Mandeville's effort to rebuild wetlands and treat its wastewater at the same time drew some skepticism at a Louisiana Department of Environmental Quality hearing Thursday, but defenders said the project is helping the environment and reducing costs.

Mandeville, which has a state permit to discharge partially treated wastewater into the Chinchuba Swamp and the East Tchefuncte Marsh, is seeking a permit renewal, something that is required every five years.

But the application, which includes a request to increase the amount of total suspended solids in the wastewater, is getting some pushback, most notably from the Lake Pontchartrain Basin Foundation.

That organization, which supported what are known as wastewater assimilation projects 10 years ago, now argues that they are proving harmful rather than helpful to wetlands.

Friday's hearing, held at the St. Tammany Parish Council chambers, allowed people to submit comments but not to ask questions of the DEQ personnel present.

Several speakers from the Lake Pontchartrain foundation asked the state agency not to relax Mandeville's standards and pointed to wetlands loss in a similar project in Hammond that they say is caused by the wastewater discharge.

"Sometimes a theory just doesn't pan out," said John Lopez, the foundation's coastal sustainability program manager. He pointed to an 80-acre area in the East Tchefuncte Marsh that he said has raised concerns.

But several Mandeville residents spoke in favor of the project, which they said has helped the wetlands. 

Cliff Seibert said he owns 60 acres of land in the middle of assimilation areas. "It's turned an area that used to be pretty barren, and now it's lush with grasses," he said. Since the project began, he said 4,000 trees have been planted and some of them are now 6 feet tall.

"Overall, it's a very good project that's done my property a lot of good," he said.

Jay Blossman, who used to serve on the state Public Service Commission, said these projects mean customers pay less for wastewater treatment while helping the environment at the same time.

David deGeneres, the public works director for Mandeville, said the city has been discharging wastewater into the Chinchuba Swamp since 1989 and into the Tchefuncte wetlands since 2010. Those areas have seen rapid growth of cypress seedlings, he said in a presentation that included information about other assimilation projects in the state.

Wetlands involved in such projects are constantly monitored, he said, and the treatment plant is constantly evolving. He called the city a "good steward of the environment."

But even though the hearing concerned only Mandeville's permit, many of those who spoke addressed the broader issue of whether wetlands assimilation is a good idea or a bad one.

John Day, an LSU professor who began studying the idea in the 1980s, urged the state to launch a comprehensive review before considering any type of moratorium. The Lake Pontchartrain Basin Foundation is urging the state to stop issuing new permits for such projects and to review existing ones.

Comite Resources, founded by Day, designed and monitors all the assimilation projects in the state, and several of those speaking in support of Mandeville's project were from Comite.

Robert Lane and Rachel Hunter, both from Comite, said that wetlands loss in the Hammond project was caused by nutrias and not the effluent released into the area.

But Chris Schultz, who said he originally supported the Hammond project, said the damage he saw was caused not by nutrias but by nutrients, flooding and lack of soil strength.

Other opponents raised concerns about nitrogen and phosphorus loads in wetlands and the potential for increased pathogens.

Comments about the Mandeville permit can also be submitted to DEQ in writing, but the deadline is 4:30 p.m. Monday. They can be placed in the agency's drop-box at 602 N. 5th St., Baton Rouge, LA 70802 or mailed to LDEQ, Public Participation Group, P.O. Box 4313, Baton Rouge, LA 70821-4313. Emails may be submitted to deq.publicnotices@la.gov and faxes sent to (225) 219-3309.

Follow Sara Pagones on Twitter, @spagonesadvocat.