BIOTREATMENT OF FISH FARM EFFLUENTS USING THE CYANOBACTERIUM PHORMIDIUM-BOHNERI

The potential environmental impact of effluent from fish farms is of i ncreasing environmental concern. Although concentrations in total nitr ogen and phosphorus are usually low, their impact on the environment c annot be ignored because of the high nutrient mass flows utilized duri ng fish farming. In this paper we investigated the use of a non-toxic cyanobacterium, Phormidium bohneri, to remove dissolved inorganic nutr ients from fish farm effluents. Wastewater was directed toward three c ompletely mixed 70 1 photobioreactors with retention time of 8, 12 and 24 h, respectively. Average efficiencies of ammonia nitrogen removal from rainbow trout (Oncorhynchus mykiss) effluent was 82% and 85% for soluble orthophosphate, over a 1 month period. From these results, the potential use of P. bohneri as an alternative for the tertiary treatm ent of fish farm effluents is analyzed. (C) 1998 Elsevier Science B.V.