Dual approach decontamination of lake quarry water

This study presents an innovative wastewater treatment approach that combines hydrodynamic cavitation with ozonation, achieving remarkable efficiency and environmental sustainability. Addressing critical issues such as water scarcity and persistent pollutants, the research emphasises the need for advanced, eco-friendly treatment technologies. The effectiveness of this novel method was tested on greywater sourced from a lake quarry in India. Over a 3-week period, the wastewater was treated daily for approximately 7 h, leading to substantial improvements in water quality. Notably, within the first week, the initial green discoloration and unpleasant odour were completely eliminated without the use of chemical compounds. The bacterial load was notably reduced from 105 colony-forming units (CFUs)/mL to 102 CFUs/mL, showcasing the treatment’s strong disinfection capabilities. In addition, the chemical oxygen demand dropped from 110 ppm to below 10 ppm, whereas the biological oxygen demand was reduced from 55 ppm to undetectable levels. Minor deviations were detected in chloride concentration, total dissolved solids, clarity, and water hardness. These results demonstrate the considerable potential of the combined cavitation–ozonation method for transforming contaminated, tarnished, and foul-smelling water into clean water, suitable for various practices.