WATERLOO - A $15 million industrial sewage treatment plant built in 1997 was expected to be an economic development gold mine.

But the 11-million-gallon basin has been sitting empty for the past decade, as industrial waste has been routed through the domestic side of Waterloo Water Pollution Control Plant to save operating costs.

Now, if the city hopes to use the idled industrial plant as a tool to attract new heavy waste water generating industries, engineers must first prove to the Iowa Department of Natural Resources that it still works.

"If we can demonstrate to them that we can start this up again in less time than it would take a major industry to be built and come on line than we do not have a problem," said Larry Smith, superintendent of Waste Management Services. "We don't anticipate that will be a problem."

City Council members voted unanimously June 15 to approve an engineering agreement with AECOM for up to $148,000 to gather data and review various aspects of the city's sewage treatment operations, including pump stations, sanitary sewer lines, issues related to renewing the treatment plant's operating permit and exactly what needs to be done for the industrial side of the plant to be started back up.

"We just received a preliminary permit for our review and there's a lot of issues in there that the DNR wanted addressed," Smith said. "There's not going to be any problem with our permit. There's just a lot of things that need to be pulled out and reviewed and we didn't have the staff to do it."

A $37 million federal grant in 1994 helped the city rebuild its sewage treatment plant, which had used inadequate trickling filters to treat all of the city's waste water. The eventual $67 million project overhauled the existing plant to handle residential waste and built the satellite industrial plant to treat industrial strength waste from what is now Tyson Fresh Meats and Eagle Tanning Co.

By separating the waste streams and expanding the size - the industrial facility covers the size of a football field at the plant on Easton Avenue - Waterloo has capacity to market the area for new water-using businesses and to handle potential population growth.

While the industrial plant worked when it started in 1997, Waste Management officials shut it down after about two years and treated it through the domestic side of the plant.

A chemical designed to balance the alkalinity of the industrial waste jumped in price to $750,000 a year. And there was also expenses for electricity and maintenance on pumps and blowers at the industrial plant.

"When the two streams were mixed, there was enough alkalinity in the domestic waste water that we didn't have to add the magnesium hydroxide," Smith said. "I think we've saved somewhere between $10 million and $15 million (in operating costs) over the last 10 years" by not running the industrial plant.

"But now we're at about 80 percent of the design capacity of the Easton site, and when you get to 80 percent or above, the DNR wants you to start making provisions to add on," Smith added. Unless the city shows the DNR that it can restart the industrial plant, a prospective new industry with heavy sewage treatment needs may not be able to get permits to locate in Waterloo.

"We don't think the cost of putting it back on line is bad, probably somewhere around $200,000," Smith said.