Water Resource Associates
A network of consultants in water resources, water quality, hydrology, hydrogeology and flooding.
Impact of phosphorus removal from effluent on the water quality of the Kennet and Lambourn SSSIs
Simulation of the in-stream phosphorus concentrations resulting from Phosphorus removal at key sewage treatment works.
Background
A three-month study was done in 2007 by Andrew Wade to determine the contribution of sewage treatment works to in-stream phosphorus concentration and loads in the Kennet and Lambourn Sites of Special Scientific Interest. The Kennet and Lambourn are two lowland Chalk rivers in southern England and the Lambourn is a candidate Special Area of Conservation [cSAC]. General concern has been raised about the deterioration in aquatic habitats of Chalk rivers in England, in particular, the loss of macrophytes, such as Ranunculus, increased growth of benthic and filamentous algae, and increased turbidity. At present, it is unclear whether flow, water quality or a combination are the cause of the deterioration. The WRA assignment investigated the impact of point sources on water quality using INCA-P, for current conditions and future scenarios of forecasted phosphorus removal. The study aimed to complement the work done by the Environment Agency using SIMCAT.
The photograph on the left shows the sewage treatment works at Marlborough where Phosphorus-stripping was introduced in 1997. On the right are stands of Ranunculus (Water Crowfoot) in the reach of the River Kennet at Mildenhall.
Sewage works with phosphorus stripping
Stands of Ranunculus (Water Crowfoot) in the River Kennet
Scope of work by Water Resource Associates Ltd
Review of existing final effluent flows and phosphorus concentrations, and consents agreed under AMP4. Application of the INCA-P model for the simulation of flows and in-stream phosphorus resultant from scenarios of further P removal.
Results
Proprietary knowledge of Thames Water plc.