Not Your Grandma’s Composter

This week’s blog is a guest post written by Nathan C., a Drummers and Gobblers alumni. Nathan is currently studying engineering at the University of Pittsburgh. Now and in the future, he hopes to work with others to create more sustainable technologies and perspectives. Whether that be in photovoltaic cell manufacturing, vertical farming, energy storage development, or something else ultimately remains to be determined. Nathan enjoys fishing, gardening, cardio, and taking naps. He came to the WLA first as a student and then twice as a volunteer to get closer to that which I hope to help preserve.

At some point—while enjoying a meal, you may have once found yourself thinking about all the effort and energy that must have gone into your food. Your drifting mind begins to grow appreciative of the many strangers, acres of land, and cunning logistics that went into providing that which lies before you. However, what is less likely to be food for thought, as you so musingly chomp away, is what happens to the remnants of your meal. It’s only natural. When thinking about waste, most people are used to separating it into two categories: recyclables and trash. Some go further and compost a select variety of produce such as coffee grounds and fruit scraps. This is great, but what about larger, organizational settings such as school cafeterias, restaurants, or grocery markets? Here each day, thousands of metric tonnes of food waste are thrown away nationwide.1 Thus increasing the size of ever-growing landfills while simultaneously releasing copious amounts of methane and CO2 as the food rots. In fact, a disheartening 8% of all man-made greenhouse gas emissions stem from decomposing food waste.2 Roughly double that of the entire airline industry.3 All of this at a time when, nationwide, the proportion of crops requiring synthetic fertilizers continues to steadily increase.4 Couple our growing dependence on fertilizer with a recently decreased global supply of it due to the ongoing war in Europe, and we can see the makings of a very serious problem. Changing all of this would require putting a stop to the predominantly linear nature of our modern food chain, to find a way to efficiently convert end-stage waste into something that could aid in the growth of new crops or animals. Some comically large compost bins might be coming to mind right about now, but as a team of environmentally conscious engineers and entrepreneurs in Pittsburgh are showing—there’s a far more scalable and lucrative solution that is helping close the food loop right now. Wherein a wide assortment of consumer-stage food products have their mineral, nutrient, and water content recycled, all while directly capturing emissions and generating electricity to boot.

I’d like to introduce you to ZEUS (a Zero Energy Up-cycling System). While not particularly pretty, your jaw may still find its way to the floor after you learn what it’s capable of. The first mid-scale anaerobic digester unit produced by Ecotone Renewables exists within the constraints set by the internal dimensions of this repurposed shipping container. Here, 385 lbs of food waste are processed weekly. Anything from uncooked meats and soft bones to fruit and vegetable matter are fair game. And, unlike traditional composting, Ecotone’s process is capable of converting solid food waste into a well-balanced, microbe-rich fertilizer in a mere 20 days. This much-needed, carbon-negative black gold diverts 90 lbs of CO2 per gallon. How is this possible? Well, traditional fertilizers are partly manufactured via the Hobber-Bosh method, a notoriously energy-intensive way to enrich nitrogen (approximately half of all the energy consumed in modern agriculture goes to produce fertilizer).5 Ecotone skips out on that, instead opting to maintain a carefully selected culture of bacteria that helps kill food-borne illnesses while breaking down more complex macronutrients into plant root accessible compounds containing nitrogen, phosphorus, and potassium. Furthermore, Ecotone captures all biogasses generated during anaerobic digestion, filters them, and in the end isolates methane. A gas which is 84X more effective at retaining thermal energy within the atmosphere than CO2. Instead of releasing it, this gas is burned to generate 135 kilowatt-hours of energy per week! Now if you know your chemistry you might be saying hold on a minute, but doesn’t burning methane release CO2? This is true, but the methane gas, which would still be generated where the food waste left to rot in a landfill or composter, is instead captured and turned into a gas which is both 1/84 as potent as before and the target of multiple emerging carbon capture technologies. And remember, the energy generated meets some of the system’s demand which would otherwise have to be supplied by a power company.

While not appetizing to you or I, the bacteria inside the apparatus aptly nicknamed “the stomach” will quickly consume the contents of all three buckets.
The deep water culture hydroponic setup (left) and some recent yields (right)

Perhaps best yet, this story is still developing. Towards the start of the summer, I joined Ecotone as an intern and have since seen firsthand what well-intentioned, disciplined individuals can accomplish when working together. Not to mention the impressive efforts of nearby community gardens, farms, and other ag-tech startups with whom I have had the pleasure of collaborating with. Once I finish this summer’s hydroponic and vertical farming compatibility trials (both of which are looking to be promising Soil Sauce applications) and have accrued enough experience servicing the system’s circuitry and equipment, I will look to transition into a more technical role. Here, I hope to work with other bright minds, directly contributing to the rapid iteration of more energy-efficient, easy-to-maintain designs. Presently, there is much underway with new systems under construction or design: from a more user-friendly experience thanks to the introduction of an automated, non-organic item detection system ‘learning’ to pick out metal and plastic debris from incoming waste to the development of a more efficient and reliable integration of methane-based generators. These are exciting times for those hoping to engineer a more sustainable way of living. If you, like I, respect those working within wildlife conservation but don’t see yourself entering the field, there are still MANY other tangible and desperately needed ways you can benefit the environment, your local communities, and the world at large.

Three years of use and this shirt still looks good 🙂

At a WLA field school, the close quarters and hard times can act as the perfect pair of conditions to forge a strong friendship. But how can you maintain such a relationship once your program ends? To better answer that question, I highly recommend reading the NextGen post written by my old friend and former field school team leader, Wulfgar Ramesy.

The photos used in this blog belong to the author.