“sewage” refers to trash from any and all commercial, Residential and Industrial. Sewage treatment plants (STPs) clean wastewater so that it can be safely discharged to the environment, reused in agriculture, or redirected for reuse in homes as flush water. Both organic and inorganic materials are frequently found in sewage. Sewage treatment is necessary before it may be released into a body of water. Sewage can contaminate rivers and other water sources if not properly treated before being released into them.