The Initiative for Green Habitats represents a long term commitment towards providing solutions for the creation of Sustainable Built Environments. This blog attempts to provide an insight to our views, commentaries on our work, ideas that we are working on, and provoke thought where there are more questions than answers.

Wednesday, July 4, 2012

Toilet Talk

Fill it, flush it, forget it. How the lowly toilet has become a serious
issue to address.
The Bill and Melinda Gates Foundation has been working on an initiative to reinvent to the western toilet as we know it, and bring forth innovative toilet systems that will address sanitation issues in many developing economies around the world. This is a truly laudable quest since more than 2.6 billion people worldwide are said to be using unsafe toilets, or are simply, defecating in the open. Poor sanitation is the root cause for many diseases, including diarrhoea, which kills about 1.5 million children a year. Contamination of groundwater surely leads to many other diseases, including cholera, which kill even larger numbers in the developing world. They believe that “smart investments in sanitation can reduce disease, increase family incomes, keep girls in school, help preserve the environment, and enhance human dignity.”

The endeavour to come up with a toilet, or toilets, that are waterless, not connected to a sewer, hygienic, and affordable is no easy task. The Foundation has set-up a ‘challenge’ in about 22 universities worldwide and is funding programmes that are potentially promising. The goals of the programme are quite comprehensive and aim to address complex multiple issues that stand in the way of innovation:

The history of the western toilet is quite interesting. While there are many variants and types evolved over time, the western toilet that we now use is attributed to Thomas Crapper (yes, yes, now you know) who popularized the model in the late nineteenth century. So, what are the other toilet types beside the western flush toilet and the Indian latrine, so to speak? Here are a myriad names for you to glean from: UDT (Urine Diversion), UDDT (Urine Diversion Dry), Chemical, Portable, High-Tech, Floating, Chamber-pot, Gauderobe, Squat, Urinal, and a host of others.

The problem is that the western toilets are too water intensive for third world ‘conditions’ and the handling of this sewage waste poses major challenges of contamination of ground water, space availability, odour and handling. New and more adaptable versions are required on the pronto. Over the past couple of decades we have seen the 12 litre overhead cisterns (a relic from colonial times) reduce to a slim-line 7.5 litre flushes, down to dual flush systems with a 6 litre flush for the big job and a 4 litre flush for the small job. There is also a product in the market that claims a further reduction to a 4.5 / 1.5 litre dual flush. Some serious challenges remain, for example the bowl design to efficiently flush all matter out using minimal amounts of water.

Here are some of the concepts are scientists and environmentalists are grappling with – if you have new one please write to the Bill and Melinda Gates Foundation. While it is not possible to describe any of them in great detail in this blog, a basic one-line description of each programme itself is quite revealing, if not fascinating.
  1. Professor M. Sohail of Loughborough University and his team are endeavouring to Harald Gr√ľndl of develop a toilet that produces biological charcoal, minerals, and clean water.
  2. Professor Georgios Stefanidis and his team at Delft University of Technology, using microwave technology, are attempting to turn the toilet into an electricity generator for local use.
  3. Dr. Tove Larsen of the Swiss Federal Institute of Aquatic Science and Technology and Dr. EOOS are attempting a functional model of a urine-diverting toilet that recovers water that is good enough for cleansing purposes.
  4. Professor Christopher Buckley and his team at the University of Kwazulu-Natal are proposing to design a toilet system that mineralizes human waste and recovers clean water, nutrients, and energy from community bathroom blocks.
  5. Brian Von Herzen of the Climate Foundation and Professor Reginald Mitchell of Stanford University are pursuing a community scale ‘biochar’ (biological charcoal) production plant fed by human waste.
  6. Professor Yu-Ling Cheng and her team from the University of Toronto are using a system of mechanical dehydration and smouldering of faeces to recover resources and energy. They are also trying to sanitize urine through membrane filtration and ultra-violet disinfection.
  7. Professor Michael Hoffman of the California Institute of Technology has envisioned a solar-powered toilet that generates hydrogen (gas stored in hydrogen fuel cells) and electricity for local use. 
  8. Professor How Yong Ng and his team at the National University of Singapore are experimenting with a decentralized modified pneumatic flushing urine-diversion dehydration community toilet block for five to six households at a time.
There have been several examples of toilet reinventions or adaptations in the Indian context. While some have addressed the design of the toilet itself, there have been those who have focused on the waste handling end of it. Sulabh, DEWATS, the segregated defecation system (where you have a separated bowls/exits for faecal matter and urine) are some of the examples. 

We encourage one and all to put on thinking caps and redefine the 'crapper'.