The city of St. Louis and the U.S. Geological Survey this month are starting a study to determine if filling demolition sites with clean soil instead of building materials can help address one of St. Louis’ biggest environmental problems: sewage overflows.
Typically, contractors working for the city fill the basement with concrete and other materials from the demolished building. In north St. Louis, they recently began filling some basements with soil that’s been tested for environmental toxins. City and federal officials want to compare how well the two methods can absorb stormwater runoff.
The Environmental Protection Agency funded the one-year study with a $100,000 grant, as a part of its initiative to improve stormwater management in cities across the country.
The research could help resolve frequent flooding issues in some parts of north St. Louis, said Laura Ginn, program manager of the Green City Coalition at the St. Louis Development Corporation.
“The more we can absorb stormwater on site and keep it out of the sewer system, the less likely folks are to have sewage backups in their basements,” Ginn said.
The study also could help justify the cost of using more environmentally safe demolition techniques. The conventional method costs about $8,000 on average, using funds from the city’s building division. The greener method costs about $11,000 on average, but the Metropolitan St. Louis Sewer District pays for it.
The EPA ordered MSD spend $4.7 billion to address sewer overflows as a part of a 2012 settlement. The Missouri Coalition for the Environment had sued the MSD, alleging that the utility had violated the Clean Water Act.
By the end of June 2019, the city plans to tear down 800 vacant buildings. Using clean soil can reduce neighbors’ exposure to harmful contaminants that may be released from demolition activities, said Patrick Brown, the city’s chief resilience officer.
“When you look at things like child blood lead levels, we know that sort of indicator spikes when you do demolition,” Brown said. “And inevitably, if you’re burying materials on site. Even [with] the most meticulous demolition contractor, you could be burying some contaminants back onto the site.”
The city of St. Louis also recently updated its demolition handbook.
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