In part one of this post, I talked about the difference between treatment and recovery. Treatments are processes applied to a material or combination of materials. Recovery is the type, quality and quantity of commodities that are recovered from applying that process. That is an important distinction, especially when you hear about various treatments for managing organics.
The solid waste industry has been treating organics in various forms for eons, with varying types of recovery. There was once a time when pig farmers would go door to door like the old rag men picking up food waste to feed to their pigs, at least from those households that weren’t composting it themselves for their own backyard victory gardens. Those treatments recovered materials for use as animal feed or important garden soil amendments. In some parts of the county local waste hauling companies grew out of those early pig-feed collection programs.
Even landfills are a form of organics treatment. Organic materials decompose anaerobically in a landfill and result in the generation of methane. Since the days of the early dump fires where that methane would leak out of a landfill and catch fire, the solid waste industry has been doing something to manage organics. First it was methane gas flares, designed as a treatment to suck out that methane, and do a controlled burn to keep the dump from catching fire and burning out of control. That was a treatment, that in modern terms, helps to mitigate the release of methane a greenhouse gas more than 20x as potent as the CO2 those flares emitted. Later, those treatments evolved and that methane was burned to make electricity or was extracted and purified to make transportation fuel for trucks. Those treatments added an additional recovery component that was absent from earlier landfill-based treatments. But while those were all forms of treatment, there was room for improvement regarding how much of the methane was recovered and how much electricity was made. Combustion-based waste to energy facilities offered an alternative form of organics treatment in which more energy was recovered and far less fugitive methane resulted than with landfill treatments. But that combustion treatment did not provide any recovery of animal food or soil-amendment commodities.
Now, there are some treatment options that have potential to recover both methane for energy and organics for use as soil amendments. But the breadth of what you apply that treatment to can impact what you actually recover. As discussed in part one, applying a treatment to more tons does not necessarily yield more recovery. Starting with clean source-separated organic feedstocks will generally yield cleaner more marketable amendments. The more contaminated those feedstocks are (which can occur even with persistent chemical contaminants in otherwise source-separated organic feedstocks), or the more you have to extract them from other wastes which may cross-contaminate them, the less viable your amendment recovery may be. Maybe the contaminants impact the quantity such that you recover far less than what you applied the treatment to. Or maybe it impacts the quality or perception of quality such that those amendments or fertilizers that your process produces are unmarketable and have to be discarded. If the only thing your new treatment recovered by diverting organics from the landfill is the same methane you would have recovered had you let it anaerobically decompose in the landfill, does your treatment have the impact that you think it does? Is it a better option than a different treatment which is applied to fewer tons but which yields a greater recovery? Other modern treatments can break down food waste, essentially a microbial garbage disposal that turns food waste solids into liquids and makes food waste “disappear.” But if you don’t recover either energy or nutrient from that food waste, what does that treatment gain you?
Many people agree that something has to be done about food waste. Now that so many other recyclables have been pulled out of the waste stream, food waste is one of the biggest components left, and one that has a myriad of treatment options. But before you commit too fully to any one treatment, ask yourself: what is the impact and recovery you hope to achieve?