Other cities provide examples of sewage treatment upgrades

However Cape Girardeau approaches the need to update its sewage treatment, it will be expensive.

The experiences of two central Missouri cities, one growing rapidly and one nearly identical in size to Cape Girardeau, show that ratepayers will likely be hit with significant increases. And if Cape Girardeau decides to ask voters for a tax measure to help finance the project, everyone will pay more.

Columbia, Mo., has grown from fewer than 70,000 people to about 100,000 in less than 30 years. During that time, the city has spent more than $135 million on sewage treatment upgrades, most recently a $77 million bond issue approved in April 2008. Sewer rates, averaging $11.56 per month for residential customers before the 2008 vote, will almost double by 2014.

In 2000, voters in Jefferson City, the state capital, approved a $52 million bond issue that financed construction of a new treatment plant. The city of about 40,000 needed to meet the latest environmental standards, anticipate growth and eliminate odor problems from the old plant. As a result, sewer rates rose from an average residential cost of $7 per month to $21 per month.

Cape Girardeau residential sewer bills average $13 per month now, said Tim Gramling, director of public works. With a new sewer plant penciled into the city's capital improvements plan at a cost of about $73 million -- a more exact estimate won't be known until detailed plans are drafted -- the goal will be to keep rates as low as possible.

Wastewater Treatment Coordinator Dennis Hale stands near the secondary filtering tanks at the Cape Girardeau Wastewater Plant on Friday, April 30, 2010. (KRISTIN EBERTS)

Jacobs Engineering Group of St. Louis is preparing studies of treatment options and rate effects. A quarter-cent city sales tax approved in 1994 for sewer upgrades will expire in 2014, and that's a likely candidate for a renewal vote, Gramling said.

The current city sewage plant at 429 Cooper St. is designed to handle 7 million gallons of wastewater daily, with a maximum daily capacity of 18.5 million gallons. Wastewater bypasses the plant when the flow reaches 20 million gallons a day, which happens about 40 times a year.

The city's daily sewage output fluctuates between 6.7 million gallons and 6.9 million gallons per day on average, Gramling said. Expanding capacity at the existing plant is not an option because of the sinkhole field that has appeared along Sprigg Street since 2007.

That means a new plant must be built, and not just to keep lack of capacity from limiting the city's growth.

The city did not meet a compliance schedule with the Missouri Department of Natural Resources that set an October 2009 deadline for updating the treatment system. The city has hired a Jefferson City attorney, Robert Brundage, to negotiate a new schedule. Talks that are still underway.

Wastewater Treatment Coordinator Dennis Hale describes how wastewater enters the Cape Girardeau Wastewater Plant on Friday, April 30, 2010. (KRISTIN EBERTS)

"The city has provided a schedule to the department, and the department has reviewed it and responded back," said Renee Bungart, DNR spokeswoman. "Since it is going through enforcement negotiations, we can't provide any additional comments."

Cape Girardeau's preliminary plans call for building a plant able to handle 11 million gallons a day on average and peak flows equal to 50 million gallons a day.

The choices made in Columbia and Jefferson City are two models for returning treated wastewater to streams that is cleaner than the streams themselves. Both cities discharge wastewater into the Missouri River, which has environmental standards similar to the Mississippi River.

In 1990, Columbia voters chose to build a wetlands treatment system that moves treated wastewater through a series of wetlands cells with cattail fields where natural biological actions remove many of the remaining pollutants. The wetlands cells cover 130 acres, with the first at the end of 2.25 miles of pipe leading from the treatment plant.

Located adjacent to the Katy Trail State Park and Columbia's MKT Trail, the wetlands provide opportunities to view waterfowl and other animals.

"When we built Unit 4, we built an observation deck, a 25-foot deck where people can get off the MKT spur at the top of the berm and get up and watch the wildlife," said Steve Hunt, manager of environmental services for Columbia.

The 2008 bond issue increased the capacity of Columbia's treatment system from 12.6 million gallons per day to 20.6 million gallons per day.

Jefferson City chose a different system, focusing on mechanical treatment processes. The plant's proximity to the city airport ruled out wetlands, said Eric Seaman, wastewater division director.

The city did build a small demonstration wetlands, but what has won national and even international attention was what is known as a Sequencing Batch Reactor. When the permit to operate was issued, it was the largest plant of its size in the United States, Seaman said.

The Sequencing Batch Reactor uses a single basin divided into four sections to combine all treatment steps. A conventional sewage plant uses several basins, each dedicated to a separate process. It handles an average flow of 11 million gallons per day and a peak wet weather flow of 50 million gallons per day.

"One reason we chose this is it responds well to peak wet weather flow," Seaman said. "This is a real old town. There are a lot of foundation drains and the flow hitting the plant during a storm could be nine or 10 times what it is normally."

It took about three years to complete the plant after passage of Jefferson City's bond issue in 2000

Cape Girardeau, at this stage, is still considering alternatives, setting a schedule with the state and designing a new plant. That will take about two years, Gramling said.

"We don't have to have it complete but we want it to be far enough along that we can inform voters what they will be voting on," Gramling said.

rkeller@semissourian.com

388-3642

Pertinent addresses:

429 Cooper St., Cape Girardeau, Mo.

401 Mokane Rd., Jefferson City, Mo.

Eagle Bluffs Conservation Area, Columbia, Mo.