No more stink in bio-toilets of Indian trains

Chennai: T Jyothimani, a Chennaiite, cannot forget her recent official trip to Kolkata in a train fitted with a bio-toilet. The moment she stepped into the washroom she had to battle foul smell and choking.

She was not alone in encountering such an experience. The main reason behind that is said to be the bio-toilet system in the trains in, which the human waste is converted into water and bio-gases with the help of anaerobic bacteria, did not have enough ventilation.

There was ventilation in the older toilet of trains through open commode chute. After bio-toilets were fixed, this chute was blocked which is said to have caused the problem of foul smell and chocking in train toilets. But soon such things are likely to come to an end thanks to a new ventilation system.

Southern Railway is likely to implement the new system soon on trains that have bio-toilets along with other railway zones, according to sources, as it has asked all zones to implement this new innovation.

The new ventilation system named ‘Natural Draft Induced Ventilation System’ (NDIVS) is said to be an innovation of South East Central Railway.

The NDIVS consists of two funnels facing forward and reverse of the direction of the train and are connected to the coach toilet through plastic pipes. Fresh air gets inducted through the front-facing funnel and pipes into the toilet as the train moves.

The fresh air purges out with foul smells from the reverse facing funnel. Due to ‘venturi effect’, a vacuum is created at the mouth of the reverse facing funnel which assists in purging out of the odorous smell, say the sources.


The problem of foul smell in bio-toilets looks to be a problem of no small proportions. Complaints are said to have been registered in large numbers. According to sources, a 2017 report of the Comptroller and Auditor General (CAG) about two lakh complaints of choking, foul smel and non-functional bio-toilets were registered.


The NDIVS system designed by South East Central Railway is said to have even earned it the first prize of Rs 3 lakh in Railways Suggestion Scheme of Best Innovation 2017-18 category.