Severn Trent Services Technology Contracted for Ammonia Removal at Sewage Facility

Severn Trent Services (UK) has been awarded a contract to supply its TETRA® NSAF (nitrifying submerged aerated filter) filtration technology to Thames Water Utilities Ltd, for the removal of tertiary ammonia down to 2 mg/l at its Standon Sewage Treatment Works. The technology’s innovative design will be supplied in a glass-coated steel tank designed for an average flow of 900m3/day and will be constructed on site in February 2011.

Severn Trent Services has previously supplied the TETRA NSAF technology to Thames Water Utilities Ltd. In 2006 and 2007, contracts for three installations were awarded for the Waddesdon, Culworth and Byfield wastewater facilities as extensions to the existing works for tertiary nitrification to meet ammonia standards. An additional seven TETRA NSAF installations have since been completed for Thames Water Utilities Ltd.

TETRA NSAF is an established and proven technology for ammonia removal. The upflow, fixed-film biological process is extremely flexible and is available in a range of sizes – from small modular units suitable for above or below ground construction to custom-made configurations for large plants. It can be combined with various solids removal processes or enable direct discharge of the effluent depending on individual site circumstances.

According to Mick Pichur, capital delivery engineer at Thames Water Utilities, “Ammonia removal technology was needed at Standon to cope with increasing demand on the works. Because of our experience with the TETRA NSAF process at other Thames Water sewage treatment works, we had confidence in the technology to meet the consent limits at the Standon facility.”