Hybrid mangrove-ultrafiltration as an environmental biotechnology innovation for industrial wastewater treatment and reuse in aquaculture

This study aims to design and evaluate a hybrid wastewater treatment system that integrates mangrove leaf powder biofiltration with membrane ultrafiltration, an environmental biotechnology innovation, to improve the quality of industrial effluent for reuse as aquaculture media. This study employs a one-group pre- and post-test experimental design. The system comprises a two-stage biofilter unit containing mangrove leaf powder packed in polypropylene sacks, followed by ultrafiltration using three 25-micron filter bags placed in a single housing. Wastewater from the washing process in West Lombok was treated, and water quality parameters – biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), dissolved oxygen (DO), pH, and total dissolved solids (TDS) – were analyzed pre- and post-treatment at each stage. The results showed significant improvements: BOD decreased from 46.5 mg·l⁻¹ to 6.1 mg·l⁻¹, COD from 130 mg·l⁻¹ to 19 mg·l⁻¹, and TSS from 120 mg·l⁻¹ to 3.4 mg·l⁻¹; meanwhile, DO increased from 2.3 mg·l⁻¹ to 6.8 mg·l⁻¹, and pH stabilized at around 7.1. The effectiveness of this system is supported by the adsorption properties of tannins and polyphenols derived from mangroves as bioremediation agents, as well as by an optimal hydraulic retention time of 4 h. The findings of this research demonstrate that this system is suitable for the sustainable reuse of wastewater in freshwater fish aquaculture.