Supply Chain - Wastewater Treatment - Chemical Dosing
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Related Content
Case Studies
- Lower Gornal STW (2024)
- Leominster WwTW (2024)
- Burnley WwTW Catchment Strategy (2023)
- Winchburgh WwTW (2023)
- The Woodlands Water Recycling Centre (2024)
- Horsham New WwTW (2024)
- Newthorpe STW (2024)
- Newthorpe STW (2023)
- Ballygowan WwTW (2023)
- Esholt STW (2024)
- Southern Water WINEP (2023)
- Warrenpoint WwTW (2023)
- Yorkshire Water P Schemes Portfolio (2024)
- Ballina Wastewater Treatment Plant (2024)
- Norton, Presteigne & Weobley WwTWs (2023)
- Melton Mowbray STW (2024)
- Monkmoor STW (2024)
- Cotton Valley WRC (2024)
- Rotherwas WwTW (2024)
Demolition of biofilter bank - Courtesy of MMB[/caption]
Construction progress (August 2023) - Courtesy of MMB[/caption]
MBBR tanks completed (June 2024) - Courtesy of MMB[/caption]
The MBBR plant was provided by FLI Water comprises two MBBR tanks, which operate in a lead/lag configuration. Flow is pumped to the MBBR plant from the tertiary feed pumping station, and passes into either MBBR Tank 1, or MBBR Tank 2; dependant on which tank is selected as the lead. Every day the tanks rotate the lead. This will be inhibited if the flow to the plant is too high (hydraulic safety), or if the ammonia monitored in between the MBBR tanks is too high (to protect the permit, if there is too much ammonia contained within the tank that would become the lag tank).
TSR plant (June 2024) - Courtesy of MMB[/caption]
Recirculation pumping station (June 2024) - Courtesy of MMB[/caption]
Completed plant (June 2024) - Courtesy of MMB[/caption]
(top left) Construction of tertiary treatment system December 2022, (top right) construction of tertiary treatment system May 2023, (bottom left) Construction of tertiary treatment system July 2023, and (bottom right) Construction of tertiary treatment system November 2023 - Courtesy of Morgan Sindall Infrastructure[/caption]
Construction of tertiary treatment system February 2024 - Courtesy of Morgan Sindall Infrastructure[/caption]
Fully constructed tertiary treatment system integrated into existing treatment works - Courtesy of Morgan Sindall Infrastructure[/caption]
Example of a Cubis Systems modular chamber and (inset) chamber being assembled at Leominster- Courtesy of Cubis Systems & Morgan Sindall[/caption]
For the smaller alkalinity MCC kiosk (not DfMA), it was decided that the kiosk would sit at ground level but as it still required access under the panel for installation, a below ground trench was required. To make the construction process more efficient, the trench comprised of innovative and sustainable HDPE recycled plastic modular units from Cubis Systems, that were put together on site and built around with minimal concrete surround and base slab and backfill to support the kiosk. As well as the material of the modular solution being more sustainable, it also led to a reduced carbon footprint in delivery due to it being very light weight. This also made it a safer and quicker installation as the manual handling involved was minimal.
Installation of DfMA low voltage distribution board MCC kiosk - Courtesy of Morgan Sindall Infrastructure[/caption]
New Fineguard inlet screens from SPIRAC Ltd with improved safe access for operators – Courtesy of Morgan Sindall Infrastructure[/caption]
(top left) Federated 3D model capture of sampling kiosk with tertiary filters - Courtesy of Arcadis, (bottom left) as built sampling kiosk with tertiary filters - Courtesy of Morgan Sindall Infrastructure, (top right) Federated 3D model capture of lift pumping station with tertiary filters - Courtesy of Arcadis, and (bottom right) As built tertiary filter lift pumping station pipework with duplex filter and tertiary filters - Courtesy of Morgan Sindall Infrastructure[/caption]
Lift pumping station - Courtesy of Morgan Sindall Infrastructure[/caption]
Installation of tertiary sand filters adjacent to railway line under agreed BAPA procedures - Courtesy of Morgan Sindall Infrastructure[/caption]
Leominster WwTW: Tertiary sand filters - Courtesy of Morgan Sindall Infrastructure[/caption]
Fully constructed tertiary treatment system integrated into existing treatment works - Courtesy of Morgan Sindall Infrastructure[/caption]
ASP under construction - Courtesy of United Utilities[/caption]
Detention tank on water test - Courtesy of United Utilities[/caption]
Primary settlement tank
The new primary settlement tank (PST) civils construction is also complete, again undertaken by A-Consult Ltd using the precast concrete panel method of construction. It has also successfully passed its water test. Mechanical installation by EPS Water is now in progress on the ‘H’ frame steel structure which will support the scraper bridge. The design of the PST incorporates a fixed bridge arrangement with rotating scrapers beneath. This arrangement is necessary as the PST will eventually be covered with a GRP roof for odour mitigation. The odour control fans, ductwork and vent stack are scheduled to be installed in December.
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PST4 and ASP lane 1 on water test - Courtesy of United Utilities[/caption]
Interstage pumping station
Due to the topography and hydraulic levels across the site, a new interstage pumping station (IPS) is required to pump the effluent leaving the four PSTs up to the new activated sludge plant (ASP) distribution chamber.
Civils FRC works are being undertaken by STAM Construction Ltd and contain 94 tonnes of rebar and 900m3 of in situ poured concrete. The pumping station structure is complete and has undergone successful water testing.
The internal benching is complete and the next activities planned for the coming period will be the mechanical installation of the pumps and pipework. As the pumping station is vital to keep all flows passing through the treatment process, a standby generator will also be installed. The IPS is a two compartment design to facilitate future maintenance activities preventing the need to take it completely out of service. The new pumps have been supplied by Xylem Water Solutions who have supported the designers in providing efficient selections for the large submersible pumps and optimising the layouts of the pump chambers.
Activated sludge plant
The ASP distribution chamber is currently being constructed with all four concrete walls having now been poured. These are curing and the structure will undergo a water test in September 2023.
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ASP constructed and water tested - Courtesy of United Utilities[/caption]
In constructing the new ASP, STAM Construction Ltd have installed 650 tonnes of rebar and poured 4500m3 of concrete. The overall size of the ASP is 48m x 48m x 6.6m deep, has a capacity of 14,500m3 and comprises four lanes. Civils construction of the ASP is complete and fully water-tested with the mechanical installation of the internal pipework, aeration grids, diffusers and access platforms and walkways taking place over the next few months.
Suprafilt Ltd will be supplying and installing the internal pipework, aeration grids and diffusers. Mechanical installation of the pump stations and access steelwork etc will be undertaken by Fluid Sealing & Engineering (FSE).
BioMag®
The Evoqua Water Technologies detail design for the new BioMag® process has been finalised and the building layout confirmed. The main equipment including four Magdrums and two shear mills, process tanks, silo and pumps, which have been manufactured and are ready for delivery to site when required. The BioMag® building is currently under construction by Gallaway Construction.
The steel frame has been erected and the gantry crane and roof cladding have been installed. External wall cladding is in progress, after which attention will turn to the internal fit-out and installation of the BioMag® equipment.
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BioMag® building being erected - Courtesy of United Utilities[/caption]
Final settlement tanks (FST)
There are four existing final settlement tanks which required refurbishing to ensure adequate performance and asset life are achieved. The scope includes civils refurbishment of the tank walls which involves cutting approximately 300mm from the top of the walls before installing new reinforcement and re-casting concrete to the required coping levels.
Cutting works is being undertaken by Holemasters and FRC works self-delivered by JMS. The mechanical and electrical work is being delivered by Jacopa and comprises refurbishment of the bridge, scraper assemblies, and other ancillary equipment. Three of the four FSTs have now been refurbished with the final one due to be undertaken towards the end of the year.
Surplus activated sludge (SAS) thickening
Civils works has been ongoing in the SAS thickening process area for the last couple of months with the storage tank, drum thickener, poly plant and kiosk bases all constructed. Underground services, ducts and pipework have also been installed and tested. The filtrate return pumping station construction is in progress with the mechanical installation due to follow on.
Chemical dosing
The new ferric and caustic dosing plants comprise storage tanks, dosing rigs and dosing pipelines, all of which have been designed and well progressed in manufacture. These are being supplied by NPS Engineering Group. A new chemical delivery facility will also be provided with civils construction in this area commencing towards the end of the year and installation of the new dosing plants taking place early 2024.
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3D model of chemical dosing area - Courtesy of United Utilities[/caption]
HV works
A new, uprated HV cable has been installed from the off-site substation to the wastewater treatment works, a length of approximately 900m, passing through a number of fields and third-party land.
Motor control centres (MCCs)
To control all the new assets a number of new MCCs housed within kiosks are required around the site, along with a new site-wide SCADA system. The MCCs are all in various stages of manufacture and factory testing. The electrical installation and system integration works, including dry testing, will be undertaken in phases over a period of months as the programme for each of the new process areas dictates.
The MCCs are being built by Technical Control Systems Ltd, electrical installation will be by PICOW Engineering Group and system integration by Tata Consultancy Services.
Looking forward to commissioning
Commissioning of the new treatment process, and transitioning from the old process in a controlled staged approach, will be complex.
The existing treatment stream and process compliance cannot be put at risk or compromised and months of hard work and planning for commissioning has already taken place. Wet commissioning is due to start in April 2024, gradually increasing flows into the new treatment process over several months while the new biological process builds up and matures to a point where the improved treatment standards are being met. The forecast project in use date is October 2024.
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Aphex construction planning software map view - Courtesy of United Utilities[/caption]
Lindred Road detention tank during construction - Courtesy of United Utilities[/caption]
Work started on site in July 2022, with the first phase involving the diversion of numerous services, including gas, fibre, BT, water and power, to clear the area for the tank construction. Enabling works to provide safe access routes, segregation, and procurement of alternative car parking for the impacted business employees was also required before the main construction work could commence.
Ground was broken in August 2022 with the tank construction continuing through to December 2022 when full depth was reached. Construction of the pump sumps, inlet channel and complex benching arrangement followed.
The spring months of 2023 saw the mechanical works inside the tank take place with the installation of the pumps, pipework and access ladders and platforms. Once the internal works were complete, the roof beams were installed and the roof slabs placed on in May 2023.
The inlet and outlet pipework for the tank has now been installed, including associated manholes and chambers. To facilitate the connection of the 1200mm inlet pipe into the existing CSO chamber, a complex timber heading arrangement needed to be constructed in order to access beneath, and protect a myriad of services crossing the vicinity. All buried pipework, chambers and ducts etc have been completed and reinstatement of the area is in progress.
The civils and pipework has been undertaken by SGC Civil Engineering Ltd and the mechanical works by Fluid Sealing & Engineering (FSE).
A new motor control centre and power supply is being installed for this facility. The new control kiosk was delivered and installed in July 2023 and the electrical installation is currently ongoing with the new power supply due to be energised in October.
Testing and commissioning is scheduled to start in November, with the site achieving project in use in February 2024.
Lindred Road: Aerial view of detention tank - Courtesy of United Utilities[/caption]
Hyndburn WwTW - 3D model of storm return pumping station - Courtesy of United Utilities[/caption]
A new below-ground wet well type pumping station will be constructed with three high-flow pumps and two low-flow pumps which provides a more flexible and efficient system with greater turn down capability. A new single rising main will return the storm flows back to the head of the treatment works. A new kiosk and motor control centre will also be installed.
Planning permissions are in place and all pre-start surveys and investigations have been completed. Detailed design is nearing completion and the site has just been established. Construction is due to start in earnest in September on the new pumping station excavation. The winter months will see the civils works progress, with mechanical and electrical works due to start in spring. The project in use is forecast for July 2024.
Aphex construction planning software Gantt chart - Courtesy of United Utilities[/caption]
Nereda® process cycle - Courtesy of Royal HaskoningDHV[/caption]
Within a Nereda® reactor, through a simple three-step cycle, the purifying biomass grows naturally as compact aerobic granular sludge, with superb settling properties. An important feature of granular sludge is that aerobic and anoxic/anaerobic zones co-exist. This enables a large variety of biological processes, including nitrification, denitrification and biological phosphate removal, to happen simultaneously.
The alternating cycle steps are:
Winchburgh site layout model - Courtesy of ESD JV[/caption]
The pumped flows from the upper and lower inlet pumping station are combined within the inlet collection chamber at the head of the above ground inlet works and screened via two screens operating in a duty/standby configuration. Grit and FOG removal are also included within the packaged inlet works and the screenings and grit discharged into dedicated skips, positioned adjacent to the units.
Full flow to treatment (FFT) gravitates to the Nereda® influent buffer tank and flows greater than FFT will spill over a weir, within the packaged inlet works, and gravitate to a storm tank.
The storm tanks are automatically emptied after each storm event, and the storm water returned to the inlet works outlet chamber via storm return pumps. At the end of each individual storm tank return cycle, a cleaning system flushes any residual solids back to the inlet works outlet channel.
From the influent buffer tank, the FFT is split between the three Nereda® reactors. Excess sludge from the Nereda® plant will gravitate to the sludge buffer tanks, the contents of which, after further settlement and supernatant return, will be transferred to the unthickened sludge tank before being pumped to two disc thickeners. Thereafter, the sludge is transferred to the thickened sludge tank. Liquors from the thickening process are pumped from the liquors return pumping station back to the influent buffer tank.
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Precast retaining wall installation - Courtesy of ESD JV[/caption]
Treated effluent from the Nereda® reactors gravitates to an effluent balance tank, which is required to attenuate the flows, prior to being passed to the tertiary solids removal plant, which is the final treatment prior to discharge to the water course.
Also included within the scope is a ferric dosing plant. This was included within the scope of supply on the Winchburgh project as a result of the lessons learned on the Inverurie WwTW project, the only other operational Nereda® plant in Scotland. The limited dosing of ferric will better facilitate P removal to a lower concentration, if required.
Extract from 4D Synchro animation – Courtesy of EPS Water[/caption]
Winchburgh 3D model (lower pumping station area) with below ground services visible – Courtesy of ESD JV[/caption]
In addition to the experience held within EPS of Nereda® treatment works they also have a strong background in the development of DfMA solutions, which combines in-house advanced digital engineering services with their substantial manufacturing capacity. The Winchburgh project was designed to be a DfMA solution, meaning that the large assemblies were designed to be broken down into modular transportable sections, taking into account the particular site delivery restrictions, that can be reassembled on site.
The DfMA approach was also utilised within the civil design, where possible. The level differences across the site led to retaining walls in excess of 4m high, most of which were constructed from precast concrete, reducing site installation time from 3-4 weeks to 6 days.
Furthermore, precast segments were used to construct the shafts required for the upper and lower catchment pumping stations, the biggest of which was 8m diameter by 8m deep. This again had programme savings, but crucially reduced the risk associated with an in situ concrete solution for such deep shafts.
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(left) Upper catchment pumping station and (right) lower catchment pumping station - Courtesy of ESD JV[/caption]
The 3D model has proved invaluable throughout the life-cycle of the project, from the early stages of the project being used to develop the design in conjunction with all stakeholders within Scottish Water, to facilitating discussions between the site team and design team during the construction phase.
A consequence of the model providing such a clear picture of the design is that meaningful discussions can be held with people of all technical levels and minimises the risk of miscommunication.
The use of digital tools was further extended to develop the programme. The construction programme and 3D model was used in conjunction with a 4D Synchro scheduling tool to develop a simulated programme of works. This assisted the site team in planning the works and identifying any clashes or pinch points in the programme whereby there may be too much activity within certain areas of the site that could lead to inefficient working, or prevent certain operations being completed in parallel.
Winchburgh WwTW (May 2023) - Courtesy of ESD JV[/caption]
The main process units/structures are installed, with the MCC planned for delivery at the end of May 2023, at which point the electrical installation can be completed, allowing dry, then wet commissioning to commence. The target date to start slowly turning the flows from the existing treatment process to the new Nereda® treatment process is October 2023, with handover to Scottish Water planned for June 2024, allowing the intervening time for process commissioning.
Rendered 3D model of The Woodlands WRC - Courtesy of EPS Water[/caption]
View of the main MBBR treatment block - Courtesy of EPS Water[/caption]
Noggerath® inlet fine screens at The Woodlands WRC - Courtesy of EPS Water[/caption]
View of the clarifier, sludge thickener & MCC kiosk - Courtesy of EPS Water[/caption]
Chemical dosing plant at The Woodlands WRC - Courtesy of EPS Water[/caption]
Tertiary solids removal plant - Courtesy of EPS Water[/caption]
New inlet screens supplied by Hydro International UK Wastewater Services division - Courtesy of CMDP JV[/caption]
The existing deep bed sand filter is being extended with three additional cells to enhance the tertiary treatment process - Courtesy of CMDP JV[/caption]
The two new Moving Bed Biofilm Reactors (MBBR) to remove ammonia from the final effluent returning to the River Arun - Courtesy of CMDP JV[/caption]
DN900 outlet pipework installed on one of the newly constructed MBBRs - Courtesy of CMDP JV[/caption]
(left) One of the two existing inlet screens being removed, (middle) one of the new 12.8m long Alpha Beta Escalator Screens being lifted carefully into place, and (right) the new inlet screens installed - Courtesy of CMDP JV[/caption]
Inside one of the new MBBRs as its installation approached completion - Courtesy of CMDP JV[/caption]
Setting out for piling works in alkalinity dosing area with sheet piling in place for bank stability - Courtesy of CMDP JV[/caption]
The new MBBR blowers are fitted with acoustic barriers to minimise any possible impact on nearby residential properties - Courtesy of CMDP JV[/caption]
(left) Garry Burgess, CMDP Construction Manager, receiving the award for the efforts of the Horsham New WwTW team and (right) CMDP JV and Southern Water staff pictured volunteering to support local charity, Ten Little Toes - Courtesy of CMDP JV[/caption]
Newthorpe STW: (left) site compound and storage, (top) existing site, and (bottom) the new expansion (August 2024) - Courtesy of MMB[/caption]
Heanor flows inlet works (August 2024) - Courtesy of MMB[/caption]
Enhanced Bio Phosphorus Removal UCT configuration - Courtesy of MMB[/caption]
Installation of the tertiary solids removal units (August 2024) - Courtesy of Mott MacDonald Bentley[/caption]
Heanor site overview (September 2024) - Courtesy of MMB[/caption]
Rising main site just outside Newthorpe (August 2024) - Courtesy of MMB[/caption]
Sodium hydroxide (left) and ferric sulphate (right) dosing systems
Google Maps image showing general scheme overview - Courtesy of Mott MacDonald Bentley[/caption]
Newthorpe: At Newthorpe, the secondary and tertiary treatment will be decommissioned. Only the preliminary treatment (screening and grit removal) and the primary settlement tanks will be retained as part of the new process stream.
The extension, which will be built on the field adjacent to the existing works, will use an Enhanced Bio-Phosphorus Removal (EBPR) process, in a modified University of Cape Town (UCT) configuration. This process aims to reduce chemical consumption using polyphosphate-accumulating organisms (PAO) to eliminate phosphorus.
Newthorpe STW extension Revit model - Courtesy of MMB[/caption]
Anaerobic & anoxic tank construction progress - (July 2023) - Courtesy of Mott MacDonald Bentley[/caption]
Final settlement tanks construction progress July 2023 - Courtesy of Mott MacDonald Bentley[/caption]
Build smart: Due to the depth of the final settlement tanks into the ground, flotation was the limiting factor in the design. In the preliminary calculations, the estimated slab thickness required for the tank to float in a maintenance scenario was above 1000mm. The project team, therefore, challenged themselves to try to achieve a more sustainable solution. The outcome was to install an active drainage system that, in case of maintenance, would lower the groundwater level to 2m below the final ground level. That reduced the slab thickness to 400mm, without having a major impact on the operation of the plant, as this drainage system will only be required during maintenance scenarios where the tank needs to be emptied.
Build efficiently: To carry out the earthworks for the new site, the site team has used GPS-intelligent plant that, utilising a 3D model of the ground, reduced the plant-operator interface on site, improving H&S as well as efficiency. The excavated ground has been re-used to screen the site and provide biodiversity net gain, instead of having to transport it off-site.
ASP Tank construction (July 2023) - Courtesy of Mott MacDonald Bentley[/caption]
(left) Ground modelling to explore coal seams and (right) detail of rising main welding area - Courtesy of Mott MacDonald Bentley[/caption]
(left) Existing Ballygowan WwTW - Courtesy of NI Water and (right) demolition in progress: (top) the existing storm tank and (bottom) the existing CAS basin tank - Courtesy of GEDA Construction[/caption]
CAS basins - Courtesy of NI Water[/caption]
New storm tank being utilised during construction - Courtesy of GEDA Construction[/caption]
Ballygowan WwTW under construction (December 2021) - Courtesy of NI Water[/caption]
Interface between new and old works during construction
The majority of the new WwTW works was to be built on a greenfield site which allowed GEDA Construction to build most of the new structures without having to work around existing infrastructure.
However, in order to construct pipelines which would eventually take the flow into the new works, and to construct the new WwTW access road, it was necessary to demolish the existing storm tank in the old works prior to the new works becoming live. GEDA Construction carried these works out by utilising the newly-constructed storm tank and incorporating a carefully developed phasing plan.
A temporary 300mm gravity fed sewer was laid from the existing inlet works to the new storm tank, which in turn rendered the existing storm tank surplus to requirements, as all storm flows had been diverted away from it. GEDA Construction also had to lay a temporary 200mm pumped sewer from the new storm tank complete with temporary pumps to send the storm flows back to the existing pumping station in order for the influent to then go through the treatment process. This in turn allowed us to demolish the existing storm tank and construct the new permanent inlet sewers to the new works ahead of turning flows. This process had to be carefully managed both hydraulically and biologically to ensure the treatment process was optimised and effluent compliance was maintained at all times.
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New permanent high-level sewer under construction - Courtesy of GEDA Construction[/caption]
Turn of flows
Influent flows were successfully diverted into the new works in early May 2022. In order to bring the new biological treatment process online, several tanker loads of seeded sludge were brought to site from another treatment facility and were introduced into the new CAS basin tanks to promote bacteria growth. With flows diverted, and effective treatment established through a rigorous sampling regime, approval was received from NI Water to proceed with the demolition of the remainder of the existing treatment works. Once the existing works were decommissioned and demolished, the entire new WwTW site was able to be finished and access roads completed.
Demolition
Post turn of flows in early May 2022, the existing treatment works was decommissioned and then demolished. Reusable mechanical and electrical assets from the old treatment process were removed for future use by NI Water, while the effluent left in the old CAS basin and pumping station was removed from the site to allow demolition to commence. Effluent was filtered through the new treatment process to minimise unnecessary removal and disposal from site.
CAS basins in operation - Courtesy of NI Water[/caption]
Solmatix Renewables Ltd solar farm - Courtesy of NI Water[/caption]
Ballygowan WwTW nearing completion - Courtesy of NI Water[/caption]
Primary ferric point of application cabinets - Courtesy of MMB[/caption]
Deep bed sand filter, post refurbishment - Courtesy of MMB[/caption]
Dirty backwash rising main - Courtesy of MMB[/caption]
Side view of primary ferric dosing compound - Courtesy of MMB[/caption]
Delivery of 3D printed draw-pits - Courtesy of Mott MacDonald Bentley[/caption]
Excavation for sub-slab level ducting and drainage pipework to the chemical dosing kiosks - Courtesy of CMDP JV[/caption]
This approach identified full no-build solutions at four sites, allowing £8m to be invested in other sites which presented greater risk. CMDP JV also invested in trials at three sites, which helped to establish that the existing tertiary treatment facilities were capable of satisfying the requirement of the new permits, thus providing millions of pounds of savings to Southern Water.
At the start of AMP7, it was decided to undertake the design work in a shared integrated space with Southern Water, CMDP JV, subcontractors and supply chain working closely together to ensure a well thought out, robust design was in place before starting on site. The main objective of this approach was to ensure the on-site delivery and commissioning of the projects runs smoothly and is ‘right first time’.
The team engages with Southern Water in weekly workshops to review design; challenging specifications and value engineering solutions by walking through the design virtually to gain buy-in to the solution and first-time approval at Risk and Value (R&V) meetings. The team approach ensures design consistency and use of standard solutions through a core design team of civils, mechanical, electrical and process designers.
(left) Lifting of tertiary treatment plant, control panel and pipework manifold and (right) loading of media into TTP pressure vessels - Courtesy of CMDP JV[/caption]
Close-up of pre-fabricated off-site manifold block - Courtesy of CMDP JV[/caption]
Directional drilling rig completing second drive - Courtesy of CMDP JV[/caption]
While an existing final effluent water supply was available for plant maintenance activities, the installation of safety showers and eye-baths required access to clean, drinkable water. The nearest connection was 350m away off the site to the west. This required a pipeline to cross private fields and the neighbouring Dale Hill Golf Club.
To reduce the impact on local stakeholders, a directional drilling technique was deployed. This involved deploying a small drill head, which can drive up to 100m underground. This only required a small number of pits to be dug, rather than digging a trench across the whole length of the pipe.
Site access
An additional challenge arose due to the treatment plant’s sole access road, which crosses the golf course. To ensure the safety of drivers traveling along this access road for work or deliveries, close cooperation with golf course management was necessary.
Timetable/progress
CMDP JV commenced site mobilisation in August 2021. Civils works began in October, followed by early M&E installation works which enabled early start of ferric dosing and phosphate and ferric monitoring.
The construction completion milestone was achieved in August 2022, with takeover and final completion due by the end of 2023, following a period of process optimisation. The project was completed with zero safety, health and environmental accidents or incidents.
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Completed installation of tertiary treatment plant - Courtesy of CMDP JV[/caption]
Construction work in progress (June 2021) - Courtesy of NI Water[/caption]
Construction progress (January 2022) - Courtesy of NI Water[/caption]
(left) Tertiary treatment unit being installed and (right) UV building and final settlement tanks - Courtesy of NI Water[/caption]
Sludge holding facilities under construction - Courtesy of NI Water[/caption]
The project team, and in particular the civil and MEICA contractor, worked hard to overcome supply chain issues. This involved developing a high degree of flexibility in the programme and delivery strategy to ensure that longer delivery times could be mitigated to ensure that the impact on the critical path could be minimised. NI Water also implemented measures to deal with the unprecedented levels of inflation that were being observed in the construction industry. This encouraged proactive discussion to mitigate the impact on price and programme and utilised an open-book approach to identify the real impact on projects and reimburse costs where required.
While Phase 1 was mainly constructed in areas of the site which were not in use, Phase 2 required the construction of a significant number of large structures in areas that contained the existing live treatment process, therefore careful phasing of the construction work was required. The main challenge involved the construction of the new final settlement tanks.
Two of the new final settlement tanks had to be built in a constrained area, where the redundant aeration tanks from the original works were located. Due to the depth of construction and the limited area, cofferdams were required to provide a safe excavation. During construction the existing settlement tanks, which were in close proximity to the new settlement tanks, had to be fully operational requiring careful demarcation of construction areas and NI Water operational areas.
The upgrades to the sludge handling facilities also required careful phasing as the new sludge holding tanks and sludge thickening facilities had to be constructed in the area where the existing sludge holding facilities were located. This required a detailed construction plan whereby the new facilities were constructed and brought online in stages, with new and existing facilities being used in different combinations during different stages of the process. The design had to account for the different pipework and valve configurations which would be required at each stage of the process, while ensuring that the final arrangement was as uncomplicated as possible.
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Phase 2 works nearing completion (November 2022) - Courtesy of NI Water[/caption]
As a result of the two-phase delivery, careful consideration had to be given to the electrical upgrade which was required at the site. A new motor control centre (MCC) was required for the upgraded works which would control the equipment provided in both Phases 1 and 2. The new MCC was installed during Phase 1.
Any assets from the existing MCC that had to be retained, until the Phase 2 works were complete, were transferred across. This required meticulous planning, communications and numerous shutdowns of existing plant and equipment and recommissioning to facilitate transitioning across to the new MCC.
Subsequently, Phase 2 plant and equipment had to be commissioned on the new MCC, which again required meticulous planning to complete without adversely affecting the ongoing operation of the works.
An unexpected challenge occurred during the construction of the final settlement tanks, when a bird nest was found in the cofferdam sheet piles. A specialist ecological consultant was brought to site to complete a survey and it was found that the nest was active and contained eggs. It was determined that work on the settlement tanks could continue, however, the sheet piles could not be removed until the birds had flown the nest, which did impact the delivery programme.
Warrenpoint WwTW - Courtesy of NI Water[/caption]
The objectives of the Warrenpoint upgrade met over the two-phase delivery are:
3D render of Thorne STW - Courtesy of Glanua Group[/caption]
The new works has been carried out in the north-east corner of the site, adjacent to the sludge balancing tank. An existing concrete spur off the access road will be broken out and replaced by a new RC concrete tanker delivery bay with ferric dosing kiosk slab adjacent. A standard 7.5m3 ferric sulphate storage tank and dosing kiosk will be delivered and installed in a single DfMA off-site fabricated SR4 rated kiosk (due to site security classification).
Aldwarke STW ferric kiosk delivery and installation - Courtesy of Glanua Group[/caption]
Lundwood STW sodium hydroxide kiosk delivery - Courtesy of Glanua Group[/caption]
Google Maps images of the sites: (top left) Thorne STW, (top right) Aldwarke STW, (bottom left) Lundwood STW, and (bottom right) Castleford STW[/caption]
Aldwarke STW ferric sulphate dosing installation - Courtesy of Glanua Group[/caption]
3D renders (left) of Aldwarke STW, (top right) Castleford STW and (botton right) Lundwood STW - Courtesy of Glanua Group[/caption]
Construction work underway at Ballina - Courtesy of Shay Murtagh Precast[/caption]
New inlet works under construction - Courtesy of Ward & Burke[/caption]
New final settlement tank under construction - Courtesy of Ward & Burke[/caption]
Scope of works (continued)
New storm water tank under construction - Courtesy of Ward & Burke[/caption]
New outfall under construction - Courtesy of Ward & Burke[/caption]
Norton SPS progressive cavity pumps - Courtesy of Morgan Sindall Infrastructure[/caption]
Norton SPS: MCC kiosk and Haigh Engineering inlet screen - Courtesy of Morgan Sindall Infrastructure[/caption]
Spider plough operation to construct the Norton WwTW pump away rising main - Courtesy of Morgan Sindall Infrastructure[/caption]
Presteigne WwTW: Ferric point of application (PoA) unit - Courtesy of Morgan Sindall Infrastructure[/caption]
Alkalinity dosing was required as a result of the new ferric dosing. The identified solution for this was a small bag dosing plant with on-site mixing to create a liquid dose. A new point of application facility located on the side of the existing PST which discharges to the biological filter. It was determined that this point had enough hydraulic mixing for an effective alkalinity dose.
The new works is achieving its ammonia consent with the current loading, but it had been identified that ammonia compliance could be a risk during AMP9. Nitrifying sand filters have been proposed as a technology to treat the ammoniacal nitrogen as a tertiary treatment solution. This has an added benefit of tertiary solids removal to give confidence in the total phosphorus consent. However, given the excellent performance of the works against consent and nitrifying capacity of the existing biofilters, the nitrifying sand filters will be phased into the works when required.
Works included a new sampling arrangement with sampling kiosk, complete with an upstream diversion and reception chamber for when the nitrifying sand filter is constructed.
Presteigne WwTW: Ferric dosing system and safety shower - Courtesy of Morgan Sindall Infrastructure[/caption]
Weobley WwTW: (left) Huber Technology inlet screen and (right) flow to full treatment pump station - Courtesy of Morgan Sindall Infrastructure[/caption]
This provided significant cost and embodied carbon savings compared to a completely new screening installation. Downstream of the screen, an inlet flume was provided for flow measurement and control of the downstream lift pumping station. The flume was constructed off-site, allowing for greater dimensional accuracy than an on-site constructed flume, as well as reduced downtime for the site.
A new lift pumping station for all incoming flows for treatment was required to provide a separate lift to the balancing tanks then the unscreened storm flows. The existing inlet pumping station was re-purposed as the storm pumping station, meaning the more efficient pumping station was operating for more of the time compared to the older storm pumping station, which only operated intermittently - hence saving on energy usage and operational carbon.
An existing multi-use returns pumping station was used to pump humus returns and storm returns to the head of the works. This asset consisted of outdated and poorly operating pumps and valve work. A solution was developed to replace mechanical equipment within the existing dry-well, saving the need for a new complete pumping station.
Weobley WwTW: Ferric point of application units - Courtesy of Morgan Sindall Infrastructure[/caption]
Melton Mowbray STW before the start of works - Google Earth image[/caption]
(top left) Groundworks underway, (right) SMR UK ASP area soil stabilisation, and (bottom left) stabilised ASP area with piling and ASP base construction ongoing - Courtesy of MWH Treatment[/caption]
The net carbon reduction profile of these activities[/caption]
(left) Inlet works physical model at Hydrotec and (right) inlet works screen baffles and dye test - Courtesy of MWH Treatment[/caption]
Refurbished inlet works with three screens & bypass pipework and (inset) the inlet works prior to the upgrade with two screens - Courtesy of MWH Treatment[/caption]
Refurbished inlet works with three screens & bypass pipework and (inset) the inlet works prior to the upgrade with two screens - Courtesy of MWH Treatment
(left) Google Maps image showing Monkmoor STW and (inset) the existing anoxic zone - Courtesy of Mott MacDonald Bentley[/caption]
(left) MABR blower from Aerzen Machines and (right) two 60m3 ferric sulphate storage tanks installed in the chemical dosing area - Courtesy of Mott MacDonald Bentley[/caption]
(left) MABR units being readied for crane lift and (right) lowering an MABR module into the support steelwork installed on the ASP anoxic zone - Courtesy of OxyMem Ltd[/caption]
MABR installation - Courtesy of OxyMem Ltd[/caption]
MABR support steelwork - Courtesy of OxyMem Ltd[/caption]
MABR module being lowered into place within a bespoke steelwork frame - Courtesy of OxyMem Ltd[/caption]
Terminal pumping station pipework to storm tanks - Courtesy of @one Alliance[/caption]
Phosphorus removal scheme - ferrous chloride storage tanks - Courtesy of @one Alliance[/caption]
Construction of the two new storm tanks - Courtesy of @one Alliance[/caption]
Terminal pumping station pipework to storm tanks - Courtesy of @one Alliance[/caption]
Terminal pumping station pipework - Courtesy of @one Alliance[/caption]
Google Maps image showing the site locations[/caption]
Interception chamber - Courtesy of Morgan Sindall Infrastructure[/caption]
Tertiary dosing POA and bypass - Courtesy of Morgan Sindall Infrastructure[/caption]
External lift pumping station – Courtesy of Morgan Sindall Infrastructure and (right) Lift pumping station: Installed pumps during construction phase - Courtesy of Arup[/caption]
Bluewater Bio Ltd’s tertiary filters - Courtesy of Morgan Sindall Infrastructure[/caption]
Dirty backwash tank and returns pumping station - Courtesy of Morgan Sindall Infrastructure[/caption]
Tertiary dosing plant - Courtesy of Morgan Sindall Infrastructure[/caption]
(top left) HV switchgear kiosk, (top right) RMU kiosks, TSR secondary dosing kiosk & safety shower, and (bottom right) MCC kiosk - Courtesy of Morgan Sindall Infrastructure[/caption]
Rotherwas internal lift PS craning in of the baffle wall - Courtesy of Morgan Sindall Infrastructure[/caption]
Mini CS & Company News
- 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™.