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China
While composting processes and equipment are relatively undeveloped now, their improved technologies would have a major role in the future of Chinese waste management.
ALTHOUGH the statistical data of organic solid wastes generated in China is incomplete, we can still make a rough estimate based on the available information which includes municipal solid waste (MSW), sewage sludge, crop residues and animal manure. Annual generation of crop residuals is estimated as 0.6 to 0.7 billion tons. About 36.6 percent was returned to farmland; 23.7 percent was used as household fuel; 22.6 percent as feedstuff, and other amounts for field burning, paper pulping or discarded.
China is the largest producer of various animal products. Total generation of animal manure has reached 2.4 billion tons in 2005 and will grow at a rate of four to five percent. The State Environmental Protection Administration of China (SEPA) reports that most of the animal manure in the countryside was untreated. Only 20 percent was applied on farmland, and just three percent of the 20 percent figure was treated by composting.
China has started to build many wastewater treatment plants since the 1990s, and the amount of sewage sludge increased from 3.45 million tons in 1995 to 13.6 million tons in 2005. Thirty-one percent of the sludge was landfilled, and 44.8 percent was used on land. Further, 60 percent of land-used sludge was discharged directly without any treatment.
In 2005, China's MSW production reached 156 million tons, and the organic solid wastes contribute around 50 percent. Separation of MSW was not adopted extensively, so 89.5 percent of MSW was landfilled in Beijing, where the organic solid waste was about 3.8 million tons in 2005. The percent of composting and incineration were only 4.8 percent and 1.6 percent respectively.
Main Composting Processes And Research
Maximizing the flow of organic solid wastes, both urban and rural sources, to organic fertilizer/soil amendments is one of the big targets for a country like China where the farmland is limited and the land is intensely used. Currently, the main composting processes used in China include traditional, windrow, "tank" and tunnel.
The traditional composting method was recorded by Chen Fu in his early book "Chenfu Agricultural Book" as early as the year of 1149, when...