Bacteria in drinking water key to keeping it clean

Scientists have found that bacteria in the drinking water may play a key role to keep it clean, a finding that can reduce the need for high dosage chemical treatments.
The study points way to more sophisticated and targeted methods of ensuring our drinking water remains safe to drink, while still reducing the need for chemical treatments and identifying potential hazards more quickly.
The research team, from the University of Sheffield, studied four bacteria found in the drinking water to see which combinations were more likely to produce a 'biofilm'.
Biofilms are layers of bacteria which form on the inner surfaces of water pipes.

"Biofilms can form on all water pipes and as these are usually non-harmful bacteria, they don't present a problem," said lead researcher, Professor Catherine Biggs.
"However, biofilms can also be a safe place for harmful bacteria such as Escherichia coli or Legionella to hide. If the bacterial growth is too heavy, it can break off into the water flow, which at best can make water discoloured or taste unpleasant and at worst can release more dangerous bacteria. Our research looks at what conditions enable biofilms to grow, so we can find ways to control the bacteria in our water supply more effectively," said Biggs.

The research isolated four bacteria from water taken from a domestic tap.

The researchers mixed the bacteria in different combinations and found that, in isolation, none of them produced a biofilm. However, when any of the bacteria were combined with one of the common forms, called Methylobacterium, they formed a biofilm within 72 hours.
"Our findings show that this bacterium is acting as a bridge, enabling other bacteria to attach to surfaces and produce a biofilm and it's likely that it's not the only one that plays this role," said Biggs.
"This means it should be possible to control or even prevent the creation of biofilms in the water supply by targeting these particular bacteria, potentially reducing the need for high dosage chemical treatments," he said.

Testing methods - as used in this research - involve DNA analysis to identify the specific types of bacteria present.
"The way we currently maintain clean water supplies is a little like using antibiotics without knowing what infection we're treating," said Biggs.
"Although it's effective, it requires extensive use of chemicals or can put water supplies out of use to consumers for a period of time. Current testing methods also take time to produce results, while the bacteria are cultured from the samples taken.
"The DNA testing we're developing will provide a fast and more sophisticated alternative, allowing water companies to fine tune their responses to the exact bacteria they find in the water system," said Biggs

The study was published in the journal Water Science and Technology.