Industrial wastewater contains different pollutants and is often more variable, concentrated, and toxic. The nature of the design, construction and operations are also different.
Sewage is generated by residential, institutional and industrial establishments. Sewage treatment is the process of removing contaminants from wastewater to use for reuse and or for safe disposal.
Water is disinfected to kill or deactivate pathogenic micro organisms by physical or chemical methods. Possible pathogens are generally viruses and bacteria. Disinfectant should kill micro organisms and provide residual effect to prevent growth in storage and distribution systems.
Clarification is the removal of colloidal suspended solids from water. Liquid solids separation under low velocity gradients takes place within a clarification system because of the specific gravity difference between the solids and liquid. Efficiency can be increased with suitable coagulants and chemicals.