Testing to maintain standards
In April 2014, the water coming out of the taps in Flint, Mich., began to turn a strange color. Residents began to complain about its taste, color and odor. The water would later test positive for high levels of trihalomethanes and lead. The ongoing water contamination crisis focused national attention on the importance of regularly monitoring the quality of our drinking water. The Environmental Protection Agency requires that water districts frequently test their water for bacteria, chemicals and metals that could harm the public. Technicians draw samples not only from the water source or the water treatment plant, but also from sites across the district. Decades ago, the only way to take these field samples was not the most convenient.
“The old way of doing it would be to go into someone’s house or place of business,” said Jim Lyon, product manager for American Machine & Conveyor, which manufactures water sampling stations. “You go out to a zone, you pick a house that’s kind of centrally located in that zone and hopefully that person’s home and will give you permission to enter the property or give you access to a spigot where you can either hook up a meter sampler or just take your cup and put it right there in the sink and take a sample. And that’s not always convenient, especially if you’re trying to time it so that people are home.”
Old and poorly maintained pipes in the home or business could also introduce contaminates not in the public water supply, yielding a false positive.
These days, technicians usually take water samples from designated sampling sites using water sampling stations. These sampling stations are outside and connect directly to the water main. American Machine & Conveyor recommends that their stations be anchored to a 2-foot concrete pad covering a French drain. A 6-inch pipe connects the water main with the above-ground sample tap. A secondary shut-off valve and check valve are also installed to protect the water supply.
Sampling stations have made it more convenient for technicians to quickly collect water samples throughout the community. They also have more control over the source of their samples, which is important for maintaining the integrity of the water sampling. Lyon said, “Now the technician can come out, unlock the sampling station, flush it or let the line run however long he’s required to and then take his sample and go. He doesn’t have to wait for anybody to give him access. He doesn’t have to hook up a sampler to a water line.” Water samples are then sent to a laboratory for testing.
But what if the sampling station itself becomes contaminated? Since the sampling tap is outside, it must be protected from damage, tampering and contamination, usually by enclosing all above-ground components in a locked metal box. “It can be a real big hassle if they get a bad test from not having a clean water sample station,” said Lyon. “So we’ve got these side wind guards and our lid is flush to the body so there’s no way even ants can get in there.”
The stations also need to be periodically maintained and occasionally replaced. The city of Coral Springs, Fla., has upgraded aging stations in the past few years.
Chief Water Plant Operator Bryan Heller for Coral Springs said, “They were in pretty decent service for as old as they looked like they were, but seeing as how we have a lot of new lead-free standards in the water industry, I just wanted to make sure that we were able to provide some lead-free ones and bring things up to standard. I pay close attention to the American Water Works Association. They print standards on everything. When they made adjustments a few years ago to all the lead-free requirements instead of just reduced-lead requirements, I wanted to make sure that we complied with that. So we got new lead-free sample taps. We also made sure to get enclosures that were durable and would not break and did not take an exorbitant amount of time to install or maintain.”
Heller has been satisfied with the results of upgrading the city’s water sampling stations. “We’ve been getting really good samples. As a matter of fact, I did notice a drop in our heterotrophic plate counts. That’s something we do that’s not really required, but we use that as a monitoring tool for our system and the fact that we have an ‘ND’ on the lab results, which means ‘Not Detected,’ every single month for the last four months, that’s a real good indication that it was a good decision to go ahead and be proactive and install those new sample taps.”
Water sampling stations have become vital to protecting the nation’s water quality. Maintaining them and occasionally upgrading them to meet new water quality standards is important for ensuring the integrity of the testing process.
“You want to maintain your standards,” said Heller. “You want to have the best equipment available. And you want to make sure that you’re not going to have any forms of false positives. It’s a small price to pay to make sure that we don’t get false positives.”
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