In urban areas, wastewater treatment is under the jurisdiction of the Department of Public Works is entrusted with the management of solid waste, sewage treatment including human wastes, rainwater drainage, etc.
Sewage treatment system in areas treat wastewater and by-products or waste from wastewater treatment as sewage sludge, sand, and screenings. The following is mostly wastewater from households and industry and this treatment is referred to as 'waste treatment' although in many city sewer lines also carry a large amount of industrial waste into the sewage treatment plant in addition to rainwater as well.
Therefore, sewage treatment mainly consists of the process of removing contaminants through a combination of physical processes, biological and chemical, and ensure that the final product environmentally safe treated water suitable for land use.
Most wastewater treatment plants 'central system' with an extensive network of large aerobic treatment systems, bio-filters, and septic tanks.
Wastewater from industrial plants and manufacturing, refineries, etc. are treated onsite through the infrastructure and facilities to ensure that the waste is treated before released into the local environment.
After the primary processes, further steps include secondary treatment, biosolids treatment, and tertiary treatment, disinfection, and sludge treatment.
Wastewater treatment provides several benefits such as preventing water pollution, ensure the environment is clean and free from damage, maximizing the use of natural resources such as water, to provide an alternative source of water for factories and industrial use, disease prevention and ensure adequate water supplies for agriculture and irrigation purposes.