Discharge From New Bio-Toilets on Indian Trains No Better Than Raw Sewage: Study

Despite sanitation experts and studies pointing out that a majority of these toilets are ineffective or ill maintained, an approximate Rs 1,200 crore has been allocated for fitting additional coaches with bio-toilets.

An Indian Railways toilet. Credit: Wikimedia Commons

A new kind of toilet using bacteria to break down human excreta has been deployed in Indian trains over the last four years at a cost of Rs 1,305 crore, but this toilet is no better than a septic tank, the Indian Institute of Technology, Madras, has concluded after a two-year long study.

As many as 93,537 “bio-digesters” – as the toilets are called – have been installed in mainline express and mail trains by the Indian Railways. These are small-scale sewage-treatment systems beneath the toilet seat: Bacteria in a compost chamber digest human excreta, leaving behind water and methane. Only the water, disinfected later, is let out on the tracks.

That is how it is supposed to work.

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However, sanitation experts and various studies – including commissioned by the railways – have pointed out that most of the new “bio-toilets” on Indian trains are ineffective or ill maintained and the water discharged no better than raw sewage.

“Our tests have found that the organic matter (human waste) collecting in the bio-digesters do not undergo any kind of treatment,” IIT professor Ligy Philip, who headed the latest study, told IndiaSpend. “Like in the septic tanks, these bio-digesters accumulate slush (human excreta mixed with water).”

The IIT study on bio-toilets, shared exclusively with IndiaSpend, was sponsored by the Bill and Melinda Gates Foundation and submitted last week to the Union ministry of urban affairs.

Despite the criticism, an additional 120,000 coaches are to be fitted with these bio-toilets, jointly developed by the Defence Research and Development Organisation (DRDO) and the Indian Railways, by December 2018. This is likely to cost Rs 1,200 crore, the railways revealed on November 2, 2017, in response to a Right to Information (RTI) request.

The bio-digester project in the Indian Railways began during the previous United Progressive Alliance (UPA) regime. But the project has been speeded up under Prime Minister Narendra Modi’s Swachh Bharat (Clean India) campaign. The idea is to meet this target in time for the celebration of Mahatma Gandhi’s 150th birth anniversary in 2019, said railway ministry spokesperson Anil Kumar Saxena. The Swachh Bharat campaign has been dedicated by PM Modi to Gandhi.

Indian Railways are often described as the world’s biggest toilet: It ejects around 3,980 tonnes of faecal matter – the equivalent of 497 truck-loads (at eight tonnes per truck) – onto rail tracks every day, according to a report released by the Comptroller and Auditor General (CAG) in 2013.

The network has 9,000 passenger trains with 52,000 coaches with toilets that discharge human waste on to rail tracks. Covering 65,500 km across the country, these trains transport 24 million passengers every day, the equivalent of the population of Australia.

Since 1993, the Indian Railways have been experimenting with a host of technologies used worldwide to replace the open discharge system. This included vacuum toilets based on suction, commonly seen in aircraft; “controlled-discharge” toilet systems (CDTS) which allow waste to be dropped only after a train acquires a speed of 30 kmph, thus keeping stations clean; and “zero-discharge” toilets, in which solid waste is stored, evacuated and then dumped in pits for composting and the liquid filtered for recycling.

In 2008, the railways decided to install the bio-digester model developed by the Gwalior-based Defence Research and Development Establishment (DRDE).

Responding to the criticism of the bio-toilet, government officials said that the flaws are being fixed. “The issues regarding the bio-digesters are of a minor nature and are being effectively addressed. Some changes (in design or execution strategies) are inevitable, as this is a continuous process,” said Saxena, the railway ministry spokesman.

Currently, there are nine units manufacturing these bio-toilets.

Questions raised about bacteria used in green toilets

Lokendra Singh, former director of the DRDE, had, after an expedition to Antarctica, brought home psychrophilic bacteria that can survive in extremely low temperatures. The bacteria were mixed with cow dung and normal soil, which have methogens (microorganisms that produce methane) capable of breaking down human excreta. This was then supplied to the manufacturers of rail bio-digesters.

“Because of the presence of a compound of bacteria, the bio-degradation process is set off in the toilet chambers – the bacteria eat up the organic matter (human excreta) and produce methane gas and water as byproducts,” Singh said.

The Indian Railways have also been toying with the idea of setting up two factories to mass produce this bacterium.

But Singh’s claims of a scientific breakthrough using the bacteria from Antarctica have been questioned on the following grounds: