RETHINKING RAS: DEVELOPING NUTRIENT BALANCE WITHIN RECIRCULATING AQUAPONIC SYSTEMS

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, excess nutrient-rich effluent produced by typical aquaculture systems leads to eutrophication of water sources, requiring extensive wastewater remediation. Aquaponics offers a new solution to mitigate this costly strain on production by combining fish farming with plant production. 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 these waste products in aquaculture systems eliminates the need for exogenous, expensive, and often synthetic nutrient supplementation to achieve adequate plant growth. Additionally, this decreases water treatment expenses while also generating extra profit from sale of the produce, ultimately lowering net production costs. This research focuses on further quantifying both soluble and particulate components of tilapia based RAS effluent for bioavailable macro- and micro- nutrients. We will then compare the resultant profile with typical requirements of various food crops to ensure sufficient fertilization. Characterizing the chemical differences within plant tissues from our aquaponic systems against those produced via terrestrial farming will confirm efficient nutrient transfer and non-inferior plant tissue growth. Further research will include characterizing species-specific effluent differences to more precisely match fish varieties to desired crops within individual systems. In conclusion, converting recirculating aquaculture systems into recirculating aquaponics systems, through our understanding of balanced supply and demand of nutrients derived from fish waste, allows for a more sustainable and economically viable model of integrated agricultural production.