The Trinity River Authority sent the following notice to the City of Colleyville regarding water taste and odor:
The Trinity River Authority of Texas Tarrant County Water Supply Project customers in the cities of Bedford, Colleyville, Euless, Grapevine and North Richland Hills may be detecting an earthy or musty taste in their tap water. Though this may be unpleasant, TRA assures its customers that their tap water is safe to drink.
The current taste and odor are being caused by the compound Geosmin (compound coming from algae) in TRA’s raw water supply, Lake Arlington. Geosmin does not affect the safety of the finished tap water and is not a public health threat. Preliminary results from samples taken Jan. 9 indicate that the Geosmin concentration in raw water from Lake Arlington has begun to decrease.
TREATMENT FOR TASTE AND ODOR
Currently, the primary treatment process for taste and odor at the Tarrant County Water Supply Project is ozonation. During events producing high concentrations of taste and odor from compounds such as Geosmin, the treatment is aided with the addition of hydrogen peroxide after primary disinfection is achieved.
PROJECTED RAW WATER CONDITIONS AND ITS EFFECTS ON TASTE AND ODOR
Lake Arlington’s water temperature plays a key role in favoring algae populations that produce Geosmin. From past observations, Geosmin concentrations are highest after the lake temperature is below 10ºC. Because of the recent warm, sunny days, there may be a retreat in populations of organisms producing Geosmin.
TRA will continue to make modifications to the ozone feed at TCWSP to improve the sedimentation basins performance. Improved sedimentation will aid the removal of a large portion of the Geosmin.
TRA recognizes that taste and odor concerns are elevated because even in low concentrations, the taste and odor produced by Geosmin is readily noticed. We are closely monitoring the raw and finished water and are applying all appropriate resources toward removing the taste and odor causing compounds.