Ohio wastewater treatment plants look for alternative disinfection systems with upgrades
In 2001, the city of Xenia, Ohio, budgeted funds in its capital program to upgrade the two wastewater treatment plants serving the city's population of 23,000.
One plant, built in 1958, treated four million gallons daily; the other, built in 1970, processed 3.7 million gallons a day.
The city was seeking an alternative to the plants' chlorine gas disinfection technology.
Chlorine gas as a disinfection solution had unacceptable safety issues and created problems for the city in complying with environmental regulation.
The existing system required frequent testing due to its high potential for unacceptable contaminant levels and environmental violations. The city accepted bids from three companies for an ultraviolet disinfection solution.
Before making a final decision, facility managers toured an Infilco Degremont installation to observe an operating system for ease of use. Eventually, Xenia chose Infilco Degremont's Aquaray 40 High Output Vertical Lamp System, began construction in November 2003 and brought the new systems online in April 2004.
Solution met requirements
Xenia chose the Aquaray 40 HO VLS because it best met the city's requirements for improved performance, low retrofit cost and improved operating and maintenance cost. The Aquaray systems fit the plants' existing channels with some modification, eliminating the need to construct new channels.
The units are vertical, rather than horizontal, an important consideration because space was an issue. They are also easy to maintain without pulling the entire system out of the water.
"Aquaray best met the city's requirements for improved performance, low retrofit cost, and efficient operation and maintenance," said Dan Leavitt, environmental-technical compliance manager for the city of Xenia, Ohio.
Performance is excellent, according to plant officials. Fecal counts are consistently in the 50s per 100 mLs, compared to 300 or more per 100 mLs for chlorine gas. Testing is required less frequently and the systems are easier to run, so staffing and operating costs are significantly reduced.
The city's partnership with Infilco Degremont facilitated its ability to undertake a substantial portion of the new systems' installation in-house. IDI engineering assistance virtually eliminated the need for outside engineering consultation. Xenia's team was able to hold preconstruction design and configuration costs to about $340,000 as compared to a possible $1 million.
Ohio's Gladys Run and Ford Road Wastewater Treatment Plants are configured as follows:
- One UV channel: 24.5"W x 72"H x 26' 00"L
- Nominal water depth: 60.00"
- Aquaray modules/channel: 4
- Lamps/module: 40
- Total lamps: 160
- UV lamp type: High output lamps
- UV-C watts output/Lamp: 52.0 UV-C watts
- Arc length/lamp: 58"
- Power consumption/lamp: 165 Watts
- Minimum UV dosage: 27,000 uWatts-secs/cm2
- Power requirement: 230V/3Ph/60hz/90.0 Amps
About the author: Judi Harrison is a Marketing Specialist at Infilco Degremont in Richmond, Virginia