• First double deck membrane plant in the UK
• Flow maintained during retrofit of existing plant
• High quality discharge parameters
• Further expansion possible
| Current Status: |
Plant operational March 2003 |
| Client: |
Welsh Water Alliance |
| Performance: |
5:5:1 BOD:SS:Ammonia |
| Total Coliforms: |
1000 cfu/100 ml |
| Faecal Coliforms: |
200 cfu/100 ml |
| Brief Description: |
Retrofit of existing plant, converting one of the 4 SBRs (each treating 17l/s) to 2 MBR tanks (each treating 50l/s). Replaced SBR and UV treatment. |
Process Description
The plant receives pumped flows from several outlying pumping stations. The influent enters the works via a new 3mm screen. Flows in excess of FFT pass through the existing 6mm screens into storm tanks, which are then pumped back to the MBR 3mm screen after the storm event. The hydraulic design of the plant then allows gravity flow through the MBR plant from the 3mm screen onwards without the need for inter-stage pumping.
To maximize the higher treatment capability of the new MBR plant, the control system is able to take account of all the incoming flow streams and forward the maximum possible flow through the MBR plant via a flow control valve after the 3mm screens.
The two MBR treatment tanks are constructed within an existing SBR tank. Each MBR tank is 9.8m long, 7m wide and 6.7m high.
Following treatment in the MBR plant, the permeate flows under gravity to a permeate holding tank where it can be used on site for washwater applications, to reduce potable water demand. The permeate overflows from the holding tank to a tidal estuary.
There is potential for more capacity to be installed into another SBR tank when flows increase in the future.
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Design data
Peak Flow:
Average Flow:
BOD load:
Ammoniacial Nitrogen load:
Phosphorus load:
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8,640 m3/d
6,990 m3/day
959 kg/d
112 kg/d
5 kg/d
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Plant data
Tank dimensions:
No of membrane units:
Membrane surface area:
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9.8 x 7.0 x 5.0m
32 x 400 panels
10,240 m2
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