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Biogas toilets in a Chinese village

Guest blog by Angela Ni, Fulbright Fellow 2010-2011, Yunnan, China (

Angela’s second instalment from the field in rural China

Here in China, more than 50% of the population lives in rural areas, often far away from urban centers, where poor sanitation can often pose a thorny public health challenge.  Preventing fecal pathogens from getting into clean water sources  is a key element for  improving sanitation. This year the World Health Organization released Sanitation and Hygiene in East Asia, which reports an increasingly healthy China in terms of excreta-related diseases. For example, in 2008, China’s annual incidence rate of diarrheal disease had dropped to 154 cases per 1,000 people, a rate lower than all East Asian countries except Japan and South Korea. But there is still much room for improvement.

In China’s rural areas, outdoor septic tank toilets are critical to improving access to sanitation. According to Chinese government statistics, 2.1 million households in Yunnan Province have biogas toilets (see my last Speaking of Medicine post for an explanation of how these units operate). This past month I traveled to Gongzhuo Village (公桌村) in Yuanmou County (元谟县), a three and a half hour bus ride north of Yunnan’s capital city, Kunming, to see these toilets.

Gongzhuo is a model farming village known for sustainable agricultural practices such as low-impact pesticide use. Gongzhuo’s 343 households are equipped with biogas toilets, some built with the help of up to RMB 500 (Ren-min-bi) in government subsidies.

A standard toilet pit that connects to a biogas tank.

The farmers I spoke with said that the organic residual biogas slurry generated by the toilets had increased their crop yield compared to using chemical fertilizers. They also used the methane gas produced by the toilet’s biodegrading of waste to fuel their cooking stoves.

Whereas most buildings in Gongzhuo are single-story structures made of brick and cement, one particular home struck me as noteworthy because of its stark above- and belowground infrastructural difference. The owner, (annual income of RMB 40,000 ), spent RMB 200,000 of his and borrowed money to remodel his family residence into a two-story house with glossy white-tile. Despite being equipped with modern conveniences like a television and washing machine, the toilet was still a squat pit located outside, adjacent to the pigsty, collecting human and animal waste in a biogas-generating septic tank.

I later relayed this situation to my colleagues, and they responded with a traditional Chinese saying: “吃家饭,拉野屎” (chī jiā fàn, lā yě shǐ), which translates as “after eating a family meal, defecate in the fields”. The saying cannot be taken too literally since WHO statistics report no more than four percent of China’s population still practice open defecation. However, this idiom still rings true for the farming communities that continue to reap the benefits of using “humanure” —essentially closing the nutrient loop in food production.

Abandoned sewage pit leaks into runoff rainwater.

Following Gongzhuo’s example, other medium-sized Chinese villages would benefit from the integration of household biogas toilets and wastewater treatment systems. Integrated systems produce greater returns on waste management by centralizing collection systems, thus decreasing the need for regular labor-intensive tank cleaning and reducing the risk of isolated leakages from abandoned cesspools (see picture above). Further analysis is required to better understand how water usage and quality are affected by the regulation and implementation of integrated systems linking water and sanitation.

  1. Good job.
    Indeed, China now is much better than in the past, but there is still a big difference in urban and rural, especially the sanitation, medical condition etc, so people in rural area need more help to improve their level of living standards. Though it is not easy to change in a short time as China has large population and many difficulties, people are making their effort to help rural area.

    The more places go, the more news you will find. Hoping for your next installment.

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