Some of them have already been installed on an expiremental basis in trains in the south. The toilets jointly developed by IIT Kanpur, Research Designs and Standard Organisation, Lucknow and a private agency in Chennai, ensure that all liquid discharges are converted into"pure water" which can be used as re-cycled water to flush and clean toilets and sanitary fittings.
The solid waste is converted into odour free paste by certain bio-chemicals or additives applied at the departing terminal. This can be stored for 15 days in a tank and can easily be emptied at the destination point through'pressurised evacuation,' V Carmelus, Chief Mechanical Engineer of Southern Railways said.
The odourless solid waste could yield revenue since the paste would an excellent manure after being dried in the sun. After some more trial runs and studies the scheme would be a permanent feature in Indian Railways, he said. Presently the system has been installed in trains running between Chennai and Jammu Tawi and Chennai-Lucknow, he said.
Carmelus said two previous experiments were found unsuitable for Indian conditions. The US model of biological microprocess was unsuccessful here on account of excessive water usage in Indian toilets.
Another model tried out - the central discharge toilet - also proved futile.In this the outlet lids remain closed when the train speed hits less than 30 kilometers per hour. This system was supposed to avert spilling of human waste along stations or platform tracks.
However, disposing of this accumulated waste was a huge problem in unequipped smaller junctions and water tended to be over used. Zero level contamination along wayside stations was not achieved from these two experiments, he added.