Composting food scraps instead of landfilling significantly reduces methane emissions. Landfills are the single biggest source of anthropogenic methane production. Methane is a powerful greenhouse gas that traps 28 times more heat per molecule than CO2 making it a significant contributor to climate change.
Let’s dig into it…
The two types of decomposition relevant to this discussion are: aerobic and anaerobic. Both types occur in nature and both are facilitated by humans, on purpose and inadvertently. These two processes involve different microorganisms, have different byproducts and produce different end products. The main difference between these two types of decomposition is the presence of oxygen. Aerobic decomposition occurs in the presence of oxygen while anaerobic decomposition occurs with little to no oxygen present.
Compost is made through a process of controlled aerobic decomposition of biodegradable materials. The byproducts of aerobic decomposition are water, heat and biogenic (aka produced by living organisms) carbon dioxide.
In landfills, most of the food scraps and other organics are inside plastic bags that are buried then compacted. This compaction reduces pore space and squeezes air (oxygen) out of the piles creating an anaerobic environment. The idea that composting facilities can produce methane is not unfounded, however, excess methane production in a composting facility may be a result of mismanagement and failure to adhere to best practice methods.
So, does Compost Crew do aerobic or anaerobic composting?
We employ a number of management practices to ensure that our decomposition is aerobic at our Compost Outpost® sites.
Composting is a biological process and, in that way, we don’t technically make compost. We facilitate a habitat for aerobic microbes and other aerobic decomposers to do that work for us! Meanwhile, we stock their home with plenty of food scraps (nitrogen), wood chips and leaves (carbon), water and oxygen!
Our microbes prefer a balanced diet, so we monitor the carbon to nitrogen (C:N) ratio closely. Our crew members track the weight of our incoming food scraps and calculate how much carbon feedstock we need to add to each pile for an optimal C:N ratio.
Unlike the compaction that occurs in landfills, compost piles should be light and fluffy. We use woodchips, a carbon source, as a bulking material to build structure and create pore space in our piles. This ensures that air can move freely through the piles, preventing incidental anaerobic decomposition and the methane production that results.
We’re not only turning our back on landfills or turning food scraps into compost. We are physically turning the compost piles! This turning is done mechanically, with a machine like a skid steer, a compost windrow turner or even a shovel. Aeration can also be achieved by using blowers to force air into an Aerated Static Pile (ASP). In our primary phase of processing, our Compost Outpost containers pump air into the piles on a timed aeration cycle. We monitor moisture, temperature, and oxygen levels to maintain optimal ranges, making adjustments as needed. All of this ensures optimal conditions for our hard-working microbes.
Compost Crew also drops off a portion of the food scraps we collect at local commercial composting facilities who use similar methods at a much larger scale. We also partner with a large anaerobic digester in Maryland that captures the methane produced by the anaerobic process and pipes it into the grid to be utilized, just like natural gas in peoples homes!
I want to avoid methane emission the best I can, what steps can I take?
We should be mindful of getting the most out of food. There are many choices we can make about food before considering how we dispose of our scraps. To limit the amount of food that is wasted, we need reform at every level of our food system from farming practices, harvesting practices, storage, distribution, utilization with disposal of waste coming at the end of a long list of alternatives.
Stay tuned to our blog for more composting news, tips and more.
