DISTRICT GETS EXCELLENT INITIAL TEST RESULTS USING NEW CARBON FILTRATION SYSTEM
John McPherson, General Manager
October 4, 2020
As previously reported in the Cedar Key News, the Cedar Key Water and Sewer District has installed four large granulated activated carbon (GAC) filtration vessels for the purpose of reducing disinfectant byproducts in the drinking water. The District has shared the problem of reducing these byproducts with many other utilities, and has tested many possible solutions over the years. The installation of an ion exchange treatment process back in 2006 brought the DBP levels down below the maximums for most of the time, but there have been occasions when the levels have exceeded the maximums, probably due to the variability of the water the District draws from its well field. Such exceedances are not an immediate health risk, but the State requires utilities to move towards reducing the levels over the long term.
The purpose of this update is to report on the initial test results after use of the new GAC filtration system. The disinfectant byproduct that the District has sometimes had high levels of goes by the abbreviation TTHM. The state’s regulatory maximum for TTHM in the system is 80 parts per billion (ppb). The TTHM results for the two testing sites after use of the GAC filtration are 8.84 ppb and 13.81 ppb. These are very low levels that the District has never achieved in the past, and they strongly indicate that the GAC filtration system is working as promised to reduce DBPs. Additional testing will be taking place on a monthly basis, and results will be reported as they come in.