Sustainable water circularity using electrocoagulation system for Leptobarbus Hoevenii aquaculture wastewater treatment in rural Borneo

Abstract

A rapid expansion of freshwater fish farming has led to mounting environmental and water resource challenges in Southern Sarawak which is also a major aquaculture hub on Borneo Island. As such, this study aims to investigate the effectiveness of an electrocoagulation system using aluminium electrodes for Leptobarbus Hoevenii aquaculture wastewater treatment by treating it into safe and economical reusable water source for fish farming operations in the tropical rural southern Sarawak region. Subsequent, this study has found the operation of electrocoagulation system at 20 V of applied voltage, 5 A of electric current, and 50 min of residence time could achieve high contaminant reduction efficiency with up to 98.74% for colour, 91.63% for turbidity, and over 95% for TOC and TSS. In this study, the treated aquaculture wastewater has met all Class II criteria under Malaysia National Water Quality Standards which indicates its suitability for safe environmental discharge or reuse in Leptobarbus Hoevenii production ponds. Additionally, the treatment of such water source cost only RM 3.98/m3 (USD 0.90/m3) which indicates the electrocoagulation system as a cost-effective system. The electrocoagulation process could also process produced Al(OH)3-rich flocs by containing 32.29% aluminium and 53.57% oxygen which effectively removed 90% of contaminants while concentrating several nutrients, specifically 2.85% nitrogen, 0.38% phosphorus, and 0.47% potassium. Overall, this study has demonstrated that the electrocoagulation treatment system offers an effective approach for transforming Leptobarbus Hoevenii aquaculture wastewater into a safe and sustainable water source for reuse in fish farming operation across the tropical Borneo region.