Aquaculture wastewater treatment using plant-based coagulants: Evaluating removal efficiency through the coagulation-flocculation process

Abstract

The ability of mixed neem, cassava, and wild betel plant leaves to act as plant-based coagulants was tested in real aquaculture wastewater through the coagulation-flocculation process. The performance of plant-based coagulant (PBC) was compared with that of chemical coagulant (alum) to observe the removal efficiency of turbidity, TSS, color, and COD. Ratio, as a new approach, was used by selecting TSS as an indicator or index to substitute for the dosage term and calculated based on a simplified equation. The extracted medium for these coagulants was prepared by using water extraction. Initial characterizations showed that the PBC had some carbon and amine groups (as also confirmed by LC-MS) with an average zeta potential of –22.83 ± 0.62 mV. Results indicated both coagulants (plant-based and chemical coagulants) successfully removed the measured polluted parameters of turbidity (85.17 %), TSS (80.28 %), color (59.42 %), and COD (54.63 %) for PBC with dosage of 0.79 mg/L and coagulant mass of 3.94 mg, while alum gained a higher removal with turbidity (99.08 %), TSS (98.71 %), color (97.29 %), and COD (75.31 %) with dosage and coagulant mass of 698.4 mg/L and 349.2 mg, respectively. This signaled that alum still acted as the best coagulant, but PBC showed a promising opportunity as a potential substitute for chemical coagulant.