"Sustainable Detoxification of Electroplating Wastewater Using Cow Dung-Enriched Microbial Consortia and Kitchen Waste Biosorbents"

Abstract

The electroplating industry generates wastewater laden with a complex matrix of hazardous pollutants, notably high concentrations of toxic heavy metals (such as zinc, chromium, and cadmium), free and complexed cyanides, and a broad spectrum of suspended and dissolved solids. These pollutants contribute to significant physicochemical variability and environmental risk. In India, the majority of electroplating units operate in decentralized and unregulated clusters, often lacking advanced technologies, process automation, and adequate effluent management systems. Consequently, the wastewater discharged from such units exhibits erratic and elevated levels of biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), total dissolved solids (TDS), turbidity, and color—ultimately leading to severe oxygen depletion and aquatic toxicity in receiving water bodies.

To address these environmental challenges, the present study investigates a sustainable and low-cost treatment strategy utilizing biosorption. Biosorption, a passive physicochemical process, involves the selective binding of metal ions to functional groups on the surface of biological materials, particularly those present in microbial cell walls. This research explores the potential of employing organic biosorbents derived from cow dung and decomposed vegetable waste—both abundantly available agricultural byproducts as effective adsorbents for the removal of heavy metals from synthetic electroplating wastewater.

A series of controlled batch adsorption experiments were conducted to evaluate the removal efficiency of these organic substrates under varying operating conditions. The results indicate that both cow dung and vegetable waste exhibit significant sorption capacities, attributable to their porous structure, high surface area, and the presence of active functional groups such as carboxyl, hydroxyl, and amine groups. These findings suggest that such organic waste materials can serve as cost-effective and environmentally benign alternatives to conventional physico-chemical treatments.

The study contributes to the growing body of knowledge on green remediation technologies and highlights the viability of organic biosorbents in industrial wastewater management, especially for applications in resource-constrained settings. This eco-centric approach not only enhances the sustainability of wastewater treatment but also promotes the valorization of organic solid waste, aligning with circular economic principles.