Skagit County Resource Recovery Facility Design of a 178 Tpd Waste-to-energy Plant

The Skagit County Resource Recovery Facility (SCRRF) was developed in the mid-1980s to combust all of the county's unrecycled garbage. The design, con­ struction and operation of this project is the first of three waste-to-energy projects (along with Spokane and Tacoma) developed in the State of Washington. Their successful development in the shadows of the highly touted Seattle recycling efforts, a nearby "incinerator," and the notorious wood waste industry "tepee burners" is remarkable. In addition, the SCRRF project was the first application of the Italian Technitalia technology on solid waste in the United States. Based on review of the SCRRF design and discus­ sions with the county staff, several design modifications may be warranted for similar projects in the future. First, the shredder at one end of the pit for oversize materials that might not pass through the kiln feed opening is a high maintenance item. The knives require sharpening every 3 months. Either a spare set of shred­ der teeth kept on hand or a second shredder providing redundancy should be considered. Second, the magnetic metal separator for the bottom ash is susceptible to frequent plugging. The use of a trommel or screen separator may alleviate this opera­ tional problem. The ash bins should be redesigned to eliminate cross members such that the lid halves close on, and support,