Project Description
Ledbury STW is a medium size activated sludge plant in Herefordshire, treating domestic sewage and trade effluent from a brewery. The current total population equivalent (PE) is over 14,000, and expected to approach 20,000 in 2028.
In AMP6, under the Water Framework Directive (WFD), the site had to meet more stringent discharge standards, including tightening the total phosphorus (TP) consent from 2 mg/l to 0.3 mg/l, with an Iron consent of 4 mg/l.
To achieve these new consent standards, Costain (Severn Trent’s main contractor) installed a chemical dosing facility and a FilterClear® plant.
The decision was based on a comprehensive whole life cost (WLC) assessment of various tertiary solids removal (TSR) plants.
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.
| Project Name: | Ledbury STW |
| Client: | Severn Trent |
| Capacity: | 160 L/s |
| Main Contractor: | CiM6 |
| Project Scope: | Design, supply & commission |
Project Highlights
• Off-site manufacture
• Consent of 0.3 mg/l TP and 4 mg/l Fe
• Rapid installation and commissioning
• No separate flocculation tank needed
Scope of Works
Design, procurement, manufacture, installation and commissioning of Bluewater Bio’s proprietary FilterClear® 4v2800 plant. Fully automated and instrumented tertiary filtration system for Total Phosphorus removal.
Project Duration
FilterClear delivered: February 2020
Installation time ~ 5 days
Commissioning time ~ 6 days
Compliant by: March 2020
Client Contact
Client organisation: Severn Trent
Contact person: Derick James (Project Manager)
Ledbury STW Process Parameters
| Average flow | 192 m3/h |
| Maximum flow | 578 m3/h (160 l/s) |
| Design Influent TSS conc. (incl. chemical solids) | 32 mg/L (average) 43 mg/L (98%ile) |
| Effluent TP consent | 0.3 mg/L (average) |
| Effluent Fe consent | 4 mg/L (95%ile) |
“The HYBACS upgrade at Tubli alleviates the current overloading problem without the requirement for green-field construction, thereby utilising the existing secondary treatment assets whilst avoiding additional land take. Early results demonstrate that the plant is operating exceptionally well and meeting the highest standards, with an overall improvement in Nitrogen removal of 80%”.
