Emerging Technologies for Mitigation of Environmental Impacts Associated with Shrimp Aquaculture Pond Effluents

Abstract

The environmental sustainability of aquaculture in general and shrimp farming in particular has received increasing attention in recent years. Discharge of nutrient rich effluent from intensive culture systems can contribute to the eutrophication of receiving waters potentially impacting both natural biota and local culture operations. Technical innovations have focused on reducing effluent volumes and on discharge treatment. A growing volume of scientific research and industry experience confirm that water exchange may be reduced or eliminated. The pond microbial community plays a major role in pond dissolved oxygen dynamics, natural food availability and nutrient recycling rates. Based on an improved understanding of pond microbial ecology, techniques are emerging for community manipulation through supplementation of limiting nutrients, selective habitat expansion, and culture additions. With appropriate aeration rates and optimal pond carbon to nitrogen ratios, bacterial biomass may provide efficient, nontoxic decomposition of waste, reducing total nutrient discharge while improving natural productivity in the pond. Technologies for treatment of effluents include sedimentation and mechanical and biological filtration. Efficiency and cost effectiveness of treatment can be improved through the reduction of exchange volumes and emphasis on drain harvest effluent. Further research along these lines will improve the prospects for more profitable and sustainable production technologies.