Advances in Biogas Technology - Biotechnology in China: Biofuels and Bioenergy - page 130

Fig. 2 Schematic diagram of the Deqingyuan biogas power project

if not properly handled, will degrade the ecological environment of farmland,
cause water and air pollution, spread diseases and bring a range of environmental
and health problems to the surrounding residents. On the other hand, these man-
ures have good biodegradability and have a high potential to be utilized as a low-
cost feedstock for biogas fermentation. With ever-intensifying environmental
pollution and energy shortages, bioenergy production from livestock manure is
becoming more and more attractive.
Farm biogas projects now mostly use livestock manure as the raw material.
Carbon material is broken down into combustible gas (methane) through microbial
metabolism under anaerobic conditions. Anaerobic fermentation of livestock
manure and sewage can not only obtain high-quality energy (biogas) but also clean
up the environment, thus realizing multi-level utilization of the biomass resources.
In this respect, China now possesses mature technology and the ancillary equip-
ment for large-scale biogas production, which is approaching the international
level. Regarding biogas project packaged technology, the whole design, including
pretreatment, anaerobic fermentation, biogas transport and distribution, fertilizer
production and post-treatment of fermentation liquor can be performed based on
the classification of pig manure, chicken manure, cattle manure and other raw
material; regarding the fermentation process, the mechanism of anaerobic fer-
mentation has been studied and highly efficient fermentation reactors, such as
UASB and EGSB, have been employed for manure treatment; regarding ancillary
equipment, China has successfully developed a series of devices, including biogas
combustion generators, industrial canning, automatic control devices, desulfur-
ization and dehydration equipment and solid-liquid separation equipment [ 32 ].
The major biogas projects for livestock waste treatment in China are summarized
in Table 4 .
The ecologically friendly park of Beijing Deqingyuan Agricultural Scientific
Co. Ltd. is the largest egg chicken-raising base in Asia. It raises 2.6 million egg
chickens each year, and produces 212 tons/d (TS 30%) of chicken manure. To treat
the manure, a large-scale thermoelectric biogas power plant was constructed. The
total installed electrical generation capacity of this project is 1 MW. In April 2009,
the Deqingyuan biogas power project started operation achieving net electricity