Scientists turn waste into gold
Millions of tonnes of unwanted waste spewed out by Australia’s powerstations, mineral processing plants and municipalities can be re-usedto create fertility, health, wealth, beauty and abundance.
Professor Richard Haynes of CRC CARE and the University of Queenslandtold the CleanUp 09 conference in Adelaide on 29 September of strikingprogress in developing new uses for substances which have become a realheadache for society to dispose of.
“A major thrust of our work is to transform industrial and municipalwastes that nobody wants into an environmentally friendly opportunityto make viable and marketable products,” he says.
“For example Australia currently produces 13 million tonnes of flyashfrom coal-fired power generation and a similar quantity of ‘red mud’from bauxite processing, along with millions of tonnes of biosolidsfrom urban sewage treatment and green waste from parks, people’sgardens, food and factory effluent.
“By combining these resources in creative ways we can produce newproducts to boost fertility, overcome soil deficiencies, absorb toxiccontaminants and beautify our urban landscapes,” Prof. Haynes explains.“These include garden mulches, organic soil amendments, garden compost,potting media and specially manufactured soils.”
Research at CRC CARE has included co-composting green waste withinorganic substances such as coal fly ash and organic resources such asgrease trap waste, poultry manure and biosolids.
“Because urban green waste usually contains a lot of shredded wood andbark it doesn’t break down all that easily. However by adding readilydecomposable material, this raises the temperature and produces a muchbetter compost.
“By adding 20 per cent fly ash to green waste we can greatly increaseits water-holding capacity, producing a topsoil replacement that ishighly suitable for use in urban settings where people want to savewater.”
Prof. Haynes team have also investigated a wide range of inorganicwastes such as steel slag, blast furnace slag, coal fly and bottom ash,red mud, water treatment sludge as well as organic sources such as treebark, sugar mill mud, spent brewery yeast and prawn processing waste
“We have shown some of the more promising materials can be used toimmobilize heavy metals in a metal-contaminated soil. This means we canuse industrial wastes to prevent the toxic contamination caused byother forms of waste disposal.
“Both sugarcane and rice have a high requirement for silicon in thesoil to grow properly – and we have found that slags, red mud, fly ashcan all provide this important nutrient to crops at low cost.
“Likewise wastewater from dairy and meat processing plants can beused to supply nitrogen and phosphorus to farming soils if applied inthe correct amounts.
By such methods, Prof. Haynes says, some of society’s worst wasteproblems can be turned into assets, helping to provide food, fertilityand healthier landscapes while saving water and preventing pollution.
Posted on October 7th