| dc.description.abstract | Sewage sludge management presents a multifaceted challenge requiring comprehensive strategies to mitigate environmental and health risks while maximizing resource recovery. There is insufficient research done on biosolids and biochar, especially with respect to their feedstock-specific properties and long-term effects. This study investigates the efficacy of biosolids and biochar on soil application. Through a combination of experimental analysis and theoretical modeling, the study assesses the removal efficiency and fate of contaminants across different treatment scenarios. High accumulation potential in the soil is observed for Cr, Cu, Cd, and Pb, with Cu and Zn having higher leaching potential. Amongst the HMs analyzed, Cu, Zn, Cd, Pb, and Cr are found to have higher toxicity potential in soil application. Pb, As, Zn, and Cd are found to be more bioavailable than other HMs in soil. In the context of soil application, biochar is deemed a much more viable option than biosolids due to the low mobility, leaching, and toxic effects of the pollutants present. Furthermore, biochar produced at low temperatures without AD leads to less leaching, toxicity, and bioavailability.
Recommendations for optimizing biochar application to soil, including thermal hydrolysis, co-pyrolysis, hydrothermal liquefaction (HTL), and biochar amendment are proposed to enhance treatment efficiency and minimize risks. Overall, this study underscores the need for comprehensive monitoring and regulation of treated sludge to ensure environmental protection and human health, particularly in the context of emerging pollutants and evolving treatment technologies. | |
