In situ hypochlorous acid generation for the treatment of brackish shrimp aquaculture wastewater

This study presents an unconventional framework for treating shrimp aquaculture wastewater based on in situ hypochlorous acid (HOCl) oxidation. The in situ oxidation process makes use of the salinity present in aquaculture wastewater to generate HOCl. The undivided electrolytic cell consisted of two sets of graphite as the anode and stainless sheets as the cathode. The electrochemical oxidation of shrimp aquaculture wastewater was carried out for an influent COD concentration of 1730 mg L^?1 at current densities of 37.2 and 74.5 mA cm^?2. The results showed that in order to achieve a residual COD concentration of 50±5 mg L^?1 at current densities of 37.2 and 74.5 mA cm^?2, electrolysis periods of 60 and 30 min are required respectively. Hence, for the above‐mentioned current densities, the corresponding energy requirements were found to be 19.4 and 13.3 W h L^?1. The cost incurred in treating 1 m³ of shrimp aquaculture wastewater was found to be RM 4 and 3 when the electrolytic reactor was operated at a current density of 37.2 and 74.5 mA cm^?2 with a salinity of 23‰. The foregoing study highlights the potential of in situ HOCl oxidation in treating brackish shrimp aquaculture wastewater.