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SAI INTERNATIONAL SCHOOL
                                                      CLASS-VII
                                            SUBJECT - CHEMISTRY

                                TOPIC- MANAGEMENT OF WASTE WATER
                                        SUB TOPIC- SEWAGE SYSTEM

                                                         LESSON NOTE









































               An effective sewage system is made up of a network of pipes that carry wastewater
               to the sewer mains of the city. These pipes that carry wastewater are called sewers.
               The pipes are normally made up of cast iron or PVC (polyvinyl chloride). The pipes
               from each house or building are connected to a sewer main that is covered by a lid
               called the manhole cover. A person can enter the sewer through this manhole to
               check any leakage or blockage for maintenance purposes. The sewer mains flow
               into progressively larger pipes until they reach the wastewater treatment plant. The
               sewage is then treated, cleaned and released into rivers and seas.



               Waste Water Treatment Plant:






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