More than half of all waste generated in the Chicago area is construction and demolition debris – the largest component of the city’s waste stream. Allied Waste Services new mechanized C&D recycling center is helping take some of the load off.
Mix it up
The key to successfully recycling construction debris in an urban environment is to keep it quick and easy for both the contractor and the waste handler. Allied Waste Services opened their new $8 million C&D recycling facility in June, 2008 in response to Chicago’s new ordinance that requires at least 50 percent of construction and demolition debris be recycled. Allied’s C&D facility simplifies jobsite scrap removal and recycling by accepting mixed-material loads that can contain metals, drywall, corrugated boxes, concrete, wood, plumbing fixtures or asphalt and automating much of the process.
“The growing demand for building green requires a convenient and easy service for recycling C&D,” says Bob Kalebich, general manager and 25-year veteran of the waste industry. “By accepting mixed, unsorted debris in one centralized container, we provide a cost-competitive solution for recycling C&D.”
The Laflin Street C&D facility, located on the near-west side of the city is the largest of Allied’s construction debris recycling facilities and its first automated construction and demolition recycling center in the United States. Allied is considering Houston, Texas, for its next site. Allied operates other transfer facilities in the area processing municipal trash and is the second-largest waste services firm in the country.
Before the new center came online, materials had to be hand-sorted before the debris was processed. It was slow and labor-intensive work. Heavy equipment and automation are replacing much of the hand labor and increasing efficiency.
The three-story facility’s meandering configuration of arching conveyors, catwalks and concrete bays can handle up to 1,500 tons of C&D debris a day on an urban footprint of less than a city block. Construction materials make up most of the debris delivered but the Allied process system can also handle corrugated cardboard, carpeting and miscellaneous office furniture. Trucks dump loads of debris into a three-story-high, open-sided shed. Specialty recyclable items that have residual value such as Chicago bricks and obvious large objects are separated out with a wheel loader. The remaining debris is pushed into large concrete stalls where an excavator grabs loads of debris and empties onto a conveyor belt that carries the scrap up to the third floor separating room. As the conveyer passes by, workers pull off coils of rebar, plastic pipe, cement chunks, cardboard – anything that is not wood scrap – and toss the materials into separate bins to be compacted, banded and sent to jobbers.
The remaining wood waste rides out of the sorting room, into a grinder that masticates the scrap into smaller, more uniformly sized pieces. A disc screen sizes the material as it rides by separating odd debris before the wood and heavy objects are conveyed to a water bath system. Heavy objects like steel and rocks that may have dodged the human and mechanical sorting system sink to the bottom of the water tank and are removed. A cylindrical mesh auger at one side of the water bath corkscrews through the bath to remove drywall dust and small debris that will eventually become compost. The cleaned wood debris, about 150 tons each day, is sent down to the truck loading area to dry and is hauled off for eventual use at the Robbins Community Power plant in nearby Robbins, Illinois. The power plant will eventually require 350,000 tons of recycled wood chips a year.
Cutting costs and getting credit
Contractors who haul their own scrap to landfills are facing higher transportation costs and tipping fees, and those who contract with hauling companies for debris removal are finding fuel surcharges added to their bills. Most of the construction and demolition debris recyclers in the Chicagoland area accept only sorted materials, which can add another layer of costs to the contractor’s disposal bill.
Kalebich says contractors using the Allied C&D center can save money on pickup and hauling costs, eliminate multiple dumpster rentals and landfill fees, and earn two of the 13 points towards the U.S. Green Building Council materials and resources category for LEED green building certification. The Leadership in Energy and Environmental Design (LEED) Green Building Rating System rates the environmental performance of a building based on characteristics of the project. Projects that meet the LEED certification requirements can qualify for tax rebates, zoning allowances and other financial incentives.
Contractors who do not meet or cannot supply proof of meeting the city’s 50-percent recycling ordinance face fines of $1,000 for each percentage point they are short. Allied’s facility is designed specifically to accept co-mingled loads, which lessens the time and labor costs spent sorting debris on the contractor’s jobsite. The combination of mechanical and manual sorting results in a high reusable material recovery rate and less landfill space requirements. Allied provides independent, third-party verification of how many tons of each material the contractor recycles as required by the city and the U.S. Green Building Council.
Part of the success with the new recycling facility is its flexibility to accommodate the various stages of construction waste produced by a project. For example, when a project is producing a lot of wood waste, Kalebich works with the contractor to process large wood loads and says he can save the contractor up to 50 percent of his recycling costs. Similarly, when a job begins to dispose of cardboard packaging, drywall or interior scrap like carpeting, Kalebich adjusts the processing cycle to suit the material.
While the center is seeing a slowdown because of the overall construction slump, Kalebich says future plans include adding a second shift as soon as the demand returns, which will increase the number of workers from the current 16.