BABBITT, Minn. (AP) — An environmental engineer working with University of Minnesota-Duluth researchers is looking for a less expensive solution to protecting wild rice from mining pollution in the state's Iron Range.

Jeff Hanson has spent the past decade studying the issue and working through design, lab tests, field tests and data crunching, according to reports . The project received funding from the state and the mining industry.

Hanson and his colleagues have developed floating bioreactors that take water with high sulfate. The bioreactors have fibers and bacteria that turn the sulfate into sulfide and discards of the sludge. The water that's returned to the lake then meets the state's sulfate standard.

The bioreactors would cost less than a reverse osmosis system, the method currently being considered as a pay to protect wild rice.

Project leaders are unsure if the technology will be adopted because of debate surrounding the state's sulfate limit.

The state adopted a rule in 1973 that limited sulfate levels to 10 milligrams per liter in waterways near wild rice.

Native American tribes, environmentalists and some lawmakers are pushing for better enforcement of the rule, while mining companies and other lawmakers argue it should be abandoned.

Discarding the standard would make it difficult to motivate people to pay for water treatment systems.

But Hanson said he's optimistic that the bioreactors will be piloted at one of the state's mines to prove it can work on a large scale.