New ozone water system is 'top of the line'
Staff reporter
We turn on the water faucet and expect clean and safe drinking water.
Simple. Right?
Well, not really.
For years, the City of Marion has done just that — provided clean and safe drinking water to its customers.
And now with the installation of a new form of water treatment, the process is even better.
The final touches are being added to the installation and implementation of an ozone disinfecting system at the city's water treatment plant.
Previously, water was treated with only chlorine.
"Chlorine causes byproducts," Marty Fredrickson, department supervisor, said. "Ozone then eliminates those byproducts caused by chlorine."
Ozone does produce a byproduct but it has not been determined to be hazardous and the city keeps a close eye on those byproducts, Fredrickson said.
Beginning in 2006, major upgrades have occurred at the city water treatment plant.
New chemical feeders, isolation valves, a cover for clarifyers, three filters are being rehabilitated, and ozone equipment.
Marion now is one of four cities in the state that has an ozone water operation — Emporia, Council Grove, and Winfield are the others.
So why aren't more cities using this method?
"This method is expensive," Fredrickson said, but the city is counting on this method requiring fewer chemicals, thus reducing the cost of those chemicals.
Fredrickson said the city hopes to be ahead of the EPA "curve" or requirements to produce water.
Each year the federal Environmental Protection Agency adopts new, more stringent requirements for water production. Kansas Department of Health and Environment then enforces many of those rules.
With ozone disinfection, the city should be in compliance at least for a few years.
The city has had compliance issues in the past because the water exceeded the maximum contaminant levels of TOC (total organic carbons). The ozone process reduces dirt and organic products before the water is treated.
Granulated activated carbon with the ozone will make the city's water plant compliant.
What does the ozone process do besides address compliance issues?
"It improves taste and odor," Fredrickson said. "Ozone eliminates the musty taste and smell from leaves in the reservoir water."
The process
The first step in ozone disinfection is to generate ozone gas. Liquid oxygen is transported to the plant and stored for use. It is then vaporized into oxygen gas. When electric currents are applied to a flow of oxygen gas, some oxygen molecules are split and bond to other oxygen molecules to form ozone molecules.
Water that has finished the flocculation process, which removes dirt and other organic matter, is piped into the ozone contact basin. Ozone is bubbled through the water. Water typically will spend 15 minutes in this system, traveling up and down a series of columns to maximize the contact with the ozone gas.
The newly ozoned treated water then moves on through the pipes to the next step — filtration.
Meanwhile, the ozone that was used in the process is converted back into harmless oxygen and released into the atmosphere.
The water is filtered to remove microscopic particles.
When water is pumped in to the plant from the reservoir, polymer, lime, alum, and fluoride are added. The water then goes to an outdoor tank clarifier with a paddle wheel. Through a process called flocculation, dirt and solids are trapped. The paddles drag the dirt to traps which is sent to a lagoon near the plant.
The water then goes to the contact basin where the ozone generators are located.
From there, the treated water goes through a filter, a clear well, and to water towers for distribution.
A new 200,000-gallon clear well was constructed in 2000.
The ozone equipment has a main control panel that monitors operations. A satellite signal notifies operators that a liquid oxygen tank needs to be refilled.
The project has taken more than 18 months but the wait is well worth it to the city and its customers.
"Our goal is to continue to produce safe water to our customers," Fredrickson said. "With this new equipment and process we will be able to do that for a long time."
