Both surface and groundwater sources are limited in the West Salem area. However, a local well driller was able to find a limited aquifer immediately north of the West Salem, which could produce up to 200 gallons per minute from two wells. The quality of this new source water was less than desirable, having concentrations of iron (1.23 mg/L), manganese (0.07 mg/L), sulfate (385 mg/L) and total dissolved solids (980 mg/L); far in excess of the Ohio Environmental Protection Agency Secondary Contaminant Recommended Maximum Levels. Furthermore, the hardness of 841 mg/L was much higher than the aesthetically pleasing and desirable range of 80 to 100 mg/L. The sulfate and total dissolved solids of the raw water could not be removed with conventional treatment methods so the decision was made to investigate membrane treatment as an option. Since this technology was not prevalent in Ohio, a pilot study was required by Ohio EPA to prove the treatment capabilities. A successful pilot study was performed by Tonka Water, a U.S. Water Brand in the summer of 2006.
The treatment system provided by Tonka Water consists of two stages. The first stage is iron and manganese oxidation by potassium permanganate followed by greensand filtration (two 8’ diameter VertaCell™ pressure filters). The second stage consists of two Flux RO/NF™ membrane skids for the reduction of dissolved solids, including sulfate and hardness reduction. Final treatment includes fluoridation by sodium fluoride addition, disinfection by sodium hypochlorite addition and stabilization by caustic soda addition. The capacity of the treatment plant is suitable for expansion by the installation of one additional pressure filter and one additional membrane filtration skid.
The treatment process has been highly effective in delivering quality water as indicated below.
|Iron (Fe)||1.5 mg/L||0.3 mg/L|
|Manganese (Mn)||0.07 mg/L||0.05 mg/L|
|Hardness (CaCO3)||841 mg/L||Blended to 90 mg/L|