Nitrogen from sewage sludge

From sewage sludge to electricity

Wednesday, 18 January 2006

A picture of the microbes that break down the sewage. The most important ones are yellow. (photo:Damien Batstone)

Sewage isn’t one of the most popular topics to talk about but studying sewage could be if you’re interested in reducing greenhouse gases.

With the support of local councils on the Sunshine Coast, the University of Queensland’s Advanced Wastewater Management Centre is currently researching the potential to produce electricity from sewage treatment waste.

Other Local Government councils around Australia have also undertaken similar projects to test the transfer of energy from waste to electricity.

The Biosolids Re-use and Energy Production Project Study will develop existing technology to enable a bioreactor to handle the supply of biosolids, capture methane and produce electricity.

Director of the Advanced Wastewater Management Centre, Professor Yurg Keller, says the technology is used worldwide but is constantly evolving.

“The method has been used for about 20 to 30 years in other areas but I think there’s a change now because of the demand on getting more and more nitrogen removal from the waste treatment process. This makes it more and more difficult to get the energy out at the same time”.

Professor Keller’s research will also determine whether a centralised treatment plant to convert sewage sludge is a cost effective option.

“Quite likely it will be… to combine all the waste sludges from the various council treatment plants, transport them to the one place and treat it in that place to gain the energy return and then dispose of the sludge as we currently do”.

An added bonus, Professor Keller says, is that there will be much less sludge to dispose of following the treatment process.

“We produce a lot of greenhouse gases because we use a lot of electricity in these waste water treatment plants… So, what can we do to reduce that greenhouse production?… The best way is to recover the energy that’s in the waste material that we’re actually discharging and that can offset the energy consumption and reduce greenhouse production”.

The project will be completed mid-year after which the local councils will decide on an option to best benefit the environment and the public.