The state Department of Natural Resources has removed language from a permit that would have allowed the Ashland Sewage Utility to perform a treatment process considered hazardous to human health by some conservation groups.

The original proposal would have allowed the utility to do so-called blending during wet-weather overflows, which involves blending fully treated wastewater with partially treated wastewater and disinfecting it with ultraviolet light.

The DNR removed the provision after a Madison-based group and some local residents complained it would discourage the utility from solving the larger problem of storm water infiltrating the sewage system during wet-weather events. They also said blending violated the Clean Water Act and argued harmful loads of bacteria and viruses can survive the blending process.

Midwest Environmental Advocates praised the city and DNR for reversing course.

"It is clear to us that the city is taking this seriously and is working on a plan to address the problem," Andrew Hanson, an attorney for Midwest Environmental Advocates, stated in a news release issued last week.

City and DNR officials said the utility never seriously considered the blending option. Chuck Olson, of the DNR, said the agency included the provision as "something the city could investigate."

"The city didn't blend, isn't blending now and isn't going to blend," he said Monday.

Ashland's sewage pipes were built many years ago when mixing storm water with raw sewage was considered an acceptable form of treatment. As a result, large amounts of storm water flow to the plant on Knight Road during wet weather.

The plant contains a basin capable of holding up to eight million gallons. This basin, along with basins located at substations, has overflowed into Lake Superior before the utility fully treated the water.

In 2004, the city received a notice of violation from the DNR for a springtime overflow of 6.3 million gallons.

To reduce the amount of overflows, the city is looking to either expand the basin's size or to create a wetland area engineered to biologically filter the water, according to Christopher Bolt, the city's public works director. The city has also been replacing old sewer pipes during road construction projects to reduce the storm water infiltration problem.

Bolt said the city is comfortable with the DNR's decision to remove the blending provision. "Having it in there maximized our flexibility because it's a huge issue that we're facing with our seasonal peak overflows," he said. "... (But) we did not see (blending) as our top option, to be honest with you. We're OK with that."