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SAI INTERNATIONAL SCHOOL
                                                      CLASS-VII

                                            SUBJECT - CHEMISTRY
                                TOPIC- MANAGEMENT OF WASTE WATER
                                      SUB TOPIC- CONCEPT MAPPING


                                                                    LESSON NOTE

                       Waste: Anything that is useless and we do not need it anymore, is termed as
                       waste


                       Waste water:

                       The dirty or polluted water that is generated after being used in various
                       domestic, industrial or agricultural activities is called waste water.

                       Water Pollution:

                       The discharged of undesirable substances into water bodies, is called water
                       pollution.


               Sources of water Pollution:-

                     Industrial waste
                     Mining Activities
                     Accidental oil leakage
                     Leakage from sewer lines
                     Chemical fertilizers and pesticides
                     Leakage from Landfills
                     Domestic waste


               Sewage: - Dirty waste water which carries waste as a form of suspension is called
               sewage or waste water.

               Sewage System:

               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.

               Wastewater Treatment Plant:

               Primary treatment: - primary treatment of sewage happens in three stages






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