When experienced water treatment professional Mark St. Hilaire first received the lab results for a point–of–entry (POE) system at an indoor athletic facility in New Hampshire, he thought there was a mistake: The iron was at 270 parts per million (ppm).
"We said, ‘It can’t be,’" says St. Hilaire, director of the residential systems group for Waltham, MA–headquartered Atlas Watersystems, Inc. So he sent out another sample, and the results were pretty much the same. That lab report on the facility’s private well water revealed:
- Iron at 209 ppm
- pH of 5.5
- Hardness of 354 ppm, about 21 grains per gallon (gpg)
- Sediment — positive
- Conductivity of 1,570 microsiemens.
In addition, the naturally occurring iron had caused the water to have "tremendous color" in an orangey tint, and an awful taste.
"It was exciting and frightening at the same time," recounts St. Hilaire. "To take on the job was somewhat frightening in the beginning, looking at the initial test result. It became exciting when you realized that the chemistry that was coming back was going to support being able to fix it."
A system ‘making mud’
Earlier this year, Atlas was called in to correct problems the facility was having with its existing POE system, which was about five to six years old. That system was designed to oxidize the water via chlorine injection, and then filter it.
That’s a common and often acceptable method for iron treatment: soluble ferrous iron (Fe+2) is oxidized into ferric iron (Fe+3), a particulate in suspension which can be removed with a filter.
However, according to St. Hilaire’s account, in this case there was simply too much iron in the athletic facility’s water: "It just couldn’t work with what it was trying to deal with. … Not gonna happen. They were just making mud."
St. Hilaire says his first reaction upon seeing the results of the lab water analysis was to suggest the customer drill another well. The customer told him they had done that already, but the water in the new well was of about the same quality.
"Under normal circumstances, we would not attempt to treat this water," St. Hilaire says. But he adds, "They were desperate."
Iron like never before
The water was essentially unusable. St. Hilaire was faced with an athletic facility housing workout rooms, an indoor soccer field, showers, a concession stand and more, and the water was so bad, no one could shower there. The owner supplied bottled water for drinking.
What tipped Atlas off and made it decide to attempt to treat the water was that it had samples of the high–iron water sitting on desks for two or three weeks that weren’t oxidizing "the way normal samples oxidize when there is that much iron," says St. Hilaire.
"Typically when you pull a sample that has iron in it, in a day or two the iron will start to convert all by itself and drop out. We had a bottle that was sitting in the refrigerator, and it just didn’t turn. Over the period of two weeks, it never turned," according to St. Hilaire.
"This was the most iron anybody here had ever seen dissolved in water; you fully expect the sample to turn color in a matter of hours, but it didn’t," he adds.
A unique solution for tough iron
After reviewing the samples of water in the refrigerator, the Atlas people decided they might have a chance of using ion exchange to remove the iron without oxidizing it.
The company began by getting to know its water user. Atlas installed a water meter to determine how much water the facility was using on a daily basis. That figure was compared with engineering specifications for water use.
With that data in hand, Atlas personnel installed a small POE pilot softening system to see what it would do. "It caught the iron down to about 0.6 [ppm]," St. Hilaire says.
The pilot system afforded enough information for St. Hilaire and his team to design a permanent solution. Working in a confined space that essentially is a boxed–in stairway, the company designed and installed a quad–flow system using AvantaPure countercurrent regenerating water softeners. The softeners rely on a standard cation exchange resin, St. Hilaire says.
Of the unique system design, St. Hilaire explains: "We put four AvantaPure systems in parallel, and essentially they clean each other out because you would not be able to backwash them with water that has 270 parts per million iron. … So every tank is pulling from the other when it is in its cleaning cycle, so they are always cleaning with clean water. We modified the valves to make that happen."
The system, installed by six technicians, includes sediment filters before the water softeners. The softeners are followed by a chemical feed system injecting chlorine and soda ash into a large retention and settling tank. "We had to deal with the color, the pH still, a little bit of iron bacteria still," St. Hilaire says.
The water then goes through a series of two multimedia filters. After all the equipment, a booster pump was installed to maintain pressure throughout the facility at an even 70 pounds per square inch (psi).
The result: "The water is clear at the tap. Iron is consistently below 0.3 [ppm], pH neutral. The state came in and did their compliance testing and was shocked," St. Hilaire says.
A little POU for good measure
While the facility owners removed the bottled water, they wanted to provide the highest quality drinking water possible for their members. Not only is the water used for drinking, but it is used to make coffee, protein drinks and more. To address this, Atlas installed two point–of–use (POU) undersink reverse osmosis (RO) units with faucets.
After four months of service, the system was delivering water with an iron level of 0.2 ppm, hardness of 0–1 gpg, and a pH of 7.4.
St. Hilaire says the facility does the daily/weekly maintenance required for the salt, chlorine and soda ash. Once a month, Atlas technicians perform on–site system maintenance, which includes testing each piece individually to make sure it is doing what it is supposed to.
"There has been not even a hiccup yet," St. Hilaire says.
