Water Filtration Systems

The Water Supply Restoration Funding Program (Program) has a state-wide contracted plumber to install and maintain water filtration systems to private potable water wells at no cost to the property owners. The Program attempts to have these filtration system serviced based on on-going contamination. They are the property of the Department of Environmental Protection. There are three basic types of water filtration systems that are used - point of entry or granulated activated carbon, point of use or reverse osmosis or ion exchange filters.

Point of Entry (POE)/Granular Activated Carbon (GAC) Filters

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These are installed when there are potential health risks associated with ingestion (drinking), dermal contact (washing hands) or inhalation (breathing the fumes coming from the water). Examples of these substances include pesticides, petroleum compounds, and solvents.

Performance data for carbon filters indicates that these filters perform extremely well for the removal of volatile organic compounds found in groundwater. The configuration of each installation is determined by the removal efficiency for that particular contaminant and the expected flow demand.

Because carbon is so effective at removing EDB, the most common filter system used for this contaminant consists of a five micron pre-filter, a flow meter, a single 54-inch tall by 10-inch diameter GAC tank, and an ultra-violet light for disinfection. This system has a capacity of 6 gallons per minute (gpm) and is sufficient for the average home. The filter media for all systems installed for EDB is exchanged (routine maintenance) annually.

GAC filters are very successful in removing solvents or petroleum products but filtering out Vinyl Chloride (VC) or Methyl-Tert-Butyl-Ether (MTBE) is more of a challenge. Filters on wells with VC are exchanged every six months and filters on wells with MTBE continue to be sampled quarterly and exchanged after a "break-through" at the mid-point.

Point of Use (POU)/Reverse Osmosis (RO) Filters

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POU filters are installed when the potential health risks are associated with ingesting (drinking) the water. Generally, in-organic substances such as Nitrate, Arsenic or Lead). RO filters are usually installed under the kitchen sink and are exchanged annually.

Ion Exchange (IX) Filters

Where Nitrate standards are above the mcl at a Public Water System (PWS), a POE filter must be installed. For these systems, an Ion Exchange Filter, containing a nitrate removal resin, is installed which is similar in appearance to the carbon filters, although the process is quite different. The filter is regenerated with a brine solution to ensure the resin is performing satisfactorily.

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