Process intensification in acidic wastewater treatment and waste valorization

Acidic waters often resulting from industrial processes and other activities typically comprise a range of perilous and harmful substances, including organic solvents, heavy metals, pose a significant environmental challenge with adverse effects on aquatic ecosystems, infrastructure, and public health. Traditional treatment methods have limitations in effectively neutralizing acidity and removing pollutants to mitigate these impacts and restore ecological balance. One promising method for treating acidic waters involves the use of lime (CaO), a versatile and cost-effective solution. However, this method generates large amount of sewage sludge presents its own set of threats in terms of disposal and environmental impact. This research presents a general overview of the treatment of acidic waters through lime utilization and explores the potential valorization of sewage sludge in diverse processes. Through a comprehensive analysis of current research and practical applications, it explores underlying mechanisms and highlights the effectiveness of lime in neutralizing acidic waters by adjusting pH levels, and removing pollutants through precipitation heavy metal hydroxides. Furthermore, this investigation delves into diverse methods, including anaerobic digestion and thermal treatment processes for the repurposing of sewage sludge. It considers its potential applications in waste-to-energy and nutrient recycling beyond conventional disposal practices, aiming to reduce landfill waste volume and environmental pollution while promoting resource recovery. The valorization of sewage sludge entails its transformation into valuable resources such as syngas, fertilizers, biofuel, and biogas. This integration presents synergistic benefits, including improved water quality and promoting circular economy principles.