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Legislative Assembly for the ACT: 2002 Week 13 Hansard (19 November) . . Page.. 3756 ..

MRS DUNNE (continuing):

Around the world, pollution of the air and water from municipal and agricultural operations which are inappropriate continue to grow. Governments and industries are constantly on the lookout for techniques that will allow for more efficient cost-effective waste treatment.

One of the technologies that I would like to deal with today is anaerobic digestion, which has been successfully used to treat the organic fraction of wastes. Members who took an interest in the presentations to the Planning and Environment Committee's inquiry into renewable energy will note that this is a technology that has come a long way. When used in a fully engineered system, anaerobic digestion, or AD, not only provides pollution prevention but allows for sustainable energy, compost and nutrient recovery. Thus, anaerobic digestion can convert a disposal problem into a profit centre.

As technology continues to mature, anaerobic digestion is becoming a key method for both waste reduction and the recovery of renewable fuel and other valuable products. The technology is new but the fundamentals are quite ancient. We know that the Assyrians were using gas, known as biogas, in the 10th century BC to heat water. In 1808, Sir Humphry Davy determined that methane was present in gases produced from the anaerobic digestion of cow manure.

The first digestion plant was built at a leper colony in Bombay, India, in 1859. This process reached England in 1895 and biogas was recovered from "carefully designed" sewage treatment facilities and used to fuel street lamps in Exeter. The development of microbiology as a science was led by Buswell and others in the 1930s. It was particularly useful during the Second World War when there were high demands on energy. Anaerobic digestion facilities have been in operation in many parts of Europe for more than 20 years.

The great advantage of anaerobic digestion is that it can be used on a small scale or a large scale. Many farm-based digesters operate in Europe, where the key factor found in successful facilities is their design simplicity. In fact, more than 250 of these systems have been installed in Germany alone in the past five years.

Other factors influencing success have been local environmental regulations and other policies governing the use of land waste and waste disposal. Because of these environmental pressures, many nations have implemented or are considering methods to reduce the environmental impacts of waste disposal. Denmark has the greatest experience of using large-scale digestion facilities and currently has 18 centralised plants in operation. We can take a leaf out of the book of countries like Denmark.

Denmark's commitment to anaerobic digestion increased with an energy initiative aimed to increase biogas production in the years leading up to 2000 and to triple it by 2005. One of the key policy tools being used to encourage technology deployment is "green pricing"-that is, allowing manufacturers of biogas-generated electricity to sell their product at a premium. Interestingly, the sales of co-generated hot water to specially built district heating systems is becoming an important source of revenue for project developers.

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