Review of waste phosphorus from aquaculture: Source, removal and recovery

The contribution of phosphorus to water body eutrophication is a global environmental problem, and rapid increases in aquaculture are considered a significant source of phosphorus discharged into the environment. The current review focuses on the source of aquaculture waste phosphorus and measures to decrease phosphorus release into the environment. Because diets are a significant source of phosphorus in fed aquaculture systems, improving the utilization efficiency of dietary phosphorus can reduce the amount of waste phosphorus at the source. A wide range of removal and recovery technologies has been identified, including adsorption, crystallization, enhanced biological phosphorus removal (EBPR), denitrifying phosphorus removal, heterotrophic nitrification aerobic denitrification (HAND) and photosynthetic organism removal. Recovery technologies were also reviewed, particularly sludge phosphorus from recirculating aquaculture systems. A new method using bacteria to immobilize waste nitrogen and phosphorus into bioflocs has been proposed as a better solution. However, most of these technologies have only been implemented at the lab scale to pilot scale. Further studies are necessary to determine the working conditions and removal capacities of related technologies on a commercial scale. Moreover, phosphorus removal methods must be selected based on a consideration of recyclability.