Panalee Chevakidagarn

pp. 633 - 639

Abstract

By surveying 63 central municipal wastewater treatment plants throughout Thailand, it was found that about 80 percent of them did not function as expected (Pollution Control Department, 2004). Most of the problems were inadequate performance and operational problems. Concerning the Songkhla Lake Basin,
there are 2 central municipal wastewater treatment plants serving only 7 percent of the basin population. These two plants were not designed for nutrient removal which is similar to most industrial wastewater treatment plants in southern Thailand. The untreated nutrients have caused eutrophication problems in
Songkhla Lake. In addition, the existing activated sludge processes which treat industrial wastewaters are facing problems of bulking and rising sludge resulting in inadequate treatment. The major reason for the bulking sludge problem was most likely an insufficient oxygen concentration. Aeration control system is
urgently required.