Tucked away at the back of the El Chaparral neighborhood just east of Columbia is Boone County’s largest sewer lagoon. Guarded by a fence and a “Keep Out” sign, the lagoon drains 166,000 gallons of treated sewage every day. It flows directly into the North Fork of Grindstone Creek, just a few miles upstream of a common swimming area.
The process is legal but not necessarily safe.
If voters on Tuesday approve, however, part of the Boone County Regional Sewer District’s $3.85 million bond issue will go toward shutting down the El Chaparral lagoon. The district wants to use more than $750,000 to connect the neighborhood to a line the city of Columbia is building along Grindstone’s north fork.
Closing the lagoon would eliminate health risks, sewer district manager Tom Ratermann said. El Chaparral’s state-permitted discharge point is only two miles from a section of Grindstone designated for “whole body contact,” otherwise known as swimming.
While the district is required to disinfect the treated sewage to protect swimmers, it’s nearly impossible to remove all pathogens, Ratermann said.
“There’s a whole host of pathogens in waste water,” he said. “We’re removing a lot, but it’s still discharging some pathogens into the creek.”
The sewer district manages about 35 lagoons in Boone County, but scores of private sewage ponds are scattered around the area.
Dangerous for other reasons
Gerry Worley, an environmental health specialist with the Columbia/Boone County Health Department and a member of the county’s Small On-site Wastewater System Review Board, said lagoons are dangerous for many reasons other than discharged pathogens.
If not properly fenced, they put small children and pets at risk for drowning.
Lagoons can also be a breeding ground for mosquitoes. And, of course, there’s that pesky odor problem.
Safe, but hard to regulate
Leland Neher of the Missouri Department of Natural Resources disagreed, saying lagoons are safe and pose no risks as long as they are maintained properly. He conceded, however, that because lagoons rely on natural processes to break down sewage, they are more difficult to regulate. As the seasons change, lagoons become more or less effective. They do their best work in warmer weather.
“It doesn’t take a lot of maintenance, but the numbers do go up and down,” he said.
Neher said the numbers even out over time. The year-round average amount of effluent per liter in sewage treated by lagoons is equal to that from sewage treated by mechanical plants, he said.
Protection for residents and the environment
Ratermann emphasized the El Chaparral lagoon must be eliminated if the district is to reduce the number of discharge points. Approval of the bond issue would pay for eliminating not only the El Chaparral lagoon but also others serving Sunrise Estates east of Columbia and Prairie Meadows south of town.
By closing lagoons and tapping into the city sewer system, the district hopes to create a regional sewer network that will eliminate the need to discharge waste water into area creeks. Accomplishing that, he said, would protect residents and the environment.
If the measure passes Tuesday, the district will connect El Chaparral to the city sewer system, then drain the lagoon into that new line. The sludge that remains in the lagoon will be tested and treated to meet state standards. The district will then fill the lagoon ditch with dirt and seed it.