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Lysimeters Determine If Human Waste Composting Can Be More Efficient

In Haiti, untreated human waste contaminating urban areas and water sources has led to widespread waterborne illnesses such as typhoid, cholera, and chronic diarrhea.

Human wastes are making their way into Haiti’s waterways.

Human wastes are making their way into Haiti’s waterways.

Sustainable Organic Integrated Livelihoods (SOIL) has been working since 2006 to shift human waste as a threat to public health and source of pollution to being a resource for nutrient management by turning solid waste into compost.  This effort has been critical to sustainable agriculture and reforestation efforts, as topsoil in Haiti has severely eroded over time, contributing to Haiti’s extreme poverty and malnutrition.

waste

This is a very famous image of the border between Haiti and the Dominican Republic. It’s often used to demonstrate how badly off Haiti is relative to their neighbors. What you’re actually seeing is the environmental scars of a very different post-colonial history.

Why Compost?  

Topsoil erosion in Haiti was estimated to be 36.6 million metric tons annually in 1990, and it is estimated that only one sixth of the land currently cultivated in Haiti is suitable for agriculture. SOIL combats desertification by producing over 100,000 gallons of agricultural-grade compost made from human waste annually.  SOIL research has shown that this compost can increase crop yields by up to 400%.  The organization has sold over 60,000 gallons of this compost to local farmers and organizations, increasing soil organic matter and nutrients throughout the country.

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Today in Haiti, only 25% of people have access to a toilet – meaning people are forced to go to the bathroom outside or in urban areas, in a plastic bag, which often times gets disposed of in a canal or an empty lot.

How Do They Do It?

SOIL distributes specially constructed toilets throughout Haiti that separate urine from solid waste.  Odors are reduced by covering the solid waste with organic cover material.  The toilet utilizes a five gallon bucket to collect solid waste that can be swapped out when full.

Waste

Instead of flushing nutrients away with fresh water, people use a dry carbon material to cover it up so that it doesn’t smell, and it doesn’t attract flies. This material also provides food for the microbes that will ultimately transform the poop.

The five gallon buckets are collected weekly and taken to the composting facility, where they are dumped into large composting bins.  It takes about 1500 buckets (3-4 days worth) to fill each bin. Bins are required to reach 122°F and left for 2.5 months in order to kill all pathogens.

waste

Wastes are safely transformed into nutrient-rich compost in a carefully monitored composting treatment process that exceeds the World Heath Organization’s standards for the safe treatment of human waste.

The compost is then removed from the bin and turned by hand. There are three concrete slabs used to manage the finishing process.  Compost is turned horizontally and then moved forward to the next slab, allowing multiple batches to be finishing at the same time, each at a different stage.  After processing, the compost is sifted, bagged, and sold, reinvigorating the agriculturally-based Haitian economy.  

waste

The compost SOIL produces is bagged under the Haitian Creole brand name “Konpòs Lakay” and then sold for agricultural application, improving both the fertility and water retention of soil. With over four billion people worldwide currently lacking access to waste treatment services, finding ways to provide waste treatment services profitability through the private sector has the potential to dramatically improve public health and agricultural outputs globally.

Understand the Impact

Watch this 5 minute video filmed by independent parties to see how SOIL is impacting Haitian citizens and the environment.

Next week:  Read how experiments using lysimeters will help SOIL make the composting process more efficient.  

Get more information on applied environmental research in our

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