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.

Filthy conditions at railway stations, corrosion of rails and the underside of carriages, and a desire to improve sanitary conditions on the nation’s vast rail network led Indian Railways to approach IIT Kanpur.

Officials wanted a system that used limited fresh water and prevented waste from coming into contact with infrastructure.

Railways Minister Lalu Prasad – who has become something of a national icon – is credited with transforming Indian Railways from near bankruptcy several years ago to a thriving enterprise now making billions of dollars a year in profit.

“Lalu Prasad wants change in India. He has traveled all over the world to look at what kind of toilet systems are being used in trains,” Tare says.

“The railways came to the conclusion that none of the toilet systems available in the world are appropriate for Indian conditions, so that is why they are interested in our research.”

A full-scale model of the zero-discharge toilet was installed at the IIT Kanpur campus more than two years ago and is still in operation.

The first stage of the Indian Railways trial will take place on the service running between Lucknow and Chennai – a journey that takes almost three days.

“The toilets are being fitted in one of the passenger carriages. Out of the four toilets in the carriage, two are being replaced with our model.

“The trial will run on this service from October 2008 for two or three months.”

Zero-discharge toilets have also been installed in the town of Aligarh, not far from New Delhi, as part of a project sponsored by UNICEF.

Four toilets have been installed in a congested locality where most households do not have toilet facilities – or the toilets discharge into open drains. Each toilet is designed for 25 users per day, so the new toilet block serves 100 people.

“It is a public toilet in a very busy area where people do not have toilet facilities in their residences. It also provides employment for local people who are responsible for maintenance of the facilities.”

The zero-discharge toilet is relatively inexpensive, particularly when compared with conventional alternatives.

“The main body of the toilet is essentially the same – we are not changing that part. Typically for a domestic toilet the additional cost (on top of the toilet itself) will equate to $US65 to $US86 per toilet.

“There is a saving in water, a saving in the cost of sewerage systems and sewage treatment plants, and over and above that we are not polluting the water bodies because this is an isolated system.

“We are not putting sewage, indirectly or directly, into the water bodies. You also need to look at the cost from that point of view.”

Tare says environmental concerns are growing in his country – even going as far as to say that India is more conscious of water shortages and global warming than Western nations.

He believes finding solutions that take local conditions and sensitivities into consideration is the key to instigating change.

“The kind of eco-friendly technologies that Western people use and recommend are quite unaffordable for us. If we can change our system and think in our own way I think that will make a difference.”

Tare is extremely proud of the project and hopes that in time zero-discharge toilets will be installed on all Indian trains and in many urban and rural towns. This will achieve the dual aim of improving sanitation and conserving water.

Points of contention
1. Proper sanitation threatens to hold India back.
2. India is trying to find solutions to sanitation shortfalls that conserve water while providing access to a greater number of people.
3. Developed in conjunction with Indian Railways and UNICEF, the new zero discharge toilet system is based on the premise of ‘ecological sanitation’.
4. The zero-discharge toilet is relatively inexpensive, particularly when compared with conventional alternatives.