Turning Poop Into Power

Using Biodigesters as a sanitation and energy solution in rural Cambodia

Long Sokhon is a small-scale farmer in Cambodia’s Pursat Province. Like 85% of Cambodians, she makes a modest living off the land. Sokhon grows rice along a scar of earth carved into the forest by day. She used to cook for her family of eight over a wood-chip fire by night. Sokhon lived the way most do in rural Cambodia—one of the poorest countries in South East Asia with a population of 15.8 million. Then, roughly one year ago, she was given the opportunity to have a 2,000 litre slate-grey tank installed in the vegetable patch behind her house.

Sokhon was shown how to feed waste into an inlet at the top of the tank—in goes a daily bucket of water and buffalo dung; out comes biogas for cooking and fertilizer with which to grow crops. Long Sokhon was the final participant in her commune to be chosen as part of a biodigester pilot project run by Engineers Without Borders Australia (EWB) and Live & Learn Environmental Education. The project aims to address sanitation and energy issues in the flood-prone region around Cambodia’s Tonle Sap. 

The Tonle Sap is one South East Asia’s most challenging living environments. South East Asia’s largest fresh water ecosystem, the lake swells to quadruple its size between the dry and the wet season. A pit latrine that’s accessible in January will be completely flooded come September. As a result human and livestock waste enter directly into the water, contaminating a precious resource millions depend on for their day-to-day survival.

Lack of access to safe water, sanitation, and hygiene (WASH) is a significant health and financial burden on rural Cambodia. Diarrhoeal diseases are the second largest killer of children under the age of five worldwide—or, as UNICEF puts it, half a million per year. The Royal Government of Cambodia has acknowledged the country’s need to invest in the WASH sector. Among its contributions to the UN Millennium Development Goals, Cambodia set targets of improving the percentage of its rural population with access to safe water sources from 24% in 1998 to 50% in 2015, and the percentage of its rural population with access to improved sanitation from 8.6% in 1998 to 30% 2015. In 2013 it was reported that the sanitation target had been met ahead of schedule, with 33% of rural Cambodians now having access to hygienic latrines. Yet this data is a simple overview of the country as a whole. Distribution is uneven. Isolation, a lack of transport access, and limited local cash flow has caused the country’s harder to reach communities to be left behind.

4.14 million Cambodians currently live in these regions, termed ‘challenging environments’—28% of the overall population. These include Pursat and Kampong Chhnang Province where the EWB and Live & Learn’s biodigesters project is taking place. 

Biodigester technology has existed for many years. But it's only now, through key innovation and the driving down of costs, that the technology is being made available to small-scale rural farmers like Sokhon. What’s been key in the success of the EWB and Live & Learn’s project is that it goes beyond a simple sanitation solution—the device is also an alternative energy technology.

“Where people see problems a social entrepreneur sees an opportunity,” says Ben Jeffreys, the biodigester program’s Managing Director.

Biological waste is digested anaerobically within the biodigester to produce biogas for cooking and fertilizer for agricultural activities. It’s the biogas, seen as a method of driving down day-to-day costs, that has early adopters excited—particularly in a country with one of the highest fees for grid power supply in the world. Sin Saroun—a small scale farmer in Kampong Chhnang Province who joined the biodigester program four years ago—pays 12,000 KHR ($3 USD) per kilowatt-hour. This is nearly nine times what she would if she lived in rural Vietnam. 

Between 2008 and 2012 EWB and Live & Learn installed 30 biodigesters, such as Sokhon and Saroun’s, around the region. In an evaluation done 12 months prior to publishing this article, nearly all the devices were still in operation. Participants gave the technology a satisfaction rating of 92%. In 2014 the project was awarded a Google Impact Challenge | Australia grant of $500,000 AUD ($360,000 USD) in order to scale the project into a market-based social enterprise. The goal is now to build a business that provides sanitation, energy and livelihood options to 1.2 million Cambodians by 2024.

“Our real vision is how many people can we reach with this technology, particularly those in flooded areas where current technologies don’t work,” says Jeffreys, who moved  from Melbourne to Phnom Penh in May with the aim of building as much of the capacity and value chain as possible in-country.

“The biodigester project's aim is to allow these communities to develop beyond mere subsistence by giving them the opportunity and resources to invest in their futures.”

Biodigesters Managing Director, Ben Jeffreys and Live & Learn Director, Socheath Sou interview Long Sokhon about her experience with her biodigester.

A major focus of the program is optimizing the product’s value proposition to the users. Maximizing uptake is critical to addressing downstream energy and sanitation affects. The current biodigester prototypes cost $450 USD per unit. This pays itself off by reducing the user’s day-to-day cost. Upfront investment; however, still stands at just over one third of the annual rural Cambodia salary. Jeffreys believes an approximate two-year payback period, similar to current solar technology in Australia, is both achievable and workable in Cambodia.

“If we are to reach our goal of 1.2 million people by 2024, then part of our job is to work with communities to demonstrate why an investment in this technology can make such a positive difference to their lives and weekly budget,” Jeffreys says. 

Saroun claims the organic fertilizer produced by her biodigester has significantly increased her rice and sesame yields. She has been able to cut back on the 900,000 KHR ($221 USD) she used to spend per season on fertilizer. Sokhon’s seen her health increase dramatically in the absence of the wood-fire smoke. Preparing a meal for her family no longer evokes fits of coughing and her head no longer aches.

Indoor air pollution, resulting from the combustion of solid fuel, has been referred to by The World Health Organisation as ‘the killer in the kitchen.’ It’s estimates that 36% of lower respiratory infections and 22% of chronic respiratory diseases are a direct result of air pollution from combusting solids in low ventilation areas. This accumulates to 1.5 million deaths each year.

Sokhon saves up to 50,000 KHR ($12 USD) on medicine each month.

It’s this stacking of benefits that makes the biodigester project a true Cleanleap technology. What originated as an alternative to centralized sanitation in Cambodia’s most challenging environments can now be viewed as a holistic approach to improving rural livelihoods through security and opportunity. Improved energy access leads to increased livelihood opportunities and reduces poverty. It improves access to education and plays a key role in reducing respiratory diseases as well as childhood mortality. More efficient fuel can alleviate the environmental damages associated with biomass use.

Sokhon and Saroun are asked where they invest their newfound time and finances. They answer the same—to give their children an education and thus a better life.