The Worth of Waste

20 February 2009

Scientists at the Crown Research Institute, Scion in Rotorua have come up with unique cost saving method of treating sludge from sewage treatment plants. And the first organisation to pick up the new technology is the Rotorua District Council who have contracted Scion to apply the technology to the sludge produced at the local wastewater treatment plant.

The disposal of sludge is a major and costly problem for most local authorities and it is commonly dumped in local landfills. But the technology being developed by Scion will see the sludge converted into a number of valuable by-products.

Daniel Gapes and Alison Slade from Scion who are leading the project say that one of the products that can be produced from the sludge is acetic acid. They say acetic acid produced from the sludge can be used to replace ethanol which is currently used in the treatment process.

They say that this process alone could save the Council $650,000 per year with $450,000 saved by not having to take the sludge to the landfill and the remainder saved by not having to purchase ethanol.

Scion staff plan to do further laboratory work and will then build a pilot plant to carefully test the process and to make sure that the acetic acid works on a larger scale as a replacement for the ethanol. Once all the testing is done, work will commence on the full scale plant.

Daniel Gapes and Alison Slade say it great to have such an excellent partner as the Rotorua District Council. They say it is the perfect situation for scientists to have the testing facilities so close to their laboratories. They are also delighted that they can do something for the local community.

If the project proves to be as successful as the initial research shows, then it is likely that the technology could be used nationally and internationally.