Energy For Water
A Paradigm: From Waste to Power to Water
The importance of extracting atmospheric moisture to solve the problem of water stress cannot be over stressed. It has become, as we have seen earlier, a central aspect of the mission of the Pure Water Foundation.

This mission itself formulated itself in our minds over a few weeks in early 2010. We wanted to take water from air to the people, to the villages, to the schools, to hospitals and wherever else there was need for pure water.

About this time, we learnt from newspaper reports that many people in a village called Krishnapuram had died from cancer of the throat in a short period, and that the villagers were in a state of near panic. The report also mentioned that the villagers felt that the deaths had something to do with their only drinking water source, a bore well, from which water was pumped and stored in an overhead tank by the local government.

We contacted the newspaper, and came into touch with the local legislator through them. We learnt that there was an urgent need in the village, for an alternative, safe, source of drinking water.

We agreed to set up an atmospheric moisture extraction (AME) system that would supply around 800 liters of water per day, as our gift to the people. Within a week the AME was commissioned and the system was inaugurated by the local legislator; and people of the village started using the system.

We followed this up by setting up a 200 liter system in a corporation primary school in Chennai, and also helped to set up 100 lpd systems in two more villages. We started putting out the word that corporate, clubs and other donors who wanted to help the rural people with pure drinking water could get in touch with us.

Unfortunately, we encountered a serious hitch right at the outset: within a few weeks of the start of the Krishnapuram mission, the system stopped yielding water. The reason was that there was inadequate power supply to sustain the use of the system. We discovered that Krishnapuram was not an isolated case; even the couple of systems that we had set up in two rural schools suffered from intermittent and variable power supply. We discovered that dependable power supply was a major problem throughout rural India. The mission was, thus, seriously in jeopardy at the very start; unless we could find the power!
Power from Waste
India is chronically short of power. Rural areas are particularly vulnerable in this respect. This, in fact, was the question posed by some officials of the Planning commission, when we approached them about our mission: how could we hope to supply water to rural folk, when there was no dependable source of power to run the AME?

We realized that we had to find power if we wanted to solve the water problem. We decided that there was no point in hoping that the power grid would be able to offer enough power for our purpose in the rural areas, even in the distant future. We were faced with the prospect of the failure of the only way in which the crisis of water could be met; unless we found a way to make power.

This is what we attempted to do over the next year. We explored possibilities of non-conventional energy. What struck us as obvious possibilities at the outset were solar and wind sources. Each of these alternatives showed itself to be of less than limited use. Let us consider solar power first: we could either use photovoltaic collectors, or solar thermal reflectors. The prevailing levels of efficiency of 15%-20% in photovoltaic collectors meant that the capital cost of energy production would become forbiddingly high; for example, to power the operation of a small 20 liter per day AME, we needed a complete photovoltaic system with back-up power storage, which would cost us 15 times the cost of the AME itself! Granted an annual maintenance bill of 10%, the maintenance expenditure of the power system would, itself, be well over the cost of an AME, each year! The solar thermal reflectors were no different: not merely were they forbiddingly expensive, but they also meant that we had to switch to a less efficient AME technology with a lower co-efficient of performance (COP) than the one we were using.

We came to a similar conclusion when we explored the possibilities of wind turbines. The dependable ones were too large for our needs, unless we generated power at some place, sold it to the grid and purchased it back at another point in the grid, a process that was beset with administrative hassles and forbiddingly high costs. Smaller wind turbines were found to be too unreliable for our power needs.

Most importantly, both the solar and wind routes were not stand-alone routes. Neither was a source of continuous power supply 24 hrs of the day. Both needed to be backed up by some other source, such as diesel power generation. They were both 'hybrid' systems.

When we appeared to be reaching an impasse, we discovered the waste route. Let us consider this in some detail. During our quest for alternative routes for power generation, we had run into a lot of information on small, effective projects involving waste management. These projects concerned, extraction of methanol, gasification of waste, manufacture of bio-diesel and methanation for power generation. While the first three of the above seemed interesting, they did not appear to offer a strong route towards power generation. On the contrary, methane based power generation, from waste, offered interesting options. We could get methane as a land-fill gas, as was the case with some of the projects in the west. Alternatively, methane could be easily extracted via methanation digesters (or biogas digesters) from different kinds of biodegradable waste and sewage slurry.

We started working towards more serious research on the issue. Soon we found out: (i) that a ton of biodegradable waste could produce enough electricity to make 375 liters of water from air; and (ii) that modern civilization produced ever increasing amounts of waste
The Paradigm
The paradigm is now clear to us: we can produce methane from waste; we can generate power from methane; and we can produce water from air, with this power. We started by understanding that the atmosphere was an unlimited source of pure water. Then we found that we had no power available to us, to enable us to tap this unlimited source of water. Now we find that waste is the source of unlimited amount of power, for waste is the perennial, and ever growing, output of modern civilization. What is more, technology exists for getting all the power we need, from waste; and for the use of the power to make enough water from air
Our Advisory Committee on the Waste-Power-Water mission
Professor Krishna Vasudevan,
Indian Institute of Technology, Madras
Formerly Superintending Engineer,
Metrowater, Chennai
Mr. K.Manavalan
Consultant, Engineering