Toilets in the AS-2 coach of the Delhi-Allahabad Prayag Raj Express don’t stink. Since May 17, they have been equipped with septic tanks using bacteria that convert wastes into a harmless, colourless and odourless liquid that is allowed to trickle away and evaporate.

“This is the biotoilet project,” said Harsh Kunwar, Information officer at the Rail Bhavan. “The Railways is trying to find a more hygienic way of getting rid of biological wastes in an environmentally friendly manner.”

The pilot project is being implemented on one of the 25 carriages of the Prayag Raj Express by the Railways’ Research, Design & Standardisation Organisation (RDSO) in collaboration with Microphor of US, and Aikon Technology of India.

The waste is collected in a stainless steel tank divided into two sections. The first contains a patented man-made bacterial culture that breaks down wastes by enzyme action. The resulting liquid — mostly water, and entirely free of pathogens — is led into the second section where it is purified by chlorine and other chemicals before dispersal. A flap valve in the commode prevents the odour generated during the process from reaching the toilet and inconveniencing users.

The only undesirable by-product is some methane gas, but the amount is negligible in comparison to that generated by normal degradation of wastes.

But the toilets don’t come cheap. Installing four such toilets in each carriage costs Rs 8 lakh and and annual maintenance for each coach works out to Rs 2 lakh. Contracts have been awarded to Microphor and Aikon Technologies to install 80 such toilets.

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