Text by Zhong He
The use of methane is already popularized amongst a third of farming households, solar heat pumps are employed for tobacco toasting, and several industrial zones have been committed to developing recycling. To the untrained eye, Songxian County in Henan Province may appear as a typical Chinese rural area, but it has been working remarkably to build a successful model of low-carbon countryside.
In October 2010, the state-level impoverished county was designated as a pilot area for sustainable development, in honor of its firm adherence to the practice of a low-carbon lifestyle.
"Before we started using marsh gas, every year we used more than 2,000 kilograms of firewood for cooking alone," recalls Li Junhua, a villager of Quli in Songxian´s Fanpo Township. "Burning wood required longer cooking times and considerably more effort, as well as enduring dust and heavy smoke. Back then, every village household raised pigs, and sewage from the pig pens drained directly into our ditches or watercourses, which caused a horrible odor when it rained." Today, thanks to the construction of methane tanks, all of these problems are history. "Our kitchens, toilets, and yards are clean, and even mosquitoes and flies are rarities," adds Li.
According to Li´s calculation, for a family of five raising five pigs, a methane tank with a capacity of 8 cubic meters saves about 2,400 kilograms of firewood each year, the equivalent of 800 trees.
While enjoying a cleaner and more convenient life after the introduction of marsh gas, farmers use biogas as a fertilizer to replace chemicals and pesticides, improving agricultural quality and production. Currently, Quli Village is developing a fruit industry by taking advantage of methane.
According to Ren Pingmin, deputy director of Songxian County Agricultural Bureau, since 1995, the county has been using the "three connections" method, which enables the methane tank to be constructed beneath the pig pen and toilet, so that both human and animal waste goes straight into the biogas digester, which in turn produces biogas slurry, residue and gas after anaerobic fermentation. So far, of the county´s 120,000 farming households, more than 40,000 use methane tanks, each one capable of adding 1,500 yuan to their annual income.