NITRIFICATION TRIALS AT DUNNSWOOD SEWAGE-TREATMENT WORKS AND PROCESS MODELING USING WRC STOAT

The paper describes an experimental programme on an existing full-scal e plant to demonstrate the conditions which are necessary to achieve n itrification. The programme was guided by parallel computer modelling of the plant using the WRc STOAT simulation package. Nitrification was successfully achieved, and the studies and computer modelling indicat ed how the plant should be extended to provide year-round nitrificatio n, The effect of storm flows on effluent quality was assessed for each process option. The effluent quality consent of 5 mg/l ammoniacal nit rogen as a 95 percentile was achieved, and there was a significant imp rovement in river water quality with respect to ammoniacal nitrogen.