STP stands for sewage treatment plant To make sewage (human waste water ) less polluting Treatment of waste water done by heterotrophic microbes present in it naturally This treatment carried out in two stages :
1 Primary treatment – These treatment step basically involve physical removal of particals from sewage through filtration and sedimentation These are removed in stages inittialy ; floting debris is removed by sequential filtration then the grit ( soil small pebbles etc ) are removed by sedimentation. All solids settle down foarm the primary sludge ,and supretant formes the effluent the effluent from primary settling lank is taken for secondary treatment.
