Treated municipal wastewater as a water source for sustainable aquaculture: A review

Aquaculture has been the fastest-growing food production sector during the last decades. The supply–demand gap for fish is constantly widening, and declining freshwater availability is becoming a major limiting factor for production. Exploring alternative water resources, such as treated wastewater (TWW), has become a growing strategy for coping with the increasing water demand in agriculture. Reuse of wastewater or TWW for agriculture and aquaculture has been practiced around the world for centuries. However, the extent of the practice and the scientific attention paid to TWW reuse for aquaculture are negligible compared to those for agricultural irrigation. The objectives of this review are to present the existing literature on treated-wastewater-fed aquaculture, to evaluate the prospective reuse of TWW for aquaculture and its economic appraisal, and to identify the scientific and legislative gaps and challenges towards implementation. Most of the published studies on fish culture in TWW suggest that it is feasible in terms of fish survival and growth. Research also shows that fish are safe for human consumption in terms of microbiological contamination and the bioaccumulation of heavy metals and certain organic-micropollutants, with levels found to be in accordance with international standards for human consumption. Moreover, reuse of TWW as an alternative water source for aquaculture holds economic and environmental advantages. It appears that the sociocultural perception is a major barrier, which can be overcome by a combination of further research, legislation and public relations, which can support the implementation of TWW reuse for aquaculture.