Water quality concerns lead to facility tour

Amid growing concern about the water quality in Uniondale and surrounding areas, local residents had the opportunity to tour the Town of Hempstead water treatment facility in Uniondale to learn more about the water purification process.

In an outing organized by the Uniondale Empowerment Resource Center, four residents spent last Friday afternoon being shown around the plant by John Markwalter, a town water quality control specialist. There are fears among community members of elevated levels of so-called “forever chemicals,” including 1,4-dioxane, in the water supply in the Uniondale and Hempstead area.

Dioxane has been found to be a potential carcinogen, and although the town Water Department has deemed that the concentration in the water in Uniondale and other areas “does not pose a significant health risk,” reports of its presence have sparked worry.

Gregory and Deborah Crayton have lived in Uniondale for most of their lives, and they have children and grandchildren living there as well. They took the tour to learn more about water purification and, they hoped, to ease their concerns.

“We have grandchildren here, (and) we want to make sure it’s better for them,” Deborah Crayton said.

“We’d like to make sure that, for our town’s sake, for our people’s sake, the water is safe,” her husband added. 

According to the state’s water quality standards for drinking water, no more than 1 part per billion of dioxane is permissible. The Town of Hempstead has been working on getting the necessary supplies for the water treatment plant to enhance the removal of dioxane from the water to comply with the state standard, Markwalter explained, but due to supply chain issues, the process has been delayed until now.

In the meantime, the water undergoes a rigorous purification process, and Markwalter showed the residents what that looks like.

The water comes from 500-foot-deep underground wells — six in Uniondale and a total of 29 throughout Nassau County. The shafts of motorized machines extend down into the wells, and propellers draw the groundwater upward, to be pumped into the purification system.

“A typical well that we have usually pumps around 1,200 gallons every minute,” Markwalter said.

The water initially passes through vats of granular activated carbon, which has long been used for water purification, because it absorbs many of the organic compounds present in groundwater. The water ends up in a tall metal cylinder, called an air stripper, that removes “volatile organic compounds” — chemicals found in household items, including pesticides, disinfectants and air fresheners, that enter the water supply by seeping into the ground. Air fills the tank and pushes contaminants to the top, while the clean water flows out the bottom and then into ultraviolet, or UV, reactors.

Next, an advanced oxidation process breaks down still more chemicals in the water, including dioxane, destabilizing their components and breaking them apart. The water is returned to the granular activated carbon to flush out the chemical remnants, and then Markwalter and his team of employees add a small amount of chlorine to the water.

“The water is naturally acidic, and so we want to raise that up so it doesn’t corrode the pipes and pull copper and lead into the water,” he explained.

The process complete, the water is pumped throughout the system and ends up in people’s homes.

Markwalter emphasized to the visitors that the town conducts water-quality checks throughout the purification process — from the wells to people’s taps at home — to ensure that chemicals are being eliminated and that nothing else is getting into the water supply.

“We do 100 bacteria tests in the distribution system every month,” he said. “We do tens of thousands of water quality tests every year.”

To learn more about the town’s water purification process and to stay up to date on developments, go to HempsteadNY.gov.