TRI CITY — The hazard of using and storing poisonous chlorine gas has necessitated a change of disinfection systems for the Tri City Water & Sanitary District.

The district decided it needed to either upgrade its disinfection system or replace it, said Vicki Howren, district manager.

The district has used chlorine gas since its inception to kill potentially harmful microorganisms found in drinking water. A study performed by Pioneer Technical Services, a Texas-based environmental science consulting firm, found that the upgrades were necessary to meet new state and federal standards and regulations of chlorine storage and use.

“We have close proximity to (Interstate 5), Old Pacific Highway, South Umpqua High School and Tri City Elementary,” Howren said. “The potential is there to actually ... have to evacuate people.”

Howren said the board of directors voted unanimously Feb. 14 to replace the system with an onsite sodium hypochlorite generation system produced by the New Mexico-based company MIOX.

“They’ve been thinking about it for a while,” Howren said. “It’s in the master plan of changing over.”

The new system could be installed as soon as summer and will not result in a fee increase, Howren said.

The 1,600 users of the water system currently pay an average of $35 per residential household based on their water usage, she said.

Robert Bynum, one of the principal owners of Hbh Consulting Engineers, which contracts with the water and sanitary district, said the initial startup cost of installing the system is roughly $85,000. Although he could not give the cost of upgrading the current system, Bynum said the cost of simply installing a new system is “less money than it was going to take to upgrade their gas system.”

The sodium hypochlorite system uses water, salt and an electric current in a process called electrolysis to create liquid chlorine, which is safer than chlorine gas.

The salt is added to the water, making brine, and the combination is sent through a power current, creating sodium hypochlorite. The liquid is then stored in a storage tank before it is pumped into the drinking water as a disinfectant.

“Instead of storing this toxic gas on site, all they have to store is salt,” Bynum said.

Doyle Tankersley, superintendent of the Roberts Creek Water District plant in Green, said his district began using a similar MIOX system about five years ago after conducting a study into the safety of using gaseous chlorine.

The district used to keep two 1-ton cylinders of chlorine at the treatment plant similar to the Tri City Water & Sanitary District, Tankersley said.

The report found that the cylinders could be vulnerable.

“If a 1-ton cylinder was to break, it would hurt a lot of people,” Tankersley said.

He said the plant now uses a 40-ton brine tank and receives salt shipments of between 25 to 35 tons about once per year. The plant pumps about 500 gallons of liquid chlorine mixed with water, or mixed oxidant, per day.

“It’ll be good for them,” Tankersley said of Tri City’s potential change. “Just getting rid of the chlorine’ll be good for them. It takes just one time for something to happen.”



• You can reach reporter Erik Skoog at 957-4202 or by e-mail at eskoog@newsreview.info.