by Xinhua writers Guo Ying, Guan Guifeng
BEIJING, June 14 (Xinhua) -- Two large machines are buzzing and emitting a slight odor of fermentation inside the kitchen waste disposal room. The 40-square-meter room is in the corner of a residential district in Beijing's Xicheng district.
Food scraps from more than 2,100 households and a canteen are "swallowed" by these two machines and undergo deep processing.
Sun Chunming, of the property service center, says each machine can dispose of 500 kilograms of kitchen waste a day. The machine grinds the food scraps and through a proprietary microbial process, 70 percent of the waste is converted into water, carbon dioxide and organic solids that can be further refined into fertilizer.
"Together the two machines can produce around 1,000 kilograms of fertilizer a day and the fertilizer is applied to nearby green spaces," Sun says.
The on-site process is used in more than 30 canteens in China's central government agencies, municipal commissions, and some schools in Beijing. Lin Jinwen, an official from Beijing Municipal Commission of Urban Management, says 128 canteens in government agencies are receiving subsidies to install this disposal equipment.
However, it is hard to spread the on-site kitchen waste treatment to restaurants and catering businesses as they are unwilling to pay for these equipment.
Liu Jianguo, professor of the School of Environment at Tsinghua University, says the disposal of kitchen waste is a challenge with Chinese characteristics. China has a long-established food culture and sophisticated cooking styles. The nature of food scraps is different from that in other countries as they contain more oil and salt. They cannot easily be incinerated like other garbage and will pollute underground water if they are sent directly to landfills.
"In Japan and some other countries, restaurants have to bear the cost of food waste disposal. However in China, restaurants do not have to pay," Liu says.
China's growing food consumption has brought a rapid growth in food waste.
In Beijing and other big cities that boost thriving catering business, the problem is particularly serious.
According to the Beijing Municipal Commission of City Management, about 2,600 tonnes of kitchen waste is produced by more than 40,000 restaurants and dining halls of institutions and schools every day and the amount is expected to reach 2,900 tonnes in 2020. However, the city's 10 food waste treatment centers, together with on-site treatment equipment, can handle only 2,000 tons per day.
FILLING THE "GAP"
China has been encouraging food waste recycling. In January, the National Development and Reform Commission issued the "Strategic Emerging Industry Key Product and Service Guidance Catalog" (2016), and kitchen waste disposal was included in the "resources recycling industry."
Beijing is building five new processing centers in Haidian, Fengtai and Shunyi districts. They are expected to be in use at the end of the year and then Beijing's processing capacity is expected to reach 2,800 tonnes per day.
Nangong in Daxing district is one of Beijing's kitchen waste disposal centers, with a daily capacity of 400 tonnes. Every day, specially-designed trucks go to designated restaurants and canteens to collect food waste and take it to the center.
The waste first goes into a solid-liquid separator. The solid material enters the composting system, and the liquid enters the leachate treatment plant.
Zhang Yang, manager of the Nangong center, says composting is a mature method of disposal, and has to some extent guaranteed the harmless treatment and reuse of kitchen waste.
But he adds that the fertilizer derived from kitchen waste has limited sales channels and low market recognition. The output return is much lower than the processing cost, so food waste disposal still needs a subsidy.
The kitchen waste collected from restaurants is not purely food scraps. It is mixed with disposable chopsticks, rags and even glass bottles and other debris, which is a headache for Zhang.
"The non-kitchen waste sometimes damages our disposal equipment. Moreover, it has greatly lowered the quality of kitchen waste, increasing the difficulty of pre-treatment and affecting the quality of fertilizer extracted," Zhang says.
"We are responsible for handling kitchen waste, but we have no right to supervise the garbage classification of restaurants. We hope the authorities can take coercive measures on that."
In March, China's State Council issued a plan requiring 46 cities to carry out mandatory garbage sorting by the end of 2020. Under the plan, all public institutions and companies are required to separate hazardous waste, kitchen waste and recyclable materials.
Beijing's Tongzhou District, the capital city's sub-center, will implement mandatory garbage sorting in public institutions and more than 500 restaurants by the end of this year.
Every day at 9 a.m., staff at Tongzhou Zhenchongqing Restaurant put the special green kitchen waste bin full of food leftovers out for the sanitation companies to collect.
"A napkin, a chopstick - even a toothpick - cannot be mixed into the kitchen waste," restaurant lobby manager Wang Liang says. "Once the recyclers find other garbage included, they ask us to take it out."
Liu Jianguo says the implementation of garbage sorting will be complex, requiring legal support and improved regulations. He hopes to see more detailed policies and regulations on kitchen waste disposal.
"The management of kitchen waste involves a number of government departments and needs a coordinated approach. How to ensure the classification of kitchen waste; how to dispose of kitchen waste more effectively -- these all test a city's management."