Sewage sludge is a semi-solid or solid waste material that is removed from the sewage during the treatment process at sewage treatment plants. This sludge is the residual material that remains after the treatment of wastewater and consists of both organic and inorganic materials.
Sewage sludge can be further classified into primary and secondary sludge, depending on the treatment process used. Primary sludge is the thick, heavy material that settles to the bottom of the treatment tank, while secondary sludge is the material that is generated during the biological treatment process.
Sewage sludge can contain a variety of contaminants, including heavy metals, pathogens, organic compounds, and microplastics. Therefore, it must be treated and disposed of safely to prevent any negative impacts on human health and the environment.
Sewage sludge is often treated further to remove any remaining contaminants and is then used as a fertilizer or soil amendment in agriculture. It can also be incinerated or sent to landfills for disposal. Proper management and disposal of sewage sludge are crucial to protect public health and the environment.