The AV desalination plant project

Why is there a need for a desalination plant?

Given the present over-pumping of groundwater, the experts agree that the aquifers in this bioregion will turn saline, and perhaps sooner rather than later. In these circumstances, it is crucial that there is an abundant source of clean, drinking water. This is what a desalination plant can provide.

In the case of the planned Auroville desalination plant, the water would also be used to fill the Matrimandir Lake?

Yes. In the first phase, the desalination plant will produce one million litres of drinking water a day. Right now, Auroville has some centralized infrastructure for distributing water to a number of communities, such as in the Residential Zone and in the Industrial Zone, as well as many individual water systems. The centralised Auroville water infrastructure cannot absorb one million litres a day at present: I am told it can only deal with a maximum of 300,000 litres per day. So, once the lake is dug, we would use the balance of the water to fill it. As the water infrastructure expands, we would increase the amount channeled for drinking water and decrease the amount used for filling the lake.

After a few years, I don’t think we will need to use desalinated water for the lake because we plan to have a storage lake where rainwater will be collected, and the lake will be topped up with this. Then the output from the desalination plant will only be used for drinking water.

Is there enough rainwater to top up the lake throughout the year? The evaporation from the surface of the lake in the summer must be huge.

We definitely get enough rain annually; the only problem is the storage. We are envisaging a large storage lake where, in the monsoon time, we can collect all the water that falls on the lake and its surroundings.

Do you envisage that at some point the desalinated plant would provide for all of Auroville’s drinking water needs?

Yes, and even much more. When the aquifers turn saline, we have to take care not only of Auroville’s water needs but also of the surroundings. This desalination plant is meant to be a model that can afterwards be scaled up or copied. If we scale it up, Auroville could be a main supplier, on a commercial basis, of water for the whole area.

The whole area means the whole bioregion?

Yes. It’s too early to say yet how we would proceed, but we can either scale up this plant or encourage the setting up of other small desalination plants along the coast to provide drinking water to the villages.

Would you seek government help?

If the government asks us to collaborate, we would do so. But I think this first project can very well stand on its own feet and the government has more than enough other problems to take care of. I would prefer that we do it on our own.

What is the present status of the desalination project?

The Detailed Project Report (DPR) and the Environmental Impact Assessment (EIA) have been done. The EIA clearly testifies that it is a non-polluting project. This is the basis for getting all the necessary permits from the various government departments.

How long will this take?

I think if we push really hard we can have all the permits within one year. In the meantime, we already have permission from the Highways Department to lay the first stretch of pipes that will bring the water from the plant on the beach to the centre of Auroville. The pipes for this stretch will be delivered in the next week or so.

We are laying a double pipeline, and each pipe will have a diameter of 40 centimetres. We are putting two pipes because we are still thinking of the possibility of hydro-energy storage for Auroville [see Auroville Today no. 271, February 2012], so one pipe could be used to fill a lake for hydro storage and the other for supplying drinking water. Alternatively, the second pipe could also supply drinking water if we scale up the desalination plant to provide more than seven million litres per day.

What are the costs involved?

Although the first phase of the plant will be for one million litres per day, we will construct infrastructure that can handle five million litres per day. The main cost is not the plant but the offshore equipment that draws the water from the open sea and releases the byproduct of the desalination process back into the sea. The offshore part will cost around 25 crore rupees, the pipeline that brings the water to Auroville will cost around nine crores, and the actual plant equipment for the first phase will cost around seven crores. So, initially, this would be around a 40 crores project.

What about the operating costs? Desalination is energy-intensive and you have to pump the water up to the middle of Auroville. Will the Varuna windmills be able to supply all the electricity necessary?

Yes. We would need around 3,500 kilowatt-hours a day of electricity to produce one million litres of desalinated water and to pump this up into Auroville. This is less power than one windmill produces on average per day over the year, and Varuna already has six of them. But if we go to five million litres a day, then one wind-generator reserved for the desalination plant will not be enough.

It is true that desalination is energy-intensive, but we are going for the most advanced technology available today – the energy-regained system – and this allows us to almost halve the usual electricity consumption for desalinating water.

What about the pollution and brine problems associated with desalination plants?

People think that the main problem with desalination is pollution of the surrounding sea because usually chemicals are used in the desalination process. However, in our plant we won’t use any chemicals, except when we need to clean the filters. Instead, we will use UV radiation and ultra-filtration to eliminate organisms in the seawater. This means that the water that comes into contact with the reverse osmosis membrane will be relatively clean, so we will not have to clean the membrane so often.

The main problem, however, is the brine. The ‘waste’ water released back to the sea after the desalination process has a higher salt content – 30% more – than seawater. But this is not the main issue. This water has been subjected to high pressures in the process and does not contain oxygen any more: it is ‘dead’ water. The heavier salt-content of the brine makes it heavier, so it sinks down to the bottom of the sea and there it forms a carpet that kills everything below it. The desalination plant to the north of Chennai produces around 600,000 cubic metres of this ‘dead’ water every day and releases it in one place, so there must be a large area of the sea floor affected by this.

Unlike Chennai, which has two 100 million litres a day desalination plants, we are planning a very small desalination plant of a maximum of 5 million litres a day, and our offshore pipes will run around 500 metres out to the sea, further than the pipes of the Chennai plants. We have done studies to ensure that our pipelines will in no way affect the marine life.

However, if we increased our capacity and made a bigger plant we might encounter this problem. This is why a number of small desalination plants scattered along the coast might be a more ecological option than one very large one.

In short, we want to provide a model plant that is not using chemicals, that is run with green energy, and which is avoiding this problem of the brine spoiling the floor of the sea.

What about the possibility of pollution from the Kalpakkam nuclear plant further up the coast. Can desalination plants deal with radioactivity in the water?

There was the case of some American warships off the coast of Japan close to where the nuclear reactor problem occurred. The sailors were getting their water supply from ship-based desalination plants, and they discovered their desalinated water was irradiated. But the membrane is so tight in our planned plant that I think 95% of the radiation would not go through. The water quality, of course, will be checked regularly.

Let us look at the social aspect. To what extent will the villages around have access to this desalinated water?

We have made an agreement with one village close to the proposed plant that everybody will get so many litres of water free per day.

But if there is rapid desalination, and one village is getting desalinated water and another is not, will this not lead to social tensions and resentment?

But the plant will ease the problem rather than aggravate it because we are creating clean drinking water which we will supply to the villagers. We may not supply it free of charge but the villagers should be happy that such a plant exists. Otherwise, where would they get the water from?

How much would you charge for the water?

This has to be seen. The Chennai desalination plant charges Rs.45 per cubic metre. If the local villagers can get desalinated water for Rs.45 a cubic metre, I think it is very fair.

And they don’t have to get the desalinated water from us. They could set up their own small desalination plants to provide water to the villages. Beach land has a very high value at present. If the owners sold only 20 acres of beach land, they could finance a small plant that could provide three villages with water. It’s a real option, and I’m sure that if the aquifers turn saline and they are confronted with a choice either to leave or to come together to finance a desalination plant, they would consider it seriously. And we may help them set up such a plant.

Of course, we are talking of providing drinking water, not water for irritating crops. Surely such a plant could not provide sufficient water for conventional irrigated farming?

It might do. But then the farmers would have to calculate how much they would be willing to pay.

Returning to a worst-case scenario where the bioregion turns saline, where the villages have no access to drinking water and it would be difficult or take time to set up alternative desalination facilities, how do you think our neighbours would react to seeing desalinated water being pumped to Auroville to fill a lake?

But whatever clean water we create, as long as we create it ecologically and in a sustainable way, will finally penetrate into the aquifers and so ease the problem of salinity. We cannot be expected to save the whole bioregion: others have to take up some responsibility. At least, we are doing something. We are creating a desalination plant that will provide much clean water.

Over the years, you have done a great deal for Auroville. You played an important role in the finishing of the Matrimandir, the Varuna project is providing free electricity to Aurovilians, and now you are planning a desalination project that will benefit the community. Yet you remain a controversial figure in some quarters, mainly because you do not participate in any community process and you are viewed as running a parallel development process over which many Aurovilians have little control. For example, there has been no community decision and only limited consultation regarding the desalination plant. Is there is still scope for the community to give its input on this?

Do you mean that the community could be asked to make a decision, yes or no? And if the majority says no, we should abandon the project? I don’t think this is the way to go.

In the Varuna team we have a clear aim and perspective. For example, we did not want to produce electricity purely for commercial benefit. Rather, we wanted very much to bring Auroville forward regarding its ideals. Auroville is meant to have a moneyless economy, so we decided to provide electricity in a moneyless way. Though this is clearly in line with the society that the Mother had envisioned, we got tremendous resistance from the community, even though today the majority of people seem to agree that we are doing the right thing. I expect the same thing will happen when we start providing desalinated drinking water and water for the Matrimandir Lake.

Perhaps the resistance is not to your intention and idealism. It comes from people feeling they are not being consulted, that they haven’t had a chance to have their say.

But if the community wants to allow everybody to voice their fears and concerns, I wonder if we will ever achieve anything. We know that there will be big resistance when we start to distribute the desalinated water. We will insist it is provided free of charge for every Aurovilian, and that we don’t want a quota system, but then this whole discussion will start up again.

Do we want to discuss it for another ten years, by which time all the aquifers will be saline? Then everybody will come to us and say, why didn’t you go ahead? If we have to go to meeting after meeting, we see no chance to get this project operational before the aquifers turn saline. This is why, while initially we planned to do this project under Varuna Auroville, we have now decided to do it under Varuna Private Limited.

How soon could the desalination plant be operational?

It is very difficult to say, but in the best possible case it could be up and running in two years. But this is an ideal scenario.