Very soon, railway passengers would be able to use aircraft like vacuum toilets on trains. The first prototype of a 'hybrid vacuum toilet' has already been installed in the Delhi-Dibrugarh Rajdhani on a trial run.
The prototype, installed in the First AC coach of the Dibrugarh Rajdhani consists of a custom designed vacuum toilet adapted from a commercially available vacuum toilet that is used in aircraft. The toilet evacuates its discharge into a biodigester tank which is now successfully proven in the bio-toilets that are already in use in many other trains run by Indian Railways, a Railways spokesperson said. The biodigester tank is fitted underneath the coach and contains anaerobic bacteria that converts human waste into water and small amount of gases before discharging the same on the track.
The design has been devised by the Development Cell of the Railway Board and combines the advantages of vacuum toilets and those of bio-toilets to create a new design of 'Hybrid Vacuum Toilet', the spokesperson said.
“The prototype has been made by modifying the standard flushing protocol of a vacuum toilet so as to create water seal and additional post flush cycles and this concept has been converted into a working prototype by Indian Railways as a first ever system of its kind to have been developed and built by any railway system in the world,” he said.
There are plans to install similar vacuum toilets at each platform of the New Delhi railway station too, sources said. The Railway spokesperson said that a conventional toilet or bio-toilet uses 10 – 15 litres of water per flush whereas the vacuum toilet consumes only 500 ml of water for flushing approximately. He said that in other countries train coaches are fitted with vacuum toilets and have retention tanks underneath coaches that holds all the human waste that is flushed out by the toilet. “These are very large tanks that need to be evacuated at the terminals stations. Since Indian Railways trains traverse the length and breadth of the country with journey times as long as 72 hours and generally over 50 passengers per coach, it is nearly impossible to hold the human waste in retention tanks on trains that travel such long distances. Also, the stationary facilities for evacuation of these holding tanks need to be maintained very carefully and meticulously or else their malfunction will render the entire train’s toilets unusable,” he said.
The Municipal Corporations at cities where these ground-handling facilities are to be created have to be taken into confidence to allow one-shot rapid discharge of human waste of an entire train into their sewer systems, which may not be possible at all stations due to constraints in existing sewer system that are already in place, he said.
“By transferring the discharge of the vacuum toilets into biodigester, the need to create separate ground handling installation and creating additional sewer load on the Municipal Corporation will be done away with,” he said.
