In this Issue:
- School kids to Breathe Easier
- Oakley's Wastewater Technology
- Solid & Hazardous Waste Board
- Drinking Water Database Unveiled
- Calendar of Events
Newsletter Links:
Sponsored by the
Utah Department of
Environmental Quality
In this Issue:
Newsletter Links:
Sponsored by the
Utah Department of
Environmental Quality
Besides its rural scenic beauty and famous rodeo, the city of Oakley in Summit County now has something else to boast about: The city has built the first membrane wastewater treatment plant in the state of Utah. Now, other communities are following Oakley’s lead.
“We wanted to be on the cutting edge,” said Doug Evans, a former mayor of Oakley who spearheaded the project in 2000.
Three years ago, Oakley replaced its aging lagoon system with a membrane bioreactor system that has gained increasing worldwide attention in the field of wastewater technology.
“For years, the state said we needed to upgrade our system so we started saving money,” Evans said. “We were able to do all of this for $1.6 million – much of it paid for by Oakley.”
The Water Quality Board did provide a $400,000 loan and $200,000 grant to build one of the most advance wastewater treatment plants. On Aug. 9, 2002, Oakley began construction on a plant with a 250,000 gallon a day capacity that can be expanded to meet future growth. The project was completed just 15 months later.
“This is a great example of how the water loan programs can help communities,” said Walt Baker, director of the Division of Water Quality (DWQ).
Paul Krauth, outreach coordinator for DWQ offered Oakley technical assistance. “This is the future of wastewater treatment,” he explained. “There are four membrane bioreactor plants in Utah and six others proposed.”
Compared to conventional wastewater facilities, the membrane bioreactor system is relatively low maintenance. In Oakley, Evans volunteers his time to serve as an operator when needed, sharing the duty with a half-time paid operator.
The plant is virtually odorless. Two parallel trains of anoxic and aerobic tanks make up the bioreactor. The membranes, which resemble long strands of spaghetti, are bundled together and suspended in large cassettes that are connected to collection pipes. The cassettes are immersed directly into the “mixed liquor” of the process tank and a slight vacuum draws the water into the membrane fiber and filters out impurities.
Since the system removes solids by filtration rather than settling, the process is much more effective than conventional treatments. The Oakley plant operates its bioreactor at 10,000 to 16,000 mg/l (milligrams per liter) of suspended solids compared to 3,000 mg/l for a conventional system, making the space required for the plant 20-30 percent of a conventional wastewater plant.
“What’s nice about this plant is that it does digest a lot of the solids,” Evans said. The sludge is hauled to a landfill but not as often as a conventional plant. “We only remove about 10 metric tons of solid a year.”
Another bonus: Oakley’s plant discharges water that is pure enough for reuse.
“This water is going to be used to irrigate a 60-acre park within the next two years,” Evans said. “It’s a water source. The turbidity is .5 – better than some drinking water.”