New Delhi: Scientist and entrepreneur N. Subburaman has constructed around 20,000 toilets since 1996 in Tamil Nadu, the cost of which ranged anywhere between 200 and 2,000.

One day, a few villagers asked him a question: “How do we use a toilet when there is no water for flushing?" It was then that Subburaman decided to make toilets that do not need water for flushing. He made the first waterless toilet, called the Ecosan, in 2002. It is technically known as the urine diversion dry toilet (UDDT).

UDDT is made up of three parts—the front consists of a hole that collects the urine, the second part contains a hole for defecation and is connected to a chamber below that collects the faecal matter for a year, and the third portion is meant for washing hands and body, as the used water goes out to a filter bed through a connecting pipe.

“The urine does not smell when not mixed with faecal matter, and can be diverted towards a garden or a farm as it contains great nutrients, while the user is required to throw a handful of ash, sawdust or lime dust on the faecal matter after defecating," explains Subburaman, director of the Society for Community Organisation and People’s Education (SCOPE), a not-for-profit organization based in Tiruchirappalli.

He explained that the ash can absorb the moisture of the faecal matter, and after a year of collection it can become compost. While constructing such a toilet costs 20,000, it saves anywhere between 8-10 litres of water per use, Subburaman said.

India has the highest number of open defecators in the world at about 626 million, and one of the main reasons for this is the lack of basic sanitation facilities, which include a flush.

The lack of toilet facilities was highlighted recently after two young women who had gone to the fields to relieve themselves were kidnapped, gang-raped and murdered by a group of men.

Some entrepreneurs say toilets that do not require water for flushing may be useful in many underprivileged areas of the country.

In the past few years, SCOPE has built over 2,000 such waterless toilets on the banks of the Ganga and the Cauveri, and in Tsunami-hit coastal villages of Tamil Nadu. Subburaman’s waterless toilet model is finding acceptance in many parts of the country. Recently, under the sustainable sanitation improvement programme of the Tripura government, the state’s Bishalgarh municipality has decided to construct 2,000 Ecosan toilets.

Manoj Misra, convener of the Yamuna Jiye Abhiyaan, also tried to set up such toilets in villages near the Yamuna river to promote river-friendly lifestyles. “These toilets are constructed on the principle that all mammals are such that their urine and faecal matter do not mix. Our toilets today are constructed in a way that ignores this basic principle," said Misra.

But while waterless toilets won’t be seen in many towns, waterless urinals are gaining much popularity in urban areas. These urinals look like ordinary urinals, except one does not flush water.

“You don’t actually need to flush down the urine. It is just that it can leave some really bad smell after a point," said Bindeshwar Pathak, founder of Sulabh International, which works in the field of sanitation.

Most waterless urinals use an odour trap, often known as an eco-trap, containing a kind of gel or oil that floats on the urinal, trapping the odours inside.

The first waterless urinal trap using the sealant liquid method was patented in 1894 by Wilhelm Beetz, an engineer from Austria.

The waterless urinals distributed by Basic Sanitations Pvt. Ltd, based in Delhi, uses a chemical liquid that allows 1,500 persons to use the toilet by just putting 90mm of the chemical in the trap, which leaves a kind of fragrance after usage.

At the Indian Institute of Technology (IIT), Delhi, the Centre for Rural Development and Technologies has developed waterless urinals by developing a new kind of odour trap that does not use the usual oil-gel component used in most other urinals.

The IIT Zerodor trap, also funded by Unicef, has an odour-sealing element made of low-density polyethelene that is either in the shape of a ball or cone or a disc lower in specific gravity than urine, and is placed inside the trap body to seal the odour emitted from the pipeline through the urinal seat.These odour traps have to be changed regularly.

Waterless urinals can result in saving 56,800-170,000 litres of water per urinal per year, according to a research paper by V.M. Chariar and S. Ramesh Sakthivel, the developers of the IIT Zerodor trap.

But some experts remain sceptical about the practicality of waterless toilets and urinals.

“Although waterless urinals are installed in various parts of Delhi, they don’t work very well in very high temperatures. The chemicals which are used in the odour traps become ineffective in high temperatures. So if you visit any of these urinals today, they will be stinking terribly," said Pathak.

“Secondly, a major flaw with waterless toilets is that more often than not, people defecate and urinate at the same time. It cannot always be planned. That can potentially spoil the composite plans for those toilets, and it is quite impractical," he added.

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