No country has ever experienced as large or as fast an increase in solid waste quantities that China is now facing. In 2004 China surpassed the United States as the world’s largest waste generator, and by 2030 China’s annual solid waste quantities will increase by another 150% – growing from about 190,000,000 tons in 2004 to over 480,000,000 tons in 2030(Delvoie 2005).
This growing waste stream has significant impact for the society, environment and economic development. The Quantity and Composition of MSW in China The definition of municipal solid waste (MSW) should include all waste generated since the municipality may be required to assume responsibility if there is no longer sufficient impetus to remove the material from the waste stream. This report defines MSW as all waste originating in urban areas from residential, industrial (non-hazardous), commercial and institutional sectors.
Most Chinese municipal solid waste generation data is presented in three categories: municipal, industrial, and hazardous waste. ‘Municipal waste’ usually includes residential, institutional, commercial, street cleaning, and non-process waste from industries. In some cases, construction and demolition waste is also included and can dramatically skew the generation rate, especially in times of high economic growth and related construction activity. ‘Industrial waste’ is usually limited to ‘process waste’ such as process by-products like scrap metal, slag, and mine tailings.
Hazardous waste’ usually refers to industrial hazardous waste generated as a by-product of the manufacturing process, medical waste, small-scale generation of hazardous waste from households, institutions and commercial establishments, and occasionally small amounts of radioactive waste, e. g. smoke detectors and medical process waste. The categorization of wastes in China is not always consistent or comprehensive from city to city and adversely affects the utility of the database.
And most available information in China is based on ‘waste collected’ data rather than ‘waste generated’data. However, waste generated data is more useful since it includes recyclable secondary materials, and encourages more full-cost accounting of the overall MSW system and program financing. Data presented in this report are waste generated estimates.
Landfill and incineration have been the most common methods to treat solid waste and now it is still popular in many places around the world( http://en. wikipedia. org/wiki/Landfill), especially in China. China now is facing a great problem of increasing quantity of solid waste and landfill is one of the most common treatments considered by the government now. According to a World Bank report (2005), China’s cities will need to develop an additional 1400 landfills over the next 20 years. It will be a big issue for both China and the world.
As the trend is unavoidable, careful consideration and management is extremely needed in China now. In the past ten years, China has made great improvement in waste management, especially in landfill management. Most larger cities are aggressively moving towards sanitary landfilling as their main disposal option. (WB, 2005) But still, for a lot of cities in China, the standard of sanitary landfilling is not achieved completely. The management of landfill becomes the most serious problem now and in the future. We are facing a lot of serious problems in the process of landfilling in China now.
The key issue among them is lack of overall consideration, management and operation. There are a lot of problems in different aspects. From the aspects of construction, the overall operating conditions need urgent attentions and especially the slops in the landfill are mostly inadequate. And also the phenomenon of over design exists a lot. For some cases, after the over-design, the constructions of subsequent phases are premature. According to the report of World Bank (2005), some synthetic liners are exposed to the elements and huge additional volumes of leachate are generated.
These problems are serious in the past and need better management and much more consideration and construction. From the aspects of the leachate, there are also a lot of troubles in this part. The collection of the leachate is inadequate and the treatment is not well organized. It is possible for them to contaminate the underground water or lead to great damage to the soil around. The contaminated soil become the “brownfields” and it will cause a lot of serious sequences. It will impact the public health and environmental quality,especially the land values will decrease a lot.
There are likely at least 5000 of these sites now in Chinese cities. The cost to clean them up is significant higher than the cost to have disposed of the waste properly in the first place. (WB 2005) From the aspects of gas, very little landfill has gas collection at present. If we can gather these gases, we can decrease the greenhouse gas emission a lot. According to the estimation, the proportion of potential saving in greenhouse gas emission can be as high as 70%. Considering the global warming and the carbon trade, it means a lot in the future. And also we can generate electricity from it, or at least, we can deal it with gas flaring.
In addition, the reuse of the landfill is needed in the near future. A lot of landfill sites are dumped without any attention nowadays. Golf sites and other use form of the landfill should be considered carefully in the future to save the space and also to improve the management after the landfill finishes. Although there are a lot of shortcomings in China right now, still in some site, these disadvantages are being quickly remedied and government has done some significant improvements, such as the waste treatment workshop in Guangzhou. They have improved their conditions of landfill very quickly according to the international standard.
Composting is the process of producing compost through aerobic decomposition of biodegradable organic matter. After composting, gas can be generated and they can be used to generate electricity or to be lighted up. China has a great demand for composting as the size of brownfields is increasing all the time. Due to the increasing city population and the soil become more important to the citizens. The remains of the composting are good medicine to improve the quality of the soil and increase the yield of the soil. Also the composting can reduce the emissions of the greenhouse gases.
Although it is more expansive than landfill, the product through the process is more useful and it takes smaller space. It is particular important for a country like China who has such a big population and relatively small distance between cities. But still, there are some serious situation existing in the composting. First is also about the management of composting. Composting is more expansive than landfill. To increase the proportion of composting, more invest is needed. There is a economic issue between it and the development. Second, careful classification is required before the composting begins.
Otherwise, the remains of composting may have high level of heavy metal or other chemicals, which will lead a bad result. Higher technology and more careful attention need to be taken by the operators, and it is also a big issue to think about. Third, the standard of composing is not very good set up in China. More detailed national operational standard and regulation is needed before building more composting sites. To sum up, there is still a long way to go before China can catch up with the developed country and reach the international standard, but we are trying to do, and significant improvement has taken place already.