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HomeMy WebLinkAboutAgenda - 02-10-1998 - Attachment 3g~e%-~~,~}-- 3C o~«y~ ~ a~ Dr. Rosemary L. Summers, Dr.P.H., MPH, Interim Director ENVIRONMENTAL HEALTH DIVISION P.O. Banc 8181 -306-C Revere Road Hillsborough, NC 27278 FAX #I 9158443006 Iillsborough 919-732-8181 x2360 ~~ 919-%8.4301 x2360 REPORT DATE: February 3, 1998 TO: Margaret Brown, Chair, Orange County BOCC FROM: Ron Holdway ~~ COPIES: John Link Rosemary Summers Paul Thames RE: Well Water Treatment Systems ~Y ~~ Jim BroMm, RS Perry Bums, RS Ater Clapp, RS, LSS Greg Grimes, RS David Hedrt, RS Ron Hedrick, RS Ron Holdwsy, RS Jan Jackson, RS Tan Konsler, RS Barbara Patterson Wendy Thigpen, RS Mebane I)urbam 910.22?-2031 x2360 919.688-7333 x2360 As a follow-up to the report on wells and groundwater contamination in the landfill area, you asked for information on well water treatment systems and their associated costs. Please note that all cost estimates are based on conversations with commercial installers and are based on "typical" jobs estimates. Most contaminants, whether they are posing a health risk or just causing aesthetic or nuisance problems, can be treated to the point where the water is acceptable and safe for human consumption. Generally, these systems are installed by private sector professionals, but can also be purchased for self installation. Long term maintenance is also a continuous consideration in these systems, both in time and costs. Groundwater contamination can come in~many forms such as microbial, inorganic chemical, organic chemical, and, sometimes, even radiological. When a private well water supply is sampled and an assessment showing contamination is given to the owner, the first consideration given by staff in the situation is whether the well itself can be repaired effectively. If the repair is not practical or is risky, we then look at treatment alternatives to counter the symptoms of the contamination based on the type and levels of the contaminants. Some well water cannot be treated effectively or the cost of treatment is too prohibitive because multiple treatment systems aze indicated. Bacteriological contamination is by far the most common problem we see in wells in Orange County, but, generally, it is the easiest and most economical to treat. Many wells that are contaminated with bacteria are so because of surface water infiltration around the well or into the aquifer somewhere near the well. In these situations, a repair using a liner or sleeve alone will often cure the problem. The cost of a liner alone is typically $1000-1500. Margaret Brown Report, 2-3-98 page 2 If the liner is not an option or is not effective, then some sort ofpre-distribution, continuous disinfection unit can be installed. Continuous chlorinators orultra-violet light units are the systems used in most cases and the costs are $500-$750 for a chlorinator and $100-$1500 for an ultraviolet light. While the UV light may be more expensive, it can have the advantage of alarming the user when it is not functioning properly and also does not add any residual chemical to the water as is case for the chlorinator". These units can also combat the presence of persistent sulfur bacteria or iron bacteria, which may not cause sickness, but might make drinking the water or its use for normal household functions intolerable. The problem causing, inorganic characteristics commonly found in Orange County are low pH, hardness, 'von and suspended solids. In most all cases, these are only nuisance contaminants and do not represent an immediate, short-term or lon$-term risk if consumed. They can be treated either singularly or, if necessary, collectively by a myriad of systems. The systems can be as simple as an in-line sediment filter to a combination of units tailored for a specific situation. Costs vary and, depending on the level and complexity of treatmen, may run from tens of dollars to thousands. Organic and radiological contamination are sometimes treatable and the type of treatment and cost is highly variable depending on the situation. Many times, a point of use, activated charcoal filter is a simple and inexpensive fix to make the water drinkable. This was the remedy recommended by State toxicologists for the Kirschner well in the landfill area. In other situations where the contamination is more severe or complex, though, the water supply must be abandoned and a new source of water sought. This scenario is usually found when underground storage tanks leak into the groundwater and gasoline or some of its breakdown products show up in surrounding wells.. I hope this helps in the Board's understanding of treatment systems. In an effort to enhance this understanding, I am trying to line up at a UV light and possibly a water softener for display at the 2-10- 98 meeting. Please advise if this is unnecessary or unwanted or if you have any further questions or comments on this matter.