This document discusses sewage disposal and pollution control. It begins by defining sewage and its origins from residential and industrial establishments. Sewage is classified as domestic or industrial. Domestic sewage typically contains human waste while industrial sewage varies more in composition. The document then outlines the three phases of sewage treatment: pre-treatment to remove solids, primary treatment to separate waste, and secondary treatment using bacteria to further break down organic matter. It also discusses different types of pollution like air, water, soil, and noise pollution. Causes and effects of each type of pollution are provided along with strategies for pollution control and prevention of environmental degradation.