摘要：Filtration, chemical coagulation and activated sludge process are applied to wastewater from a “Sozai” processing plant. Filtration was performed through the rotating sieve to which 250-mesh nylon cloth was firmly attached. The removal rates of SS, COD and BOD were 95.4%, 62.9% and 63.4%, respectively, and the specific filtration area was 0.5m2/l. The BOD removal was represented well in terms of the first-order reaction kinetics and the calculated value of the BOD removal coefficient was 6.3×10-5 (1/mgSShr). After the activated sludge treatment, the chemical coagulation was tested. In the chemical coagulation, 500mg/l of FeCl3 was added and pH was adjusted at 6.5 by the addition of a NaOH solution. Then, the mixture was stirred for 3min. at 150rpm and for 10min. at 30rpm in a jar tester. The coagulation efficiency was marked more than 90% if the subject was pretreated for 12hr or more by activated sludge. The final COD and BOD were below 28mg/l and 5.1mg/l, respectively.
