Drinking Water Quality: Turbidity
One way to measure drinking water quality is to examine the turbidity, or the relative clarity or the clearness of the water, through Nephelometric Turbidity Units (NTU). This measure indicates the presence of suspended solids like clay, silt, plankton, or other contaminants. Austin Water (AW) attempts to achieve the lowest NTU possible to ensure that potable drinking water is safe. Water turbidity is also an excellent measure of plant optimization to ensure maximum public health protection.
The finished drinking water turbidity is measured with a bench top turbidity meter at each water treatment plant every four hours, and continuously monitored by online turbidity meters. AW reports the readings to the Texas Commission on Environmental Quality (TCEQ) for every four-hour period the water treatment plant is treating water. Maximum possible readings of 186 are collected for each water treatment plant and appear on the Monthly Operating Report (MOR).
FY 2015-16 Results
The goal for this measure is 0.10 NTU. AW’s 0.08 NTU result was under the TCEQ level of 0.30 NTU by 0.22 and under the AW goal by 0.02. Lower NTU demonstrates that the quality of water produced has a higher fine-particle removal rate.
Assessment of Results
Austin’s drinking water NTU of 0.08 is well below the state standard level of 0.30 NTU. The NTU is below the permit level due to continuous improvements in plant chemical monitoring, filtering, and treatment processes that provide high-quality drinking water to customers.
The City of Austin draws water from the Colorado River into three water treatment plants: Davis, Ullrich, and Water Treatment Plant 4. Davis Water Treatment Plant was constructed in 1954 and Ullrich Water Treatment Plant was constructed in 1969. Water Treatment Plant 4 became operational in FY 2014-15 and draws water from Lake Travis, providing an additional capacity of 50 million gallons per day. Austin Water continues to operate and maintain the plants in a manner that ensures high-quality drinking water.
For more information contact Mehrdad Morabbi, Treatment Manager, at (512) 972- 0159.