Human Waste Reuse: Solution to a Growing Sanitation Problem?

2015•11•19 Jeff Smith

Scientists are influencing sanitation policies in South Asia and demonstrating composting technology to turn human faecal sludge into fertilizer pellets for agricultural use. Their work presents solutions for a growing global sanitation problem that can reduce the environmental impact of development and contribute to efforts to sustainably intensify agricultural production.

After examining an International Water Management Institute (IWMI) project on faecal sludge management in Bangladesh the World Bank’s Water and Sanitation Program recently asked IWMI to jointly develop policy advisory notes on wastewater reuse and septage (septic tank sludge) management for the central government of India. IWMI, which leads the CGIAR Research Program on Water, Land and Ecosystems, has also been asked by the World Bank to help develop septage strategies for selected towns in India’s Madhya Pradesh state.

In Sri Lanka, IWMI has signed two national-level memorandums of understanding to help the island-nation improve its septage management policy and develop human waste composting and co-composting initiatives. A project has also commenced in northwestern Sri Lanka to demonstrate techniques for safe composting and turning human waste into a pellet fertilizer.

Turning an environmental and social risk into an opportunity

The work, under WLE’s Resource Recovery and Reuse program, comes amid growing concern about the world’s ability to handle a massive sanitation problem. Rapid urbanization in Asia and Africa has dramatically increased the number of poor people living in the margins of cities, putting immense pressure on already strained water and land resources.

Globally, more than a billion people lack access to adequate sanitation. In India alone more than 160 million septic tanks and pit latrines without septic tanks contribute to surface water pollution due to lack of septage treatment facilities. In Sri Lanka, researchers recently found that only 10 percent of human excreta from septic tanks was being collected, and only 1 percent treated.

Researchers are working to convert human waste into a resource that benefits farmers, creates jobs and generates business opportunities. Business models for faecal sludge management and the production of a safe, high quality fertilizer are being tested in ten cities across the world.

fertilised cabbage

This cabbage was fertilized using composted human excrement from an EcoSan waterless toilet and additional doses of stored urine. Photo: SuSanA Secretariat. Creative Commons BY (cropped).

“While human waste management is a challenge, it also offers a business and development opportunity that could benefit millions of poor farmers,” said Pay Drechsel, leader of WLE’s Resource Recovery and Reuse research theme.

The technical knowledge is available. And in many cultures, wastewater reuse and waste composting have a long tradition, at least at the household level. However, local perceptions of the practices vary, as do the capacities of governments and institutions to implement these efforts.

“While human waste management is a challenge, it also offers a business and development opportunity that could benefit millions of poor farmers,” said Pay Drechsel, leader of WLE’s Resource Recovery and Reuse research theme.

The World Bank’s Water Sanitation Program became interested in WLE’s waste reuse work after visiting a project in Bangladesh where IWMI is working with BRAC, one of the largest NGOs in the world.

BRAC has installed a million single pit latrines across Bangladesh and wanted a solution to manage the collection and treatment of fecal sludge. Researchers worked with a compost company to test a fecal sludge based co-compost technology. Co-composting is the controlled degradation of organic material, using more than one feedstock such as fecal sludge combined with solid waste or sawdust. Composting sanitizes the material and it becomes valuable to the farmer when it is turned into pellets that are less bulky to fertilize crops.

“Reuse helps to not only close the service delivery chain, but also improves the sustainability of the project,” said Joseph Ravikumar, a senior institutional development specialist with the World Bank. “What I saw of IWMI’s work in Bangladesh further strengthened my conviction and it is important to take market opportunities seriously.”

In addition to interest by the World Bank and the Madhya Pradesh state government to adopt the technology in India, there is potential for the research results to be adopted by BRAC in Bangladesh, said Krishna Rao, who leads IWMI’s business model analysis and enterprise development. “The key lesson we’ve learned is the need to match agricultural demands with the engineering know-how in local areas.”

Sri Lanka sees septage solutions as key to sustainable development

As of 2011 less than three percent of Sri Lanka’s population was covered by piped sewage systems, and that service was mainly in the city of Colombo. Elsewhere, there are large numbers of septic tanks and pit latrines that require periodic emptying and disposal. Of the total septage collected from on-site facilities nearly three-quarters is dumped into landfills, depressions or the ocean, according to estimates from a 2013 IWMI field survey.

“The septage dumping practices and subsequent pollution of surface and groundwater threatens to undermine the progress Sri Lanka has made under the Millenium Development Goals to provide access to safe water supplies from wells and reservoirs,” said Sudarshana Fernando, a resource recovery and reuse expert at IWMI who leads the Sri Lanka septage project.

The project is working with the Sri Lankan government to improve septage management practices, and has started a demonstration project in Kurunegala in northwest Sri Lanka to convert faecal sludge into fertilizer pellets.

The Sri Lanka Ministry of Water Supply and Drainage is interested in selling the organic fertilizer made from human faecal sludge and organic municipal waste as a means to more quickly recover the costs of its more than 100 compost stations in the country.

Based on the success of its projects in South Asia, researchers are ready to accept calls from other state governments in India, as well as donors and entrepreneurs across South Asia. “Eventually, we hope that business schools and the private sector can take over much of the work,” Drechsel said. He said more than 100 business schools are currently being screened to explore their capacity in sanitation-agriculture work and to tailor research to their needs.

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Human Waste Reuse: Solution to Growing Sanitation Problem? by Jeff Smith is licensed under a Creative Commons Attribution 4.0 International License.
Based on a work from the International Water Management Institute’s CGIAR Water, Land and Ecosystems website. The title and photos have been modified here.


Jeff Smith is a science writer and former journalist. He has covered development issues in Asia and Africa since the late 1990s.