This is one of our recently completed rainwater harvesting projects in Bangalore.
The design is to capture the rooftop rainwater and storing it in the underground sump to be used for all purposes including drinking.
The filtration has 4 stages namely
1. FRS or first rain separator : This is the plumbing arrangement to drain out initial few minutes of water.
2. Sedimentation tank or rain Barrel : This is a loft tank placed at an elevation. The overflow from the FRS goes into this tank. The water stored in this tank can be used for non potable purposes like gardening and car washing . In a way one can say , this is an extension of FRS .
3. 2 Stage Up-flow modified rapid sand filter : The input to this tank is the overflow from the FRS. This is the filtration tank consisting of two chambers . Each chamber has filter media in a certain proportion (depending on the catchment area) . Filter media consists of River pebbles , sillex of 20 mm and 10 mm and activate carbon .
The filter also has a provision of backwash after every rain to keep the filter clean.
