The optimization of wastewater treatment via combined techniques: Part I: Combined biological — chemical treatment

The optimization of sewage treatment by the combination of high rate biological treatment with chemical coagulation to remove both organic and inorganic pollutants with special reference to phosphorus has been investigated. In an attempt to study the minimum biological treatment which will not adversely affect the efficiency of the combined system, three different organic loads, namely, 9.48, 20.0 and 27.85 BOD₅.m^?2d^?1, were examined. The coagulants used were ferric chloride and alum. Calcium oxide was used as a coagulant aid with ferric chloride. The results obtained showed that the efficiency of the combined system was found to be slightly affected by the organic load. The combined treatment technique used in this investigation proved to be very promising in removing both inorganic and organic pollutants.