THE PERFORMANCE OF A PILOT-SCALE SERIES OF 10 PONDS TREATING MUNICIPAL SEWAGE IN NORTHEAST BRAZIL

The performance of a pilot-scale long series of ten ponds was evaluate d in terms of the removal of BOD5, COD, suspended solids and faecal co liforms with data from two experiments with total mean hydraulic reten tion times of 19 and 28.5d. Overall removals were very good and in bot h experiments the final effluent of the series complied with the recom mended FC count of less than 1000 per 100ml for unrestricted irrigatio n, and unfiltered BOD5 concentrations were less than 20 mg/l. The long series of ponds was concluded to be a land-saving alternative compare d to other pond configurations previously studied at EXTRABES. Copyrig ht (C) 1996 IAWQ. Published by Elsevier Science Ltd.