Chicago officials boast of having the world's largest sewage treatment plant, but that also means the metropolitan area produces massive amounts of wastewater that pollutes rivers all the way to the Gulf of Mexico.
The Stickney Water Reclamation Plant, which handles the waste of 2.3 million people in Chicago and the Cook County suburbs, is the biggest single source of phosphorus in the entire region that drains into the Mississippi River. Combined with other sewage plant releases and farm runoff, the pollution triggers algae growth that kills fish, makes drinking water taste sour and contributes to a Connecticut-sized dead zone in the Gulf every summer.
Scientists, regulators, lawyers and advocates have been debating how to tackle the problem for years. Now a private company is promising to scour some of the phosphorus from the Stickney plant's effluent and turn it into slow-release fertilizer — a project local officials contend is a model for other communities in the region.
The Metropolitan Water Reclamation District, the taxpayer-funded agency that operates the Stickney plant, agreed to finance the Ostara Nutrient Recovery Technologies project while facing court challenges from environmental groups that want more stringent legal limits on the district's phosphorus releases into local waterways.
"Usually utilities don't do anything until the courts or the permit writers tell us what to do," said David St. Pierre, the district's executive director. "I don't think legal battles should paralyze us or prevent us from continuing to improve."
The $31 million project diverts wastewater through three reactors that use catalysts to form tiny, nutrient-rich "pearls" for the fertilizer industry. The district estimates the equipment will produce up to 10,000 tons a year, reduce the Stickney plant's phosphorus discharges by about 30 percent and eventually generate $2 million annually through a licensing agreement with Ostara.
The Vancouver-based company already has upgraded about a dozen smaller plants in the U.S., Canada and Europe. It attracted early financial support from Robert F. Kennedy Jr., an environmental activist who has been involved in multiple lawsuits against sewage plant operators as president of the nonprofit Waterkeeper Alliance.
"I've sat across from plant operators many times telling them they need to do more to reduce pollution," Kennedy said in an interview. "This is a better way to achieve those goals."
The need for more aggressive and widespread action is especially acute in Illinois, which by most estimates is the largest contributor of phosphorus and nitrogen pollution to the Gulf of Mexico.
A state task force concluded that sewage treatment plants are responsible for about half of the phosphorus pollution in rivers that drain into the Mississippi. But until recently operators have not been legally required to do anything about it.
In 2013, the water reclamation district volunteered to limit its discharges to a monthly average of 1 milligram per liter. District officials say the Stickney plant often releases concentrations about half that amount.
Environmental groups are challenging the district in federal court. Based on the latest science and guidelines from the U.S. Environmental Protection Agency, the limit should be at least 10 times lower, said Ann Alexander, senior attorney for the nonprofit Natural Resources Defense Council.
The Ostara project is a good start, Alexander and others said. But more needs to be done.
"We need a shirt and a pair of pants," said Albert Ettinger, another environmental attorney involved in the lawsuit. "Just because they have a nice new shirt doesn't mean they can skip wearing pants."