Towards zero waste: Sustainable waste management in aquaculture

Increases in aquaculture production due to higher demand for aquatic foods result in an increase in the amount of aquaculture wastewater. This situation highlights the need for the effective treatment of wastewater in sustainable aquaculture. Today, instead of traditional physical and chemical methods in the treatment of wastewater originating from aquaculture, ecosystem-sensitive and by-product-oriented systems have begun to be adopted. The main principle of the zero-waste approach is the recycling of the nutrients in the wastewater to produce another food. In this new innovative approach, the production of other organisms from the different trophic levels using the wastewater of aquaculture in the integrated multi-trophic systems (such as aquaponics) is possible to recycle the nutrients. It has been considered the integrated multi-trophic systems (IMTA) more valuable as these systems can be used both in environment-friendly wastewater treatment and in the conversion of nutrients in wastewater to biomass. The nutrients such as nitrogen and phosphorus in aquaculture wastewater can be utilized to produce two organisms (i.e. fish+mussel) or three organisms (i.e. fish+mussel+seaweed) through IMTA. Aquaculture wastewater can be used to reduce the nutrients in constructed wetlands and plant lagoons representing the reasonable approach for sustainable aquaculture and wastewater treatment. 
Here, the innovative approach to sustainable aquaculture wastewater treatment was reviewed for the current and innovative technologies. It was emphasized that the need for environment-friendly wastewater treatment Technologies such as aquaponics, enlargement of constructed wetlands, or increase in using the integrated multi-trophic production systems (IMTA) in practice are recommended for sustainable aquaculture.