In order to solve the problem of solid waste treatment and improve the resource utilization of solid waste, the government has proposed the construction of a “no waste city”. In this way, the organizers of WieTec will join hands with the National Eco-Environmental Science and Technology Achievement Comprehensive Service Platform to build a one-stop environmental technology platform for environmental protection enterprises and contribute to the construction of a “zero waste city”. This article introduces how to build a “zero waste city” through two cases of domestic waste and industrial solid waste.
During the 13th Five-Year Plan period, the solid waste treatment market has become the most promising market. According to the “Annual Report on the Prevention and Control of Solid Waste Pollution in Large and Medium-sized Cities in China” issued by the Ministry of Ecology and Environment in 2019, 200 large and medium-sized cities produced 1.55 billion tons of general industrial solid waste, 46.43 million tons of industrial hazardous waste, and 81.7 million medical waste in 2018. Such a huge annual amount of solid waste, if not properly treated, will cause serious pollution to the environment and waste resources.
The aim of the initiative is to solve the problem of solid waste treatment, promote the resource utilization of solid waste, minimize the amount of landfills, and minimize the environmental impact of solid waste. In 2018, the General Office of the State Council issued the “Zero Waste City” construction “Pilot Work Plan”.
The plan identified 11 cities including Shenzhen, Baotou, Tongling, Weihai, Chongqing (main urban area), Shaoxing, Sanya, Xuchang, Xuzhou, Panjin, Xining, as well as Xiong’an New District, Beijing Economic and Technological Development Zone, and Sino-Singapore Tianjin Eco-City , Guangze County, Fujian Province, Ruijin City, Jiangxi Province, and other five special areas, as suitable for “zero waste city” pilot project. The project revolved around solid wastes, focusing on industrial solid wastes, agricultural wastes, domestic wastes, construction wastes, and hazardous wastes, while strengthening full resource utilization and promoting safe disposal.
On March 11, 2020, the 16 “zero waste cities” pilot program was finalized, and the construction of “zero waste cities” entered the actual operation stage. Zhejiang proposes that by the end of 2023, the province will basically complete the construction of “waste-free cities” in the entire region and formulate concrete measures and task arrangements for practical use, while vigorously promoting electronic management and establishing and improving a unified hazardous waste collection and transportation system.
The construction of a “zero waste city” is a long-term process that cannot be achieved overnight. It requires a close cooperation of the Government, enterprises and society. The government must implement the responsibilities of all parties, improve legislative supervision, continue to increase financial support, adjust industrial structure and increase publicity for the construction of “zero waste cities”. The entire society needs to abide by the agreed rules, the general public must also actively participate in environmental protection causes. This will inevitably lead to environmentally friendly products becoming more popular.
This article introduces the concept of “zero waste city” from the aspect of domestic waste and industrial solid waste.
Domestic waste disposal
1.Garbage classification is not enough
In the “2019 National Large and Medium-sized Urban Solid Waste Pollution Prevention and Control Annual Report” issued by the Ministry of Ecology and Environment, the amount of domestic garbage generated by 200 large and medium-sized cities in 2018 was 21,147,300 tons. According to industry analysis, the proportion of China’s kitchen waste in urban domestic waste is roughly 37% -62%. In 2018, China’s kitchen waste production was about 100 million tons per year, and by 2020 this figure may exceed 120 million tons.
Source: National Annual Report on Environmental Pollution Prevention and Control of Solid Waste by Large and Medium-sized Cities in 2019
Food waste is different from other wastes in that it has a large water content. Traditional kitchen waste treatment is mainly landfill and incineration. The landfill has a large amount of sewage and it is difficult to treat sewage. Similarly, incineration treatment will increase the consumption of incineration fuel and increase the cost of treatment because of the high water content.
So is it possible to reduce the cost of treatment and reduce the production of harmful substances while improving the utilization of kitchen waste resources?
Sichuan Jiabowen Biotechnology Co., Ltd. put forward a good idea to turn the kitchen waste into fertilizer for soil. Food waste is rich in organic matter, and this organic matter is a good raw material for soil fertility, but food waste cannot be directly composted in the field, so they use microorganisms to degrade the organic matter in food waste. A product called biological humic acid is a product which can be used for soil improvement.
- Bio-enhanced humification technology for urban organic waste
After many experiments, the reserchers have successfully developed an organic waste biochemical treatment machine, which can produce humic acid content ≥50 after aerobic fermentation at 60-80 ° C in the organic waste biochemical treatment machine for organic waste and compound microbial strains.
This technology is also used in the Chengdu Urban Kitchen and Kitchen Waste Disposal Project (Phase 1), which consumes 66,000 tons of kitchen waste per year in the central urban area of ??Chengdu, and basically solves the kitchen waste treatment problem of urban population of 2 million. Organic matter resource utilization rate is over 95%.
Industrial solid waste treatment
After talking about domestic garbage, let’s look at industrial solid waste.
The sludge in industrial solid waste also has the characteristics of high water content. High-yield, high-moisture sludge is not convenient during storage, transportation, loading and unloading, and there are high potential environmental safety risks and hidden dangers. Therefore, we need to dry the sludge.
However, conventional sludge drying consumes a lot of heat energy and electric energy, resulting in higher treatment costs, and if harmful substances are present in the sludge, the volatilization of harmful substances will be accelerated and secondary pollution will occur.
So if the sludge can be dried at a lower temperature, can it not only achieve the purpose of sludge drying, but also reduce the volatilization of harmful substances?
After research, Shanghai Hehui Ecological Environment Technology Co., Ltd. has developed a low temperature physical depth reduction technology for sludge. The low chemical temperature of the medium can prevent the volatilization of harmful substances in the sludge. At the same time, the sludge has a good drying effect and a high reduction rate. No secondary pollutants were generated.
This technology has been well applied in Jiangsu Helun Petrochemical Sludge Reduction Project. The wet sludge with a moisture content of 85%, after drying, has a moisture content of about 7% and a weight of 16.67%.
At the same time, the economic benefits of the project are also very obvious. The indirect benefits of sludge drying are 133,328 yuan a day, and the operating cost is 29,564 yuan a day. The total project investment is calculated as 15.913 million yuan. Five and a half months into the project, the entire investment can be recovered.
Technology is at the core of the construction of a “zero waste city”. Advanced technology can help us improve the resource utilization of waste, reduce treatment costs, and generate higher economic benefits. Therefore, we promote advanced technology to pilot cities. At the same time, we must also take corresponding measures to ensure the smooth implementation of technology.
Therefore, solidly promoting the construction of a “zero waste city” also requires the following aspects:
- Relevant government departments should prepare implementation plans, clarify pilot objectives, determine task lists and division of labor, establish work coordination mechanisms, strengthen pilot work guidance, implement the responsibilities of all parties, and coordinate research on major issues.
- Increase funding support, encourage pilot city governments to use relevant support policies, and increase fiscal funds’ support for the construction of “zero waste cities”.
- Strengthen the supervision and inspection of the reduction, recycling and harmlessness of the pilot urban solid wastes, and investigate the responsibilities according to law if the solid waste supervision responsibilities have not been put in place.
- Strengthen the guidance of the construction of a “zero waste city”, give full play to the role of social organizations and the public, and guide the public from bystanders to builders of the “zero waste city”.
Only when all aspects are in place can we truly promote the source reduction, resource utilization and harmless treatment of solid waste, and promote the construction of a “zero waste city”.