Synergy and enhanced performance of combined continuous treatment processes of pre-chemical coagulation (CC), solar-powered electrocoagulation (SAEC), and post-adsorption for Dairy wastewater

This study investigated a novel, continuous, and solar-powered treatment system for dairy factory effluent, targeting the efficient removal of total organic carbon (TOC) and turbidity. The system comprised three sequential processes: chemical coagulation (CC), solar-powered electrocoagulation (SPEC), and column adsorption. In the CC stage, ferrous sulfate (FS) and ferric chloride (FCh) performance as coagulants were evaluated under varying doses and pH levels. The subsequent SPEC stage examined the influence of flow rate, electrode configuration (arrangement and number), initial TOC concentration (TOC 0 ), and current density (CD) on treatment efficacy. Finally, the adsorption stage utilized sea sand (SS) as an adsorbent, with the impact of adsorbent bed height (H), flow rate (F), and TOC 0 on TOC removal being assessed. The integrated system demonstrated excellent performance, achieving removal efficiencies of 50.4% for CC, 76.5% for SPEC, and 80.2% for adsorption. The overall three-stage process achieved a remarkable 97.1% removal efficiency. Furthermore, under optimal conditions, the solar-powered treatment system yielded a cost of 0.22 JD (0.31 USD) per cubic meter, representing an 83% reduction in operational costs (OPC) compared to conventional methods. These findings highlight the potential of this integrated, solar-driven approach for sustainable and cost-effective dairy wastewater treatment, producing high-quality effluent suitable for reuse. • Continuous treatment system of CC, SPES and adsorption was used to treat dairy wastewater. • Several operational parameters in the three steps including flow rate were tested. • The final TOC concentration from the third step was about 40 mg/L • The removal efficiency of the system achieves 97.1 %. • The use of solar powered reduces the operational cost by 83%