Maybe wetlands would be a nice place for sewage.

It may sound crazy, but Robert Kadlec thinks wetlands might help solve Lawrence’s pending sewage issues and could be a natural – and feasible – alternative to a mechanical sewage plant needed along the Wakarusa River.

Kadlec’s proposal, presented Wednesday to an audience at City Hall, is to build a wastewater wetlands to help filter the city’s sewage before it drains back to the river.

“The performance you get depends on what you put in,” he said during the presentation.

Kadlec is a professor emeritus of chemical engineering at the University of Michigan.

The project, he said, could be covered with part of the nearly $80 million the city plans to spend on a new wastewater treatment plant due in 2011.

Kadlec said during the presentation that the wetlands would help filter nitrogen and phosphorous according to environmental standards. For a city that uses as much water as Lawrence, the wetlands would likely need to cover 6,000 acres.

Kadlec also presented smaller wetlands options, but they either wouldn’t filter the water completely or couldn’t handle all of the water.

City Commissioner Mike Rundle, who was in attendance, said he was concerned about the size of the wetlands that Kadlec proposed.

“It just doesn’t seem feasible,” Rundle said.

Rundle said that he would rather see greenhouse-type water treatment facilities that would also filter water naturally but wouldn’t require the large amount of space.

The city has between 30,000 and 40,000 acres available in its urban growth area, Rundle said. Building a 6,000-acre wetlands to filter the water to nitrogen and phosphorous standards wouldn’t fit in the city’s development plan, he said.

After the public meeting, a city-appointed civic group presented other options, including the greenhouse-style “Eco Machines,” in a closed-door meeting.

The group will present issues heard in the meeting on Monday at South Junior High School.