#nutrientcycle

I want to now share some of my work and reflections from two projects that I completed over the last two years in the Master in Development Practice (MDP) program at Cal Berkeley.

For my practicum project, I accepted a design assignment for an ecological sanitation (Ecosan) project in South India. Specifically, the challenge was to design a more compact and affordable dry compost toilet system for individual households in a rural village setting. My client, a small NGO called EcoPro, had previously built 28 urine-diversion dry-toilets (UDDTs) in the village of Boodheri. Facing the need to build 200 more for the remaining households, Ecopro determined that a more cost-effective and compact structure design would be necessary to avoid overcrowding the village’s small properties.

After extensive research and consultation on the Berkeley campus (see my thread in the Sustainable Sanitation Alliance Forum), I completed a recommendation package for EcoPro which included three potential designs. The director, Dr. Lucas Dengel, was pleased with my recommendations and welcomed me to visit his headquarters in Auroville to build the prototype.

Within a week of arriving in India, I had inspected the existing UDDTs in Boodheri (not a glamorous task by any means, but I was surprised to find that the households took great pride in their personal toilets, which all included a shower space that afforded the women in particular much-needed privacy.) After seeing the UDDTs and experiencing the climate of the dry tropical forest firsthand, I scrapped my early designs and begin anew.

The bulk of my research phase had been dedicated to searching for a suitable material for the containers in which feces and ash were collected separately from urine. EcoPro requested that I find a bio-degradable container, specifically ‘non-plastic’. Most examples that I found involved UDDTs with removable containers and on-site storage using large plastic barrels. By identifying the limiting design factors, I was able to rule out metal, wood, ceramics, and cement as potential materials.

Cost: The total cost of the containers for each UDDT must not exceed the savings in construction costs achieved by reducing the building size.

Availability: The container material must be locally abundant and accessible to village people.

Weight: The containers must not be too heavy for a single woman to transport ( less than 30 Kilograms)

Durability: The container must not break over continued use for at least five years.

Usability: The container must be easy for users to close and transport. It also must prevent any contact with or exposure to unsanitized feces. Management of the container should not cause disgust.

Climate: The container must resist the hot and wet conditions of tropical India with annual monsoons, and thus be immune to rot and rust.

Animals & Pests: The containers must not allow dogs, rats, mice, snakes, cockroaches, and other insects to damage or nest inside the container.

Theft: The container must not be too valuable as an asset so as to attract thieves or require expensive storage conditions.

With not a little disappointment, EcoPro and I begrudgingly accepted that without manufacturing an entirely new product, recycled 55-liter plastic barrels would be the only feasible solution for a containerized household UDDT system. However, I learned that these barrels were ubiquitous throughout South India and that a neighboring fabric dye business generated extra barrels every few weeks. Sometimes, design forces us to compromise. In this case, our primary goal was to develop a safe sanitation system for users.

Pros of the containerized UDDT

·      Sanitized feces is ready for transport in barrel; no shoveling necessary.

·      If necessary, additional barrels may be added to the cycle.

·      Risk of contamination of a barrel during storage is almost zero because the barrel has been removed from beneath the pan. Whereas in the cement chamber system previously constructed by EcoPro, users can potentially contaminate the entire storage chamber by mistake.

Cons

·      Barrel must be changed at various intervals. More frequent management.

·      Barrels may tip over and spill.

·      Barrels may slow desiccation – ventilation holes required

After completing a digital mock-up with the dimensions of the recycled 55-liter barrels, I then collaborated with Auroville’s renowned environmental architect, Suhasini, whose local experience provided four critical design suggestions, including the recommendation that I create a short presentation/binder of slides to give potential users the choice between the previous design which is lower maintenance and more expensive or the new barrel-system design. Her insight into the user standpoint—providing options—is an excellent example of good design thinking in development contexts.

Notice that the barrels are stored beneath the shower space in an sheltered area enclosed with metal mesh. By utilizing this area, the design removes the need for a second concrete storage chamber and results in a 33 percent saving in size, labor, and concrete cost.

The door for the chamber beneath the pan required attention to detail. Taking suggestions from the EcoPro team, I designed a simple door made of a thin granite slab, which is locally available in Tamil Nadu and surprisingly inexpensive. The slab rests against a lip inside the door frame. On either side of the frame, gouges in the cement allow users to grip the slab from the side.

For the pilot site, EcoPro selected a forest sanctuary several kilometers west of Auroville. The sanctuary is commonly used as an environmental education center for school children. The compost toilet would be a living lesson, whether EcoPro decided to use it for the remaining 200 households in the village or not. 

After weeks of delay, local masons and I began construction in late July. The first day, the masons dug a foundation larger than the design specs. I realized that they were unable to read the technical blueprint. The next day I returned with a basic blueprint drafted in Illustrator. Together we dug the correct foundation and I helped them lay the mix of gravel and concrete. Over the next few days we laid the brick courses. The Tamil language is extremely difficult to learn, but we managed to communicate, mostly through gestures and much laughter at my expense.

Another scheduling delay with the masons pushed back completion a month and I was forced to return to Berkeley for the fall semester without seeing my prototype finished. EcoPro eventually sent the following picture.

Because UDDT sanitation requires a year of storage, testing for my prototype was scheduled for December 2015. To assess sanitation: 12 months after the first barrel of the pilot UDDT is closed for storage, EcoPro planned to test for pathogens using the standard proxy means of less than 1 helminth egg and 1,000 E. coli bacteria per gram (Source: WHO). As of this writing, in January of 2016, I have not heard back from EcoPro. Things move at a different pace in India; I am confident that EcoPro will assess the prototype’s effectiveness—as soon as possible.

Of the many insights I gleaned from my experience working on this project, perhaps the most striking came from an observation made by one of the woman at the forest sanctuary. She was relatively better educated and more wealthy than the servant girls who worked at the Sanctuary. One day she said that she would never change out the barrel in the toilet; she would have a servant do it. Upon hearing this, I realized just how important the element of behavior change is in such situations. My design had created a chore.

The woman in this anecdote is not so different from any of us. She was disgusted. Who wants to manage their own waste? The common practice for many people in India is to simply poop in the bushes and walk away. In the “developed world”, our flush toilets distance us from the reality of our place in the great nutrient cycle. Ecosan, in contrast, restores us to a responsible pattern within the nutrient cycle. Properly managed, our piss and shit becomes gold in the form of a rich compost amendment safe for mixture into the subsoil of gardens or around trees. Until our societies can close the nutrient loop, however, we will continue down a linear waste path of our own making—from field to store to table to toilet to sanitation plant to ocean or landfill—at a massive cost in water and public funds.

Another anecdote that EcoPro’s director Lucas Dengel often tells in his presentations is that the length of the sewage plumbing in the United Kingdom would stretch to the moon. That is 384,000 kilometers of metal pipe for a mere 69 million people. In contrast, half of India’s 1.1 billion people lack access to a toilet. There is simply not enough water or resources to construct a comparable sewage system in India. Ecosan designs like the barrel-system UDDT I co-designed with EcoPro offer feasible strategies for a sustainable future—if only we can get past the disgust factor and recognize that our bodies do not generate waste, we generate a resource.