Photo by Dylan de Jonge on Unsplash

What you start with is what you get.

In part one of this post, we established that people with a variety of goals all agree that organics is the next big thing. But now things get interesting because depending on the motivation that leads you to want to tackle organics, your final outcome may look very different.

While different processes will create additional products as well (e.g. biofuels, fertilizers, etc.), most organics management processes will claim to create compost. But keep in mind that different feedstocks and different processes create different products that they call compost. While there are some voluntary nascent compost classification standards within the industry, many regulations do not include classifications of different types of compost. That can lead to a lot of misperceptions because some of it may be a far cry from the stuff you think of for your backyard victory garden. At the risk of over-generalizing, when you manage organics, you are likely to produce one or three categories of compost.

Clean Compost

This is the stuff you typically think of when you hear compost, the “black gold” of backyard gardens and sustainable agriculture. This is one of the highest and best uses for organic wastes and typically provides the water retention benefits, nutrient benefits and soil tilth benefits that you think of when you think composting. However, the purity standards that people expect from your finished compost product may limit what you can include in the process. As a result, if the driving motivation is to maximize the amount of organic material that you divert from the waste stream, some of the materials that you want to target may not be compatible with this process.

Lightly Contaminated Compost

This is generally the result of a process that makes compost from contaminated feedstocks that result in “compost” with sufficient physical or chemical contaminants that it can’t be used in many applications (e.g. food production). You might see it in applications like highway median strips or other civil engineering applications where it provides some of the soil benefits of compost but in areas that are already a little contaminated and/or less sensitive to the contaminants in the compost.

Heavily Contaminated Compost

Or inert material – if your goal is just to stabilize organic waste so that it doesn’t generate methane in a landfill, this may be what you end up with. It won’t generate much methane (if any) in a landfill, but won’t do much else either. It may be applicable for some civil engineering applications and may be able to be used for things like landfill cover, but otherwise may not be much more beneficial than waste combustor ash (another way to stabilize the organic waste). Without aligning your goals to the products you are making, things have the potential to go awry. Let’s look at California’s SB1383 as an example. Despite what you have read in the news stories about a composting law, SB1383 is not a composting law. It does not charge the soil conservation service to ensure the production of high quality compost to apply to depleted soils. SB1383 is a global warming solutions law. It garners its authority from the California Global Warming Solutions Act of 2006 which deals with monitoring and regulating sources of emissions of greenhouse gasses. Specifically, SB1383 is about regulating short-lived climate pollutants (i.e. methane) from livestock operations and landfills. In its goals, it is much more like the European Union’s landfill directive which requires waste to be treated before it is disposed. As noted in this prior post, there is a distinct difference between treatment and recovery.

Here’s where it gets interesting

SB1383 requires municipalities to add food waste collection to their waste and recycling collection offerings. Many will do so by incorporating food waste into existing collections of leaf and yard waste so as not to add another collection bin and risk making things more complicated for homeowners. But, will this produce the same quality of compost, or will the food waste come with other contaminants that will lessen the quality or render some of that compost unusable? Landscaping wastes like fallen deciduous leaves, brush pruning and grass clipping generally do not come packaged. An awful lot of food does and some of that food packaging isn’t compostable. If homeowners aren’t meticulous in their separation, that packaging has the potential to add physical and chemical contaminants to the finished compost. If you’re a user of compost, will the new compost law make it harder to source the clean black gold you are looking for? Conversely, SB1383 requires municipalities to use finished compost. So if they focus on composting programs that make the best quality compost so they compost that meets their soil augmenting needs, will that mean excluding certain contaminated organics, organics that don’t make great compost, but still make methane when they’re discarded in a landfill? Will the advocates that want to maximize landfill diversion and ghg reduction accept that? Hopefully, if we learned anything from recycling over the last decade it’s that we need to preserve the recovery of materials to their highest and best use even when we go over additional materials that are not otherwise being recovered. Hopefully, these growing composting programs learn from that. Ideally, I could see California and other states developing a hybrid system, something like what the EU does with recycling and MBT facilities (what some in the US would call “dirty MRFs,” but with a biological recovery element as well). The advantage of that system is for recycling that the MBT facilities act as a backstop in concert with source-separated recycling programs. The source separated programs recover what they can for their highest and best use and the MBT facilities are used as a backstop to additionally recover or treat what the source separated programs missed. If such a hybrid system can be developed, it could both provide for the recovery of high quality feedstocks to make high quality compost to maximize soil health, and provide for the recovery and treatment of otherwise hard to recover materials (e.g. packaged food) or marginal materials which still cause methane issues in landfills even if they don’t make the best quality compost. If not, I wonder if the coalition of folks who think that organics are the next big thing will be as happy and cohesive in a few years.