Microbial Remediation of Seafood Processing Effluent Enhances the Removal Efficiency of BOD, COD, and Nitrogenous Compounds and Evaluating its Toxicity

Abstract

The environmental effects of industrial wastewater on terrestrial and aquatic ecosystems are a significant global issue. With the growing demand for processed seafood, the seafood processing industry is under increasing pressure to produce more, resulting in greater wastewater discharge into adjacent waterways. This study finds that Salmonella enterica BSE-13, isolated from seafood processing effluent, is highly effective in removing BOD, COD, nitrites, nitrates, and nitrogen. When starch is added, among the 7 isolates BSE-13 achieves higher removal efficiencies of 72.5% for BOD, 65.8% for COD, 41.6% for nitrites, 69.6% for nitrogen, and 54.3% for nitrates. Response Surface Methodology (RSM) using the Box-Behnken Design (BBD) optimized media conditions to maximize the removal efficiency of the potent BSE-13 strain. Under optimized conditions, removal rates reach 83.94% for BOD and 73.15% for nitrogen. In a glass column setup, BSE-13 removes 62.25% of BOD by the 12th day. A pot trial shows that the treated effluent improves plant growth compared to untreated effluent. Toxicity tests reveal significant chromosomal and nuclear abnormalities in onion root tips exposed to untreated effluent, while brine shrimp studies show that treated effluent and controls have fewer aggregates and less morphological change, with untreated effluent causing severe toxicity. Therefore, the results of this study suggest that using eco-friendly microbes for treating effluent offers a cost-effective and environmentally friendly method for cleaning wastewater. Microbially treated effluent demonstrates significant potential for reducing various pollutants and enhancing plant growth.