When the Florin Resource Conservation District's (FRCD) Water Service set out to design the Water Treatment Plant, a primary objective was to find a single process that could remove all three of the source water contaminants that exceeded the soon-to-be new state and federal drinking water standards (iron, manganese, and arsenic). The media (filtration material) at the Hampton Village Plant is capable of iron (Fe) and manganese (Mn) removal, and the manufacturer claims it can also remove arsenic (As); however, we had never seen this to be true. Due to the pending federal arsenic standard (from 50 parts per billion [ppb] to 10 ppb), a flood of claims are being made by manufacturers that their product can remove arsenic. Regrettably, water chemistry is not so simple. All source water has its own unique characteristics that can either negatively or positively impact the treatment process. There is no panacea, universal remedy, to water treatment, and since the water treatment industry is not well regulated, we take a strong "buyer beware" posture.
A second objective was to avoid the proprietary filter media or material that is so common today (i.e. Hampton Village and most County of Sacramento plants, etc.). We didn't want the Elk Grove Water Service to be locked into a particular media and filter vessel, whereby additional media and filter components could only be obtained from one manufacturer, therefore, costing more money. We didn't want to be held at the whim of one manufacturer; therefore, the engineers we hired, the H20 Group, designed the filters and found an alternate media/ filtration material.
to assist them with finding the right process for removal of all three of Elk Grove's source water contaminants, if possible. They pilot tested four types of filter material that held some promise. Of the four, two adequately removed all three contaminants without excessive coagulant additives. After selecting the best media for us, the engineers required that the manufacturer apply for and obtain a National Sanitation Foundation 61 certification for use with potable water (a Federal Department of Health Services requirement). Then they followed up with a full-scale pilot test of the filter material at the Hampton Village treatment plant. Once the full-scale tests came back positive, they ordered media. It was a long process, but it ensured that the filtration media was the right fit for our water service. The media we are using in the Railroad Plant filters is a natural mineral that is mined here in the U.S. and was found to have adsorptive properties with an affinity for iron, manganese, and arsenic. This is just one interesting aspect of our new Water Treatment Plant.Director Sandi Russell, Florin Resource Conservation District