The proposed WWTP will include the following features:

Waste Water Transfer Tunnel and Tunnel Corridor[FS1] 

                   Waste water will be transferred from the existing WWTP using a new 2.5km tunnel[FS2] [FS3] . The tunnel will have an internal diameter of 2.4m and will be up to 22m deep. It will intercept the existing tunnel at the Cambridge (Milton) WWTP and transfer the flows to the terminal pumping station (TPS) shaft located at the new Cambridge WWTP. There will be a further four intermediate shafts positioned along the route to support construction. Three of these are temporary and will be back filled.  Intermediate shaft 4 (to the east of the River Cam) may be required as a permanent installation to provide mid-route access to the tunnel (for inspection and infrequent maintenance). Reception shaft 6, will accommodate the terminal pumping station located at the new WWTP

The Waste Water Treatment Works[FS4] [IB5] 

The main treatment works will comprise the following features[FS6] [IB7] :  

  • Terminal pumping station, pumps lifting waste water and stormwater flows from the tunnel up into the WWTP.
Figure 2‑3:Current Terminal Pumping Station at the Existing Cambridge WWTP
Source:  CWWTPRP Design Team
  • Preliminary treatment, including screens and grit removal, removing larger solids and floating debris from the waste water before further treatment.

Figure 2‑5: Mogden[KB8] [SS9]  WWTP (West London) inlet works

Figure 2‑6: Example inlet screen[IB10] 

  • Stormwater storage, storing excess flows during heavy rain events, which are then returned for treatment in the WWTP after waste water flows have returned to normal levels.
  • Primary settlement, which retains the waste water in tanks for a period of time to enable settlement (by gravity) and removal of suspended solids and the bio-chemical oxygen demand (BOD), nutrients and other contaminants they contain. Conventional primary settlement tanks, as used at the existing Cambridge WWTP, are a simple, economic and low energy (hence low carbon) way of reducing the amount of contamination in the waste water.
  • Secondary (biological) treatment, are large tanks in which the settled waste water is aerated, creating conditions under which selective microorganisms can develop, reproduce, and consume remaining (soluble) contaminants in waste water (particularly BOD, ammonia and phosphorus), hence, converting soluble BOD, nutrients, metals, etc., into a solid sludge which can then be removed from the waste water.
Figure 2‑7: Existing Cambridge Activated Sludge Process
Source:  CWWTPRP Design Team
  • Tertiary Treatment, xxx
  • Sludge treatment, to treat the solid by-product of the primary and secondary treatment stages described above, producing a stabilised product that is suitable for use in agriculture (as a soil conditioner and fertiliser) as well as biogas, which is used to generate renewable heat and power for use by the WWTP.

Figure 2‑15: Knostrop sludge treatment centre

[FS11] [IB12] 

Treated Effluent Outfall Pipelines and Outfall Corridor

                   Treated effluent will be discharged via a 1.25km pipeline to a new discharge location on the east bank of the River Cam. The effluent pipeline will be laid adjacent to the storm outfall (which is provisionally set to include two pipelines, each of 1.5m internal diameter). The effluent and storm pipelines will be provided with access manholes where required.

  • Illustrative design (video/flythrough) – something like the one below – do Anglian Water have something similar?

 [FS1]Show tunnel and shafts on map

 [FS2]Map tunnel and shaft locations

 [FS3]Embed map link

 [FS4]Illustrative engineering layout drawings needed – speak to April

 [IB5]Engineering drawings copied into the folder on the link below: Cambridge WWTP Relocation Project – Figures – All Documents (

April flagged that figures 5, 13, 19 and 22 are being updated

 [FS6]The scheme description in the main scoping report has photos of these elements – please can we get copies

 [IB7]Added the indicative layout of the proposed WWTP iif needed?

No figures of stormwater storage and primary treatment

 [KB8]Why Mogden? KB requested all photos where possible are from AWS sites / and more similar to expectations around project – on call w Ian Austin 28 Sept.

 [SS9]Do not have any other to show, this is most representative example available

 [IB10]Both figures showing preliminary treatment, not sure which one is better?

 [FS11]The project was supposed to be producing a clearer flow chart – please can we get a copy

 [IB12]The below is a new schematic. Better than the old one? Can we use it?

Zone 3 – Waterbeach transfer pipeline

                   A new pipeline (rising main) is required from Waterbeach to the new WWTP to support the development of Waterbeach New Town as there is insufficient capacity within the current network to accommodate these flows. The housing development at Waterbeach New Town expected to have been constructed before the new WWTP and the pipeline has been designed to take flows into the existing Milton WWTP for an interim period, if required.

                   The new rising main will comprise twin 500mm pipes to be laid below ground (with the potential exception of the section within the existing Milton WWTP whilst may be above ground). The new rising main will be approximately 8.4 km in length in total, circa 5.6 km to the new works and circa 2.8 km from the new WWTP to the existing Cambridge (Milton) WWTP.

The pipeline will be located at an average depth of 2-5 metres below ground level except where it passes beneath the River Cam, larger drainage ditches, the A14 and the railway where it will be a maximum of 20 metres deep. The exact depth will be determined through further environmental assessment, more detailed design including confirmation of the construction technique and agreement with the owner of the feature being crossed under as is legally required.