Covanta Energy is one of the world’s largest owners and operators of infrastructure for the conversion of waste-to- energy. Covanta operates and/or has ownership positions in 44 energy-from-waste facilities, primarily located in North America, and 20 additional energy generation facilities, including other renewable energy production facilities in North America. Covanta-operated facilities convert 20 million tons of trash annually into 9 million megawatt-hours of clean, renewable energy and more than 9 billion pounds of steam sold to a variety of industries.
Covanta Energy’s Grand Rapids location has a unique situation where waste haul trucks entering and leaving the site spread contaminated stormwater during wet periods. Contaminated stormwater is collected in an open basin and slowly released into the adjacent Grand River. Since 2006, the Michigan Department of Environmental Quality (MDEQ) has targeted specific outfalls to the Grand River monitoring the Total Maximum Daily Loads (TMDLs) for pathogens, metals and other pollutants. The site’s stormwater would often exceed the maximum allowable TMDLs creating a risk to the river and greater watershed. The MDEQ and the Kent County Department of Public Works requested Covanta develop a long-term solution to protect the river and meet the established water quality standards.
Engineering firm AECOM and Covanta proposed a long-term solution of creating an underground storage system for a 25-year event. AECOM designed a new stormwater system for the entire 2 acre site directing all stormwater into a 96 inch diameter electro-fused DuroMaxx steel-reinforced polyethylene detention system providing 22,844 CF of storage. The final piece of the puzzle involved the Kent County DPW and the City of Grand Rapids which allowed Covanta to tap into an adjacent city sewer trunk line. Once the DuroMaxx system is near capacity, Covanta can release the contaminated stormwater for treatment at the local wastewater treatment plant. DuroMaxx was the ideal solution for the site because it provided the required storage capacity in limited space with long-term durability and significantly low leakage; less than 88 gallons over 24 hours.