Bio-toilets in trains like septic tanks, waste left untreated: IIT-M 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 digests human excreta, leaving behind water and methane. Only the water, disinfected later, is let out on the tracks.

However, sanitation experts and various studies -- including those commissioned by the railways -- have pointed out that most of the new “bio-toilets” are ineffective or ill maintained and the water discharged is 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, said. “Like in the septic tanks, these bio-digesters accumulate slush (human excreta mixed with water).” 

The IIT-M study 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 DRDO and the Indian Railways, by December 2018. This is likely to cost Rs 1,200 crore, the Railways revealed on November 2, in response to a RTI request. 

The bio-digester project began during the previous UPA regime. But the project has been speeded up under Prime Minister Narendra Modi’s Swachh Bharat 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.

Responding to the criticism, 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. 

Sources said there are serious issues with the bio-toilet venture. These were discussed at a high-level meeting convened by the Railway Board on October 26. “Cost escalation is inevitable, as manufacturing costs have been rising,” said Manoj Jha of Faridabad-based Arkin Technologies that manufactures and supplies bio-digesters to the Railways.