Compatibility of Waste to Energy and Recycling
People often express concern that use of waste to energy technology will prevent recycling or that the plant operators and the recyclers will be in conflict over the materials. This is not the case. There is more than enough garbage to go around!
Waste to energy and recycling are compatible, and recycling generally increases the efficiency of the plant. Problems only arise when a WTE plant is over-sized, and the Spokane facility is not. Following are some of the ways that recycling benefits waste to energy:
Removal of Metals and Glass:
Increases the Btu value per ton of remaining garbage by about 10%.
Reduces abrasion wear in the furnace.
Reduces weight of ash. Typically five hundred pounds of ash includes: 58 lbs. of iron (currently recovered and recycled post-burn)
- 375 lbs. of aggregate
(glass, non-Fe metals, rocks, etc.)
- 67 lbs. of fly ash
Removal of Vehicle Batteries:
Keeping vehicle batteries out of the waste stream greatly reduces the lead going through the plant. Annually U.S. manufacturers use over 1 million tons of lead and 72% of it is in car batteries.
Removal of Yard Wastes:
Leaves and grass are not good fuels unless they are very dry. Fresh grass and leaves have a high moisture content and actually lower the Btu value of the garbage. Yard waste contains a relatively high concentration of Nitrogen which, when burned, results in emissions of Oxides of Nitrogen at levels higher than those produced from garbage. This is of some concern, but the primary reason we want these materials separated from garbage is so that it can be composted. Composting results in the return of nutrients to the soil which is a higher and better use than any type of disposal. See Benefits of Composting for more information.
Removal of Paper:
Recycling paper does lower the Btu value of the remaining waste, but only by 1 or 2%. This loss is easily offset by the benefits gained from recycling other commodities.
Handling as much of the material as we can through recycling and composting means less waste for disposal, and our WTE plant is nearing capacity.