TREATMENT OF HIGH-STRENGTH AMMONIA LIQUORS USING THE AMTREAT PROCESS AT ASHFORD STC, SOUTHERN WATER


Download Image

The Amtreat process is a high-rate activated sludge plant for treating high-strength ammonia liquors. The compact, high-rate ammonia treatment system has a relatively small footprint compared to conventional activated sludge treatment processes, and full nitrification of highstrength ammonia effluent can be achieved, with typical ammonia removal rates in excess of 97%.

In 2008 Southern Water installed an Amtreat sludge liquor treatment plant at their sludge treatment centre at Ashford. The plant replaced an existing SBR liquor treatment plant, and treats liquors arising from pre-digestion thickening, post-digestion dewatering, and condensate from a sludge dryer. The plant comprises a balance tank with mixing system, hot and cold liquor blending system and the Amtreat plant. The Amtreat plant is configured for nitrification, denitrification, and alkalinity recovery; with a pre-anoxic tank for denitrification; the Amtreat reactor for nitrification; and final settlement for solids removal. The plant includes an internal nitrate recycle and RAS recycle to optimise denitrification and alkalinity recovery, which in turn minimises caustic dosing.

This paper discusses the operation of the Amtreat plant at Ashford STC since initial
commissioning in 2008, up to the present day.

The full version is available as a download: