Enhancement of dairy wastewater treatment efficiency in batch chemical-assisted solar-powered electrocoagulation-adsorption system

Abstract

This study conducts a multi-stage approach to enhance the treatment of dairy wastewater, focusing on efficiently removing of total organic carbon (TOC). The investigation comprises three sequential treatment processes: chemical coagulation (CC), solar-powered electrocoagulation (EC), and adsorption. In the initial stage, a range of organic and inorganic coagulants were evaluated under varying conditions, including dosage, pH, and dilution. Ferrous sulfate exhibited superior performance, achieving a TOC removal efficiency of 68 % at pH 5.6 for a concentration of 1 g/L. The subsequent EC process investigated the impact of electrode type, number, arrangement, current density, and dilution on TOC removal during the electrocoagulation process. Both Al and Fe electrodes displayed similar performance with a maximum 47.1 %. The EC removal efficiency was maximum when using six electrodes with MP-S arrangement. In the final phase, the effectiveness of various inorganic adsorbents (zeolite, sea sand, shale oil ash, commercial activated carbon) was assessed, considering factors such as adsorbent type, dosage, temperature, and pH. Shale oil ash and sea sand exhibited the highest capacities with removal efficiencies of 75 and 69 %, respectively compared to 80 % for activated carbon when using a TOCo of 100 mg/L and an adsorbent dose of 1.25 g. These results indicate that this research integrates three processes with an overall removing of efficiency of 98.6 %. This combined treatment system represents a promising approach for effectively treating dairy wastewater, and addresses environmental concerns associated with dairy industry effluents.

Keywords

• Combined treatment processes
• Dairy wastewater
• TOC removal
• Electrocoagulation
• Adsorption
• Chemical coagulation