April 2022 Ι Landscape Architecture Magazine
Smoke stacks of deserted steel plants keep the skyline of Big Marsh Park in Chicago spare. an Wetlands dominate the soggy ground between Lake Michigan and Lake Calumet, Chicago’s other Great Lake, so endlessly dredged and filled that it’s become a hammer-headed series of slips and canals. This part of the city, within city limits but nearly 20 miles from the skyscrapers of the Loop, is remote if not quite rural. There are sand dunes, forest, prairie, and a haven for birds and birders. It’s a place where swans and herons swoop over scrap yards. These wetland denizens might also be joined by mountain bikers hurtling skyward off the ramps and pump track of the park’s 40-acre bike trail. The Ford Calumet Environmental Center is the gateway to this 280-acre park, an eco-recreation hub with bike tracks and trails on southeast side of Chicago, developed by the Chicago Park District with help from the non-profit Friends of Big Marsh.
But the wetlands here aren’t what they used to be. “Most of this vast tract of wetlands was filled and re-shaped and drained,” says Stephen Bell, the center director for the Chicago Park District’s environmental center. Surrounded on three sides by shuttered steel sites, Big Marsh sits on what was a dumping ground for construction debris, municipal waste, dredge material, fly ash, and slag, the impurities pulled out of molten steel during the production process by the addition of limestone. Residents of the southeast Chicago neighborhoods are a modest community primarily made up of Black and Brown households who have seen their industrial base and access to quality jobs disappear. In the 1980s, the area lostg 20,000 jobs through the collapse of the domestic steel industry, leaving environmental degradation in its wake. The city has cleaned up and capped 45 acres of this site, but today dozens of acres are permeated with slag, sometime 20 feet deep. Landfills cover more than 800 acres here, and a dramatic (for manhole-cover flat Chicago) series of landfill hills punctuates nearly every view.
Bernard Jacobs, FASLA, whose firm Jacobs/Ryan Associates designed the Ford Calumet Environmental Center’s landscape, calls it a “totally manufactured, busted site. You have to appreciate what it takes to turn a site like that around. It’s like planting plants on the moon.”
There’s no part of Chicago that offers such a surreally clear juxtaposition of ancestral landscapes and the incision of commerce and industry . But unlike previous occupants of this place, the environmental center sits lightly on the land. With native plantings and a wastewater recycling system (the first of its kind in Chicago), the center does its work with closed loops of waste and renewal. Designed by Biohabitats, the center’s recycling system converts sewage into clean water through a system of tanks, a trickling filter, a constructed wetland, and more before it is discharged into the groundwater. It’s managing an accelerated and exactingly engineered nitrogen cycle that can treat up to 4,000 gallons of wastewater per day with biological and mechanical agents.
This recycling system came about because of the remoteness of the site. The closest connection to the city sewerlines was several miles away, at the southern city limits. It would be “$2 million just to flush the toilets,” says Alexander Raynor of Valerio DeWalt Train Associates, which designed the building. An onsite wastewater recycling system would be approximately half as expensive. And if it was clearly presented, it could support the center’s educational mission, complementing the community event space’s exhibits on the history, industry, and ecology of the Calumet region, which stretches from the southeast side of Chicago through Indiana along Lake Michigan’s shoreline. So Raynor and his team sited the constructed wetlands and the above-ground trickling tank just off to the side of the center, next to its main signage, unmissable from the parking lot and added a a diagram explaining how the system works. “Once the plants are grown, you’re going to see the plants before you see the building,” he says. With a such a prominent site, it was important to dress up the stacked rings of pre-cast concrete that make up the above-ground tank. So Raynor wrapped the cylindrical tank in a weathering steel scrim, to match the rusted patina of the building. “We want this thing to be as beautiful as it could possibly be even though at the end of the day,” he says, “it’s for treating sewage.”
The wastewater recycling system is the most visible and impressive element of the ecological infrastructure at the center. But really, it’s basically a “fancy septic tank system in terms of principle,” says Pete Munoz, senior engineer at Biohabitats. The process begins when wastewater flows from the center into the underground preliminary treatment tank. Solid waste settles to the bottom (and will eventually have to be pumped out via several ground-level ports, like any septic system).
Liquid wastewater then flows into the tricking filter dosing tank. From there, the water makes its way to the partially above ground tricking filter, and the 7,000-gallon tank sprays water onto a filtering media (a waffled plastic ball-like shape that maximizes surface area) that’s been seeded with beneficial bacteria. As the water trickles through the filter in an oxygen-rich environment, the bacteria consumes carbon and then nitrogen in the water, strictly in that order. “It’s kind of a cascading, self-regulating treatment system,” says Munoz. “The carbon is all the sugary stuff in our wastewater.” (“Sugary” to the bacteria, that is. It’s feces and toilet paper.) “When there’s no candy left, there’s, like, a bunch of brown rice.” (That’s the nitrogen, present in urine.) The choice for the bacteria becomes: “I’m not going to choose brown rice, but if there’s nothing else, I’ll eat it,” he says. Bacteria in the trickling filter converts nitrogen in the chemical compound ammonia into nitrate, a form of nitrogen plants can use, and a common ingredient in fertilizer.
Next, the reformed wastewater moves on to the 1,350-square-foot constructed wetland. To build it, the Biohabitats team excavated down several feet and placed a liner. Contained by rectangular low concrete curbs, it was filled with gravel and planted with broadleaf cattails, bulrushes, and wetland grasses, a palette Jacobs/Ryan and Biohabitats collaborated on. Mulch on top brings added planting medium, keeps plants warmer, and adds carbon to the system. Jacobs/Ryan Associates specified sprouted plugs to hasten the function of the recycling system. As water flows in one end and out the other of this oxygen-poor environment (mimicking the oxygen levels of natural wetlands), plants absorb the nitrates in the water and exhale nitrogen into the atmosphere; the dominant component of the air we breathe. The wetlands are “a nutrient management tool,” says Munoz. “We’re transforming [nitrogen] in the trickling filter and removing it in the wetland.” The wetlands are critical because the prevalence of nutrient-laden water is a massive problem in the Great Lakes region, or anywhere large-scale industrial agriculture spews animal waste or fertilizer into local waterways, which can choke out native flora and fauna with severe eutrophication and algae blooms.
“One of the reasons that this innovation is so fitting for the FCEC is that it’s almost as if we’ve come full circle,” says Bell. “These same biological functions that once existed to clean and manage the water are the same ways this constructed wastewater wetland is cleaning the water that the building produces. That’s one of the main ways that we’re able to tie the building and that system and our patrons together–to tell that story.”
From the constructed wetlands, the water moves on to a mound dosing tank and then to its final destination: the mound dispersal system. This mound is a raised drain field, 20 by 200 feet; a stubby, 3-foot-tall imitation of the landfill mound that the center backs onto. The dispersal mound increases the vertical distance water travels through before it reaches groundwater, especially important at Big Marsh because of its high water table. It’s made of medium-grain fill (like sand) to let water percolate through at a moderate pace. All told, it takes about a week for any drop of wastewater to move through the entire system.
There are a significant number of steps along the way, but the process is powered by just three fractional horsepower water pumps. “The complexity in the system really comes in the different ecologies that we’re creating, and the robustness that those ecologies create by putting them together,” says Munoz. “We often talk about this as mechanically simple [and] biologically complex.”
Jacobs/Ryan Associates selected plantings along the front perimeter of the building (which sits on top of a cap) that augment the biological complexity of the constructed wetlands. The polluted ground necessitated bringing in fresh soil to accommodate two sets of native wildflower and prairie grass plantings. Just beyond a walkway to the building, wildflowers including purple prairie clover and pale purple coneflower take center stage, with three young Jefferson Elms standing sentry. A separate group of shade-loving plantings hug the building, kept sheltered by the center’s raised steel hangar doors that open to uncover floor-to-ceiling windows. These are a bit more subtle–a mix of ferns, Pennsylvania sedge, among others. Jacobs/Ryan also planted some nodding wild onion, closely related to the wild alliums that Chicago was named for. (“Chicagou” was a French translation of the Indigenous Miami-Illinois word for wild onion.) And with these plantings, Big Marsh takes a step toward reacquainting Chicagoans with their ancestral landscapes.
Similarly, Munoz says the prominence of the wastewater recycling system is a way to highlight the faded connections between land, water, and resources obscured by contemporary urban and suburban life. “If you live out on a farm, you know that your water is coming from a well, your wastewater system is probably in the backyard, and your food is grown on site,” he says. “In an urban environment, you don’t have any of that tangible connection.”
It’s hard to say if Big Marsh is definitively urban or rural. But as a seam between the two, the marsh is a great place to demonstrate how relative remove from densely populated areas and close links to existing transit infrastructure (like rail lines and ports) made the area an attractive location for industry. Those same qualities make make it a desireable location for infrastructural remediation today.
“Once people understand where their infrastructure is, and how it’s supporting them, then they start to care about it,” says Munoz. “And if they care about it, they’re not going to mind as much paying for its upkeep, and they’re not going to abuse it unintentionally.” With each pound of concrete poured, bucket of soil dug, and storage tank buried, Munoz wants to layer added value—biodiversity, aesthetic, and educational–into each infrastructural intervention. “How do we make infrastructure more valuable than the primary service it’s providing?” he asks.
That’s a lesson the Chicago Park District wants to keep close to home, especially considering the legacy of environmental justice activism on the southeast side of Chicago. “More and more of the people that are walking through the doors are residents of the communities that ring Big Marsh Park,” says Bell. “Ultimately, that’s really the vision of the Park District: a community asset.”