Innovation

Recharge well Underground stores of freshwater

An NGO innovates a well design pressurised recharging well that gathers fresh rainwater in the saline. Aiming ‘Life is Water’.
Recharge well Underground stores of freshwater

Water. Freshwater. Whenever an eye is out for wonders, it finds them, they reflect the magic, it’s the water. An NGO innovates a well design pressurised recharging well that gathers fresh rainwater in the saline. Aiming ‘Life is Water’.

The earth is the densest planet, it is the third planet from the sun, 70 percent of the earth is water. Ahh!! It’s all the known facts from the kinder general science knowledge. But the most threatening facts about the water, the importance element for lives to exist, is, it is finding its way towards their extinction. Oh! The water here refers to pure safe drinking water.

In a nutshell: 20 percent of the world’s population or more than 1 billion people lack access to safe drinking water, 50 percent of the world’s population or more than 3 billion people lack access to sanitation, 80 percent of all illnesses and more than one-third of all deaths in developing countries are related to water. It is estimated that worldwide, around 7 million die yearly from diseases linked to water. Every eight seconds a child dies from a water-related illness, that is about 4 million a year. More seriously over 2.8 billion people in 48 countries will face water stress by 2025, based on United Nations report.

Indian scenario

Talking about India, a whopping 80,000 square miles of land is estimated to contain water that’s too salty to drink. Much of the groundwater there is brackish and has high salinity, and desalination resources available cost and energy intensive making it suitable for most – leaves this water completely useless for drinking, and largest ineffective for irrigation or any other use.

“It is impossible to drink the saline water. Every household in most of villages in Mewat, no matter how poor, calls for a water tanker every month and shells out Rs 500-600 to have sweet drinking water. This works out to be very expensive, but it is a necessity here,” said Ahmed, a villager from Untka village in the district of Mewat, Haryana.

Very few villages in this district have access to fresh water. Most villages’ groundwater is comprised of saline. This prohibits villages from using the water for drinking and irrigation. It is estimated that more than 78 percent of district Mewat is affected by groundwater salinity.

The states of Rajasthan, Haryana, Gujarat and Punjab are severely affected by salinity. It is less severe in Uttar Pradesh, Delhi, Madhya Pradesh, Maharashtra, Andhra Pradesh, Karnataka, Bihar and Tamil Nadu. Saline groundwater also often contains a high concentration of nitrates, fluorides and lead salts. When this water is consumed, it can lead to many health issues including damage to kidneys, bones, eyes and nervous system.

A clever way of getting safe water

An Indian NGO found a solution and engineered a well that could provide safe drinking water. The Sehgal Foundation, a 16-year-old not for profit organisation, ginned up a clever well design that does a better job of gathering fresh rainwater that can be safely collected from wells.

And the man behind the innovation, Lalit Mohan Sharma, Director, Adaptive Rural Technologies at SM Sehgal Foundation ensures safe drinking water quality under real life conditions.

Explaining the process of pure water collection, Sharma points out that in India many communities use recharge wells: concrete tubes in the ground designed to collect rainwater runoff from places like rooftops during monsoons. That water is pushed back into the ground in a process called ‘groundwater recharge’. “In many nations, as the population increases, humans have started pumping too much water out of the ground. As a result, many of our aquifers underground saturated with usable water are now running dry. So recharge wells can help solve this by ‘recharging’ the underground water supply,” says Sharma.

The problem is once collected in some of these recharge wells, that rainwater floats atop that existing salty groundwater that many Indian states have to deal with since the rainwater is lighter. This rainwater spreads over large areas and ultimately forming a thin layer over saline. This makes it impossible to extract the fresh water without mixing it with salty water. Mostly the depth of groundwater in saline areas of Mewat is very shallow, too, Sharma adds.

Therefore, to bring a solution in the rainwater harvesting systems which can provide villages with access to safe and healthy water, Sehgal Foundation has innovated pressurised recharging.

They have increased the depth and height of recharge wells to below the groundwater table and above the ground. This creates hydrostatic pressure (the pressure exerted by a fluid at a given point due to force of gravity). As a result of the hydrostatic pressure, rainwater pushes aside the existing saline groundwater to form a sizeable pocket of harvested rainwater within the saline aquifer. The pressure exerted by the surrounding saline groundwater keeps the rainwater pocket intact. A hand pump is then used to extract the harvested rainwater from the water pocket formed within the saline aquifer.

“So, our team had to redesign recharge wells. They basically stretched it out in both directions, like it was putty: The part above ground became taller, and the part underground extended deeper into the earth. This new shape increases the hydrostatic pressure within the well. When the pressurised water is collected, it pierces through the saline groundwater underneath and actually forms a pocket of freshwater within the saline water,” further explains Sharma.

Biological contaminants in water are the highest cause of death and disease around the world. To address the risk of that, the water is run through a bio-sand filter. The filter is comprised of four natural filtration stages. These various stages remove biological contaminants and make it safe for drinking.

The Department of Science and Technology for the Indian Government provided Sehgal Foundation with the funds to set up a rainwater-harvesting unit at the Untka government school. It was installed at Rs 3 lakhs.

Mohammad Musaraf, a 10-year-old student from the school, says, “We used to drink the water bought by our teachers from a tanker. It used to be dirty. We would go home to drink water and then not come back to school.” Vajika Nazia, another senior student, adds, “We have learned about a new scientific property after seeing this model work on our school premises.”

“The system has made a lot of difference to the quality of education in the school. Attendance of the children has gone up significantly. Mid-day meals are cooked on time. Before we had this system, children frequently did not get food, as there was no water to cook the meals. It is a boon for our school,” said Hamid Husain, a senior teacher. The pressurised recharge well is very cost effective, as it does not require any additional cost to create a storage structure. This model can be replicated in areas with high groundwater salinity and in coastal regions where seawater is a major challenge. Also, it needs a very small ground space for recharge well to form a big potable water pocket under the ground.

This innovation was selected by United Nations for Solutions Summit immediately following the conclusion of the historic UN Summit to adopt the post-2015 development agenda. At New York in the Headquarters of United Nations, during the Solutions Summit held on Sep 27, 2015, where Lalit Mohan Sharma was invited to present his technology, concluding the fact the Chief Technical Officer of White House (USA) even complimented the innovation and the man behind the innovation Lalit Sharma, and stated clearly that, “Groundwater salinity is a widespread problem around the world with adverse consequences on health, soil quality and overall ecosystems. Lalit Sharma found a simple and effective way to create freshwater pockets for potable use within saline aquifers. By digging the recharge well deeper and extending height, the well creates hydrostatic pressure and pierces the saline water even in very shallow aquifers creating a pocket of freshwater. The water is then extracted via a hand pump and run through a Biosand filter to make it safe for use. Nothing can be more innovative than this.” 

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