At around 7 am, trucks loaded with several metric tons of chicken bones, heads and intestines arrived at a waste disposal plant and dumped the nonedible chicken parts into an underground container through a small hole.

"It's like filling oil tanks in a gas station," said Jiang Haijun, general manager of the plant in Guangze county, East China's Fujian province.

The waste was then pumped into a chain of cauldrons and tubes in a separate room for high-temperature sterilization, steaming and drying. Five hours later, the waste was converted into fish feed.

The plant, which is able to treat 300 tons of chicken waste each day, is owned by Fujian Sunner Group, one of Asia's largest chicken breeders, headquartered in Guangze. The poultry giant supplies chicken products to KFC and McDonald's in China.

Last year, Sunner's breeding farms in Guangze produced 300 million broilers along with 60,000 tons of waste, which were turned into 8,000 tons of animal feed by the plant. Jiang said the feed was sold at up to 13,000 yuan ($1,880) per ton.

"It's an eco-friendly way of treating poultry waste, and to make profits," Jiang said. "If we dump untreated waste into fish ponds, we might risk polluting groundwater or spreading diseases."

He added that a large amount of steam and hot water generated during chicken waste processing was later sent back to the nearby poultry slaughterhouses and used for plucking chicken feathers.

Jiang's waste disposal facility offers a glimpse into Sunner's efforts to go waste-free.

About five minutes' drive from the facility lies a cluster of plants that disposes of chicken blood, feathers and sewage produced by Sunner's farms. One plant turns chicken blood into protein powder, while another converts chicken feathers into animal feed.

Last year, a local biomass power plant used around 28 tons of chicken manure from Sunner's farms to generate 163 million kilowatt hours of electricity. Most of the electricity, which was worth more than 100 million yuan, was provided to the State Grid. Fu Longrun, vice-director of Guangze's ecology and environment bureau, said Sunner's model of the circular economy is indicative of Guangze's efforts to make full use of solid waste and build a zero-waste city.

Enterprises in Guangze have developed techniques to convert bamboo scraps into charcoal sticks and turn construction waste into sand. Guangze is among 11 cities and five areas in China selected by the government last month to pilot waste-free programs. Other participating cities include Shenzhen, downtown Chongqing and Sanya in Hainan province.

According to Du Xiangwan, an academician from the Chinese Academy of Engineering, about 10 billion tons of solid waste are produced annually in China.

The amount of waste, if poorly handled, would be a huge burden for the environment and a waste of resources. "The long-term goal is to minimize solid waste production, maximize the use of recycled resources and ensure safe waste disposal," Du said.

Xinhua