Indian Railways' experimentation with eco-friendly toilets

By R K Srinivasan
Published: Monday 31 March 2008

Indian Railways' experimentation with eco-friendly toilets

-- If you happen to travel in Rewa Express, you will notice a slight change in its coaches small steel tanks fitted between the wheels. These are part of environment-friendly toilets, where the excreta is treated and stored. Coaches in Rewa Express, running between Delhi and Rewa in Madhya Pradesh, are being equipped with biological treatment facility. Unlike a normal toilet, in the bio-toilet only the water trickles down the track, while the sludge is retained in the tank.

Bio-toilets are part of an experiment to try out different types of eco-friendly toilets in trains. The Indian Railways plans to install eco-friendly toilets in all its 9,000 trains by 2011-13. And it is about time the railways changed tracks from open to 'biological' toilets, for an estimated two million passengers use its toilets daily, wasting a huge amount of water and creating hygiene problems.Presenting the Railways Budget, union minister Lalu Prasad Yadav announced a provision of Rs 4,000 crore for "discharge-free green toilets" in all 36,000 coaches in the eleventh plan period.

It is a tough challenge and the railways' previous experiments with eco-friendly toilets have not always been successful. Nonetheless, a beginning has been made. The bio-toilet developed by the railways' Research Designs and Standards Organisation with Microphor of the us and Faridabad-based Aikon Technology, was first tested in the Delhi-Allahabad Prayagraj Express. In this system the excreta is collected in a tank, which is divided into two chambers. The first chamber contains a patented bacterial culture that breaks down waste in six-seven days by enzyme action. The resulting liquid is led into the second section where it is treated with chlorine before disposal.

This toilet uses less than 5 litres of water per flush against uncontrolled use of water in open toilets. In a year, about a kg of waste will be collected in the tank, which will be cleared manually. Though it will save water, the bio-toilet comes at a price. For every coach, the railways will have to shell out Rs 8 lakh as equipment cost and Rs 1.5-2 lakh as operations cost per year.

Weighing options It is not the only eco-friendly toilet the railways is experimenting with. iit Kanpur has developed a cheaper "zero-discharge" toilet that will separate 90 per cent of the liquid from the waste and reuse it for flushing (see 'Flush and forget', Down To Earth, January 31, 2008). It will soon be tested in a Chennai train, says N S Vyas, coordinator, Technology Mission on Railway Safety, and professor at the Mechanical Engineering Department of iit Kanpur.

Functioning of bio-toilets
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There are critics who say bio-toilets will be a flop. T S Seshadri, who patented his model of a toilet in 2000, says, "In 1994, bio-toilets of Microphor were installed in the Tamil Nadu and Grand Trunk Express coaches, and were a complete failure." Seshadri, who had then reviewed the functioning of bio-toilets, says clogging of the filter led to foul smell, cockroaches and worms, and the toilets had to be removed within six months. Bio-toilets, however, are back, and this time the emphasis is on maintenance. Aikon Technology has been given the contract of maintaining them in Rewa Express.
Choked drains In the prevalent system in trains the excreta is dropped on tracks through a hole. Stained tracks are manually cleaned at the station and excreta discharged into drains, which are usually chocked. The 2006 Comptroller and Auditor General of India (cag) report says of the 358 stations it reviewed, drainage systems in 101 stations were clogged. Therefore, it is necessary to shift to zero-discharge systems.

Collecting and treating excreta from 9,000 trains, handling approximately 1.4 crore passengers per day, is a tall order. G Raghuram, professor, Indian Institute of Management, Ahmedabad, estimates that every day 2,74,000 litres of excreta is dumped on rail tracks.

Seshadri suggests railways should focus on collecting and disposing of toilet waste, not treating it. In his model, a tank of 600-900 litres capacity for each commode will be fitted between the wheels. He claims his model will cost only Rs 60,000--excluding commode, flush and overhead tank--with an annual maintenance cost of Rs 5,000. The Janshatabdi Express uses a similar system called the controlled discharge toilet system (cdts). In this the excreta is stored in a sealed tank and emptied slowly when the train leaves the station and hits a speed of more than 30 km per hour. The cost is Rs 7.5 lakh per coach.

Under the Integrated Railway Modernisation Plan, the railways has to install cdts in 5,000 coaches by 2010. Until March 2006, only 261 coaches had been fitted with cdts, said the cag report. The railways have not yet exhausted their options. Says Arvind Nautiyal, director, mechanical division, coach maintenance the railways will also be trying out the vacuum toilets, a technology used in aircraft (see box). In vacuum toilets the excreta will be sucked out using minimum water and the collected waste will be discharged in closed drains at railway stations.

The idea smells good.

Target is to install 'discharge-free' toilets in all coaches by 2011-13
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Right turn Compared to open toilets (left), zero-discharge (centre) and bio-toilets will not discharge excreta on the tracks

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