland - we want you to be part of it!
- Awards: Stantec were awarded the International Consulting Firm of the Year and Best place to work - Large Consulting Firms at the 2024 NCE awards as well as being consistently recognised in the top 10 Corporate Knights most sustainable companies in the world.
- Great Benefits: Competitive salary, pension plan, holidays, free private medical insurance, discounted gym membership and lots more.
- Flexible working arrangements
- Great Projects: We have secured positions on both the Uisce Eireann and NI Water Frameworks and are delivering a wide variety of projects that will make a real difference to our communities
- Industry leading training and development as well as paid for professional subscriptions
About Stantec
The Stantec community unites more than 31,000 employees working in over 450 locations across 6 continents. We have been working with our clients and communities in the UK for over 150 years. We plan, design, deliver and manage the development and infrastructure needed to support the creation of sustainable, healthy and prosperous communities. Our teams provide effective and relevant solutions, translating our clients’ vision into valued consents, deliverable plans for projects and programmes, and efficient designs for delivery, based on technical excellence and deep market insights. We deal with today’s challenges, but also keep a fairer, better tomorrow in sight, looking at how we deliver clean growth, support radical changes in our economy and meet the needs of future communities. Stantec provides equal employment opportunities to all qualified employees and applicants for future and current employment and prohibit discrimination on the grounds of race, colour, religion, sex, national origin, age, marital status, genetic information, disability, sexual orientation, gender identity or gender expression. We prohibit discrimination in decisions concerning recruitment, hiring, referral, promotion, compensation, fringe benefits, job training, terminations or any other condition of employment. Stantec is in compliance with laws and regulations and ensures equitable opportunities in all aspects of employment. Building an inspired, inclusive work environment that attracts, supports, and develops world-class talent is a crucial key to our success. If you are excited by this role but worry that your experience doesn’t exactly align, we encourage you to apply. - Senior Civil Engineer (6463)
Senior Civil Engineer (6463)
The Opportunity
Following a number of successful frameworks bids across the water industry, and in preparation for the most challenging AMP ever, we are expanding our high-performing engineering teams across the country. In Newcastle, we are excited to have been appointed as a Strategic Technical Partner by Northumbrian Water for the AMP8 period. Stantec provide a range of technical enabling, solution delivery and design services to support Northumbrian Water in achieving its vision to be the leading provider of sustainable water and wastewater services. As part of our long-standing relationship with Northumbrian Water, including the ongoing ESH-Stantec joint venture, we will continue to develop innovative solutions to support their delivery of capital investment across both infrastructure & non-infrastructure projects. In order to continue providing our clients with our expert service, we are looking to recruit a Senior Civil Engineer into our team Newcastle on the picturesque Quayside. You will become part of an international team, redefining our landscape with sustainability, the environment and the communities we serve at the heart of everything we do. As a Senior Civil Engineer, you will work across the entire project lifecycle in asset planning, strategy, concept design, outline design & detailed design. You’ll be responsible for delivering civil engineering solutions, guided by our Principal Engineers & Design Leads, whilst also supporting & mentoring our more junior engineers.You can find out more about our work in the water sector here: Stantec H2O+U - UK.
About You
We are interested in speaking with passionate engineers with design experience within the UK water industry. You’ll hold a degree in Civil Engineering and ideally have achieved Chartered status with a relevant professional body such as ICE or CIWEM. You will have gained experienced delivering community focused projects, whilst working collaboratively with multi-disciplinary teams to delivery innovative solutions. We will support your growth & development through training & project exposure, though prior experience within storm overflows, SUDS, surface water management & sewage treatment would be beneficial.
About Stantec
The Stantec community unites more than 31,000 employees working in over 450 locations across 6 continents. We have been working with our clients and communities in the UK for over 150 years. We plan, design, deliver and manage the development and infrastructure needed to support the creation of sustainable, healthy and prosperous communities. Our teams provide effective and relevant solutions, translating our clients’ vision into valued consents, deliverable plans for projects and programmes, and efficient designs for delivery, based on technical excellence and deep market insights. We deal with today’s challenges, but also keep a fairer, better tomorrow in sight, looking at how we deliver clean growth, support radical changes in our economy and meet the needs of future communities. Stantec provides equal employment opportunities to all qualified employees and applicants for future and current employment and prohibit discrimination on the grounds of race, colour, religion, sex, national origin, age, marital status, genetic information, disability, sexual orientation, gender identity or gender expression. We prohibit discrimination in decisions concerning recruitment, hiring, referral, promotion, compensation, fringe benefits, job training, terminations or any other condition of employment. Stantec is in compliance with laws and regulations and ensures equitable opportunities in all aspects of employment. Building an inspired, inclusive work environment that attracts, supports, and develops world-class talent is a crucial key to our success. If you are excited by this role but worry that your experience doesn’t exactly align, we encourage you to apply.