16 April 2012:
Australian science is helping to solve one of China’s
biggest and smelliest problems – what to do with the waste
produced by its 700 million pigs.
Working with Chinese scientists and technology firm HLM Asia
Ltd, Australia’s CRC for Contamination Assessment and
Remediation of the Environment (CRC CARE) has helped develop novel
digester technology to help deal with the estimated 1.4 million
tonnes of manure and 7mt of urine produced by the burgeoning
Chinese pork industry annually.
CRC CARE managing director Professor Ravi Naidu said the new
technology can produce clean energy (biogas), fertiliser and other
valuable products from nutrient-rich waste, in a system with great
potential for application in other industries worldwide.
China has 700 million pigs in 1.8 million farms, which supply two
thirds of the country’s rapidly-growing meat consumption.
“However these piggeries also produce enormous volumes of
waste, only a tenth of which is currently being treated,” he
explains.
Despite tighter regulations, large amounts of nitrogen, phosphorous
and contaminants are being discharged into the environment where
they damage ecosystems and pose a threat to human health. The
nutrients lost in the waste of one pig alone are worth about $50 a
year, but there is no technology in place yet to recover and use
this vital resource.”
Prof Naidu says the joint project has developed a two-step
underground anaerobic bioreactor for treating piggery waste, and
established the settings for load and digestion time. It has
identified a particular combination of anaerobic treatments that
can recover the nutrients and produce clean biogas energy as
well.
“The technology has been demonstrated in the field and is now
being scaled up to treat large volumes of wastes from a number of
piggery farms,” he says.
The technology is expected to have widespread application not only
in China but throughout Asia, wherever animals are farmed
intensively, and to create fresh export opportunities for
Australian technology solutions to similar contamination
problems.
In this project the CRC is providing scientific expertise,
including supervision of six PhD students at Huazhong University of
Science and Technology in Wuhan Province with links to research
skills at the University of South Australia.
The project is being managed by HLM Ltd on the ground, taking
advantage of the relatively low cost of technology trials and
scale-up work in China. “It’s a perfect partnership
between Australian science and Chinese technical expertise,”
he says.
Prof Naidu explains that the main scientific and technical
challenges solved by this project are the high N and P loads in pig
waste compared with domestic sewage, the current small size of
biogas reactors, their slow rate of digestion, the limiting
influence of temperature, and the presence of heavy metal
contaminants which restrict the use of residues as
fertiliser.
So far, the technology has been able to overcome each of these,
and is now moving to full-scale trials.
“The market for a successfully packaged solution to this
suite of problems is clearly very large – both in Asia and
around the world. Besides handling livestock wastes, similar
bioreactor technology can be used to manage and cleanse the runoff
from urban landfills and organic waste streams from other
industries,” Prof Naidu says.
“We anticipate that the scientific and technical knowledge
gained in the course of CRC CARE’s research will have real
value for Australia’s intensive livestock and food industries
– and will help protect our environment from these types of
wastes.
“At the same time we are producing a new source of clean
energy for industry or domestic use, and a vital supply of
nutrients to help secure the future of food production."
More information:
Prof. Ravi Naidu, Managing Director, CRC CARE, 08 8302 5041 or 0407
720 257
Peter Martin, Acting Communications Manager, CRC CARE, +61 (0)417
776 494
