Shanghai has built China's first refuse-derived processing power plant in order to treat over 1,000 tons of the cities garbage -- 1/14 of the daily amount produced by Shanghai's urban and rural households.
The city plant processes 1,100 tons of refuse by incineration and creates power to supply 100,000 homes. What is environmentally successful is that the refuse is not buried in harmful landfills.
Situated at Yuqiao Industrial Zone in the Pudong New Area in Shanghai, the plant is 80,000 square meters and the result of a 670 million yuan (US$81.04 million) investment that supplied three refuse incinerators and two 8,500-kilowatt power turbine engines.
Approved by the Environmental Protection Bureau of Shanghai City, the plant has cutting edge imported facilities that began trials on September 20, 2002 with a daily production of 300,00-350,000 kilowatts.
The central work area of the plant is a multi-storied ivory colored building. The central controlling unit, housed on the third floor, has a rotational staff of 42 engineers working round the clock. The operational software for the plant was developed and installed by Chinese engineers.
The refuse is collected from a 12.5 meter dump that is near to the central unit and has a capacity to hold between 6-7,000 tons of garbage. All the refuse from the Pudong area is brought there after it has been compressed. Special equipment recycles 115 tons of sewage coming from the dump daily.
Before being incinerated, the refuse is dried in order to vaporize moisture. Then it is magnetized to eliminate metal that cannot be burnt before going on to the next stage.
Three refuse incinerators on the first floor of the central area can handle 15.2 tons of refuse each per hour. Observation windows allow the operators to view the incineration process.
The incinerators then heat water boilers up to temperatures of 4000C to propel two power turbine engines. The plant has produced 60.41 million kilo-watt-hours of electricity since December 2001.
"The most economical way to utilize heat is to provide heating for nearby households. It's more profitable than generating power," said Huang Zhaocheng, the general manager of the plant.
Dioxin fumes that normally come from burning refuse contain deadly substances or carcinogens. The World Health Organization is particularly scathing about the needless production of this gas. In the burning process, the dioxins can be synthesized. But the plant at Pudong has successfully rectified this problem. Zhang Yi, an expert with Urban Environmental Sanitation Association explains:
"The pollution level of the exhaust gas emitted by the plant is no higher than required environmental levels in the European Union (EU). The plant does two things to eliminate the gas. First, it raises the temperature of the furnace to 8000C, the critical point when dioxin automatically decomposes. Second, it uses active carbons to assimilate dioxin in the fumes."
The use of multi-layer filters eliminates further gases and dust particles from escaping into the atmosphere. The plant has an 80-meter-high chimney that allows the fumes to appropriately be released. Analyzers in the chimney activate alarms when any excess toxin is produced. Dust particles and used active carbons are deeply buried after being treated with cements. About 252 tons of solid waste that the plant produces everyday are converted and re-produced into building materials.
A refuse-generated power plant such as this is significantly better for the environment than anything that came before. Clearly it helps to promote environmental care. Most of the 14,000 tons of domestic refuse produced in Shanghai everyday, as well as 15,000 tons of construction debris, ends up in the ground. Unfortunately, landfilled areas become uninhabitable, unconstrutable and no good for agriculture either, leaving only tree planting as an option.
It is suggested that the building of the plant has promoted environmental care at a local level. In order to successfully fuel the plant, refuse in the area was divided into types and although this took some time to work smoothly, the refuse is now never mixed.
Incineration has been chosen as the primary method of refuse disposal in developed countries and as such Shanghai is now planning the building of a second plant for Jiangqiao in Jiading and a biochemical refuse facility in Pudong. It is hoped that with all these facilities, the city will see a drop in environmental damage, in being able to treat 1/6 of the garbage it produces.
(解放軍報(bào) [PLA Daily], translated for china.org.cn by Chen Chao, February 20, 2002)