World's Largest Wastewater Treatment Plant Takes On Nutrient Recovery

David St. Pierre, Executive Director of the Metropolitan Water Reclamation District of Greater Chicago, discusses the city’s nutrient recovery program and protecting citizens from stormwater events.

The following is an excerpt from a Q&A with Water Online Radio. Click on the Radio Player above to hear the full interview.

Water Online Radio: What makes up the Metropolitan Water Reclamation District of Greater Chicago?

David: The district serves the entire Cook County region. We serve about 5 million residents. We have seven treatment facilities and treat about one billion gallons of wastewater a day.

In 2004 we took on the arduous task of stormwater management for Cook County. If people have not visited here, it is a marshland and extremely flat. Storm water presents some incredible challenges for the district.

We are really trying to make sure with the weather changes that we have had up here that the people and their property are protected.

Water Online Radio: You also operate the world’s largest wastewater treatment facility, correct?

David: We do have a plant that is the largest in the world. It treats about 1.44 billion gallons of wastewater a day. It has the capacity.

Water Online Radio: What kind of challenges does that present, having such a large facility versus a smaller one?

David: You know it is not that different from any treatment facility. You have the same basic processes. You are just dealing with a lot bigger equipment and a lot more water.

Water Online Radio: I understand that you recently announced that you are adopting nutrient recovery. Why did you make that decision?

David: Nutrients are the number one hot button issue right now that regulators across the country are trying to get their hands around. If we don’t take the lead as water professionals on how to address this issue then the pattern has been that we’re forced to do that work to catch up with technology.

We volunteered for a nutrient limit at our three big plants and we are moving forward with bio-P removal and a process that can actually recover the phosphorus and be resold as a fertilizer material that is a very high quality fertilizer.

Water Online Radio: You just mentioned that nutrient recovery is a big very hot issue right now. There are all kinds of other issues and problems that we have to deal with; climate change, aging infrastructure, regulations…talk about the pecking order in terms of what you are focused on.

David: Well, we have a lot of things going on. You are exactly right. And the industry all over the country does. Aging infrastructure is an issue that you can manage through a good maintenance program and that is what it amounts to. We look at our system every 5 years and take care of defects that we find. We have a very good program to make sure that our infrastructure stays in good condition.

As far as combined sewer overflows, everybody has dealt with those issues in big old cities. We have our share of combined systems. We began on the tunnel and reservoir plant in 1968. Chicago was out in front. Before there was a long-term control plan, we had a long-term control plan.

When we have completed that program, we will have 20 billion gallons of storage to mitigate combined sewer overflows. It is the biggest program in the country…

Click on the Radio Player above to hear the full interview.