China's urban garbage disposal started very late, in the 1980s. Before that, garbage was piled up in the open.
According to the information from the Municipal Waste Disposal Committee of China Environmental Protection Industry Association (CEPIA), China's municipal waste disposal rate was less than 2% before 1990. After entering the 90's, China's urban garbage disposal has been improved continuously. 1999, China's municipal cities are 668, **** there are 696 garbage treatment plants (fields), including less than 200 harmless treatment plants, garbage disposal rate of 63.4%, harmless treatment rate is only 20.3%.
At present, there are more than 700 harmless treatment sites for domestic waste only in Chinese cities, and the national rate of harmless treatment of urban domestic waste is 52%.
Waste disposal in Chinese cities starts with collection. Currently, China's urban garbage collection is basically mixed collection. Although the Chinese government advocated separate collection in 2002, separate collection of garbage currently accounts for only 16% of the total.
There are three main ways of mixed collection, one is to place collection containers in fixed locations, such as residential neighborhoods, both sides of the street, and other public **** places. Specialized sanitation personnel are responsible for collecting garbage from these containers every day. Second, there are fixed garbage collection stations in residential neighborhoods where residents can throw their household garbage to the garbage station every day. Thirdly, there are garbage lanes. In high-rise residential buildings in China, the garbage lanes are already designed when the buildings are built, and they run from the first floor to the top floor, so residents can throw their garbage into the garbage lanes and the sanitation staff will take it away from the bottom floor. Collecting residents' garbage through garbage tunnels used to be the most common way of collecting garbage in residential areas. However, after the SARS outbreak in 2003, it was banned in many cities because it was conducive to the spread of bacteria. Cities such as Beijing, Guangzhou, and Shanghai have all mandated that new residential buildings do not have garbage lanes, and some cities have also closed garbage lanes in already built residential buildings.
The collected garbage is transported to the garbage transfer station by specialized garbage trucks. The garbage trucks are completely sealed. The garbage is transported to the transfer station for the first step of processing. It is first classified by a sorting machine into organic and inorganic materials, as well as utilizable and non-utilizable. Bulky waste is also compressed. After that, the waste is sorted and transported away.
From the transfer station out of the garbage, some are transported to the sanitary landfill, the garbage will be filled into the pit has been prepared with a good cover and compaction, so that it will undergo biological, physical and chemical changes, decomposition of organic matter, to achieve the purpose of reducing and harmless. Special pipes and impermeable layers are laid in these pits to collect the gas and leachate produced by the fermentation of the waste. The gas is combusted, part of the leachate is purified and processed into water, which is used to clean the garbage trucks and the dust on the ground, and part of the leachate is filtered to meet the national level standards before it is discharged, which will not cause pollution to the environment.
Others were transported to a composting plant, where they were composted and turned into hygienic, odourless humus, which was used as fertilizer for plants.
Others are sent to incinerators, where the combustible components of the waste are fully oxidized and the heat generated is used to generate electricity and heat. Currently, there are 140 waste-to-energy plants built, under construction, and in the process of being approved in China. One ton of garbage can generate 300 degrees of electricity, and the waste heat can also be used for heating. Tianjin Shuanggang garbage power plant, the daily treatment of 1200 tons of garbage, annual power generation of 120 million degrees, for 50,000 residents a year of living electricity, equivalent to saving 48,000 tons of standard coal.
For recyclable garbage, it will be recycled and reused.
In the process of dealing with garbage, China has formulated a number of relevant standards, such as the standards for agricultural control of urban garbage, the sanitary standards for harmlessness of feces, and the standards for emission of incineration exhaust gas.
Among the current waste treatment methods, incineration is slower to develop in China, mainly because of the lack of funds. The initial investment in incineration is large, and the construction of an incinerator with a daily capacity of 1,000 tons of garbage and ancillary heat recovery equipment requires about 700-800 million RMB. Moreover, because incineration produces dioxin gases when treating waste, many cities do not use incineration much except for the need to treat medical waste. Many cities use more sanitary landfills, which are considered by environmental officials to be more suitable for China's national conditions.
According to information from the China Environmental Protection Industry Association (CEPIA) Municipal Waste Disposal Committee, 70% of China's municipal waste is disposed of in landfills, 20% is composted, 5% is incinerated, and the rest (including open piles and recycling) accounts for 5%.