Performance of Chemical-Based vs Bio-Based Coagulants in Treating Aquaculture Wastewater and Cost-benefit Analysis

Abstract

Aquaculture sector plays important role for the economic development in Malaysia, but environmental concerns are arising due to the pollution caused by the discharge of untreated wastewater. Coagulation-flocculation-sedimentation is currently the best practice of aquaculture wastewater treatment. This research aims to compare the performance of chemical-based (alum) and bio-based (neem leaves) coagulants in treating aquaculture effluent while also studying the economic feasibility. Alum showed higher removal efficiencies of total suspended solid (99.7%), turbidity (98.8%), and color (97.3%), while neem coagulant showed a lower dosage needed to achieve the optimum performance. The total cost included capital and operational costs, while total benefit included the potential of water reuse and reclaimed valuable products from sludge. The net profit reveals negative values for both scenarios, while cost-benefit ratio showed 0 and 0.06 values for alum and neem coagulants, respectively. These values indicated that both scenarios are not feasible to gain economical profit, while the utilization of neem coagulant present benefit for water reuse and sludge utilization. A deeper analysis using Social Return on Investment (SROI) method is suggested to include the non-traditional calculation in cost-benefit analysis such as social and environmental values of the scenarios.