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Food scraps from businesses will soon be turned into fertilizer and biogas

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Even the smallest among us can play a role in protecting our planet.

Consider the mighty microorganism.

These wee ones will soon be joining forces with foodservice businesses and our regional and local governments to manage big-scale problems such as turning tens of thousands of tons of food scraps into fertilizer and biogas, and curbing climate change.

Food is the biggest component of what the greater Portland area throws away — enough food to fill 5,000 long-haul trucks a year. More than half of that food comes from businesses. When food gets to a landfill, it rots and generates methane, a potent contributor to climate change.

Two big changes are coming to our region that will put food scraps to better use: 1) new business food scrap requirements and 2) a new “anaerobic digester” that will turn food scraps into fertilizer and biogas.

Business food scrap requirements gear up this spring

Four green compost roll carts are shown under a calendar with the date March 2023. Next to it are 2 compost roll carts with a Sept 2023 date. Finally, one compost roll cart is shown under Sept 2024.

For more than 15 years, Metro and local communities have worked to keep food scraps out of landfills and put them to better use. Today, food scraps from participating restaurants, grocery stores, and other businesses across the region are converted to compost at nearby facilities.

Despite these voluntary efforts, a lot more food can be captured. Food scraps diversion has stalled out at about 24,000 tons per year.  So Metro Council adopted an ordinance that requires food service businesses in the Metro boundary to separate food scraps from garbage. Under the new ordinance an estimated 59,000 tons of food scraps will ultimately be collected per year.

Portland and local governments in the region have begun notifying food service businesses of these requirements as well as the technical assistance and resources available to help them make the transition.

Learn more about the requirement

How do businesses get started?

Every business can request free assistance from waste reduction specialists to help determine when they need to comply with the requirement and provide free tools such as internal collection containers and labels. Specialists can also provide technical assistance on how to set up food scrap collection, donation and waste prevention practices. 

How to set up compost at your business

Biogas anaerobic digester under construction

Currently food scraps from participating businesses go to nearby facilities in our region. These facilities work with air-loving microorganisms. Compost is laid out in large rows that are regularly “turned” to give the microorganisms air and mixed with yard debris to give them carbon to eat. Then these microbes do the work of turning our waste into fertilizer. This type of composting is ideal for residential material because homes provide a lot of woody debris from yards.

Compost from the food service industry doesn’t have yard waste and can be harder to manage in compost piles. The food scraps from businesses are also high in nitrogen and are ideal for feeding the type of organisms that don’t like air. In fact, if you deprive these organisms of air, they become active and create biogas that can be captured for fuel.

Our region is poised to start working with these non-air-loving microorganisms!

Poop to Power

Photograph of a City of Portland truck being fueled at an RNG fueling station located at the Columbia Boulevard Wastewater Treatment Plant

The City of Portland Columbia Wastewater Treatment plant has been capturing gas from sewage for years, generating heat and electricity to power the plant while selling a portion to a local business. But even with this reuse, some methane is still burned off, released to the environment as carbon dioxide.

Through the Poop to Power Project, Portland is on its way to maximizing the reuse of the methane produced at the treatment plant and turning this waste into a valuable resource. The City is retrofitting the treatment plant to receive food scraps and will deprive microorganisms of air to create biogas. The resulting renewable natural gas (RNG) will be used to replace dirty diesel in commercial vehicles. 

Once the system is operational, food scraps from most of our region’s businesses will be sent to this “anaerobic digester”. The food scraps will be mixed with the treated sewage and fed to the microorganisms that produce biogas. There will also be a final product that makes excellent fertilizer for agricultural use.

Food scraps versus wasted food

These two new programs are all about putting food scraps to better use. Food scraps are the leftover materials after prepping food to be eaten. Orange rinds, banana peels, carrot tops, eggshells are all ideal for food scrap composting.

However, edible food has its greatest benefits if it is eaten.

Project Drawdown identifies reducing wasted food as the second most important action we can take to curb climate change. Their scientists say, “A third of the world’s food does not make it from farm or factory to fork. Producing uneaten food squanders a whole host of resources—seeds, water, energy, land, fertilizer, hours of labor, financial capital—and generates greenhouse gases at every stage.” Interventions can reduce wasted food, thereby reducing overall demand on our planet.

Meanwhile, 1 in 4 Oregonians are food insecure and could use the food.

Businesses can find resources on food donation, tips on tracking food and strategies to avoid wasted food through Metro’s page on Preventing Food Waste. Businesses can also request assistance from a waste reducation specialist.

This blog post was written by the Master Recycler program. Read more articles from the Master Recycler program.