This guest article has been prepared and submitted by Don Francisco. We want to express our appreciation to Don for this very nice community contribution. Residents can find his contact information listed in the 2016 Fearrington Village Directory and Handbook.
I am a retired clinical professor of environmental biology from the UNC Department of Environmental Sciences and Engineering. My specialty was limnology (study of freshwater systems), wastewater treatment microbiology, and drinking water treatment. I was the first to study Jordan Lake beginning just after the dam was closed in 1982. I began my career researching taste and odor problems in drinking water reservoirs. We lived in Chapel Hill for 48 years, and we are now residents of Galloway Ridge.
Some residents have told me that they are very concerned about the quality of our drinking water. Some are even regularly boiling their drinking water. I think this concern is overblown.
Our raw (untreated) water comes from Jordan Lake just to the north of US 64 on the east side of the highway bridge. It is transported from there to the treatment plant on the south side of US64. The Town of Cary also takes its raw water from this same intake.
The North Chatham Water Treatment Plant is a standard design treatment facility that provides suspended solids (turbidity) removal, pH control, and chlorination for disinfection. Occasionally, they use powdered activated carbon to control tastes and odors. I have visited the plant and talked with the operators. While the plant is small, it seems to be quite competently operated. They also have a close relationship with the personnel at the much larger Cary plant that treats the same raw water. I’m confident that they do a good job treating our drinking water.
There is no reason to be concerned about the quality of our water. It is basically the same as all other drinking water produced from reservoirs in North Carolina. The greatest hazard is that runoff containing nutrients (phosphorus and nitrogen) will promote excessive growth of algae in the Lake. Many of these produce compounds which cause objectionable tastes and odors. This is an aesthetic problem not a human health problem.
The most accepted means for limiting the growth of algae is to limit the amount of nutrients entering the Lake. The greatest current source of these is in runoff from agricultural and urban land uses. This is what the recently canceled “Jordan Lake Rules” were intended to accomplish. The best way to show concern for the quality of our drinking water is to advocate rational means for limiting the input of nutrients into the Lake.
Of course, treated wastewater is introduced upstream from the Lake. Most of the reservoirs in the US have treated wastewater discharged upstream. In our case, the wastewater treatment plants are some of the most advanced in the world. They remove contaminants to very low concentrations. When discharges enter the reservoir, they are diluted by a huge volume of water. This further decreases the concentration of the contaminants.
