Effective nutrient removal from aquaculture wastewater utilizing an indoor nutrient film technique hydroponic system

Abstract

Aquaculture wastewater treatment must remove nutrients to prevent eutrophication of receiving waters and to allow for possible re‐use of the treated water. This study aims to evaluate the shoot and root growth of crops produced in Nutrient Film Technique hydroponic systems and treat aquaculture wastewater using phytoremediation. The average physico‐chemical parameters of the aquaculture wastewater during the study period were pH 6–6.4, temperature 25°C–27°C, EC 0.7–0.8 mS/cm, and total dissolved solids (420–560 ppm). The operating conditions of hydroponic treatment units were hydraulic loading rate of 857.28 m/day, hydraulic retention time of 0.3 h, organic loading rate of 12567.8 Ibs‐BOD5/ft^2/day (BOD5 is 5 – day Biochemical Oxygen Demand) and flow rate of 54 L/h. The study found that the average elimination efficiency of nitrate‐nitrogen in aquaculture wastewater treatment varied from 78.28% by Money plants (Epiprennum aureum), 71% by Crotons (Codiaeum varigatum), 70.25% by Arrowhead plants (Syngonium podophyllum), 67.25% by Purple Heart (Tradescantia pallida), 68.62% by for Spinach (Spinacea oleracia), and 42.85% by Brinjal plants (Solanum melongena). The average removal effectiveness of BOD5 varied from 71.07% by Money plants (Epiprennum aureum), 68.62% by Crotons (Codiaeum varigatum), 78% by Arrowhead plants (Syngonium podophyllum), 72% by Purple Heart (Tradescantia pallida), 68% by Spinach (Spinacea oleracia), and 70% by Brinjal plants (Solanum melongena). Thus, environmentally friendly and economically advantageous method for reducing and removing nitrate‐nitrogen and BOD5 from aquaculture effluent is hydroponic phytoremediation. The promising potential of using indoor NFT hydroponic systems for nutrient removal particularly nitrate‐nitrogen, from aquaculture wastewater. Each plant species is assessed for its ability to uptake and reduce nitrate‐nitrogen levels, growth patterns, and overall suitability for wastewater treatment. The study emphasizes the eco‐friendly and sustainable wastewater management nature of the proposed method.