Nearly half a million residents in Toledo, Ohio, experienced a smack to its water quality this summer, which led to a drinking ban lasting for weeks.

• Mixing: potassium permanganate, alkaline and lime are mixed together.

• Flocculation and coagulation: After chemicals are mixed, they go through a flocculation chamber and form flocc, which draws in organic compounds.

• Sedimentation process: Happens after flocculation, once the flocc forms and gets heavier, it then settles out. The sedimentation process takes four hours.

• Filtration: Any particles left are taken out in a filter. Lime is added again to adjust the water's pH level, and chlorine, which kills any bacteria, especially if there is a water line repair.

• Fluoride: Fluoride is added to the water to, among other reasons, prevent tooth decay.

• Water goes straight to town.

Water treatment steps

The problem: harmful algal blooms. Algal blooms generally don't cause a huge issue, but during the summer months, in open water when the weather is much hotter, the overabundance of phosphorous can cause the blue-green algae to release toxins called microcystins.

Aiken Technical College professor Dr. Kent Cubbage said it's not likely that issue will affect Aiken's water.

“It's not necessarily a problem in and of itself,” Cubbage said. “Usually, there are other chemicals washed in, but those are mostly discarded of during the water treatment process. Most drinking water treatment plants are regulated by the Environmental Protection Agency and the S.C. Department of Health and Environmental Control very heavily.”

Cassandra Harris, with DHEC media relations, said to DHEC's knowledge, there have not been any freshwater harmful algal blooms in South Carolina that caused an event such as in Toledo.

“Given recent national events, we have taken precautionary measures to remind all of the state's water utilities to continue to be vigilant of potential algal blooms. We will work directly with any utility that identifies a potential problem,” Harris said.

City of Aiken employees — Water Plant Supervisor James Bryant and Chief Operator and Lab Technician Keith Lowe — regularly test water samples throughout the day.

In one week, staff pull roughly 15 samples from faucets, taps and raw water. Those samples are located in sites determined by DHEC.

“Once a day, we pull a tap sample, and then we pull a sample of raw water and set it up to look over its bacteria and E. coli count,” Lowe said. “We also run the pH of the water every 45 minutes and check the chlorine. We're constantly testing the water.”

If a public water supply issue occurs, staff will put out a public announcement about a boil advisory or a boil notice. A boil advisory is to advise residents to boil their water for 24 hours because of a water main break, and a boil notice notifies residents that there is a problem with test results and water must be boiled.

“Basically ... if we do have a problem, crews go in and repair the line and shut it down,” Lowe said of water main breaks. “There's enough chlorine to kill anything if it does get in there, like the dirt particles that can get it. When there's a notice, we know there's definitely a problem. That notice means you have to boil.”

Chlorine not only kills any bacteria in the water, but also helps to bleach the color of water so it doesn't turn a brownish color, according to Bryant.

Another component added to water is fluoride, a chemical that helps to decrease tooth decay.

“There was an issue with horse owners in the past; they didn't want us putting it in because they said it causes their horses bones to brittle,” Bryant said. “ ... We did, however, reduce the amount of fluoride that goes in, probably about a year ago. The state allowed the reduction, although they still want it in the water. You have to satisfy both people — the ones who want it and the ones who don't.”

As South Carolina, particularly Aiken County, grows in industry and manufacturing business, plant employees must keep a vigil eye on both the water and the companies.

“One time, back when there was the Carlisle tire fire in the late '80s, (firefighters) poured 50 million gallons of water, which ran back into the creek,” Bryant said. “You couldn't shut the plant down, because of the fire. But you couldn't drink the water for a week or two. We had to flush the whole system. We don't want that to happen because EPA and DHEC will be here around the clock.”

Malayan Schechter is the local government reporter with Aiken Standard. Follow her on Twitter @MaayanSchecter.