(PRESS RELEASE) – Water plants that use surface water (above ground) as their source are required by the EPA to use chlorine to meet disinfection standards. TTHM is a naturally occurring byproduct of this disinfection process.
All water systems that add chlorine test for TTHM, but surface water plants have the hardest time regulating these levels.
The EPA requires Delta to test for TTHM twice each quarter (three months) of the year, and report those test results at the end of each quarter.
The maximum level of TTHM in drinking water set by the EPA is 0.080 mg/L. Delta’s Fourth Quarter TTHM sample results were well below this amount (Sample 1 – 0.0618 mg/L & Sample 2 – 0.0561 mg/L). These results reflect the water quality for operating months August, September, & October 2023.
However, the EPA does not use just the most current sample results when determining if we are required to send TTHM notices out, instead they use the average of all results for the prior four quarters (12 months).
If this “Annual Running Average” is above the maximum amount we are still required to send the TTHM notice, even though our current levels are not in violation.
Delta’s Annual Running Average remained just over the maximum level set by the EPA due to higher sample results during the third quarter of 2023, months May, June, and July.
TTHM levels are historically higher in the summer months due to the higher organic load in the source water.
Over the last decade, we have been experiencing higher than normal temperatures during the winter months, and the lack of extended periods of freezing temperatures is steadily increasing the amount of organic matter in the reservoir.
What we are doing to address this issue: In August of 2023, we gained EPA approval to isolate the industrial corridor west of town and supply it with water from Fulton County.
This change has allowed the operators at the Delta Water Treatment Plant to lower the plant production setting and reduce the total operating hours.
Both changes provide higher quality finished water and ensure regular water turnover rates in the distribution system. We have also applied to the OEPA (Ohio Environmental Protection Agency) seeking their approval for a pre-treatment pilot (test).
Pre-treatment is projected to increase the effectiveness of organic removal by our filtration system and potentially lower the amount of chlorine needed to meet disinfection and maintain proper regulated residuals (TTHM) in the distribution system.
We are also reviewing the possibility of adding a secondary treatment process that would reduce the TTHM levels even further.
As always, if you have any questions, please contact Jammie Flores at 419-822-4143 or jflores@villageofdelta.org.