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A new kind of toilet using bacteria to break down human excreta has been deployed in Indian trains over four years to 2017, 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
