Biogas? China size it

During the current 10th Five Year Plan, China is developing 2,200 power grid biogas engineering projects for wastes from intensive animal husbandry and poultry, treating more than 60 million tonnes of manure a year, that’s in addition to the 137,000 installed digesters to treat sewage.

According to The Chinese Academy of Sciences and Geography, the total annual production of manure and night soil could theoretically generate about 130 billion m3 of methane, equivalent to 93 million tonnes of coal; and 80 per cent of industrial wastewater can also be used to produce methane. The number of large scale grid power plants are planned to increase to 30,000 by 2030, a 15-fold increase.

As the idea of cleaning up the environment starts to take traction in China, dealing with sludge from urban and industrial wastewater treatment that has traditionally been dumped into landfills, oceans and waterways is taking centre stage with a catchy campaign “Recycle Waste into a Resource”. The Chinese central government is showing great interest in medium and large scale biogas plants and integrated agricultural and agro industrial biomass with waste handling plants to reduce water pollution.

To facilitate the usage of biogas the government set up biogas technical training courses in Shanxi Province and in 2005 trained 6,000 farmers, 4,000 of which gained National Biogas Professional Technician Certificate. The Ministry of Agriculture which administers The Chengdu Biogas Scientific Research Institute (BIOMA) also operates an international training and research center in Chengdu, Sichuan Province.

Farmers from Yunnan Province that graduated from the course are experimenting with a "four-in-one" biogas plant that incorporates a pigpen and a household latrine to provide feedstock, then uses methane to heat a greenhouse for growing vegetables and raises carbon dioxide within the greenhouse to boost plant yield.

Biogas feedstock programs throughout China are just beginning to utilise industry waste from other sources such as alcohol manufacturers and paper mills. Tianguan Alcohol Factory, which consumes two million tonnes of shop worn grains a year to produce denatured alcohol, is now recycling the dregs of the distillery to produce biogas in a 30,000 m3 digester, supplying more than 20,000 households or 20 per cent of Nanyang city’s population.

Hongzhi Alcohol Corporation located in Mianzhu, Sichuan Province which is the largest alcohol factory in south-western China, uses its industrial organic wastewater, sewage and dregs to produce biogas. The city of Mianzhu treats 98 per cent of municipal sewage including wastewater from hospitals through digesters with a total capacity of 10,000 m3.

Recently, Chenming Paper Co. which generates 300 tons of sludge a day is adding its own start up biogas program using pulp wastes. The same goes for intensive animal husbandry on many large or medium size livestock and poultry farms in the suburbs of cities.

China’s power generation is starting to morph into local energy generation for local residents from local industry using local feedstock, which is a model we should get used to in a world of high energy prices: Local production, Local consumption.

As our globalised “distant point of manufacture”, “long delivery chain” lifestyle changes year upon year with declining crude oil availability, we, as a world, will need to find crude oil substitutes to supply base chemicals for industrial and manufacture processes. Using biogas directly for cooking or co-generation of electricity and heat is especially feasible when the biogas is used at or near the site of generation.

Biogas methane can also be used to make methanol, an organic solvent and an important chemical for producing formaldehyde, chloromethane, organic glass, and compound fibre. Good quality fertiliser and the electricity generated are additional bonuses.

Finally, biogas can be used to prolong storage of fruit and grain. An atmosphere of methane and carbon dioxide inhibits metabolism, thereby reducing the formation of ethylene in fruits and grains prolonging storage time and the same atmosphere kills harmful insects, mould, and bacteria that cause diseases.

My minds eye sees a future where food storage will be in local communities, The just-in-time delivery system will encounter problems as fuel becomes more expensive and disposable income is reduced. I envision a return to a bulk delivery system of dry goods, which will be weekly or bi weekly, and local communities will store their own grain and bulk food utilising biogas to keep pests and rodents out of the food supply.

The small shipments we are used to today will need to be restructured into a bulk delivery system. Foods from supermarkets packed in small individual boxes, bags or wrapped in plastic will have present problems for manufacture and delivery.

This will give biogas an edge by offering solutions to two probable side effects of continuing rising oil prices: food storage and fertiliser.