National Institute for Water Resources, Water Resources Research Institute Program
3/1/2002 - 2/28/2005
Advanced treatment must be provided to wastewater used for freshwater aquaculture in order to meet effluent water quality standards. Because such treatment can be expensive and because freshwater is also increasingly in short supply around the world, an attractive management alternative was to develop a closed aquaculture system that supports effluent treatment and reuse while overcoming obstacles of high treatment cost and a short freshwater supply. The research objectives for FY 2001 and FY 2002 were (1) to investigate the nitrogen build-up in freshwater aquaculture of tilapia, (2) to develop a wind-powered reverse osmosis (RO) nitrogen removal system, and (3) to evaluate the economic feasibility of the wind-powered RO system for removing nitrogen from aquaculture wastes.
The studies on removal of nitrogenous aquaculture wastes by a wind-powered RO system was followed by a second phase of research on a new pollution issue—namely, the discharged concentrate. The mechanisms of the RO membrane system are such that the discharge concentrate has a higher nitrogen concentration level than that of the untreated wastewater from the fish tank. Thus, the concentrate cannot be recirculated in the system; rather, it must be discharged or further treated before it can be reused. The research objectives for FY 2003 and FY 2004 were (1) to further investigate the nitrogen build-up in discharged concentrate from the RO system and (2) to develop a duckweed-based pond system to remove nitrogen from the concentrate.
View the related publication: CP-2004-07