During the past five years or so, many cities, counties and states have implemented broader sustainability initiatives by incorporating more holistic waste diversion goals that include not only traditional recycling, but also waste minimization, materials re-use and a rather heavy emphasis on the diversion of rapidly degradable organics. Typically, the end point technologies or practices considered to manage disposed organics (e.g. food waste, yard trimmings, non-C&D wood wastes) include:
• anaerobic digestion,
• animal feed,
• rendering, and
• conversion to fuel (e.g. heat, biofuels).
Of these, composting receives a lot of attention for being one of the key solutions for organics management. Indeed, in discussing sustainable waste management solutions with various food waste generators (e.g. restaurants, grocery stores), the conversation invariably gravitates toward composting. While many city or county composting programs are implementing trials to explore food waste recovery, it appears the majority of them still focus on yard waste. Yet, nationally the U.S. EPA notes the fraction of municipal solid waste (MSW) that is composted has essentially flatlined over the past decade at 8.2 percent in 2004 (20.5 million tons) compared to 8.1 percent in 2010 (20.2 million tons).
With so much dialogue for so many years about the merits of about composting, why hasn’t the practice grown as recycling has during the same timeframe? While all organics management options have their limitations, composting is subject to some that appear to have kept a lid on its widespread adoption. Studies done in the late 1990s by researchers at N.C. State (Renkow and Ruben, “Does municipal solid waste composting make sense?”, Journal of Environ. Mgt., 53(4), 1998) and Cornell University (Regenstein et al., “Small to medium scale composting of food wastes in New York City", 1999) both came to the same conclusion: The cost to compost MSW is substantially higher than other options, such as landfilling. While rising tipping fees in some areas, especially urban settings, are helping to make composting a more attractive option, its economic viability nationwide may be one of the key limiting factors.
Another factor is that end markets for waste-based compost tend to be substantially limited depending on the feedstock material. According to the Northeast Recycling Council, compost derived from yard trimmings, for example, has many more end markets compared to that sourced from mixed MSW, primarily due to the presence of glass fragments, small plastic particulates and other contami- nants that detract from its usability. As more restaurants adopt composting as a disposal option, arguably one of the stronger potential growth areas for composting, the issue of contamination looms large since keeping a clean feedstock would involve substantial customer education. Even “back of store” operations can have similar issues, since in many cases food wastes have some type of packaging that must be removed before composting.
Altering restaurant customer behavior, for example, to remove the non-biodegradable plastic lid from the biodegradable paper coffee cup and put them into two separate bins, or ensuring random trash isn’t thrown into the compost bin (e.g. foil, plastic wrappers, drinking straws, etc.) will no doubt be a significant challenge. Simply offering 100 percent compostable packaging in a restaurant may not work since people throw many things besides restaurant waste into restaurant waste receptacles.
Bin labeling is a challenge unto itself. Witness my recent experience at a local fast-food restaurant that composts. While I consider myself reasonably well educated on these kinds of things, I found myself standing for a full five minutes in front of three bins labeled, “Landfill,” “Recycle,” and “Compost,” trying to figure out which materials to put where. As three other customers glanced quickly at the labels then promptly dumped their waste in the bin marked “Landfill” I concluded that perhaps I really wasn’t overthinking it and that, yes, the bin labeling was in fact confusing. This suggests that implementing composting as a disposal option in places such as restaurants may require more than simply providing the option. Some substantial analysis and research may be needed in order to determine how to properly educate and direct behavior of customers and employees. Otherwise, composting may continue to play a smaller role relative to that of other disposal options.