ABSTRACT
The characteristics of biosolids play an important part in their use for land application. They can be broken down into three categories: physical, chemical, and biological. Physical properties affect the method of application, as well as the soil’s physical and chemical properties. The solids content of biosolids affects the method of land application. Liquid or low-solids biosolids will generally be injected into the soil to prevent vectors and provide better aesthetics. Dewatered or semisolid biosolids are usually spread on the surface and subsequently plowed into the soil. The concentration of solids adds organic matter to the soil. Biosolids contain trace elements, including heavy metals, primarily from industrial, commercial, and residential discharges into the wastewater system. Trace elements and heavy metals are ubiquitous. They are found in natural soils and plants. They are also in fertilizers since they are part of the mineralogical composition of the mined materials.
