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India trials new train toilet Author: Angela Tufvesson 4 March 2009
Tags: Sanitary Equipment, Toilets, Toilet Testing / Performance, Wastewater pumping, Eco management, Transport, Disease outbreak / control, Gray Water / Black Water, Innovation, Water Quality, Southern Asia Page 1 of 2 | Single page
A new toilet system developed in India has the potential to reduce fresh water use and improve national sanitation levels.

The rise of India on the global stage should not be underestimated.

As home to more than 1.13 billion people – the world’s most populous democracy – this sub-continental giant has cultural signatures that have spread well beyond its national boundaries.

But a lack of access to proper sanitation in rural and urban regions threatens to hold India back.

World Health Organization statistics show that in 2006 only 28% of the population had sustainable access to improved sanitation.

Conscious of water shortages, an ever-increasing population and its important role in tackling climate change, India is trying to find solutions to sanitation shortfalls that conserve water while providing access to a greater number of people.

The Indian Institute of Technology (IIT) Kanpur has created just such a solution – a zero-discharge toilet.

Developed in conjunction with Indian Railways and UNICEF, the new toilet system is based on the premise of ‘ecological sanitation’.

“Indirectly, sewerage systems pollute water supplies,” project head Dr Vinod Tare says.

“And the water consumption of a normal toilet is very high because more water is required to transport waste to the sewerage line.

“Ecological sanitation is based on minimum use of water, or none, for conveyance of waste to avoid it entering the waterways.”

The main body of the zero-discharge toilet is identical to a conventional model, but the collection and processing of waste is entirely different.

“What we have done is install a tank and separator device to the P-trap (water seal) below the toilet that divides solids and liquids.

“We get two streams from this toilet – one is solids and the other is liquids. The separator generates a thin film of water that adheres to the surface and flows outwards, collecting liquids, and the solids gravitate into the central retention compartment.”

The water is collected, filtered and treated then recycled to be used for flushing.

“We treat the water to a certain level, as it is used only for flushing and remains in the closed loop. Specially developed microbial cultures are used for eliminating odors.”

This recycling technique removes the need for fresh water in flushing. No compromise is made on hygiene, as the toilet is flushed with adequate volumes of water.

“We are not using fresh water for flushing. Recycled water only is used for flushing – that is the difference between the conventional toilet and our toilet.”

The only fresh water used in the operation of the toilet is for personal cleaning.

“In India we use wet cleaning rather than dry cleaning. About 1.5L (3.2 US pints) is used by every person every time they use the toilet, and on average about 1-1.5L of urine is added per day.”

Over time, the quantity of the flush solution increases, so the excess is taken out every two to five days. It is then evaporated using solar energy to obtain valuable nutrients present in human urine.

The solids gradually disintegrate to form a slurry, which is removed from the toilet periodically. It is then converted into quality organic manure via activated aerobic composting followed by vermi-composting.

“In a conventional toilet the fresh water that is used for flushing is up to 50L (13 US gallons) per person per day. With our toilet that usage is not there.

“As a result there is zero discharge from this toilet – so it is environmentally friendly.”

A large proportion of the Indian population do not have access to public toilets, let alone a domestic connection, so the zero-discharge toilet is being tried out in the public domain.

At the request of Indian Railways, via government funding, Tare and his team at IIT Kanpur were asked to develop a new sanitation system for the national railway network.