The Effect of Food Waste Diversion on Waste Heating Value and WTE Capacity

Most communities use curbside recycling and yard waste composting programs to reduce the amount of solid waste that needs to be disposed in a waste-to-energy (WTE) facility or landfill. Communities with well established programs have come to realize that there is a practical limit to the amount of solid waste that can be diverted using these methods. To increase waste diversion rates further, some communities have begun to target other materials. One material that is receiving increased attention is food waste. Food waste represents a significant portion of the remaining waste stream and several alternative options are available to manage this material, including composting and anaerobic digestion. In some cases, communities have already begun to implement separate residential food waste collection programs—commonly referred to as the “green bin.” In addition, several jurisdictions have already enacted regulations to promote the diversion of food waste from commercial generators such as food processors, restaurants and supermarkets. Since food waste has a relatively high moisture content, removal of this high-volume component can significantly affect the composition and characteristics of the remaining waste, most notably the heat content. It is important that current and future WTE facility owners understand the potential impacts to their WTE project should they implement a food waste diversion program. This paper evaluates the potential outcome of food waste diversion on the heating value of the remaining waste based on recent waste characterization data collected by Metro Vancouver. Metro Vancouver represents a good case study since they currently own a WTE facility and are considering constructing a second one. Metro Vancouver’s long-term solid waste management plan also includes implementing a food waste diversion program in order to increase their overall waste diversion rate from 55 to 70 percent by 2015. The potential effect of food waste diversion on the capacity of Metro Vancouver’s existing WTE facility as well as the capacity and cost of a new WTE facility is also examined.