This Video shows the filter media filling for a conventional rainwater harvesting filter.
A typical Rooftop rainwater harvesting system consists of a sedimentation tank and a filtration tank. The sedimentation tank is used as a pre-filter to make the heavy particles settle at the bottom of the tank.
The Filter shown here sometimes referred to as Modified rapid sand filter consists of the following ;
1. 40 mm aggregates;
2. Pebbles.
3. Activated carbon.
4. Silex.
It is put in layers. On top, a splasher stone is placed which ensures the spread of water on the filter media.
There are many good Rainwater harvesting filters available in the market. This is one of the many designs one can adopt for filtering rainwater.