Rlys develops hybrid vacuum toilets

Minister of Railways Suresh Prabhu had announced in his Budget Speech 2015 that the Indian Railways shall install vacuum toilets in trains.

Now, development cell of the Railway Board has come up with a technology that combines the advantages of vacuum and bio-toilets to create a new design of ‘hybrid vacuum toilet’. 

A prototype has been made by modifying the standard flushing of vacuum toilet to create water seal and additional post flush cycles. The concept of a hybrid vacuum toilet is a <g data-gr-id="24">first ever</g> system of its kind to have been developed and built by any railway system in the world. This newly developed toilet has been fitted in one coach no. 153002/C FAC in Dibrugarh-Rajdhani on a trial basis. 

The prototype consists of a custom designed vacuum toilet adapted from a vacuum toilet used in aircrafts, which evacuates its discharge into a bio-digester tank. The bio-digester tank is fitted underneath the coach and contains anaerobic bacteria that converts human fecal into water and gases before discharging the same on the ground or track. 

Typically, a conventional or bio-toilet uses 10-15 liters of water per flush, whereas the vacuum toilet consumes only 500 ml (approximately) of water for flushing. 

Water is a precious natural resource. This innovation will help save at least 1/20th quantity of water that is used in the current design of <g data-gr-id="28">biotoilets</g> or conventional toilets. 

Further, in foreign countries, where the train coaches that have vacuum toilets, there is a ‘retention tank’ underneath the coach that stores the human excreta that is flushed out. These large tanks need to be cleared at all terminals stations.

Since the 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 store human 

waste in retention tanks in trains that travel such long distances. 

Also, stationary facilities for <g data-gr-id="21">evacuation</g> of these tanks need to be maintained meticulously, else their malfunction will render all toilets in  the train unusable.