Project Description
Cheddar Sewage Treatment Works (STW) is a medium
sized oxidation ditch works. In AMP7, under the Water
Framework Directive (WFD), the total phosphorus
(TP) consent is tightened from 2 mg/l to 0.7 mg/l, and
Iron consent is 4 mg/l. To achieve these new consent
standards, Wessex Water installed a FilterClear® plant.
The decision was based on a comprehensive whole life
cost (WLC) assessment of various tertiary solids removal
(TSR) plants. As the TP consent is fairly relaxed, further
cost saving were achieved by treating partial flow using
3 filters and leaving a space for the 4th filter if the TP
consent becomes more stringent in the future.
The FilterClear® skid was assembled and hydraulically
tested off-site at Bluewater’s works, before being
transported to site for installation on a flat concrete
slab. The site was commissioned with Ferric dosing
for P removal, and the FilterClear® performance
demonstrated that the compliance can be
achieved reliably.
| Project Name: | Cheddar STW |
| Client: | Wessex Water |
| Capacity: | 80 L/s |
| Project Scope: | Design, supply & commission |
Project Highlights
- Off-site manufacture
- Consent of 0.7 mg/l TP and 4 mg/l Fe
- Rapid installation and commissioning
- No separate flocculation tank needed
Scope of Works
Project Duration
FilterClear delivered: January 2022
Installation time: ~2 weeks
Commissioning time: ~2 weeks
Client Contact
Client organisation: Wessex Water
Contact person: Andrew Gulliford (Process Manager)
Cheddar STW Process Parameters
| Average flow | 67 L/s |
| Maximum flow | 80 L/s |
| Design Influent TSS conc. (incl. chemical solids) | 48 mg/L (average) 55 mg/L (98%ile) |
| Effluent TP consent | 0.7 mg/L (average) |
| Effluent Fe consent | 4 mg/L (95%ile) |
