Solid Waste Management – Manejo de Residuos Solidos

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Composting as Waste Management:

Ben Lewis, Louis Lefebvre, Graham Taylor, Brant Haflich

Problem Statement:

Although the people of San Pablo have already established ways to eliminate various wastes that are produced through day to day living, we propose that these wastes can be dealt with in a more efficient manner, that can also produce a beneficial end product. To accomplish this better efficiency, we propose the implementation of a waste management system based around the use of a centralized, community compost pile. This compost pile would be able to take advantage of nearly all waste streams generated by the people, and especially human solid waste through the use of a compositing toilet system.

Waste Management:

Waste management is defined as the collecting, transporting, managing, processing, and disposing of all waste streams. An established waste management system could improve sanitation through the potential elimination of incineration of waste, and the elimination of a septic tank system. Nutrient recycling and usable fertilizer could be created through a proper waste management/composting system, and aesthetically, it could reduce the amount of waste that is incinerated and eliminate pit toilets.

Refining Scope of Project:

After performing background research on the community of San Pablo, it was discovered that, in general, not much solid waste is produced that isn’t already being managed by the community. Currently most solid waste that would generally be considered trash is burned, while food and agricultural wastes are minimal if not already reused beneficially. This allowed our group to identify human solid wastes as a waste stream that is not currently being optimally reused. Since the identification of this under-serviced waste stream, our goal has been to innovate a human waste composting methodology that will permit and encourage its transformation to a service based enterprise for a local community member(s). To achieve this idea of human solid waste management, we are proposing that composting toilets be installed throughout the community, which would then be collected and emptied by a designated person or persons. By effectively creating a composting toilet system, we could potentially eliminate the negative effects of pit toilets and septic tanks, and the use the fecal matter in the compost pile to promote nutrient recycling and usable fertilizer.

Executorial Processes:
The process schematic below depicts our group’s predicted and recommended project execution progression.



Infrastructure Choices
With this type of waste management system, we recognize that an education aspect is critical for both the people of San Pablo and us, the researchers. The people of San Pablo must be educated on not only how this system will function, but also the dangers of the current system that is in place. Along with that, it is necessary to teach them the benefits that a centralized composting pile, and composting toilets could have on their society. We as the researchers also need the help of the people of San Pablo to educate us on the various cultural ideas and boundaries that we are not aware of, as well as the workings of their town to determine the best possible way to create a successful waste management system.

Pit Toilet Systems:

  • Although pit toilet systems, otherwise known as latrines, are easy to install and require virtually no upkeep, they come with a number of disadvantages. The two main dangers associated with pit toilets are disease transmission and ground water contamination. Since the human solid wastes are allowed to simply sit at the bottom of the pit, a number of harmful bacteria and other organisms can potentially harm the inhabitants of that pit latrine. In addition, the harmful byproducts are allowed to soak back into the earth, which then find their way to nearby streams, thus contaminating the water, and once again causing potential harm to the townspeople.

Septic Tank Systems:

  • If properly maintained, septic tank systems pose little to no threat on the community, and they provide our very nice porcelain toilets that we have come to know and love. However, the downfall occurs when they are not properly maintained. Given San Pablo’s remote locale, it is reasonable to assume that large trucks are not coming frequently to empty the septic tanks in use. If not emptied, the tanks can overflow causing a very unpleasant experience as well as ground water contamination and potential disease transmission.

Composting System:

  • A compost system allows for the wastes produced by the townspeople to be broken and recycled into an end product that can be reused for agriculture. With composting toilets, the human waste is collected in a bucket and covered with saw dust to eliminate foul odors. Since there is no contact with the earth, there is no way that this system can cause harm to the ground water. In addition, with a proper system set in place to collect the buckets regularly, there is far less time for harmful bacteria and organisms to grow and cause risk of disease transmission. However, though there are a lot of positives to composting in general, composting human solid waste can be difficult and must be done properly in order to not contaminate the entirety of the pile.

Water Cycle
Understanding the water cycle is of utmost importance for the San Pablo community members to realize potential dangers of current dangers as well as potential benefits of change. Through water cycle education the community will better understand interactions between source waters, human excreta, contamination, and public health. Furthermore community members will apply their knowledge of the water cycle and we will jointly identify possible sources of contamination within local source-water watersheds.

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Hygiene & Waste Handling
Critical to safe handling during compost operation is comprehension of hygiene. Short courses focused on the need to wash ones hands after going to the bathroom, handling wastes, and other pathogen sources will be the focus of hygiene education. This educational exchange will allow us to better understand preferences and current practices of hygiene and waste handling. Additionally, demonstrating proper composting will is required to ensure a consistent pathogen kill.

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Nutrient Cycle
In effort to further encourage adoption of a composting system, education on nutrient recycling through composting will be pursued. Benefits such marketable composting by products like fertilizer and soil amendments will be emphasized. Nutrient recycling is a great opportunity to demonstrate the environmental stewardship affiliated with keeping nutrient cycles local.

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Essentially, a composting toilet consists of a normal toilet seat, and a five gallon bucket. Ideally, we would like to have a seal that fits over the bucket between uses to decrease undesired condensate, etc. A urine diverter is placed slightly in front of the bucket to carry urine away from the solid waste. Saw dust is keep near the toilet to cover the feces a
nd decrease the odors that are emitted.


Wholistic Resolution:

A collaborative democratic process by which the best method for a human waste sanitation system will be selected, is the only way to successful long lasting solutions. After and during the bi-directional education process solutions will be pooled, collected, and processed. Decision matrices will be used to visually demonstrate the best solution(s). Below is a preliminary decision matrix that our group has proposed, however input from the community is needed for a comprehensive matrix.


All of the available technologies were evaluated on the above criteria and given a score from 1-10 for each. Each criteria was then weighted based on its importance for project implementation. The weighting factors were multiplied by the corresponding score for each option, then each options scores were summed and displayed in the totals column on the right hand side. The stand out option is a centralized composting site. This system incorporates satellite deposit sites where human waste is placed in a temporary storage container (e.g. five gallon bucket). On regular intervals these buckets will be picked up and emptied at the centralized compost pile for thermal treatment and nutrient recycling.

Community Implementation:
It is the desire of our group for the San Pablo community to take full ownership of the project after the educational and resolution processes have been executed. Predicted involvement from our group would be initial over sight and/or assistance with construction, operations, and handling of wastes.

Service Oriented Human Waste Composting Enterprise:
Rather than simply instruct the people of San Pablo to poop in buckets and make their own compost pile, we want to try to make a service industry out of the collection and compost of wastes. This could help the community through the creation of more jobs and a continued sense of community.

Possible Benefits:

  • eliminates need for difficult-to-maintain septic systems
  • eliminates need for potentially hazardous and “eye sore” pit latrines
  • promotes nutrient recylcing
  • promotes stewardship of water resources and natural environment
  • potential for service based composting enterprise
  • marketable by products of enterprise (fertilizer)
  • improved sanitation

Associated Challenges of Human Waste Composting Enterprise:

  • lack of education with regards to:preference for status quo
    • water cycle
    • hygiene
    • nutrient cycle
    • waste handling
    • infrastructure choices and consequences
  • composting operation proximity to community (NIMBY)
  • cultural stigmas
  • identifying individual(s) to carry out the service

Community Led Dissemination:
Through the educational processes, democratic decision making, highly autonomous implementation and operation the community of San Pablo will be well equipped to spread their knowledge to neighboring communities. Identification of sources of fecal contamination of the San Pablan water supply would the most ideal locales for sharing this knowledge. This would further protect San Pablan water sources while opening up potential revenue streams for neighboring communities or even San Pablo itself. As a community, by spreading the knowledge gained from this experience, San Pablans will be empowering their neighbors by improving health and simultaneously revealing new means of income, thus broadening the global struggle against poverty.

Resources, Connections, and Networking:
**Sustainable Organic Integrated Livelihoods (SOIL)**
Our group has has developed a connection with SOIL in Haiti. SOIL’s mission statement: “[SOIL]is dedicated to protecting soil resources, empowering communities and transforming wastes into resources in Haiti. We believe that the path to sustainability is through transformation, of both disempowered people and discarded materials, turning apathy and pollution into valuable resources.”

This class, our group, and Guateca have a developed relationship with Alterna. Here is Alterna’s mission statement: “
Alterna is a Center for Innovation and Entrepreneurship based in Quetzaltenango, Guatemala. Our mission is to develop technologies and build local businesses that satisfy basic needs and provide economic growth opportunities for the Guatemalan people in an environmentally sustainable way.” Alterna has project histories in microhydro, efficient woodstoves, biodigesters, and organic fertilizers.

**EcoSanRes (Ecological Sanitation Research)**
EcoSanRes is a forum for advancements in low tech ecological sanitation in a developing world context.

**Sustainable Sanitation Alliance (SuSanA)**
“The Sustainable Sanitation Alliance (SuSanA) is an informal network of organisations who share a common vision on sustainable sanitation. SuSanA came into existence in early 2007 and works as a coordination platform, working platform, sounding board, contributor to the policy dialogue on sustainable sanitation and as a “catalyst”. At the present time, the secretariat function is carried out by GIZ (German International Cooperation) and the current number of partners is 173”

Relevant Research and Projects:

EPA P3 Website: EPA P3 Research Competition
Our Proposal Efforts: Composting Toilets in San Pablo Guatemala
Our Second Presentation: Grant Writing Presentation

Relevant Websites:
WASTE: Advisers on urban environment and development