Recycling: What’s Included?

In my article Refining the Definition of Recycling, I explained where the EPA and I differ on the definition of recycling. Whether the differences are substantive or semantic will depend on how the EPA applies it’s definition. For that I cruised this page, which turned out to be a good starting point.

Overall, the EPA did confirm that my differences are substantive. First, they don’t ever address the idea that one can recycle a by-product that was never intended for the waste system. I am not surprised and I am fine with that.

Even within their own definition of recycling, my concerns remain substantive. They do not account for pre-consumer waste, human waste, or by-products that never enter the waste stream in recycling estimates. In addition, they leave out waste-to-energy (WTE) processes.

That said, I was pleased with the EPA’s documentation and I am interested in their more encompassing models. In fact, they are making efforts to estimate other waste by-products that leads me to believe we are more aligned on definitions than I suspected.

Below are some observations related to the differences in opinion on recycling.

  1. Post- and Pre-consumer waste

In their national overview of waste and recycling, the EPA refers to waste as Municipal Solid Waste or MSW. Generally, the definition of MSW has gone through some changes. From what I can tell, early uses referred to waste entering the municipal waste stream, collected by the municipality, either directly or through contracted collectors. The EPA uses the phrase to refer to post-consumer waste broadly, with less regard to who collects it (municipality or private haulers) or generated it (households or businesses). Generators of MSW include households and businesses, including restaurants, apartment buildings, corporate offices, etc.

Post-consumer waste are by-products from the consumption of a final good. This isn’t a perfectly delineated concept, but you can think of this as the food waste from making dinner, or from a restaurant. Whether it’s from preparing the food or leftovers on the plate, but it’s close enough to the final good. What is excluded is pre-consumer or industrial waste, i.e. by-products generated from producing another input into production. By ignoring the recycling or reuse of pre-consumer waste, a part of the economics of recycling is missing from the story. From The Economics of Waste,

For example, though postconsumer plastic is still little recycled in the United States, 95% of all preconsumer plastic scrap was already being recycled a decade ago (OTA, 1989b)

2. Incineration as Recycling

Incineration or combustion involves burning the materials, which reduces volume and makes materials cheaper to dispose in a landfill. A by-product of incineration is all the heat produced as a result of combustion, which can be converted into energy. The process by which waste is used as a way to produce energy is called “waste-to-energy” or WTE. In the United States in 2018, waste-to-energy by incineration accounted for 34 million tons of solid waste processing.

Is WTE recycling? Absolutely — not only by my definition, but as well as the EPA’s. Looking at the EPA’s definition of recycling, electricity certainly qualifies as a “new product” and the materials used to create the energy qualify as would “otherwise be thrown away as trash”. In fact, that is why the trash is being incinerated. However, waste-to-energy is not included in the EPA’s recycling estimates, nor is it discussed as a way to recycle waste.

If waste-to-energy was added to the recycling rate, the recycling rate would increase by about 37% from a rate of about 32% to a rate of about 44%.

3. Human Waste Treatment as Recycling

Another by-product missing from the conversation is human waste, in particular that which is carried away by water. Much like pre-consumer by-products, it is excluded from MSW entirely, so it is neither in the denominator nor the numerator of recycling rates. It is not intuitive to me why human waste doesn’t qualify as a post-consumer by-product or why water treatment isn’t recycling. You could say that it’s reuse and that treatment of the water is “maintenance”, but I don’t see it that way. Many societies have sourced human waste as an input into the production of fertilizer and I don’t see how sourcing human waste in the production of potable water is any different.

I didn’t pull any national data, but Washington, DC is home to one of the most advanced water treatment plants in the country, treating about 300 million gallons of water a day, or about 1.3 million tons. I am not sure if this number is the total amount of water entering the system by volume or the amount of potable water leaving the system, but this is only for one metropolitan area.



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