INCREASE IN PHOSPHATE REMOVAL FROM WASTE-WATER BY ALTERNATING AEROBICAND ANAEROBIC CONDITIONS

Increase in the efficiency of phosphorus removal from wastewater is be coming of outmost importance in order to comply with the quality stand ards foreseen by the international codes. In fact, efficiencies not ex ceeding 30% are usually ensured by traditional wastewater treatment pl ants through settling and removal of excess sludge. The Phostrip, Bard enpho and A/O processes, recently developed and implemented in industr ial plants, have allowed for substantial improvements in the biologica l removal of phosphate. Aim of the present paper is to describe how th e efficiency of the original A/O process has been optimized in a labor atory-scaled single basin, through an alternate sequence of aerobic an d anaerobic phases. Using a ratio of aerobic/anaerobic phases duration of 0.6, phosphorus removal yields higher than 90% have been ensured f eeding wastewater containing phosphorus levels up to 100 mg/l.