The world’s first municipal solid waste (MSW) incineration project using a cement rotary kiln has been set up in the city of Tongling in Anhui Province, treating some 250 tons of garbage a day, Tongling Vice Mayor Ye Ping said.

The Tongling Conch Municipal Garbage Incineration Demonstration Project was built by Tongling Conch Cement Company, the world’s largest clinker maker in a single plant, in Oct 2008, and put into operation in March this year.

Speaking at a news conference, the Vice Mayor noted that as a prefecture-level city with industrialization and urbanization rates all surpassing 70 percent, Tongling’s 740,000 residents no longer need to fear the problems with burying municipal garbage, which occupies land and pollutes the environment in the region located in the southern bank of the Yangtze River in southern Anhui.

Tongling, a beautiful mountain city with a 3,500-year history in bronze production using ample copper and tin deposits, is dubbed “the bronze capital of China.”

With a total investment of 247 million yuan (US$36.3 million), the project is being built in two phases, with the first phase already finished treating 300 tons of garbage each year and fully meeting the city’s need, and the second treating another 300 tons when completed, she said.

“This is an effective energy conservation project that benefits the local residents immensely,” said Li Quanfeng, general manager of Tongling Conch Cement Co that can produce 10 million tons of clinker and six million tons of cement a year.

Li explained that after being broken up, the garbage is sent into two vaporization furnaces which can treat 300 tons of MSW a day, with combustible gases resulting from vaporization of flammable garbage being transported into new-type cement rotary kiln for further burning, and the gasifier slag being sent for use in cement raw material or clinker powder systems. The incineration exhaust heat is discharged after treatment through the existing cogeneration, or combined heat and power system and electrostatic dust collection system in the rotary kiln.

He added that as the waste pretreatment plant is completely closed, the odor produced from the garbage will be pumped by negative pressure into vaporization furnaces as combustion gases, leaving no room for it to flee outside, while the garbage liquid is pumped to the gasifier for burning.

Currently, Ye said, China’ s MSW increases at an annual rate of five to eight percent, likely to reach 264 million tons this year, 409 million in 2030 and 528 million in 2050.

As many cities take a simple way of burning, burying garbage and composting, with landfills in many large- and medium-sized cities almost full, the problem of mounting garbage is very grim, she said, affirming that choosing the sites of burning and burying is also a trouble to cities and can provoke an outcry from urban dwellers.

Meng Fanjun, general office director of Tongling Conch Cement, noted that over the years, the country has piled up municipal garbage of about six billion tons, with 200 cities out of the 660 cities around China under siege of MSW.

Li said that with his company’s independent intellectual property right, the project is ushering in the world’s first new-type dry treatment of MSW via cement kiln.

The most noteworthy feature of the technology is that there’s no need for garbage classification and all the original MSW can be directly used for processing, while the dioxins produced in the processing of garbage effectively decomposed and absorbed in the decomposition furnace’s high temperatures ranging between 900 C and 1,100 C.

He stressed that generally speaking, 10 percent of the MSW will be construction waste and non-combustible matters, and 40 percent to 45 percent is organic material, with the remaining being water.

“At present, all the system of the project is running smoothly, and it has treated 41,200 tons of municipal garbage by the end of August,” Li said, adding that after treatment, the MSW has turned into harmless resources.

Sha Kaiye, director of Tongling City Environment Protection Bureau, said as a large enterprise with a high awareness of environmental protection and serving the public, Tongling Conch Cement has leading technologies in China as well as the world in the spheres of equipment and production management method.

The current project for municipal refuse disposal is a win-win for both the local government and the enterprise itself, as the government, now having no worries on MSW, will subsidize Tongling Conch for its service to the public while the company can earn a small profit, Sha said.

The government can collect a MSW treatment fee from the local residents, who don’t mind paying the money as the garbage can be effectively treated without any pollution, he said.

The collection and transportation of the municipal garbage is being taken up by the city government while the storage, crushing and burning of the garbage is the duty of Tongling Conch Cement, Sha said, noting that the move can help the city to reduce 200,000 tons of MSW a year, save 13,000 tons of standard coal and cut emission of 30,000 tons of carbon dioxide each year.

Li Bisheng, managing director of the Publicity Department of the city’s Party committee, stressed that back in April 2009, the city government decided to built Tongling into a National Model City in Environmental Protection within three years starting from 2010, in a bid to foster the construction of an ecological city and promote its sustainable development.

Tongling, set up as a city in 1956 with its typical mining resources, was listed as the first batch of national pilot cities for circular economy in Oct 2005, he said.

With the operation of the new project, the city has closed its previous Baoshan MSW Disposal Plant, a site that has operated since 1985 by burying some 400 tons of municipal garbage each day in a discarded open-air mining pit, said Luo Hanchang, director of Tongling Urban Outlook Management Bureau.

He noted that during the past 25 years, the disposal plant has been plagued by problems of garbage liquid infiltration polluting underwater, the emission of garbage odor and methane from waste fermentation, as well as spontaneous combustion that sends out a lot of smoke polluting the air.

With the closure of the plant now burying some 3 million tons of MSW, the city will invest some 80 million yuan in eco-recovery and rehabilitation with advanced technology so as to make it into a park by 2014, said Liu Jun, director of the city’s Urban Hygiene Division.

Sha Kaiye reiterated that since 2008, the city, which consumes a lot of mining resources a day, has tightened its efforts in environmental protection.

Currently, the city’s forest coverage is about 36.4 percent in its three districts and one county under its jurisdiction, while the urban green coverage reaches some 42.02 percent, he said.

Sha also noted that Tongling wants to industrialize the city’s municipal garbage incineration demonstration project, hoping to spread the new technology into other areas.

(China Daily September 13, 2010)