UPGRADING EFFLUENT QUALITY FOR LAGOON-BASED SYSTEMS

To establish Best Available Technology Economically Achievable (BATEA) in non-urban communities which presently use conventional lagoon tech nology, an investigation was undertaken to evaluate alternatives which can be used to improve lagoon effluent and establish costs. Evaluated were the ''Sutton'' and the intermittent sand filtration or ''New Ham burg'' processes. The Sutton concept consists of a nitrifying extended -aeration plant followed by polishing lagoons, with waste sludge disch arged into the lagoons, The New Hamburg concept consists of aerated or facultative lagoons, with tile lagoon effluent sprayed intermittently over sand filters. The Sutton plants produce an improved effluent qua lity relative to conventional facultative lagoons in terms of BOD5 and TSS concentrations. Increases in ammonia concentration across the pol ishing pond occur after 5-7 years of plant operation, suggesting a nee d to implement a regular program of sludge removal from the lagoon. Th e New Hamburg process results in a significant improvement in effluent quality in terms of BOD5, TSS, TP, TKN, NH3-N and H2S concentrations. Approximate capital costs for upgrading the existing conventional lag oons in Ontario to Sutton and New Hamburg process facilities are estim ated at US $221 million and US $93 million, respectively.