This innovative method tests water quality in real time – no lab required

Posted 24 April 2017

Looking for a highly sensitive, on-the-spot method for testing water quality and microbial performance in your water network? A method developed by one Queensland utility might be the answer. 

Unitywater has been trialling an adenosine triphosphate (ATP) field kit to look for the markers of microbial activity in its drinking water network – without having to wait for lab results.

ATP is the energy source produced by living organisms, and its concentration provides an indication of microbial activity in the drinking water network, says Unitywater Water Quality Specialist Anna Wilson. 

“Previously we'd used more traditional methods like E. coli, total coliforms and heterotrophic plate counts, but they're all time-consuming methods because they take lab-based analysis and a number of days,” Wilson said. 

“We wanted to find something that gave us an instantaneous result and that we could do in the field.”

The test kit involves a handheld luminometer that measures light when ATP and the enzyme luciferase react. The result can be converted to an approximate microbial count. 

Unitywater has incorporated ATP testing into its monitoring program and used it for assessing water quality improvement projects. 

“For our mains cleaning projects, we've used ATP for microbiological analysis and it's been really sensitive,” Wilson says. 

“We've been able to see a reduction in the ATP and validate the water quality improvement projects in a way that we weren't able to do before from a micro perspective.”

However, Wilson said they found some limitations to this testing method that other utilities should be aware of if they want to trial it themselves. 

Unitywater planned to provide the kits to any crew member, but they discovered that the water quality testing kits need to be operated by a trained technician.

“It has to be carefully used at a constant temperature; it wasn't as robust as we were hoping it would be,” Wilson said.

The tests are also relatively costly, so they're better suited to verification monitoring and project work, rather than routine monitoring, she added.

“It costs almost $50 per test, so it's higher than your traditional HSC and total coliforms. However, it is more sensitive so you're getting a better resolution of what's going on in your water supply.

“When you're doing extensive water quality improvement projects, it's worthwhile.”

To learn more about innovative approaches to public health and safety issues like this, attend the upcoming Ozwater’17 conference in Sydney. To view the full program and register, click here.