Aquaculture produces 44% of the 167 million tons of seafood consumed annually worldwide. Capture fisheries continue to decline at a steady rate, while the aquaculture industry has grown nearly 6% annually in the last decade. However, the costs associated with the treatment of nutrient-rich effluent produced from aquaculture production systems is typically internalized, thereby increasing the break-even price of aquaculture products. Integrating aquaculture with other agricultural cropping systems offers an opportunity to mitigate this costly strain on production by combining fish farming with plant production similar to other animal agricultural production systems. Past waste-solids research on recirculating aquaculture systems (RAS) suggests that the nutrient load in the captured solids meets and may exceed the demands of terrestrial plants. Using the waste nutrients from aquaculture may reduce or eliminate the need for exogenous synthetic nutrient supplementation to achieve adequate plant growth, however a complete characterization of plant-required nutrient production must be conducted to understand what treatment is required to make the nutrients plant-available for hydroponic crop production. The integration of aquaculture and hydroponic production systems also reduces water consumption when compared to separate aquaculture and hydroponic system water use.
Aquaculture waste nutrient research characterization studies were conducted at the University of New Hampshire in the Anadromous Fish and Invertebrate Research (AFAIR) lab located on the Durham, NH campus. Three replicate 5 m3 recirculating aquaculture systems (RAS) utilizing drum screen filtration and nitrifying moving bed bioreactors (MBBRs) were used to evaluate nutrient production and fractionation in the effluent stream (dissolved and particulate) from tilapia and rainbow trout growout in terms of plant-required macro- and micro-nutrients. Results will be presented demonstrating effluent stream nutrient profiles and the fractionation of plant-required nutrients in the dissolved and particulate forms, respectively. Nutrient production rates will be quantified and normalized to provide estimates for larger feeding operations, and allow for scalable integrated aquaponic system designs.