DNA to reveal sources and help tackle bane of bad taste and smells in tap water

TECHNOLOGY UPDATE

DNA analysis of bacteria in reservoir water is being used by United Utilities and Cardiff University to improve understanding of the causes of taste and odour issues in drinking water.

The water company has teamed up with and the university’s School of Earth and Environmental Sciences and School of Biosciences in a two-year project. The study will seek to speed up and improve the detection of the exact sources of two naturally occurring organic chemicals that can cause a musty or earthy odour and taste in tapwater. According to United Utilities, the proposed approach could also help it and other water companies to save money – United Utilities said it spends some £2m a year dealing with taste and odour issues in its drinking water.

The offending chemicals – geosmin and 2-MIB – are produced by various cyanobacteria – commonly known as blue-green algae. Existing methods used to detect these microscopic organisms in water samples are labour-intensive. So the Cardiff University team is deploying techniques that detect the DNA of various species in the environment (eDNA) to give a detailed view of the types of natural bacteria in reservoir water and how this varies with the seasons. This provides better visibility of the exact sources of the chemicals much more quickly than conventional techniques. And, according to United Utilities, it gives water companies the information they need to address the causes of taste and odour issues in a quicker, more targeted way.

In the United Utilities and Cardiff University project, water samples will be taken from a reservoir every two weeks until December 2023. They will be tested and the results analysed to provide recommendations for further studies or changes to processes.