Wastewater treatment

As a result of environmental engineering research at the University of Queensland in Australia, generating clean energy and high-quality recycled water from two of the main sources of household waste is one step closer to reality.

Simon Tannock, a PhD student from the BioMass BioEnergy (BmBe) group in the School of Engineering, has designed a wastewater treatment plant to recover energy and non-potable water from food waste and wastewater.

A pilot plant integrating the environmentally sustainable wastewater treatment system pioneered by Tannock and fellow PhD student Beth Rounsefell is now in operation at the St Lucia campus of the university.

The plant provides a complete treatment system that digests household waste and wastewater under anaerobic conditions to produce methane and high-quality non-potable recycled water.

According to Tannock, the plant offers a more effective way of dealing with the serious waste and wastewater treatment issues facing Australians across the country.

'We are treating two major sources of domestic waste in a way that will reduce energy use and carbon emissions, while ensuring the maximum recovery of two valuable resources - energy and water,' he said.

'The recycled water generated by the plant is expected to be Class A+ standard, so it will be safe to use around the home for toilet flushing or in irrigation systems. The methane is a clean, renewable energy source.

'Importantly, the pilot plant has been designed to meet Brisbane City Council requirements for onsite water treatment at large building developments and rural areas and this research will confirm that we do meet those requirements,' added Tannock.

The technology incorporates an environmentally sustainable process known as biological nutrient removal.

Tannock said that in biological nutrient removal treatment systems, naturally occurring bacteria were encouraged to remove nutrients such as nitrogen and phosphorus.

'The food scraps that are fed into the system act as a source of carbon for the bacteria so that they can treat the wastewater and bring these nutrients down to an acceptable level,' he said. 'The rest of the carbon from the food scraps is biologically converted into methane, which can be captured and used to produce heat and electricity.'

Further research will determine if the system will be able to generate enough methane to operate off its own electricity supply.

The project is supported by an Australian Research Council linkage grant awarded to associate Prof Bill Clarke from the Faculty of Engineering, Architecture and Information Technology and Prof Jurg Keller from the Advanced Water Management Centre.

Companies interested in forming partnerships to commercialise the system are now being sought.