Could constructed wetlands clean up Newtown Creek?
A Long Island environmental consulting firm says it has the latest solution to help reduce New York City’s sewage water contamination problem.
The firm, Roux, gave a presentation to the North Brooklyn Chamber of Commerce Friday morning to pitch Constructed Treatment Wetlands, or CTWs, to help reduce the pollution from sewage water flowing into the city’s waterways, using the federal Superfund site Newtown Creek as an example.
CTWs are an engineered system designed to improve water quality using the natural treatment processes of wetlands, said Kelly Coulon, a senior engineer at Roux. Once a system that would require large expanses of space, CTWs have evolved to maintain a smaller footprint that Coulon said could give them the opportunity to find their place as a means of reducing the impact of CSOs on waterways like the creek at Brooklyn’s northern border.
More than 1.2 billion gallons of combined sewer overflow, or CSO, enter the creek each year. CSO occurs when stormwater runoff and wastewater overwhelm the city’s sewer system during heavy rainfall, causing the toxic mixture to pour into local waterways.
As part of a long-term control plan between the federal Environmental Protection Agency and the city, a massive tunnel to be installed underneath the waterway is expected to reduce the amount of CSO in the creek by about 63 percent by 2040.
Coulon said the CTWs could act as an aid in cleaning the water in addition to the tunnel if the EPA decided the city needs to take additional action beyond their plan.
Roux used a conceptualization at Maspeth Creek as an example to demonstrate how CTWs would work on polluted waterways. The firm proposed installing a treatment wetland of two separate floating bays lined with plants that send their roots into the water. One bay would help eliminate odors and provide protection against direct contact and act as pre-treatment, Coulon said.
The other would sit on a gravel bed and focus on treating the excessive levels of biochemical oxygen demand (BOD) and nitrogen in the water. High levels of BOD and nitrogen indicate polluted water.
As of now, Roux has not helped install any CTWs in New York City, but has overseen several upstate. One of the reasons it’s been hard to push for them in the city is because many professionals in the field still consider CTWs to use an excessive amount of space, said Christopher Proce of Roux. The status quo of using gray infrastructure, like the proposed CSO tunnel, is also a hurdle, according to Proce.
“People are traditionally going toward gray infrastructure,” Proce said. “It’s simpler, it’s straightforward, there’s concrete costs. This hasn’t been done on the scale of New York City CSO.”
CTWs have been used for over 100 years and began as people putting wastewater into wetlands and realizing it made the environment cleaner.
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