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Legislative Assembly for the ACT: 2002 Week 13 Hansard (19 November) . . Page.. 3755 ..

MRS DUNNE (continuing):

and animal matter capable of being decomposed by micro-organisms and includes natural textiles, paper and wood, although recycling and reuse are the preferred management choices for paper and wood.

The rapid disposal of this waste is imperative for obvious public health reasons. In the summer especially, organic material rots and gives off unbearable odours after only a few days. If not managed properly, it is liable to attract vermin and release pathogens that contaminate water, air and food.

If composted, on the other hand, organic material produces a soil-like product, which is essential to plant and crop production. Compost improves soil fertility and water retention and returns nutrients to the soil, reduces erosion and lessens the need for pesticides. Diversion of organic waste for composting, therefore, has a major environmental as well as agricultural benefit.

Approximately one-third of municipal waste can be composted-that is, food scraps, green waste such as dead leaves and grass clippings, and tissue paper. Industrial, commercial and institutional establishments also generate compostable organic materials, especially in the form of food processing residuals and wood waste.

While putrescible materials are not toxic in and of themselves, they are the main source of pollution at disposal sites. When incinerated, for example, their high water content lowers the temperature for incineration to such an extent that the materials are not fully combusted and they contribute therefore to the formation of highly toxic chemical substances such as dioxins and furans.

In landfills, the anaerobic breakdown of organic matter produces odorous, explosive gases that can migrate through the ground and into nearby buildings, where they can accumulate, posing a threat to human health and vegetation. These gases also contribute to the greenhouse effect.

In addition, the decomposition of organic material leads to acidification, which facilitates the mobilisation of other pollutants, such as heavy metals, and releases organic compounds which migrate with leachates discharged by landfills and can pollute the ground water and surface water, making them unfit for human consumption and even harmful to aquatic organisms.

Therefore, Mr Speaker, dealing with putrescible waste in a safe fashion is an important issue and it needs to be addressed in the no waste by 2010 strategy. Safe landfilling of putrescible waste requires sophisticated and, as Ms Dundas has pointed out, costly leachate collection/treatment and gas recovery systems. I think this is a path we need to follow if we are to take a truly responsible approach to putrescible waste.

When performed properly, composting poses no threat to human or environment health-at least none that is uncontrollable. Adequate leachate and odour control are required to prevent adverse effects on the environment and especially on the quality of life of those living nearby. Its water-absorbing capacity makes compost a valuable soil amendment as well as an excellent replacement for soil as a cover for material landfills. Water evaporation during the composting period reduces waste volume by 30 per cent.

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