Physical Chemical Treatment of a Combined Sewer Impacted Secondary Effluent

摘要

Physical-chemical treatment of conventional biological secondary effluent for the removal of organic and inorganic pollutants is used and considered applicable in areas where secondary treatment alone is incapable of producing satisfactory effluent quality. This report describes the results of a pilot scale study performed at East Chicago, Indiana, in which an evaluation was made of the effectiveness of treating biological secondary effluent impacted by combined sewer and industrial wastes with lime coagulation, dual media filtration and activated carbon adsorption. The 2840 cu m/day (0.75MGD) physical-chemical wastewater treatment facility demonstrated the effectiveness of chemical coagulation, filtration, and activated carbon adsorption on a combined sewer and industrial waste impacted secondary effluent. The costs associated with the operation of the treatment processes were also studied. Treatment consisted of: the addition of cationic coagulants (calcium hydroxide and ferric chloride); two stage coagulation; solids contacting and high rate sedimentation; dual media filtration; pH adjustment; and granular activated carbon adsorption. The primary coagulant (calcium hydroxide) dosage generally ranged from 185 mg/l to 415 mg/l, while the secondary coagulant (ferric chloride) was added at the rate of 17 mg/l when in use.