Episode 9: Composting with Jeremy Brosowsky (Compost Cab)


So you've got some coffee grounds, a tea bag, and some random saw dust. These go straight to the trash, right? Not so much. Jeremy Brosowsky, the founder of Compost Cab, explains why composting is so important, how his company's business model works, and where the composting industry is going in the future (which is obviously into fresh soil).

Learn about more environmental topics impacting our natural environment here!

What We’ll Cover

  • What is compost?

  • How does composting work?

  • What can you compost? What can’t you compost?

  • Why is it important to compost?

  • What is the current state of composting?

  • A little bit about Compost Cab…

Why are we talking about Composting?

-Because composting is a double-win. It can reduce the amount of waste we are sending to the landfill and create nutritious soil that we can use to create more food.

-One of my favorite soil quotes (not that I have many soil quotes): “The nation that destroys its soil destroys itself” (FDR). Composting is one way that we can get access to healthy soil. .

What is compost?

  • Compost is simply decomposed organic material. (1)

  • Composting is a human-created process made to mimic- and accelerate- decomposition found in nature. It is intentionally managed to change organic waste into nutrients which can be put back into the soil. (1)

  • Food scraps and yard waste currently make up 20 to 30% of what we throw away and should be composted instead, according to the EPA.

How does composting work?

  • Compost needs water, air, food, and microorganisms.

  • Microorganisms eat, multiply, and convert the raw materials into compost as long as the environment is right.

  • Bacteria are the powerhouse of a compost pile. Bacteria make up 80 to 90% of the billions of microorganisms typically found in a gram of compost. They break down plant matter and create carbon dioxide, water, heat, and humus. Compost can get up to 100 to 140 degrees Fahrenheit. (2)

  • Larger critters such as worms, slugs and insects also digest the decomposing matter, excreting finished compost as they munch their way through. Their secretions improve the compost’s texture, binding small particles into larger crumbly bits. (2)

  • When adding raw materials to a pile, it's important to balance nitrogen-rich plant scraps (called greens) and carbon-rich leaves, wood chips, coffee grounds and even bits of paper (called browns). Compost scientists (apparently that’s a thing) say that you want to maintain a C:N raio somewhere around 25 to 30 parts carbon to 1 part nitrogen. 

  • If there is too little nitrogen, the microbes may not be able to raise the pile's temperature enough to kill most pathogens and dangerous bacteria in finished compost. But too much nitrogen and the tiny composters will not be able to handle it all, releasing odorous ammonia gas. In other words, too much carbon means decomposition slows down and too little carbon means you end up with a stinky pile.

  • Turning compost over with a shovel or pitchfork and adding dry, bulky material can allow oxygen back in and reduce smelliness. Other good moves for your compost include moving partially decomposed from one bin to another. (2)

  • The compost is ready when it no longer resembles its raw materials, which can take anywhere from a few weeks to a few months depending on how much inputs you have.

What can you compost? What can't you compost?

Here’s a helpful guide: http://eartheasy.com/grow_compost.html.

Why is it important to compost?

  • Every year, Americans create 254 million tons of trash- of which, 167 million tons end up in a landfill. This Municipal Solid Waste (or MSW) is basically everything thrown away after being used. (4)

  • About 96% of food that could be composted ends up in landfills and incinerators. (4) In 2013, this wasted food was more than 37 million tons. (5)

  • If you’re looking for some analogies, that’s the same as… (6)

    • 18, 556 Olympic-size swimming pools filled with food waste

    • In blocks of one foot by one foot by one foot, these blocks to go all the way to the moon and back ⅓ of the way

    • Covering the entire space of a football field with food waste, the stack would reach almost 29,000 feet, almost as high as Mount Everest.

  • Keeping waste out of landfills is important because the food in landfills has no access to water and oxygen and rots. This rotting produces methane gas, which a very strong greenhouse gas with more than 21 times the global warming potential compared to carbon dioxide. (7)

  • Additionally, composting creates high quality soil. This grows food better, improves water retention in the soil, supports native plants, and reduces the need for fertilizers and pesticides because of higher soil health and structure.

Current Access to Composting

  • According to the Compost Council, about 200 U.S. communities have curbside food waste collection. Over 2.55 million households across 18 states are served by curbside food scrap collection programs. Between 2007 and 2012, the number of households served by curbside compost collection grew by 239% (10).

  • A 2014 BioCycle study looked at 4,914 composting operations across 44 U.S. states and found that about 71% compost only yard trimmings. Clearly there is room for growth in the composting of both food waste and biosolids (waste-waste from humans and animals) (10).

A little bit about Compost Cab

  • Compost Cab picks up compostable materials from homes and businesses in the District of Columbia and turns that “trash” into soil. (8)

    • Costs $32/month

    • Has more than 500 subscribers

    • Customer base is 5 times larger now than it was in 2011

  • What does the customer get? (9)

    • A countertop collection basket and an airtight bin lined with a compostable bag to minimize smells and keep away rodents

    • Compost Cab picks up things in the bag once a week

  • Company rule: “If it grows, it goes [in the bin to be composted].” (9)

  • Compost Cab also picks up at the Dupont Farmers market, Hyatt Regency on Capitol Hill, and Qualia Coffee, and delivers the waste to urban farms like Eco City Farms and the Washington Youth Garden.


  1. http://organicgrowersschool.org/for-gardeners/composting-101/ 

  2. http://www.livescience.com/32719-how-do-compost-piles-work.html 

  3. https://www.epa.gov/recycle/composting-home 

  4. https://www.epa.gov/sites/production/files/2015-09/documents/advncng_smm_infogrphc.pdf 

  5. https://www.epa.gov/sustainable-management-food/sustainable-management-food-basics#what 

  6. http://bigoxenergy.com/how-much-food-waste-goes-to-landfill-in-the-us/ 

  7. https://www.epa.gov/sustainable-management-food/sustainable-management-food-basics#what 

  8. http://www.elevationdcmedia.com/features/socialentrepreneurship_081914.aspx

  9. https://www.washingtonpost.com/lifestyle/food/2012/11/26/3b531338-3288-11e2-9cfa-e41bac906cc9_story.html 

  10. https://smartasset.com/mortgage/the-economics-of-composting