Beijing, Tianjin, Shanghai, Chongqing, Guangzhou, Handan, Taiyuan, Dalian, Changchun, Nanjing, Suzhou, Hangzhou, Ningbo, Hefei, Tongling, Fuzhou, Xiamen, Nanchang, Yichun, Zhengzhou, Jinan, Tai'an , Qingdao, Wuhan, Yichang, Changsha, Shenzhen, Nanning, Haikou, Chengdu, Guangyuan, Deyang, Guiyang, Kunming, Lhasa, Xi'an, Xianyang, Lanzhou, Xining, Shijiazhuang, Urumqi, Shenyang, Yinchuan, Harbin, Shigatse, Hohhot, etc.
With the rapid development of cities, the improvement of living standards and consumption levels, and the rapid development of the catering industry, the output of urban domestic waste continues to increase, and the composition of waste is becoming more and more complex. The pollution problem caused by garbage is also becoming increasingly serious, and the disposal of garbage has become a serious problem faced by people. According to statistics, our country generates nearly 1 billion tons of garbage every year, of which the amount of domestic waste is about 400 million tons, which is still increasing at a rate of about 5-8 per year. Of the more than 600 large and medium-sized cities in the country, 70% are surrounded by garbage. Taking Hangzhou as an example, the garbage generated by Hangzhou in three years can fill the entire West Lake.
The accumulation of garbage in landfills not only takes up farmland, but also pollutes soil and crops. White pollution such as plastic bags, plastic cups, and foam plastic products will not degrade for decades or even hundreds of years after being landfilled. In addition, due to the toxic components and heavy metals contained in them, these cultivated lands have lost their use value. It causes the soil quality to deteriorate, inhibits the growth of crops, and reduces plant yields30.
Garbage leaks through rainwater and pollutes groundwater or enters surface water, causing water pollution.
During the decomposition process of garbage, harmful gases such as ammonia, methane and hydrogen sulfide are produced, forming stench and seriously polluting the atmosphere.
Garbage dumps are breeding grounds for almost all microorganisms. Including viruses, bacteria, mycoplasma, mosquitoes, flies, cockroaches and other disease transmission media. Endanger people's health and cause diseases.
Hazardous waste directly or indirectly harms human health. Such as waste lamp tubes, waste paint, especially waste batteries. Because batteries contain heavy metals such as mercury, cadmium, and lead. Mercury is highly toxic; lead can cause neurological disorders, nephritis, etc.; cadmium mainly causes kidney and liver damage as well as bone diseases such as osteoporosis, rickets and fractures; radioactivity can cause cancer.
So what are the benefits of garbage classification?
The main methods of municipal solid waste treatment adopted at home and abroad include sanitary landfill, high-temperature composting and incineration.
Among them, incineration is a municipal waste treatment technology widely used in countries around the world. The incineration process can also recover heat energy, which can be used for power generation, heating, etc., becoming the mainstream method of waste treatment.
Waste incineration
But the dioxin pollutants brought by waste incineration are one of the deadliest toxic substances on earth. Dioxins can spread over long distances after being emitted. Once it enters the human body, it will stay for a long time, destroying the human immune system, changing thyroid hormones and steroid hormones, and reproductive functions. The most sensitive thing is affecting human development and causing fetal malformations.
According to foreign scientific experimental research, the conditions for the generation of dioxin from garbage incineration are: the combustion temperature is lower than 800°C, the combustion temperature in the furnace is uneven, and the incomplete combustion of garbage leads to the generation of dioxin. If a large amount of wet waste is mixed with the incinerated waste, the combustion temperature will be lowered. In the mechanism of producing dioxin, there is another essential element - chlorine. Chlorine mainly does not come from table salt in kitchen waste or polyvinyl chloride in plastic waste. If garbage classification can be done properly, the harmful substances produced by garbage incineration will be greatly reduced.
We saw that garbage in Shanghai is classified into: recyclables, hazardous waste, wet waste, and dry waste. Sorted garbage is easier to handle.
1. The main force in recycling recyclable waste.
Mainly includes paper, metal, plastic products, textiles, waste electrical appliances, etc. These can be processed through the recycling network. For example, waste plastics and rubber can be made into recycled plastic products through pretreatment and plasticization. Waste paper can be used to produce recycled paper products.
2. Special treatment of hazardous waste.
Mainly include waste batteries, waste lamps, expired medicines, pesticide containers, etc.
These garbage will seriously pollute the soil, atmosphere, and water quality, thereby affecting human health. Hazardous waste can be disposed of harmlessly by professional companies.
Third, wet waste composting and power generation.
Including leftovers, vegetable stems and leaves, animal offal, fruit shells and melon rinds, stumps and fallen leaves, etc., which are mainly used for composting and power generation.
Kitchen waste is treated with on-site resources and used for biogas power generation or biochemically treated for sanitary landfill.
Fourth, dry waste incineration and power generation.
Dry waste is mainly waste with no recycling value and low moisture content. This type of waste can be burned to provide power and heat, and then landfilled, which can greatly reduce the landfill space.
Therefore, classifying garbage properly can not only save resources, reduce environmental pollution, and reduce land occupation, but it is also a must for human health and sustainable social development.
Garbage classification is a reform of the traditional way of garbage collection and disposal. It is a scientific management method for effective garbage disposal. On July 1, 2019, the "Shanghai Domestic Waste Management Regulations" were officially implemented, and Shanghai began to implement compulsory garbage classification generally. The Ministry of Housing and Urban-Rural Development announced that it will implement garbage classification in 46 key cities across the country and clearly incorporate garbage classification into the legal framework.
46 key cities for waste classification
Beijing, Tianjin, Shanghai, Chongqing, Guangzhou, Handan, Taiyuan
Dalian, Changchun, Nanjing, Suzhou, Hangzhou, Ningbo, Hefei
Tongling, Fuzhou, Xiamen, Nanchang, Yichun, Zhengzhou, Jinan
Tai'an, Qingdao, Wuhan, Yichang, Changsha, Shenzhen, Nanning
Haikou, Chengdu, Guangyuan, Deyang, Guiyang, Kunming, Lhasa
Xi'an, Xianyang, Lanzhou, Xining, Shijiazhuang, Urumqi
Shenyang, Yinchuan, Harbin, Shigatse, Hohhot