the fluidized bed boilers or stored until needed at night or during weekends.
   Unique patented Heil 4-foot diameter augers are used to evenly distribute RDF to four fuel feeders per boiler.
   The RDF preparation system produces a high quality, low ash fuel with an estimated heating value of 6,170 BTUs per pound.  This homogeneous fuel, in conjunction with the CFB technology, produces a combustion efficiency of 99.9 percent and a boiler efficiency of 81 percent as compared to 70-75 percent for conventional RDF boilers.  Removal of aluminum and ferrous (including zinc, cadmium, and chromium-plated ferrous) helps reduce air emissions, provides a more environmentally friendly ash residue from the boilers, and contributes to plant revenues.
   Table Two compares the continuously-monitored stack emission rates of the facility to the IEPA emission permit limits.
   After nearly one full year of operation, the Robbins Resource Facility has established new benchmarks for waste-to-energy plants.  The recovery rates have exceeded the 25 percent recovery goal.  Table Three shows the recovery rates for specific recyclable materials.
   "It has been a formidable venture, one which has pushed the envelope in RDF technology as well as recycling," said Grinsteiner.  "A project of this dimension with all of its challenges has widened and deepened our expertise in this field and cannot help but benefit future projects.  We're proud to have been a part of it."

The Heil processing system includes primary and secondary trommels, magnetic separators, and shredders.

secondary Heil trommels where a glass-rich stream is recovered for further processing.  The glass recovery sub-system is common to both processing lines and yields an organics-free glass product and compostable organic material.  The glass can be used in building materials and road aggregate, the compostable material as a soil conditioner.
   Oversize material from the primary and secondary trommels, which can be processed to remove additional recyclables, is conveyed to shredders where it is reduced to 3.5 inches or less in size.  The shredded MSW passes through two additional stages of magnetic separation to remove the ferrous metal liberated during shredding.  The remaining material (RDF), some 75 percent of the MSW input, is conveyed to the RDF storage building where it can be used immediately to feed

ROBBINS, IL--It is a plant that lends itself easily to superlatives.  It is the largest circulating fluidized bed (CFB) boiler waste-to-energy plant in the world.  And Heil Engineered Systems, one of the nation's leading suppliers of equipment to process solid waste, was part of it.
    The Robbins Resource Recovery Facility, located south of Chicago, built and managed by Foster Wheeler Power Systems Group, is a kind of Everest of environmental installations, one that aimed higher, pushing waste recovery and recycling to its limits.  It was designed as an alternative to landfill disposal of trash in a congested metropolitan area.
   Solid Waste Technologies Magazine said, "The song Robbins provides is enchanting, as the facility is technically one of the best ever offered by the municipal waste combustion industry.  The facility recovers as many resources as possible from the municipal waste stream; recyclables, compostable material and energy."
   Power Magazine stated, "For combining CFB technology and large-scale recycling into what many consider the world's most advanced resource recovery facility, Robbins Resource Recovery Facility receives POWER'S 1997 Powerplant Award."   
   The Robbins facility converts municipal solid waste (MSW)--1,600 tons per day--into refuse-derived fuel (RDF) and produces enough electricity to run the plant and provide service to 50,000 homes.  Some 75 percent of the MSW is converted into RDF.  The balance yields compostable material and recyclable aluminum, ferrous metal, and glass.  Even the fly ash residue from the Foster Wheeler circulating fluidized bed boilers can be reclaimed for use in the manufacture of cement.
   Heil Engineered Systems comes to the partnership with Foster Wheeler naturally.  "We had completed more than 50 projects around the country," said Craig Grinsteiner of Heil.  "Overall, our equipment is processing some eight thousand tons of waste every twenty-four hours which is the amount that about 3.2 million people generate each day.  We brought a lot of experience to the project.  Even so, the performance requirements of Robbins were really challenging," he added.
   Heil supplied and installed the equipment for the two processing lines in the Robbins plant employed to handle this diverse stream of material.  (Table One lists typical constituents.)  Each of the Heil lines is designed to handle eighty-five tons per hour.
   Trucks bring non-hazardous MSW to the tipping floor of the Robbins facility from surrounding communities Monday through Saturday.  The MSW is first conveyed through environmentally-controlled sorting rooms where non-processables are removed and other recyclables such as corrugated can be recovered.  On both lines, primary trommels open garbage bags, break glass, and separate any material less than six inches in size.  The minus six inch material is conveyed past magnetic separators to recover ferrous before entering two stage