Biosolids management and utilizations: A review

Biosolids, derived from wastewater treatment processes, have garnered increasing attention as a valuable resource due to their rich organic and inorganic constituents, which can be beneficially utilized in multiple sectors, including agriculture, civil engineering, and energy recovery. The present review article begins by providing an overview of biosolids, including their production methods and classification based on treatment processes. Subsequently, the chemical composition of biosolids is explored, highlighting the diverse array of organic and inorganic components present. The characterization techniques employed for analyzing biosolids, such as spectroscopy, chromatography, and microscopy, are thoroughly discussed, emphasizing their role in determining the quality and suitability of biosolids for different applications. Furthermore, the environmental impacts associated with biosolids disposal are extensively examined. This includes the potential risks posed by heavy metals, pathogens, and emerging contaminants, as well as strategies for mitigating these risks through proper treatment and management practices. In addition to environmental considerations, the article explores the various products that can be derived from biosolids. These include organic matter-rich soil amendments for agricultural applications, inorganic nutrient supplements for enhancing plant growth, and the potential for energy recovery through anaerobic digestion and thermal conversion technologies. The utilization of biosolids in civil engineering projects, such as landfill capping and construction materials, is promising. Land application of biosolids also can have economic and waste management benefits (e.g., conservation of landfill space; reduced demand on non-renewable resources like phosphorus; and a reduced demand for synthetic fertilizers).