The first time a young Arunachalam was introduced to the concept of saving rainwater was when his mother called him to help her collect rainwater in an unda (giant copper vessel). His family was able to collect 500 litres of water in each of the four vessels they had. Though rain for him was a time to play with his friends, he was intrigued at the idea of collecting the rainwater.
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From then on, the arrival of the monsoons for Arunachalam living in Kallal village, Tamil Nadu, meant not only fun but also collecting rainwater for daily needs.
He recalls how his mother covered each vessel with a veshti (a garment that is typically wrapped around the waist) to filter the water which was then boiled and used for drinking and cooking purposes.
No wonder that his favourite subject in his Civil Engineering course was Hydraulics where he formally learnt various water-saving concepts including Rain Water Harvesting (RWH).
After graduating, he joined the engineering division of the Public Works Department in Madurai. Pursuing his faith in the concept of RWH, he promoted the concept across Madurai in educational institutes, corporations and government offices through many awareness programmes.
In fact, he was instrumental in helping government offices harvest water.
During my 33-year-old career with the PWD, I have lived in two houses and in both of them, I did not take the government water connection as the harvested rainwater sufficed the water needs of my family, he tells The Better India (TBI).
Arunachalam has come up with a simple but unique method of conserving rainwater which has been adopted by schools, multinational corporations and apartment buildings.
Here’s How The RWH System Works
The middle the terrace where the majority of the water gets collected is lower than the rest of the terrace. The water collected in this pit is sent to the tank on the first floor via pipes. The mouths of each pipe are fitted with a netted cloth to stop debris and other waste from entering the pit.
The pit has three layers of filtration – river pebbles, charcoal and fine sand. Arunachalam advises that for hygiene purposes, one must wash the pebbles in a mixture of antiseptic liquid and water multiple times before placing them in the pit.
In the final step, the filtered water is transported to another tank with a capacity of 11,000 litres. This water is used for cooking and drinking purposes.
In times when the tank overflows, the spillage is sent to an underground sump connected to a borewell which supplies water to Arunachalam’s home for non-potable use and also helps with underground water recharge process.
The pH value (a measure of the acidity or alkalinity of a solution) of the filtered water at Arunachalam’s house is 7, which is the standard level recommended by health experts, “The water is safe enough to prevent health complications like kidney stones. The rice cooked from using this water is extremely healthy.”
When asked what one can keep in mind before installing a rainwater harvesting system, Arunachalam gives a basic formula for a family of four:
Water for Drinking: 12 litres per day
Water for Cooking: 16 litres per day
Total water consumption per day: 28 litres
Annual consumption: around 11,000 litres (10,220 litres + extra for guests)
While adopting rainwater harvesting, one has to keep in mind that the size and capacity of the structure not only depends on consumption but also the rainfall patterns. For instance, an average 110 mm rainfall is needed to harvest 11,000 litres of water and Madurai gets 840 mm of rain on an average every year. So it takes just a week for Arunachalam to store water for an entire year.
The innovator has named his terrace ‘Akshayapatra’ (an inexhaustible vessel) as it is the area that collects the majority of the rainwater, “We use our terrace for saving water, gardening, walking and also to generate electricity via solar panels. It is amazing to see how one area can be used for multiple things.”
The structure at Arunachalam’s house saves 16,000 litres of rainwater annually. The entire process is a one-time investment that costs around 2.5 lakhs and it has been almost three decades since Arunachalam received a water bill as he does not use government supplied water.
The potential for conserving rainwater in states like Maharashtra, Karnataka and Tamil Nadu is very high. A city like Mumbai receives up to 700 mm of water in a single day [during monsoons]. If every citizen practices RWH then water-related problems could be cut significantly, says the 72-year-old.
At a time when more and more cities in India are turning into water stressed regions, Arunachalam has a special appeal, “We are extracting groundwater without giving back to Mother Earth. In olden days my mother used to say ‘do not waste money like water’. It has now changed to ‘do not waste water like money’. I request every citizen to take steps and conserve as much water as possible.”
If you wish to get guidance about installing a Rainwater Harvesting System at your home or workplace, you can reach out to N Arunachalam at: 877-8654745.
(Edited by Saiqua Sultan)