Case Example of rainwater harvesting in a school for storage and reuse

A school located in Bangalore, has a strength of around 1500 students from Kindergarten to Std. XII. Water consumption in the school is primarily in the toilets. Gardening forms a small percentage and the use for drinking is minimal. However, one set of drinking water fountains is provided for the students. The layout plan is shown in Figure

Show figure Rooftop area considered for rainwater harvesting – 586 m2 Rooftop type – Flat RCC roof with weather proofing. There is adequate slop towards the downtake pipe. The school has an existing underground storage sump of capacity 35,000 l. Two sets of two overhead tanks (each of 1000 l capacity) are located on the rooftop. The overhead tanks are connected to toilets and drinking water taps. The school receives its water from a borewell. Although the school had a large underground sump which could be used for storage of rainwater, a limitation in implementation was that this sump supplied water for all purposes including drinking and hand washing. Possible options to ensure that harvested rainwater is not supplied to the drinking and handwashing points were:

Option 1:To construct a separate sump to collect the rainwater. A separate tank would be required to receive the rainwater and divert it into the toilets. This option would be cost-intensive and would also require extensive plumbing.

Option 2:Separate the drinking water line by creating a separate tank that receives water directly from the borewell. As a result, the underground sump can be used for storing the harvested rainwater. This water can then be used for every other purpose in the school except for drinking. This was considered the best option as it would reduce the overall cost. Control valves and pipelines could be provided to ensure borewell supply during the non-rainy months. Calculations Rainwater yield Yield (l) = rooftop area (m2) * annual rainfall (mm) * runoff coefficient * filter efficiency Rainwater yield = 3,63,788 l Figure 53 depicts the rainwater harvesting system that was designed for the school. The implementation was completed in 2006 and the cost of the entire system amounted to Rs. 70,000/-. The bill of materials is shown in Table Show table and photos

Rainwater Harvesting in Jain Gurukul Senior Secondary School_Rajasthan (size 0.96MB).