Selbyville officials are hoping that 2010 will bring an end to the town’s water woes. The town has been working to address high levels of a disinfection byproduct (DBP) called total trihalomethanes (TTHM) that has been found in its water. The disinfectants, used in the treatment of drinking water, can sometimes react with naturally occurring organic and inorganic matter present in the water, causing the byproducts, and the town has been flushing the system and is looking into other treatments in an attempt to reduce them.
DBPs are often associated with a small amount of water usage in comparison to the large amounts of water that needs to be available for adequate fire protection. The town’s geography, paired with the sparse population, means some of the water system is being used less often, causing the DBPs to form over time.
While 10-inch pipes used to provide town water may appear to be more than needed just to provide household water in some areas of the town, fire code regulates the pipes’ size, and the water that can sit in the pipes, unused, can become contaminated with DBPs.
The United States Environmental Protection Agency (EPA) sets drinking water standards and requires the disinfection of drinking water. According to EPA, the maximum contaminant level of TTHM is limited to 80 parts per billion (ug/L) in treated water.
Selbyville water samples gathered by the Division of Public Health in late 2008 and March and June of 2009 show that, while people using the water do not face an immediate risk, the town’s water system violates the 80 ug/L standard.
In attempt to remove the DBPs from the town’s water, sample tests were taken at six locations, and the water system has been flushed in an effort to purge the unused water and replace it with fresh water from the town’s wells. Flushing will continue, as needed, until the average contaminant levels are brought down to EPA’s standards.
The highest levels seen in the testing came from samples taken near the wastewater treatment plant, the Pepper Ridge Water Tower and the terminal point on Hudson Road, near the town’s Route 54 border. These locations are near the town’s extremities, as noted by Town Manager Bob Dickerson – in its least populated areas.
The lowest (i.e. safest) readings came from a sample taken from the Georgia House in downtown Selbyville. TTHM levels there were almost nonexistent, coming in around 2 to 4 parts per billion, well under the alloted 80 ug/L.
While flushing has brought DBP readings down, the town will continue administering the flushes to bring down the average reading.
Those who use the town’s water should not worry about their health because of the byproducts, officials said. According to town engineer Erik Retzlaff, those EPA standards are set at stringent levels, and studies show that a person would have to drink 2 liters of water measuring above the maximum acceptable contamination level, per day, for an entire lifetime, to have a 1-in-1-million chance of seeing resulting heath effects.
In addition to flushing the town’s water system, the Selbyville Town Council approved at their Jan. 4 council meeting the submission of applications to the state Office of Drinking Water for two General Water Facility Plan grants.
The first application would assist in the funding the cost of a hydraulic water model, or a blueprint of the town’s water system.
“This would help the town map out the entire water system, rather than looking at four or five different maps,” said Dickerson of the model. “We could use the model to see the areas that need to be flushed, repaired or updated.”
The second grant would assist in funding the treatment options available to reduce the DBPs in the drinking water and evaluate feasibility of expanding the existing treatment facility to accommodate additional equipment and exercise cost-effective measures.
“There may be options we have for lowering the organic carbons that are reacting with the chlorine and the disinfectants,” said Dickerson. “It gets too expensive to reduce the iron in the water or raise the pH level, so, for now, we’re flushing it out. This second grant looks at our other options.”