Restaurants across Oahu are more than three months into a phaseout of single-use plastics, but there’s still nowhere on the island that can compost most of the single-use compostable utensils, cups, and takeout containers that businesses are supposed to offer in place of plastic.

“We have the capability to do it here, but we don’t have any of that technology at scale,” said Nicole Chatterson, founder of Zero Waste Oahu and longtime advocate of the plastic ban.

The Honolulu plastic ordinance, which passed in 2019, was delayed four months during the pandemic. And while advocates say it’s a good first step in reducing waste, alternatives are presenting their own challenges.

Kamilo Beach Microplastics Caps Debri
Thousands of tons of plastic, like this assortment on Kamilo Beach, wash up on Hawaii’s shores every year. Kuʻu Kauanoe/Civil Beat/2020

“By and large restaurants are using PLA which is often corn-based and that will not break down in your home compost pile,” Chatterson said.

Honolulu’s restaurants and consumers became even more reliant on single-use items during the pandemic. Takeout and delivery increased and many restaurants and coffee shops are still not accepting personal reusable containers, even if they welcomed it before the pandemic. That’s all led to an increase in compostable containers that have nowhere to go but the trash.

Honolulu City Council Chair Tommy Waters said that the aim of the ordinance was to reduce plastic pollution, and he’s already heard positive feedback from constituents who said they’ve seen less plastic.

“That was the whole point of the Ordinance — to reduce the single-use fossil fuel plastics that are drowning our beaches and oceans, and replace them with safer materials like paper and plant-based plastics,” he said via email.

While there are no plans to build public composting on the immediate horizon, Waters said passing the plastic ordinance makes it easier to pursue large-scale composting in the future.

“Once the waste stream has less plastic in it, we can definitely look at the idea of a separate composting facility and the sorting process that would be required for that,” he said.

In the meantime, there are private groups working to find a balance between sustainability and convenience. The island’s first large-scale composter is being tested in Waimanalo. A recent University of Hawaii graduate invented a process that can recycle bioplastic while producing clean energy and Chatterson is working on a reusable takeout container program on the North Shore.

“The most sustainable solution is to use what you already have,” she said. “But there’s always going to be visitors and folks who can’t or feel too overwhelmed to think about bringing their own reusable.”

Large-Scale Composting

Rafael Bergstrom, the executive director of Sustainable Coastlines Hawaii, said one of the main reasons he wanted businesses to replace plasticware with compostable items is because plastic is made from fossil fuels.

“While it’s not the best to still be using something once and throwing it away, it is better in the sense that we’re getting plastic out of our waste streams,” he said.

While there are compostable food containers that are made completely from natural fibers and can break down in a backyard compost bin, most compostable dinnerware is made of bioplastic. Bioplastic is made from starchy crops, usually corn, and is popular because it retains many of the benefits of plastic, like being lightweight and strong.

But that strength means it requires a high-heat commercial composter to break it down. Although Bergstrom says using these bioplastics is better than single-use plastic, he recognizes that single-use items made from bioplastic are still wasteful. So he helped set up the first commercial composting machine on the island in a 20-foot shipping container.

The composter can process up to 1,000 pounds of food waste per day. Courtesy: Sustainable Coastlines Hawaii

“We just finished adding a solar system to it so it’s going to be run completely off-the-grid,” Bergstrom said.

The use of a shipping container alleviated many of the health department’s concerns about smell, pests, and stormwater runoff, said Bergstrom. He’s still working on the permitting process, but he hopes to bring the composter to events like surfing competitions so attendees can know that their food waste and bioplastic plates, cups, and utensils will have another life.

It cost Sustainable Coastlines Hawaii between $70,000 and $100,000 to set up this first composter. Bergstrom hopes costs will decrease as the operation scales up and hopes to one day see composting units in communities across the island.

The shipping container in Waimanalo is still a pilot project and they partnered with a local farmer to test how different mixtures react under different circumstances. This is important for Bergstrom because he said self-contained composters like this would be more economically feasible if the owners could sell the finished compost.

The testing is important because there’s no guarantee bioplastics are safe to compost.

“We don’t know what those bonding chemicals are — it’s proprietary information — so whether they’re toxic or not we do not know,” Bergstrom said. “We’re going to be doing some testing on that to see if there are any problems with these bioplastic single-use items.”

Fuel from Food Waste

The possible toxicity of bioplastics is a growing concern for many scientists, including Sydney Le Cras. She was working on a master’s degree in civil and environmental engineering at the University of Hawaii when she learned that when it comes to harmful chemicals, bioplastics and plant-based materials are just as toxic as the conventional plastics they aim to replace.

This could be a potential concern if bioplastics were being mixed in with food waste for composting, Le Cras said.

“It really inspired me to look at alternatives to composting bioplastics,” she said.

She helped develop a system that uses anaerobic bacteria to completely break down food waste and bioplastics, including toxins. Le Cras said this makes the resulting compost from the food waste free of anything harmful that may have been added to bioplastics.

“It’s a local way to break down the material as an alternative to making or building a composting facility,” she said.

Anaerobic digestion also produces electricity and natural gas, which can be used for energy.

Similar to how H-Power burns trash to produce electricity, this process would break down food waste and bioplastics to produce energy, but Le Cras said the process doesn’t emit nearly as much greenhouse gas and pollutants as burning trash.

In 2018, H-Power emitted 682,759 tons of CO2 into the atmosphere. Courtesy of the City and County of Honolulu

“It would be more clean than trash incineration,” she said.

Another useful byproduct: biogas, which can be used to make a type of reusable plastic.

“This bioplastic is more biodegradable than corn-based bioplastic because it’s made from bacteria,” she said. “The idea is that we could create a semi-closed system of compostable bioplastic production in Hawaii.”

Le Cras is confident in the science, but the economics are holding her back. She recently completed The Pacific Asian Center for Entrepreneurship’s business accelerator program and estimated it would take at least $30 million to set up a system for waste collection and waste pretreatment, to build a large-scale anaerobic digester and to build infrastructure to refine the biogas.

“It is a bit overwhelming to see how much the startup cost is going to be,” she said. “But this bioplastic revolution is going to happen in the next two years and as an engineer, it’s one of my duties to try to improve the existing system in a way that can actually be implemented.”

Le Cras is watching the growing number of bioplastic companies in Silicon Valley and has studied the use of anaerobic digestion to fuel trucks in Denmark and Sweden. She predicts that in 10 years bioplastics will be commonplace and cities across the world will be generating energy from their food waste.

But she’s open about the fact that creating more bioplastics, even if they’re made from food waste via anaerobic digestion, isn’t a perfect solution.

“It’s not going to save the world, but I don’t see single-use items going anywhere,” she said.

Takeout Alternatives

Chatterson of Zero Waste Oahu recognizes that the demand for single-use items is unlikely to disappear anytime soon, so she’s working to make using reusables easier for residents and visitors alike.

Inspired by successful programs in California, Oregon and Switzerland, four restaurants in Haleiwa recently partnered with Zero Waste Oahu to test out reusable takeout containers.

“Starting in a couple of weeks anyone who signs up for the program will be able to order their takeout food in reusable containers from those restaurants,” she said.

After eating their meal, a customer has seven days to drop off their dirty container at a dropbox, where it will be sanitized and reused. Similar to bike-shares, the program will be run through a mobile app.

Haleiwa Joes, Cosmic Kitchen, Rajanee Thai Haleiwa and Cholo’s are the four restaurants offering reusable take-out containers. Claire Caulfield/Civil Beat/2020

“As long as they return them within seven days, then the program is totally free,” she said. “If they don’t return the containers, then we’re going to charge them a fee so that we can replace them.”

Chatterson won a grant to fund the reusable container program in October 2020 and was initially worried the pandemic would make restaurants hesitant to join, but she said that hasn’t been the case. After testing out the system for about six months with the four restaurants, she hopes to expand with other restaurants that have already expressed an interest.

She sees it as a good option for people who still want the convenience of takeout and delivery without the environmental impact of single-use containers. The reusable containers are made from recycled plastic and can be used between 300 and 1,000 times before needing to be replaced.

“The impact per container is dramatically less than single-use plastic,” she said. “But even that has been an interesting journey because the last thing I wanted to do was use reusable plastic containers.”

She was set on using stainless steel because, unlike plastic, steel can be fully recycled. But it would have more than quadrupled the cost. Then she started reading about the environmental impact of mining iron ore and producing steel.

“At the end of the day, there’s pros and cons to everything,” she said. “The best thing we can do for now, in this reusables and refillable space, is start normalizing it and start building the system and the policy to enable it.”

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