The Dilemma of Disinfection:
What Would the Precautionary Principle Suggest That We Do?

Background

The Metropolitan Water Reclamation District of Greater Chicago is one of the largest sewage treatment systems in the country that does not currently disinfect the treated wastewater at its three biggest plants before discharging that wastewater into the Chicago Area Waterways. As a result, the effluent contains high levels of bacteria, viruses, and other pathogens that can be harmful to human health. New water quality standards proposed by the Illinois Environmental Protection Agency would require the District to install disinfection technology at the Stickney, Calumet, and North Side Wastewater Reclamation Plants. This would cost a great deal of money, consume a significant amount of energy, and kill most of the bacteria in the effluent from these plants during the recreational season from May 1 through November. These new standards are currently the subject of rulemaking hearings before the Illinois Pollution Control Board.

The conservation community, Chicago’s Mayor Daley, recreational users of the Chicago waterways, and the Chicago Sun-Times, among others, have expressed their support for disinfection. The MWRD is, at this point, opposing the new standards requiring disinfection because District staff feel the science is not sufficient to support it.

Hence, the dilemma of disinfection!

Precautionary Principle

The precautionary principle is a decision-making framework championed in recent decades by environmental and public health advocates. The principle states that a lack of scientific certainty should not be used to delay action to address potential harms.

If applied to the issue of disinfection, what would the precautionary principle suggest that we should do? That was the question I posed to David Reese, a recent graduate of the University of Chicago assisting me on several special projects.

David’s nuanced and careful analysis is posted here.

Essentially David concluded that the costs to the environment and to human health from the increased energy use required to disinfect effluent using ultraviolet light — and the moral imperative of distributive justice — outweigh the potential benefits of disinfection to recreational users of the CAWS.

I am not suggesting that this is the final word on the dilemma of disinfection nor that I have framed a final position on the issue. I offer this in the hope of soliciting your thoughts and guidance — and in the interest of sharing in a public way my own efforts to consider this important issue carefully and thoroughly.