They want them to treat sewage.
Lawrence city commissioners are expected Tuesday to approve a $15,000 expenditure to pursue state permission for "contained" wetlands -- a greenhouse that holds wetlands plants to soak up sewage nutrients before the water is discharged.
But approval is hardly a sure thing. Lawrence's proposal seems to be the first of its kind in Kansas, and officials say the state is jittery about the idea.
"The technology's been proven elsewhere," Mayor Mike Rundle said Friday. "We're just dealing with institutionalized inertia."
Assistant City Manager Debbie Van Saun said the idea isn't so different from traditional technology.
"The wastewater treatment plant uses biological processes," she said. "Essentially, little bugs eat up the bad stuff in the waste before it's released."
The city is trying to figure out how to treat sewage as operations grow at the airport, which is on the north edge of town. Building a traditional pumping station would be expensive, about $1.8 million, with little material expected to flow back to the city's wastewater treatment plant.
An original proposal for the contained wetlands was even more expensive: $2.4 million. That prompted early discouragement by the Kansas Department of Health and Environment.
"KDHE said they wouldn't permit anything that's less economical than traditional methods," Van Saun said.
But a more recent proposal to build the wetlands in modules reduces that cost to between $1.1 million and $1.8 million. And according to consultants, the contained wetlands require less maintenance and offer more odor control than traditional pumping methods.
It may even be more effective.
"By virtue of the type of treatment in the contained wetland, water essentially cannot leave the greenhouse until it has been treated," said a report by city consulting groups.
Rodney Geisler, chief of KDHE's municipal programs section for the Bureau of Water, isn't so sure. In a July letter to city officials, he questioned whether connecting to an existing wastewater treatment facility wouldn't be more effective -- and whether a "nondischarge treatment system," such as a lagoon, might not be more environmentally helpful.
"KDHE finds connection to the city system clearly the superior option, environmentally and economically," he wrote.
That, however, was not an official ruling. And now the city is preparing to make its case, arguing for long-term efficiency.
"We need to be looking at alternatives," Rundle said. "I think it's a little bit visionary for us to try to break new ground."
-- Staff writer Joel Mathis can be reached at 832-7126.