As the truck pulled over to the side of the road, two men got out and went in a noodle restaurant on Beiyuan Road in Beijing. They emerged within five minutes, dragging two big white plastic barrels filled with leftover food, with chopsticks and napkins poking out. Emptying the barrels into the metal containers on the truck, they turned their attention to a hot pot restaur

 ant next door, before driving to their final destination - pig farms on the outskirts of Beijing. 

"We get around 120 kilograms of swill each day and the collector pays us 700 yuan ($114) for it each month to feed pigs," the noodle restaurant owner, surnamed Qiu, told the Global Times, in comments echoed by others in the restaurant neighborhood.

Half an hour later, at around 10:40 pm, the swill-laden truck started its engine again and drove out of town, slopping some leftovers on the road as it drove over bumps.

This trade represents another link in the underground kitchen waste market. This, along with the illegal trade in waste "gutter oil," has been at the forefront of public attention after recent series of food safety scares.

Telling porkies

"Illegal collectors are making fortunes while certified companies can't collect enough swill," said Wang Qingwen, chief press officer of the Beijing Municipal Commission of City Administration and Environment, the agency in charge of kitchen waste management.

According to regulations, restaurants should collect and classify their waste and hand it down to certified agencies for transportation and processing. Beijing restaurants generate around 2,000 tons of kitchen waste per day, but only 500 tons are properly recycled, while the city's 25 certified recycling companies and environmental service centers have a processing capacity of 750 tons, Wang told the Global Times. Profit is the simplest yet biggest incentive for both restaurant owners and swine farmers to recycle waste illegally. "Food waste decomposes easily and you don't wait for the certified companies to collect the filth, especially when you're out of storage, plus there's the easy money and loose supervision," said Qiu.

A swine farmer in the outskirts of Daxing district surnamed Liu did the math for the Global Times. "On average, it takes four months and 700 kilograms of pig feed to raise a piglet of 120 kilograms for sale, costing 2,100 yuan. On the other hand, it needs eight months if you feed the pig using swill, but you can get 3.6 tons from a restaurant per month for only 700 yuan. It works out to about three times the profit."

However, when it comes to certified companies, money is the main problem. "We don't pay the restaurants for the waste so we have big difficulties promoting our service to restaurants and can't get enough of them," a manager surnamed Jiang with Beijing Zhongyuan Energy, a certified company, told the Global Times, adding that they mostly cooperate with government agencies and research institutes instead, installing on-site equipment at their canteens to process kitchen waste into organic fertilizer for their lawns.

Unhealthy pigs?

The issue raises the question - why is unprocessed swill illegal at all?

Although the public balk at the idea of eating swill-fed pigs, there isn't yet any conclusive evidence as to whether eating pork from these pigs directly causes diseases in humans, but a general scientific consensus indicates that these pigs are more prone to health problems.

Surprisingly, well-cited research by Xinjiang Agricultural University in 2012 found that the pork from swill-fed pigs had better flavor and tenderness than those eating feed. There was a serious catch however - they had higher levels of heavy metals including lead and mercury in their livers and kidneys, suggesting food safety risks that they could accumulate to dangerous levels in humans if they consumed the meat over the long term.

Zhang Lijun, a researcher at the Wuxi agriculture and forestry bureau, said microbial infection is another serious problem as these pigs are usually raised in unhygienic conditions and can easily become infected with parasites or diseases.

"Swill doesn't provide balanced nutrition, and contains high levels of oil, fat and salt, which will cause health problems for the pigs and might affect the meat," Ding Zhimin, a Beijing-based animal nutritionist and ecological pig farmer, told the Global Times.

The Beijing Municipal Bureau of Agriculture did not respond to the Global Times queries about regulatory and punitive measures regarding swill-fed pigs as of press time, but pig farmers said that healthy ones could still pass quarantine tests and some are butchered illegally and manage to enter the market.

Under the regulations, if swill-fed pigs have contagious diseases, the authorities can order them to be put down, but this runs the risk of prompting civil action from farmers. If the pigs are healthy, the officials can only try to persuade the farmers to change to using feed.

A lot on their plate

Some companies are making progress.

Shandong-based Sifon Environmental Protection and Bio-Energy, which has the biggest market share in the industry, processes waste into biofuel, organic fertilizer and methane.

"We have three processing plants in construction in Qingdao, Kunming and Ji'nan, but in terms of waste collecting contracts, we still need strong government support as restaurants don't see any profit in it," Ran Xiujing, Sifon planning manager, told the Global Times.

Wang noted that reducing kitchen waste and improving waste recycling awareness is a long-term endeavor. The government agency has planned several campaigns this year to publicize the issue and provide incentives for restaurants to get involved.

"Our waste collection and transportation mechanisms are undeveloped in terms of processing capacity. Punishments aren't severe enough, city agencies should jointly supervise the issue and could, say, withhold restaurant licenses if they failed to obey recycling rules," said Wang.

On the brighter side, "pioneer" waste recycling restaurants are enjoying brand benefits for following the regulations. "We installed equipment and process our own daily waste into fertilizer, and assure customers about our social responsibility. It's working pretty well," said a staff member with X.E. Flavor, a Hunan chain restaurant that was among Beijing's first to purchase on-site kitchen waste processing equipment in 2004.