Sustainable Treatment of Aquaculture Effluents—What Can We Learn from the Past for the Future?

TLDR

Aquaculture produces large volumes of wastewater rich in suspended solids, nitrogen, and phosphorus, and its waste load rises with fish production, prompting the use of conventional and cost‑effective constructed wetland treatments. This review aims to evaluate integrated aquaculture‑plant systems and provide recommendations to reduce water resource pollution. The authors survey historical and current practices, focusing on combined aquaculture‑plant systems, and outline strategies to mitigate nitrate and phosphate loads.

Abstract

Many aquaculture systems generate high amounts of wastewater containing compounds such as suspended solids, total nitrogen and total phosphorus. Today, aquaculture is imperative because fish demand is increasing. However, the load of waste is directly proportional to the fish production. Therefore, it is necessary to develop more intensive fish culture with efficient systems for wastewater treatment. A number of physical, chemical and biological methods used in conventional wastewater treatment have been applied in aquaculture systems. Constructed wetlands technology is becoming more and more important in recirculating aquaculture systems (RAS) because wetlands have proven to be well-established and a cost-effective method for treating wastewater. This review gives an overview about possibilities to avoid the pollution of water resources; it focuses initially on the use of systems combining aquaculture and plants with a historical review of aquaculture and the treatment of its effluents. It discusses the present state, taking into account the load of pollutants in wastewater such as nitrates and phosphates, and finishes with recommendations to prevent or at least reduce the pollution of water resources in the future.