Among many areas of broad agreement on environmental issues, all the candidates for Chicago mayor have come out in favor of disinfecting wastewater that flows into local waterways. The region’s effluent is treated, but not disinfected to kill harmful germs. Disinfection has been controversial, largely because of its cost. A 2006 report commissioned by the EPA puts the capital cost near $400 million.

The decision actually rests with the Metropolitan Water Reclamation District. But advocates said leadership from the mayor could make a huge difference.

“Having a mayor stand up and say we won’t put with this,” said Margaret Frisbie of Friends of the Chicago River, “We think that that will really help change the minds of the commissioners at the Metropolitan Water Reclamation District, the staff there, who have been working to improve the river for years, but have really dug their heels in against disinfection.”

A District spokesperson declined to comment.

The mayoral hopefuls had few disagreements in their responses to a questionnaire from environmental groups released yesterday. All but one candidate – Rahm Emanuel – support an ordinance to force Chicago’s coal-fired power plants to clean up or shut down.

See the candidates’ complete responses to the questionnaire.