Keeping summertime water tasting crystal clear
As summer brings warmer weather, for TasWater, it also brings warmer water. Combined with increased sunlight and nutrients in the water, it can result in the growth of algae in streams and rivers which supply water for drinking. These algae sometimes cause taste and odour in the water.
TasWater’s Luc Richard, Leader of Water System Performance, says the water develops an earthy taste and odour.
“People tend to say the water tastes or smells mouldy, muddy or musty.”
The reason we get these bad tastes and smells is that sometimes algae produce harmless compounds called Geosmin and Methyl-Isoborneol (MIB).
The Australian Drinking Water Guidelines (ADWG) indicate that most people will notice these compounds when they reach around 10 nanograms per litre in the water.
And that varies very much between individuals.
“In terms of who can and who can’t taste it, I’m not sure exactly why but it’s been shown that some people just don’t pick it up and other people are way more sensitive to it than what the ADWG say.”
TasWater has a panel who taste tests the water weekly, and if there is any earthy/musty taste, we increase treatment through the addition of activated carbon.
“In simple terms, it involves putting the water in contact with activated carbon. The taste and odour compounds will stick to the carbon allowing untainted water to flow to customers.”
As taste and odour is a developing issue in Tasmania, TasWater has been busy retrofitting carbon dosing facilities at many of our water treatment plants. It can slow the overall process and, in some cases, reduce the daily output of the plant, therefore is a contributing factor to the current need for water restrictions.
Luc says that the risk of taste and odour is considered in the design of all new water treatment facilities and is also part of any upgrades at existing water treatment plants.
“Any treatment plant where there is a risk of taste and odour issues in the catchment has carbon dosing integrated into the process, and where that risk is not currently evident, allowance is made in the design to include it at a future date, Luc said.”
TasWater also has mobile carbon dosing stations to address taste and odour in the water at our smaller treatment plant locations where an occurrence of taste issues is unlikely.
Bryn Estyn Water Treatment Plant operator Jason Hall monitoring machinery installed as part of the treatment process to manage taste and odour of the water.