The city of Lemoore attempted to make its drinking water safe by adding chlorine, however another problem was created – trihalomethane. A solution is in the works, but it will cost water users an additional $31.80 per month for the next 30 years.
The U.S. Environmental Protection Agency says trihalomethane (TTHM) causes cancer in lab animals. The city added chlorine in attempt to meet state health standards and deal with naturally occurring chemicals in the city’s water supply.
Quad Knopf engineer Rick Joyner said the best way to deal with unsafe trihalomethane levels is a process that uses chlorination with filtration.
“Basically you put some chemicals in the water, run it through the filter, the chemicals grab a hold of your arsenic and organics and it settles out in the filters. Then you back wash and dispose of the filters,” Joyner said in a report to the Lemoore City Council on Tuesday.
The city is facing an Oct. 1, 2017, deadline with the State Water Board to lower the high TTHM levels. By building the treatment facility, the city would address the TTHM violation and remove the water’s color, taste and odor and reduce arsenic levels.
“Coagulation filtration basically takes care of everything,” Joyner said. “The only issue is maybe the organic color. Some additional tests will have to be done to see if it meets that.”
Water testing will continue, but the engineer says the method is preferred since the other two options studied won’t treat the arsenic, chemicals or iron color in the water.
The federal government changed how it measures TTHM and now the city is in violation of federal standards. Failure to comply with the new standards will result in fines or penalties.
Lemoore Public Works Director Nathan Olson said the city is already attempting to deal with other water issues.
“Our water is pretty unique in the fact we’ve got arsenic in the north wells, we’ve got ammonia in town and right now we’re averaging (the chemical amounts) with blending. We have feeder lines and it’s a manual process, so we pull water from different wells.”
To lower contamination levels, the city would build treatment facilities with a state loan and repay it over 30 years.
The additional cost for each of Lemoore’s 6,662 residential water customers to build coagulation filtration facilities is estimated at $5.50 per month, plus the ongoing operation and maintenance costs of $26.30 per month.
Those figures however do not include longer-range infrastructure goals from a Community Investment Program.
Councilman Ray Madrigal wanted to know how firm those numbers are and how such a facility allows for future growth in the city.
“How confident are we about the different cost breakdowns for the different treatment options?” Madrigal said.
Joyner said that the amounts were calculated for worst-case scenarios and that the recommended plan is expandable.
“We’re at the high side of the numbers. As far as future growth, it’s expandable if we have to treat more water,” Joyner said. “We’re recommending coagulation filtration because it‘s the most expandable and the easiest to run. You can install another filter.”
Joyner said a final report will be filed with the State Water Board once environmental reports and final facility specifications are included.
“Once we get the initial draft back and comments, our next stage is to get the city to adopt it and the state,” he said.