#ecosan

Um banheiro fora da rede



Vi recentemente no Gatesnotes, varios modelos de banheiros, o que mais me interessou foi o que não esta conectado a rede sanitária da cidade e não consome água.

Mas hoje já existe em desenvolvimento vários tipos de banheiros sustentáveis, com diferentes soluções para resolver o mesmo problema e alguns funcionam com energia solar, para que possam operar fora da rede. O vaso nanomembrana…

Toilets that churn gold for the soil

Nidhi Jamwal On an average, the annual faecal matter and urine of one human being contains 4.6 kg nitrogen, 0.6 kg phosphorous and 1.3 kg potassium, all recyclable.

Till two years ago, Kairi, a Tharu tribe village of 138 families in Pashchim Champaran, Bihar, did not have even a single toilet. Fed up of the difficulties faced by female members of his family, who had to walk long distance to…

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.

I couldn’t be more pleased to have worked with such an effective, socially responsible organization this past summer. In my time with Sustainable Organic Integrated Livelihoods (SOIL) I’ve come to more fully appreciate the gravity of the global sanitation crisis, being that over 2.5 billion people across the globe lack improved sanitation facilities. In Haiti, over 70% lack access to a toilet leading to a high rate of child mortality from waterborne diseases.  While SOIL’s contribution to mitigating this problem sometimes feel like a drop in the ocean in the context of these staggering data, the fact still remains that close to 7,000 Haitians are currently benefiting from SOIL’s products and services. In addition, SOIL focuses on designs and services with the potential to be scaled up through social business development so it’s exciting to see how this small project might help address the international challenge of increasing global access to sanitation.

SOIL implemented the first urban waste treatment site in all of Haiti in 2009. Considering how densely packed Port-au-Prince is, this is truly astounding to imagine. SOIL now operates two out of four waste treatment sites in Haiti. The capacity of these sites is clearly inadequate to suit the needs of the country, but Haiti is moving in the right direction with their new Water and Sanitation Authority and the public and private sector are working together more closely than ever to quell the cholera epidemic and implement long-term sanitation solutions.

SOIL’s ecological sanitation (EcoSan) composting toilet has several huge advantages. First, it is a low-cost, simple model constructed within Haiti and that can be easily replicated. Second, it transforms the endless supply of potentially dangerous feces into compost, a much-needed soil amendment in Haiti where over 98% of the hills have been deforested and topsoil depletion is severe.

This is how SOIL gets waste to their treatment site: first, customers buy an EcoSan toilet and pay a very small fee to have their waste collected weekly. SOIL staff pick up the buckets of waste on the “Poopmobile” and dump it at the compost site. Then the waste is covered with carbon matter and watered a few times of week until it transforms into nutrient-rich compost!

This sanitation supply chain is demand driven, which demonstrates a strong willingness and ability to pay. In other words, the most vulnerable of people are not being priced out of the market and they themselves are choosing to adopt the technology. SOIL’s successful projects are showing that with the cost recovery of small monthly fees, the potential for successful sustainable private sector sanitation enterprises is well within grasp, even in Haiti, where people are not accustomed to paying for sanitation services.

For eight weeks this summer I will be working as the social media and outreach intern for the 501(c)3 non-profit organization Sustainable Organic Integrated Livelihoods (SOIL), started by the inspiring Reed alumna Sasha Kramer. SOIL uses methods of ecological sanitation (EcoSan) to mitigate the ongoing sanitation crisis in Haiti that was only worsened by the 2010 earthquake. One of their most promising projects is the implementation of EcoSan toilets that turn human waste into much needed compost for sustainable agriculture.

Haiti came into the international limelight after the earthquake, and it seemed that every journalist and pundit felt entitled to present the public with their half-baked theories about why poverty persists in Haiti. International commentators have gazed at the Haitian poor with a mixture of disgust, pity, and fascination for centuries. In a 2010 New York Times article, David Brooks suggests that “Haiti, like most of the world’s poorest nations, suffers from a complex web of progress-resistant cultural influences.” And although he does recognize that Haiti has “a history of oppression, slavery, and colonialism,” he points out that “so does Barbados, and Barbados is doing pretty well.” His analysis, like too many others, blames the victim and clearly ignores the particular history of colonization, slavery that has brutalized so many Haitians, starting with the indigenous population that was decimated by the Spanish in the mid-sixteenth century. Brooks cites the “progress” of Barbados without explaining who is benefiting from that “progress.” Barbados has been hospitable to tourism and transnational capital, but their economy still favors accumulation of capital with the elite classes and the benefits of tourism are not necessarily distributed equitably. It is not justified for arrogant observers like Brooks to patronizingly define universal “progress” and dictate what that should mean to Haitians. 

Á la Arturo Escobar, I have serious reservations about mainstream development practices and the role and efficacy of NGOs and non-profits working in marginalized communities like in Haiti. Through working in Tanzania, Venezuela, and Saint Kitts, I have learned many lessons about community organizing and the importance of critically assessing the many representations and discourses of “progress” and the “other” that we have inherited as a part of our cultural milieux.

How can NGOs and non-profits work together with Haitians while avoiding the superiority complex that Brooks’ comments so exemplify? So many organizations flooded into the country after the earthquake with good intentions and often little historical awareness and certainly not a nuanced analysis of the politics of representation. Although many of these NGOs have been largely ineffective, it is not fair to dismiss the work of all organizations as examples of “NGO-ization,” the buzzword that refers to the trend of NGO proliferation amidst a hubristic Western view of development and a misunderstanding of power relations. 

Ecological sanitation - What is it?

Eco Sanitation works on the principle that urine and faeces are not simply waste products of the human digestion process, but rather are an asset that if properly managed can contribute to better health and food production and reduce pollution.

Eco-sanitation latrines:

Store and prepare faeces for use in agriculture by encouraging the formation of humus by the addition of wood ash and/or soil;

Allow the application of urine as fertiliser in agriculture, in case urine is separated;

Remove faeces and urine from the immediate environment thereby contributing to better health; and

Are dry systems that make contamination of groundwater extremely unlikely.

An old practice revisited

Since  early Chinese history, human excreta was commonly used in agriculture to complement farm manure in improving soil fertility. Farmers owned ‘Outhouses’ where they invited visitors to leave behind their ‘valuable’ excreta. In early Europe, Greek and Roman societies collected human excreta and used it as fertilizer. The Romans found that urine contained high value nutrients and collecting it was a good business. Emperor Vespasian introduced a ‘urine tax’ along with the proverb pecunia non olet (Money does not smell).

In Britain, Queen Victoria used an earth-closet at Windsor Castle, although many types of water-closet were available. Henry Moule in 1840’s was the champion of the earth-closet and backed up his belief with a scientific experiment where he persuaded a farmer to fertilise one half of a field with earth from his closet, and the other with an equal weight of superphosphate. Swedes were planted in both halves, and those nurtured with earth manure grew one third bigger than those given only superphosphate.  For many years, the earth- and water-closets were rival systems with champions and detractors on both sides.

The nutrition value of urine and faeces as fertilizers

Fertilizer

500 litres of Urine

500 litres of Faeces

Total

Fertilizer needs of 250kgs of cereal

Nitrogen5.6kg0.09kg5.7kg5.6kgPhosphorus0.4kg0.19kg0.6kg0.7kgPotassium1.0kg0.17kg1.2kg1.2kg

(500 litres of urine and 50 litres of faeces are about the amounts produced by one adult in a year)

Note that most of the nutrients are in the urine, though the vast majority of the pathogens are in the faeces. Although faeces has a lower nutrient content, its high organic matter aids water retention and is a good soil improver.

Fig1: Nutrients for plant growth present in human faeces and urine

Ecological latrine design

Ecological latrines can be divided into two main types: (i) dehydrating urine separating toilers and (ii) composting toilets.

(i) Dehydrating urine separating toilets

The urine and faeces are collected and stored separately by the use of specially designed pedestals and slabs.

Fig.2 Dehydrating latrine with urine diversion and the principle of a urine diversion latrine

The urine is collected and stored until it can be used as a fertilizer on plants or crops. The faeces drops into a pit, vault or container to which a handful of either ash or lime is added. This has the effect of drying the faeces and increasing the pH which has a positive impact on reducing smell (less ammonia emission) and destroying pathogens (see GTZ-EcoSan Datasheet-2).  After 12 months of  storage the resulting ‘humanure’ can be applied to the land. Some form of alternating double or multiple storage system is required to avoid mixing fresh and composted manure.

(ii) Composting toilet

The double-pit or vault composting latrines do not separate the faeces and urine, so that both enter the same vault or pit. A handful of a mixture of soil and ash is added to the pit after each use which has the effect of keeping the pit contents relatively dry and aerobic, as opposed to anaerobic and smelly. ‘Composting’ is not technically the correct name as the temperatures never rise high enough to create themophilic composting conditions. After 12 months of storage the resulting ‘humanure’ can be applied to thet land as a fertilizer and soil conditioner. The simplest form of composting latrine is called the Arborloo or ‘walking latrine’ (see below).  

Fig3:  Arborloo as introduced in Southern Africa

Arborloo

A shallow (1-1.5m) unlined pit covered by a concrete slab and a movable simple superstructure.  Once the pit is 2/3 filled (usually after some 4-6 months), the superstructure and slab are removed to a new pit. The old pit is further filled up with soil and a young tree is planted in the pit. Banana and Paw Paw grow particularly well in the old pit.

Reasons to adopt ecological sanitation

In many Developing Countries poor soil fertility and the  increasing cost of artificial fertilizer is making it difficult for subsistence farmers to grow enough food to feed their families. Survival becomes more perilous as population growth means new land to cultivate is not available. The fertilizer producing qualities of ecological latrines can help the household economy of poor families as demonstrated by the following comments collected from Malawian farmers who have been using eco-sanitation for a number of years,      

In their testimony, these farmers allude not only to the nutrient quality of the ‘humanure’, but also how the organic matter from the faeces improves soil structure. 

The act of adding ash and/or soil and separating the urine has the effect of drying the faeces and the possibility of pathogen transmission to the water table is eliminated. This makes eco sanitation a particularly good option in areas where contamination of groundwater is a sensitive issue.

In water stressed or arid areas, ecological sanitation (which needs no water for flushing) can help save this valuable resource. In the developed countries of the north it has been estimated that use of ecological sanitation could reduce domestic water consumption by 20-40%.  

Conventional sewage systems effectively remove faecal material and the pathogens it contains from the immediate household and community environment and deliver it to a sewage treatment works. In many countries the sewage works are incapable of effectively treating the waste as the volume entering the plant exceeds its design capacity (either because of population growth, the high cost of electricity or the mixing of sewage with storm water). The result is that poorly treated sewage is discharged into streams and rivers with detrimental effects on the rivers' flora and fauna. It is argued that if eco-sanitation was more widely used, the need to build and operate expensive sewage works would diminish and the water quality in the rivers would improve. 

In developing countries, areas with high groundwater tables and collapsing sandy soils are notoriously difficult in which to build permanent traditional latrines.  Ecological latrines with their shallow pits or vaults can provide good, sustainable affordable solutions.

Reasons NOT to adopt ecological sanitation

Faeces in all cultures is regarded as disgusting and to many people, the thought of using it for food production is repulsive. In addition, many cultures have strongly-held beliefs and taboos regarding faeces that make ecological sanitation unworkable. This avoidance instinct has self preservation at its heart as faeces contains many pathogens that are harmful to man if ingested. Even where there is no risk of disease transmission, the cultural perception may be different as demonstrated by this Malawian farmer: “If I eat crops and fruit grown in my own excreta, it can provide disease”.  

People generally prefer toilets where faeces cannot be seen and where no further handling by the users is required. With a water closet the only necessary further user action is the pulling of a handle; out of sight out of mind. With eco-sanitation there is always some form of secondary handling of the faeces and user reluctance to do this could be high. Even if an individual is willing to adopt eco-sanitation, they may be put off from doing so by the fear of being ridiculed by the rest of the community.          

Sanitation systems are one of the key defences in breaking the faecal-oral transmission routes of many diseases. The capacity of a latrine to either ensure no further human contact with faeces or to reduce the pathogens to safe levels is an essential prerequisite. With ecological latrines, their ability to perform the latter is questionable. 

The potential health risks associated with ecological sanitation

Ecological latrines use the following techniques to ensure pathogens die off:

Long storage timesMust be 12 months or moreLow moisture contentsMust be 25% or lessLow pHMust be pH 10 or moreHigh temperaturesMust be 36°C or higherEncouraging predationMust be presence of ovicidal fungi

  Ascaris is the most persistent pathogen in faeces and is therefore used as an indicator of pathogen removal efficiency. In a well managed ecological latrine where one or a combination of the above environmental conditions has been acgieved in the pit or vault, Ascaris eggs will be reduced to a level where they do not present a risk to public health. Problems arise when the latrine is not well managed and the user has either misunderstood or does not followo the management regime stipulated by the designers. Unfortunately this is common and is one of the major weaknesses of ecological sanitation.

However, pathogen destruction in ecological sanitation is often viewed from the negative angle of what it does not achieve with regard to Ascaris die-off, and never from the angle of what it does achieve with a whole host of other pathogens. Ecological latrines, where storage times are greater than 3 months, will reduce to safe levels the pathogens responsible for Ameobiasis, , Giardiasis, Hepatitis A, hookworm, Trichuris (whipwork),  Enteribius vermicularis(threadworm), Hymenolepis nana, Rotavirus, Cholera, Campylobacter, Eschericia coli,Salmonellosis, Shigellosis and Typhoid.

The debate about the safety of ecological sanitation often occurs in isolation of the context in which it is being practiced and the larger question of whether the introduction and practice of ecological sanitation will improve the overall health of a community is never addressed. Generally speaking, from a health perspective an ecological latrine is better than no latrine at all and any possible health risks must be weighed against the potential improvement in the household economy and a family's  ability to feed themselves.

Ongoing research and learning on EcoSan      

Research, demonstration and full-scale programmes are financed by many Southern and Northern governments and organizations. Some major donor-supported programmes are GTZ EcoSan (www.gtz.de/ecosan), Sida-supported EcoSanRes (www.ecosanres.org).  The websites give also reference to other ongoing research. Three international EcoSan Conferences/Symposia have been organised (China, Germany and South Africa).

References

GTZ (2002) Ecological Housing Estate, Luebeck, Germany.  Datasheet for EcoSan Projects 004. GTZ, Eschborn, Germany. www2.gtz.de/ecosan/download/ecosan-pds-004-Germany-Luebeck-Flinenbreite.pdf 

Jenssen, D. et al. (2004) Ecological Sanitation and Reuse of Wastewater.  A think piece on ecological sanitation. Agricultural University of Norwayhttp://www.dep.no/archive/mdbilder/01/34/ecosan034.pdf 

Luo Shiming (2001) the utilization of human excreta in Chinese agriculture and the challenge faced. South China Agricultural Universitywww.ias.unu.edu/proceedings/icibs/ecosan/luo-02.html 

Mara, D. and Cairncross, S. (1989) Guidelines for the Safe Use of Wastewater and Excreta in Agriculture and Aquaculture.  WHO, Geneva.

Medina, Martin (1998) Scavenging and Integrated Bio Systems: some past and present examples www.ias.unu.edu/proceedings/icibs/medina/paper.htm 

Morgan, P. (2004). An Ecological Approach to Sanitation in Africa.  A compilation of experiences. Aquamore, Zimbabwe www.ecosanres.org/PM%20Report.htm 

Sawyer, R. (2003) Sanitation as if it really matters Mexicowww.gtz.de/ecosan/download/sawyer-toiletsoutofcloset.pdf 

Stenstrom, T.A. (2002) Reduction Efficiency of Index Pathogens in Dry Sanitation compared with Traditional and Alternative Wastewater Treatment Systemswww.ias.unu.edu/proceedings/icibs/ecosan/stenstrom.html 

WASTE (2005).  At the End of the Pipe? Insights, visions and ideas on a shift in the sanitation paradigm. Summary from expert meetings 2005. Gouda, The Netherlandshttp://www.ecosan.nl/page/828 

Werner, Ch. (2003) Reasons for and principles of EcoSan. Paper at 2nd Int. Symp. on EcoSan, GTZ, Luebeck, Germanywww2.gtz.de/publikationen/isissearch.Publikationen/details.aspx?RecID=BIB-GTZ063412  

Winblad, U. et al (2004) Ecological Sanitation. Revised and enlarged edition. Stockholm Environmental Institute, Swedenhttp://www.ecosanres.org/PDF%20files/Ecological%20Sanitation%202004.pdf 

Major Websites and Contacts

EcoSanRes (Sweden) www.ecosanres.org with many publications and links

www.gtz.de/ecosan with many EcoSan publications and links

www.ecosan.nl by WASTE

www.sanicon.net with oublications, websites and FAQs