From well to tap, tour shows how drinking water is treated

Inside one of the three buildings at the Suffolk County Water Authority’s pump station in East Northport, production control supervisor John Flynn opened up a spigot at the base of a filtration tank. As the water spilled out, Flynn noted its clarity.

“It looks clear,” said Flynn, 46, of the water, which had been pumped from a nearby well and was just beginning the treatment process. “You can’t see the contaminants.”

There are three wells at this station that tap into the aquifer system at depths ranging from 453 to 608 feet. Depending on which one the water is extracted from, it could contain nitrates, perchlorate, and various organic compounds including fertilizers and pesticides, Flynn said. Since these contaminants are not visible to the naked eye, Flynn said SCWA’s lab tests the water regularly, weekly at this station, to make sure the filters are working properly.

Each year, SCWA pumps approximately 70 billion gallons of water to about 1.2 million people from its 234 pump stations, which contain a total of 581 wells, according to spokesman Tim Motz.

The East Northport station is unique, because it’s one of two stations in SCWA’s system equipped with a nitrate removal filter, but the only one currently in use. The other, located in Southold, is not needed at this time, he said.

“Depending on what part of the Island, you’re going to have different water quality,” Flynn said.

This station, located at the end of Meadow Lark Drive, pumps 1 to 2 million gallons per day in the summertime and 100,000 to 500,000 in the winter. The process begins when water is pumped from one of the wells. If it contains perchlorate or organic compounds it will be directed via underground pipes to a nearby building that houses two pairs of large tanks. Each one contains either a perchlorate or granular activated carbon filter.

“The GAC filter acts like a big Brita filter,” Flynn said.

If the water contains nitrates, as is the case for Well No. 1, it will go to another building located a few paces away. Here, a rotating turntable of filters constantly removes the nitrates.

“We never have to shut it down for rinsing or backwashing,” Flynn said. “It continually rotates.”

From there, it will go to the chemical treatment building, where it will treated with lime if the pH needs to be corrected.

Lastly, all the water, regardless of what well it came from, will be treated with chlorine to address bacteria issues before it’s sent out to the distribution system and into customers’ homes, he explained.

The whole process can take about 40 minutes, less if the water contains fewer contaminants.

All the while, monitors keep tabs of the water quality. If, for instance, the nitrate level hits a 9, the system will automatically shut down and trigger an alarm. The station also has a backup generator, which was used during superstorm Sandy, to keep the system running during power outages.

Like all water authorities, SCWA has to meet New York State drinking water standards, but Flynn said they also want to deliver the best possible product.

He said customers might be surprised by how much filtration actually takes place, but added, “I think they would be happy to see we’re going the extra steps to ensure their water is safe to drink.”