How South Korea puts its food scraps to good use

Worldwide, most of the 1.4 billion tons of wasted food every year it goes to landfills. When it rots, it contaminates water and soil and releases enormous amounts of methaneone of the most potent greenhouse gases.

But not in South Korea, which banned food scraps from its landfills nearly 20 years ago. Here, the vast majority is turned into animal feed, fertilizer and fuel to heat homes.

Food waste is one of the biggest contributors to climate changenot only because of the methane but also because the energy and resources that went into its production and transportation have also been wasted.

South Korea’s system, which keeps about 90 percent of wasted food out of landfills and incinerators, has been studied by governments around the world. Officials from China, Denmark and elsewhere have toured the South Korean facilities. New York City, which require all residents to separate his food waste from other trash for next fall, he’s been eyeing the Korean system for years, a city spokesman sanitation department saying.

While several cities have comparable programs, few if any other countries do what South Korea does on a national scale. That’s because of cost, said Paul West, principal scientist at project decline, a research group studying ways to reduce carbon emissions. Although individuals and businesses pay a small fee to dispose of food waste, the program costs South Korea about $600 million a year, according to the country’s environment ministry.

Still, West and other experts say it should be emulated. “The example of South Korea makes it possible to reduce emissions on a larger scale,” he said.

The South Korean culinary tradition tends to result in uneaten food. Small side dishes, sometimes a few, sometimes more than a dozen, accompany most meals. For years, virtually all of those leftovers ended up in the dirt.

But the country’s mountainous terrain limits how many landfills can be built and how far they can be from residential areas. In 1995, the government introduced mandatory recycling of paper and plastic, but food scraps continued to be buried along with other rubbish.

Political support for the change was fueled by people living near the dumps, who complained about the odors, said Kee-Young Yoo, a researcher at the government-run Seoul Institute, which has advised cities on the food waste management. Because casseroles are a staple of Korean cuisine, the food thrown away here tends to have a high water content, which means higher volume and worse odors.

“When all of that went to waste, it gave off a terrible stench,” Yoo said.

Since 2005, it is illegal to send food waste to landfills. Local governments have built hundreds of facilities to process it. Consumers, restaurant owners, truckers and others are part of the network that collects and turns it into something useful.

At Jongno Stew Village, a popular lunch spot in the Dobong district of northern Seoul, pollock stew and kimchi jjigae are top sellers. But no matter the order, Lee Hae-yeon, the owner, serves up small side dishes of kimchi, tofu, boiled bean sprouts, and marinated perilla leaves.

Customers can help themselves to more, and “people will take more than they are going to eat,” Mr. Lee said. “Koreans like to err on the side of plenty when it comes to food.”

Mr. Lee pays a price for that: about 2,800 won, just over $2, for every 20 liters of food he throws away. Throughout the day, leftovers go into a bucket in the kitchen, and at closing time, Mr. Lee empties it into a designated bin outside. On the lid, he glues a district-bought sticker, evidence that he paid for the removal.

In the morning, companies contracted by the district empty these containers. Park Myung-joo and his crew start rolling through the streets at 5 am, tearing the stickers off the bins and dumping the contents into the tank of their truck.

They work every day except Sunday. “Even waiting a day would cause enormous amounts of debris to accumulate,” Park said.

At around 11 am, they arrive at the Dobong processing facility, where they dump the sludge.

The waste (bones, seeds, shells) is collected by hand. (The Dobong plant is one of the last in the country where this step is not automated.) A conveyor belt carries the waste to a shredder, which reduces it to small pieces. Anything that is not easily shredded, such as plastic bags, is filtered and incinerated.

The residues are then baked and dehydrated. The moisture goes into pipes leading to a water treatment plant, where a portion is used to produce biogas. The rest is purified and dumped into a nearby stream.

What remains of the waste at the processing plant, four hours after Mr. Park’s team dropped it off, is ground to the final product: a dry brown powder that smells of earth. It is a feed supplement for chickens and ducks, rich in protein and fiber, said Sim Yoon-sik, manager of the facility, and is delivered to any farm that wants it.

Inside the plant, strong odors cling to fabric and hair. But on the outside they are barely noticeable. Pipes run through the building, purifying the air through a chemical process before it is expelled by the exhaust system.

Other plants work differently. At the biogas facility in Goyang, a suburb of Seoul, food waste (nearly 70,000 tons per year) undergoes anaerobic digestion. It rests in large tanks for up to 35 days while the bacteria do their work, breaking down organic matter and creating biogas, which consists mostly of methane and carbon dioxide.

The biogas is sold to a local utility company, which says it is used to heat 3,000 homes in Goyang. The solid matter that remains is mixed with wood shavings to create fertilizer, which is given away.

Every ton of food waste that rots in a landfill emits greenhouse gases equivalent to 800 pounds of carbon dioxide, researchers have found. Converting it to biogas cuts it in half, said Lee Chang-gee, an engineer at the Goyang plant.

Critics point out that for all its benefits, the South Korean program has failed to achieve one of its goals: getting people to throw away less food. The amount of food thrown away nationwide has remained more or less stable over the years, according to data from the Ministry of the Environment.

The system has had other failures. There have been scattered complaints: In Deogyang, a district of Goyang, residents of a village said the smell from a processing plant was once so strong that they couldn’t leave the windows open. That plant has been inactive since 2018 due to protests by neighbors.

“When the plant closed, all the problems disappeared,” said Deogyang resident Mo Sung Yun, 68.

But most plants across the country, unlike the landfills they are essentially replacing, have generated little to no serious complaints from neighbors. Government officials say that the constant improvement in technology has led to cleaner and more efficient operations.

It has also made removal easier for many. At apartment complexes across the country, residents are issued cards to scan each time they dump food waste in a designated bin. The container weighs what they have dropped; at the end of the month they receive an invoice.

“The bins have become cleaner and less smelly,” said Eom Jung-suk, 60, who lives in one such complex.

Ms. Eom has never been charged more than a dollar for the service. In April she paid 26 cents. But her monthly bill makes her more aware of how much she throws away.

“Just today at breakfast I told my daughters to have enough to eat,” she said.