Closing the Loop on Food Waste Through Composting Systems

An op-ed about how composting food waste can help Hawaiʻi build a closed-loop food system — reducing emissions, cutting costs, supporting local agriculture, and turning waste into a valuable resource for farmers.

Retrieved from: Granger Waste Services

Food is a precious and vital resource, but so is food waste. In creating systems to better reuse food waste, Hawaiʻi could capitalize through developing effective composting programs that would reallocate food from our landfills. There are a multitude of benefits to keeping nutrients local in streamlining the ability to transform food waste into compost. We can increase the supply and availability of soil supplements, making them more affordable for Hawaiʻi farmers, strengthen agricultural production, decrease the state’s carbon footprint, and meet our local food goals by creating a closed-loop food system.

The Current State of Hawaii’s Food Waste:

Right now, Hawaiʻi wastes about 237,000 tons of food each year. That’s more than $1 billion worth of food, about $700 per person. On Oʻahu, food waste is 20% of everything we throw away.

Most of this food waste is sent to H-Power. H-Power, a waste-to-energy facility on Oʻahu which generates revenue primarily by selling electricity produced from burning municipal solid waste to Hawaiian Electric (HECO). H-Power burns trash to make electricity, but it also burns food scraps and yard waste that could be turned into compost. This means we lose important nutrients that could help our soil and crops. And burning waste also creates pollution, going against our environmental goals. While it earns around $65 million annually, operational costs sometimes exceed revenue, requiring city support to cover losses. Overall, its funding comes from electricity sales and city-backed financial support.

The Benefits of Composting:

Composting is a process that involves recycling organic matter– like food scraps and green waste–and transforming it into a nutrient-dense soil amendment. Composting decreases the amount of waste sent to landfills and incinerators, which additionally reduces the monetary and environmental burden of processing food waste. It also provides an opportunity to support local green jobs and economies rather than shipping out food waste to be processed by H-Power. Composting also helps to “close the loop” on waste by recycling organic waste and adding it back into the system. Nutrients from the food that keeps yourself and your ʻohana healthy can be recovered from food waste and used to feed the soil to grow even more food.

Retrieved from: U.S. Environmental Protection Agency

One man’s trash is another man’s treasure, right? Well, this is why farming communities refer to compost as “black gold”. Food scraps that are typically thrown in your trash can be transformed into a dark, nutrient-rich substance that can be used by local farmers as a soil amendment, seed starter, or Earth-friendly fertilizer. Compost helps to revitalize poor soil by enhancing microbial activity, supplying nutrients, and suppressing plant diseases which promotes plant growth and yields. The use of compost by local farmers can also decrease reliance on imported chemical fertilizers and soil amendments which are costly to their wallets and the ʻāina. Increasing accessibility of local compost to our farmers encourages sustainable agricultural practices like regenerative farming which aids in the growth and viability of local farming operations.

Current Food Waste Efforts:

The O’ahu Compost Pilot Program aimed to implement a closed loop system for food waste to be turned into compost for local agriculture, and ran from January 2023 to January 2024 by the Office of Resiliency. By taking food waste from 8 restaurants in Chinatown, they kept food waste out of landfills and the H-Power incinerator, as well as reduced reliance on imported soil nutrients. The program created 39,537 pounds of compost to be distributed to local farms, diverted 30,000 pounds of food waste, and reduced carbon emissions by 8.12 tons of CO2eq by avoiding the use of incinerators. The pilot program was a success in using a closed loop system for food waste, and demonstrated our island agriculture could become more accessible through the implementation of a compost program that supplied local farmers.

Efforts by the county and city of Honolulu include recycling food waste through the help of Hawaiian Earth, who provide organic soil and compost on O’ahu and Big Island. As well as current legislation that would ensure curbside collection of food waste and manufactured compostable materials by April 1, 2026. It’s encouraging to see our city push for sustainable solutions to food waste, and it’s important that as a community we take action to support local agriculture.

Retrieved from: The Office of Climate Change, Sustainability and Resiliency

Conclusion:

As a state that imports a vast majority of our food, but is still wasting 237,000 tons of food annually, composting can be a solution to offset this massive waste. By using the H-Power incinerator to avoid landfill use, we are wasting soil nutrients and producing gas emissions that contradicts our sustainability and food security goals. Implementing a closed loop food system in Hawai’i would drastically cut down on our food waste through composting, and give back to our agricultural community. As seen in the success of the Oahu Compost Program, and other organizations that work towards reducing food waste through composting, it would be highly beneficial for Hawai’i to work towards a closed loop system of food waste management.

About the authors

India Buchanan is a sophomore at the University of Hawaiʻi at Mānoa majoring in Political Science and American Studies. Raised on Maui, she is passionate about food sovereignty and exploring how political systems impact Indigenous agriculture and sustainability in Hawaiʻi.

Alisa Elshout is an Anthropology student at UH Mānoa with roots in Belgium and New Zealand. Her experiences working at the International Student Services office and volunteering on local farms have deepened her interest in culture, agriculture, and the power of policy to create meaningful change.

Sydney Haas is a farm assistant at Lokoea Farms and a Food+ alum. Originally from New York, she holds a master’s in Sustainability from Hawaiʻi Pacific University, where her capstone research explored Oʻahu’s food hubs. She brings a strong background in nutrition and a deep passion for regenerative agriculture.