Decentralised wastewater system guide released for utilities

Australian water utilities considering installing decentralised water and wastewater systems now have a comprehensive resource to help decision making.

A new Water Research Australia report outlines current and emerging options, along with local case studies, to help utilities evaluate the costs, benefits and risks of decentralised supply solutions.

“The information was available and work had been done but it was locked away in reports that were not readily accessible,” said Victoria University Institute for Sustainability and Innovation Research Fellow and co-author Dr Peter Sanciolo.

“So we put all that information into one report to see what's been done already [so utilities do] not have to repeat it again if they want to trial something – they now have a document in place that can be used as a starting point for discussion.”

The Australian case studies featured in the report were taken from GWMWater, Coliban Water, TasWater, Water Corporation and Yarra Valley Water.

The review assesses and compares key variables including source water quality, available technology, operability, maintainability, cost, health risks for non-compliance, performance and reliability.

Sanciolo said the study found there were great opportunities for decentralised potable water provision now.

“The technology that's available now for decentralised treatment is really quite advanced and it's well proven that it can perform,” he said.

“The studies showed that you can achieve good quality water in decentralised systems but because of cost issues you can't have an individual unit for each property – you might have to go to a multi-house system for small towns.

“Also you've got to overcome some problems with stagnation of water…and you need some remote monitoring to make it less expensive.”

However, decentralised wastewater treatment continues to prove difficult and Sanciolo called for more work to be done in the area.

“In the wastewater area, the situation is not as favourable in that a lot of the technology has been scaled-down versions of larger centralised treatment processes and they don't cope very well with the kinds of changes in loads and flows that happen in decentralised systems,” he said.

“The best option is that which has been outlined by Sarah West – a septic system for the house connected in a cluster-type arrangement to a centralised place that can treat the waste further.”

Sanciolo stressed the importance of developing viable, environmentally sustainable methods for delivering decentralised systems.

“Putting up with cloudy, poor-quality water and resorting to drinking rainwater is really not acceptable in the 21st century,” he said.

“Sooner or later we're going to have to meet our obligations to provide safe drinking water to everyone and provide environmentally safe wastewater treatment for all places.”