Kimchis, fresh vegetables, fruit, fish, seafood, meat, pickles, pancakes…. One of the many pleasures of dining out in South Korea is the selection of banchan, or side dishes, that accompanies most meals.

But seldom — if ever — do all banchan get eaten. Diners take a few mouthfuls of this and that, then the meal is over. Just finishing the generous main dish is often enough of a challenge. For a first-time visitor, the joy of discovering so much variety on one table is quickly followed by bemusement at how much of it goes unconsumed.

So what happens to it all?

On the edge of a building site in Seoul’s eastern Gangdong District is a complex of green buildings. Hang around there for a while and you’ll see food waste trucks turning up from all over southern and eastern Seoul. The complex is operated Naen, a private contractor that recycles some three to four hundred tonnes of food waste every day into animal feed.

Upon arrival at Naen, the waste is dropped into underground tanks, then carried by screw conveyors to a separator, where non-food content — mostly plastic bags — is removed. The waste is then squeezed in a conical screw press to get rid of as much moisture content as possible. Typically, food waste consists of 80 to 85 percent moisture.

The orange “juice” squeezed out at this point is collected in another underground tank, then sent off to a wastewater treatment plant where it is fermented to produce methane. The methane is then used as fuel.

The squeezed waste is then carried to steam dryers, where it is dried for three to four hours at 120˚C. Next, any remaining impurities are removed and the dried waste is powdered. The animal feed is ready.

“A lot of businesses like ours sprang up after 2005, when the landfilling of food waste was banned,” said Naen official Lim Chang-ho.

In fact, South Korea has a pretty strong handle on its food waste by global standards. Some 95 percent of food waste is currently recycled: into compost, animal feed, methane gas (through anaerobic digestion) or solid fuel.

This is based on mandatory separation rules that see households and businesses nationwide throw out food waste in dedicated plastic bags sold in supermarkets, specially made buckets or even at computerized collection points.

Plenty to deal with

Food constitutes a relatively small segment within South Korea’s waste scene: It makes up some 40 percent of household waste, but household waste accounts for only 13 percent of all rubbish thrown out in the country (the biggest source is construction material waste, at 48 percent). But in terms of sheer amount, masses of food waste are generated every day.

According to the Ministry of Environment, an average South Korean throws out 930 grams of rubbish each day, 40 percent of which is food waste. That makes for more than 130 kilograms of per capita food waste a year. (In comparison, per capita food waste by consumers in Europe and North America was 95 to 115 kilograms a year, according to the Food and Agricultural Organization of the United Nations.)

In 2016, South Korea produced 14,388 tonnes of food waste nationwide every day, and 3,075 tonnes in Seoul alone. About two thirds of this are processed outside the capital; the rest is treated by five plants within the city limits, of which Naen is one.

With all their screw conveyors and other moving parts, plants like Naen’s rely on consumers not to leave rogue items in their food waste that can put a literal spanner in the works.

“We’ve had bowling balls, blankets and bricks in the past,” said Lim. “And once we found a fridge. But things have got a lot better now, thanks to government efforts to educate people better. Now we just get a few spoons and rice bowls here and there.”

Each time a rogue item causes part of the plant to break down, the whole line has to be stopped for an hour or two while the problem is identified and fixed.

Meanwhile, local authorities are working to reduce food waste at the source.

In 2013, Songpa, a district in southeastern Seoul, began introducing a radio-frequency identification (RFID)-based centralized system of food waste collection at multiple apartment complexes across the city. Residents were issued with unique electronic ID tags, which they use when depositing food waste at one of several hundred collection points. Machines weigh each deposit and charge each user accordingly.

Within four years, some 4,000 RFID collection points had been installed in apartment complexes and approximately 2,000 in non-apartment residential neighborhoods. In 2017, Songpa District authorities calculated that the system had reduced food waste by a total of 36,000 tonnes, or 25 percent of what was being thrown out in 2012, and achieved 7 billion won in budget savings.

But some argue that solutions like RFID merely deal with the results of food waste, not the causes.

“The RFID has nothing to do with actually reducing food waste,” said Lee Seok-kil of Korea Food Recycling Association. “It’s just another way of dealing with waste that already exists.”

Lee says the best way to deal with the problem is education. “For example, a high percentage of food waste is due to people buying more food than they need, letting it go bad in the fridge, then throwing it away. And then there’s the Korean culture of serving more banchan than people can eat. In other countries you have to pay extra for side dishes, but that goes against Korean sentiment. We need more publicity to change this culture, but I don’t the the government has done enough on that front yet.”

Entomological enthusiasm

Still, other innovative possibilities abound for exploiting the opportunities presented by food waste. One comes in the form of a large plant in Gimje, southwestern South Korea, that buzzes with some 2 billion black soldier flies.

While flies are normally associated with poor waste management, these ones are working away in large, net-lined chambers to break down some 100 tonnes of food waste every day.

Soldier fly larvae are raised for a little over two weeks on the food waste. After that, they are separated from their own excrement and dried. Oil is extracted from the larvae, then they are dried and pulverized for use as animal feed. Their excrement is used as fertilizer.

Meanwhile, the oil squeezed from the larvae before drying is used as a natural additive to any animal feed as an immune system-boosting agent.

“The animal feed made from the flies is high in protein, while the oil squeezed from them contains lots of [natural] antibiotic substances, which help boost animals’ immunity to disease,” said Kang Seung-ho of CIEF, the company that operates the Gimje facility.

CIEF’s ultimate plan is to open 100 similar plants around South Korea, which, Kang said, could process the country’s entire food waste output. It’s a neat and profitable solution to a once-stinking problem.

The South Korean government has embraced the potential of the nascent black soldier fly industry, amending regulations in October 2017 to legalize it as a means of large-scale food waste processing. The country’s Rural Development Administration has hailed the technology’s potential to create new insect-based industries and much-needed jobs for rural communities.

In addition to its economic potential, using insects to produce high-quality animal feed on a large scale could replace other animal feed sources such as soybeans, the production of which is becoming increasingly notorious for its association with environmental damage and deforestation.

Back at the consumer end of the chain, the most effective way to combat food waste is to avoid the fridge-to-bin phenomenon by buying only as much as you’re likely to eat. If you want to get really militant, you can ask restaurant owners why they serve more side-dishes than you can eat, but they probably won’t appreciate it. Other options include asking them to put leftover food in a container for you to take home and eat later. This is becoming more common and is generally welcomed.

And don’t forget to look out for black soldier fly larvae-fed steaks in your local supermarket.

Cover image: Food waste. (Source: U.S. Department of Agriculture via Flickr, CC by 2.0)