Why Composting is Critical
- Only 60 Years of Farming Left-Scientific American
- How Compost Boosts Carbon Capture-Science Alert
- Can Dirt Save the Earth- NYT
- Wasted! The Story of Food Waste, movie
- What Soil Is and How Industrial Ag depletes it
- Storing Carbon in Soil: Manchester Cricket
- Statewide Composting, GHG and Economic benefits: Biocycle
- Study: Farms save money, more crops, better soil, better environmental impact with compost
- Summary of composting benefits and Black Earth Compost's role: HIngham Anchor
Composting, Farm Digestion, And Wastewater Treatment Plants
Farm based AD, where food is mixed with manure, creating electricity and also a liquid fertilizer that can be spread on that same farm, is a better form of AD because the nutrients go back into the food chain. The problems with both forms of AD is that they are less suitable for residential waste because compostable bags (a necessity for residential programs) can’t get put through this process easily. Neither can many of the forms of carbon that are very common. Compostable cups, forks, leaves, and other rigid compostable items end up getting trashed because they don’t liquify. Residential programs are very high in these carbon sources. Large commercial stops are therefore more suitable for AD than residential collection.
AD is more expensive to operate, requires a very high upfront investment that takes decades to payback, is very particular in its recipes, and less adaptable. Finding places to bring the liquid fertilizer, of which there is significant amounts, in winter can be a challenge. Compared to composting, generally it is much more challenging and expensive but can handle much higher volume on a smaller footprint, and less odor for that footprint. It is best suited for very large commercial loads with low carbon. On-Farm AD is a great resource for large commercial organics diversion, especially with high contamination like packaged materials that get depackaged in the first step.
Composting is great for the smaller commercial and residential materials high in carbon. It breaks down carbon from wood, leaves, horse manure shavings, compostable bags, cardboard, etc. It has much less upfront investment than AD. Therefore it is easier to start and shut down a compost site than an AD. It has less ability to control odors and vectors and less capable of handling such large volumes of food waste. The resulting compost from food scraps is very rich in nutrients and excellent for gardens and yards.
While you might say composting is the winner here (or that we're biased), there isn't enough capacity in the state to compost a large percentage of the organic waste stream. Land is tight here in eastern MA, and AD works well to manage high loads of organics. So Black Earth partners with both Vanguard Renewables and Agri-Cycle Energy to send a portion of collected material most suitable to their farm based AD.
In WWTP digestion, the food scraps collected get slurried and what can liquify gets added to sewage sludge to help create methane gas. Figures suggest 13-20% of that gas created is flared off (a source of CO2), 3-5% is leaked (methane is 25x worse than CO2 as a heat trapping gas), the rest is converted to electricity to run the plant and excess power is sent to power nearby houses. The resulting material is then dried and is more suitable for landfill cover and roadside remediation than it is for growing food. We believe in the recycling of sewage and that investment in WWTP should be targeted towards better filtration of modern contaminants like pharmaceuticals, microplastics, PFAS, heavy metals and more, and less for taking food waste that could go to farm based AD or composting.
Mandatory Compost Supplementation to Soil
Compost reverses global warming through deep carbon storage, AND reinvigorates out our ability to grow food. A major challenge being in MA, is that the vast amount of food we eat comes from outside New England. So we are a net importer of nutrients, and it is not cost effective to ship compost out of the area. We must expand our outlets of where compost should be used to make sure the whole system works. If compost manufacturers over-produce compost, the price plummets, and the cost of collecting food waste rises to offset that. Cities on the west coast know this and have implemented mandatory uses for adding compost to post construction soil to help cities manage rain water run-off problems due to composts' ability to soak in moisture like a sponge: https://kingcounty.gov/depts/dnrp/solid-waste/programs/green-building/home-builders-owners/soil-standard.aspx
So step one is to divert the organics, and step two is to make sure compost has end markets. I would argue step two should be combined limiting our chemical warfare on the environment with an effort to decrease chemical fertilizers due to over fertilization causing algae blooms, low oxygen in the water, and depleting fish stocks. And even more important, restricting the use of pesticides and herbicides.
Illinois has a new law requiring municipalities, DOT, and other state agencies to use of compost:
PFAS and Contaminants in Drinking Water
PFAS are a class of chemicals that are used in a plethora of common household materials like waterproof clothes, furniture, teflon pans and other cookware, fire extinguisher foam, grease resistant paper products, carpets, cosmetics, and more. Just like the rest of the environment and our homes, composts can contain PFAS residual as a result of society's use of these chemicals. PFAS act as grease and water barriers that protect paper fibers in food packaging from becoming soggy. Over the last 15 years some PFAS chemicals have been phased out in the US and as a result, their levels detected in humans and the environment have been dropping.
With most environmental contaminants, as a society until we stop producing PFAS chemicals for use, we will continue to see these 'forever chemicals' in our households, environment and drinking water. We at Black Earth Compost do extensive testing to ensure our compost is high quality. We have rules on what we can accept. We grow food out of our compost that we feed to our families too, so we want to create a very healthy compost that we can use ourselves. This is why we continue to require everybody use BPI certified compostable food service packaging. BPI has a very strict threshold regarding PFAS that is in sync with the European standard.
The primary concern for us is to be careful on getting the right paper products, especially pressed fiber products such as trays, plates, and pizza boxes. That's why we ask that "when in doubt, throw it out". Seek out BPI certified compostable products and inquire respectfully to business owners about certifications they require for their compostable service items. With the public's recent awareness of this issue we can push for adoption of BPI's high standards and leadership. Bottom line: use BPI certified stuff not for composting's sake, but because you don't want PFAS in your food.
List of BPI certified items...
-CEH comprehensive list of PFAS-free compostables
-EcoProducts 'Vanguard' products (Limited availability currently)
-Earth To Go - http://earth-to-go.org/ -Trays and plates
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