Waste free city creates a new benchmark for solid waste treatment

Public data show that at present, Beijing produces nearly 26,000 tons of domestic waste every day, about 1.2 kilograms per capita per day, if transported by trucks with a load of 2.5 tons, these trucks are connected in a string, can line up a circle of the Third Ring Road. Coupled with the industrial solid waste, construction waste and other solid waste generated in the production of all walks of life, the volume is even more amazing.

China is a country with a large population and one of the countries that produce the largest amount of solid waste. Du Xiangwan, an academician of the Chinese Academy of Engineering, introduced that at present, China's accumulated stock of all kinds of solid waste is more than 80 billion tons, and the annual production is nearly 12 billion tons, and it is growing year by year.

"Such a huge accumulated stockpile and annual output of solid waste, if not properly handled and utilized, will cause serious pollution to the environment and a great waste of resources." Du Xiangwan said.

At present, of the more than 600 large and medium-sized cities in the country, a quarter of the cities lack suitable places to pile garbage, and non-compliant disposal of urban garbage occurs from time to time. In recent years, in order to promote the source reduction and resource utilization of solid waste, and minimize the amount of landfill, China has carried out the construction of "waste free city".

On January 11, 2024, the Opinions of the CPC Central Committee and The State Council on Comprehensively Promoting the Construction of a Beautiful China were released, proposing that by 2027, the proportion of "waste-free cities" should reach 60%, and the intensity of solid waste generation should decrease significantly; By 2035, the construction of "waste free cities" will be fully covered, and eastern provinces will take the lead in building "waste free cities" in the whole region.

Li Jinhui, a professor at the School of the Environment of Tsinghua University and executive director of the Basel Convention Asia Pacific Regional Center, believes that the concept of "waste free city" is highly compatible with the goal of "dual carbon", and the two integrate the resource flow and waste flow in the economic system from different entry points, reduce the use of raw materials and waste generation, and reduce environmental risks. Promoting the construction of "waste free cities" will strongly promote the realization of the "double carbon" goal.

More than 100 cities to build "waste-free cities"

"Waste free city" is an advanced urban management concept, which refers to the urban development mode that promotes the formation of green development mode and lifestyle, continuously promotes the source reduction and resource utilization of solid waste, minimizes the amount of landfills, and minimizes the environmental impact of solid waste.

In December 2018, The General Office of the State Council issued the Pilot Work Plan for the construction of "Waste Free Cities". In 2019, the Ministry of Ecology and Environment determined the "11+5" pilot, that is, to carry out reform pilots in 11 cities such as Shenzhen and five special areas such as Xiongan New Area.

On April 24, 2022, the General Office of the Ministry of Ecology and Environment issued the construction list of "waste free cities" during the "14th Five-Year Plan" period, clarifying the target cities of 31 provinces, regions and municipalities as "waste free cities" in the region. The list also includes Weihai in Shandong province, Shijiazhuang in Hebei province, Changchun in Jilin Province, Tongling in Anhui province, Xi 'an in Shaanxi Province, Tianshui in Gansu province and Yushu in Qinghai province. The construction of "waste-free cities" has expanded to 113 cities and eight special regions.

Industry insiders believe that the construction of "waste free city" is a powerful starting point for deepening the reform of comprehensive solid waste management at the overall level of the city, and it is also a forced mechanism to promote sustainable economic and social development.

On the one hand, the construction of "no waste city" is an inherent requirement for in-depth fighting the battle of pollution prevention and control and achieving carbon peak carbon neutrality.

There is a "triple coupling" relationship between solid waste, waste gas and waste water in environmental pollution and its treatment.

First of all, untreated solid waste pollutes the atmosphere, water, soil and living things due to rain, evaporation, wind erosion, spontaneous combustion, chemical changes and other effects.

Secondly, in the process of waste gas and wastewater treatment, some harmful substances are converted into harmless or stable states, and most pollutants are transferred to the solid phase and enter the environment in the form of solid waste, such as gypsum after desulfurization and sludge after sewage treatment.

Thirdly, in the process of solid waste treatment and disposal, there is also the risk of polluting the atmosphere, water and soil; The final form of treatment is also solid waste, such as solid waste utilization, landfill and incineration processes and end products.

The pilot practice shows that the construction of "waste free city" provides a path for systematically solving the management of urban and rural solid waste, and becomes a powerful starting point for comprehensive treatment, systematic treatment and source treatment of solid waste at the city level.

The daily production capacity is as high as 26,500 tons, and the need for solid waste treatment is urgent. Weihai has taken the pilot project of "waste free city" as an opportunity to increase the local harmless disposal capacity and resource utilization and disposal capacity of various types of solid waste from the original 22,125 tons per day to the current 31,850 tons per day.

On the other hand, the construction of "waste free city" is an effective carrier to promote high-quality urban development.

Lin Tao, a researcher at the Institute of Urban Environment of the Chinese Academy of Sciences, believes that with the construction of "waste free city", the urban industry, consumption and end treatment and the surrounding geographical and ecological environment will form a benign interaction, promote efficient, circular, intensive and eco-friendly technological innovation, and radiate the city's production, life and ecology-related fields, and give birth to new green industries.

Promoting the construction of "waste free city" will also help the application of smart city technology, carry out information management of the whole process of solid waste generation, transport, and treatment, and ultimately improve the modern management level of the entire city.

"Three chemical" reduction of pollution and carbon coordinated growth

Instead of paper tickets, a one-code (pass) ticketing system will be used, allowing tourists to visit the island with only their ID cards and QR codes. There are drinking water facilities or water supply points in the visitor center and other places, effectively reducing the waste of mineral water bottles, beverage bottles... In the Liugong Island scenic spot in Weihai City, reporters can feel the "no waste" concept revealed here everywhere.

"The electronic ticket of Liugong Island scenic spot can save 2 tons of paper every year, if the A4 paper is stacked up as high as a 15-story building." Weihai Cultural Tourism Development Group Co., LTD. Deputy director of the engineering management department Chen Zhigang said.

In recent years, China's "waste free city" construction area to "waste free" as the main line, follow the "reduction, resource, harmless" principle, to help the city green low-carbon transformation.

First of all, focus on the reduction of solid waste at source, and promote the green and low-carbon transformation of production and life.

-- Promoting green industrial production. Carbon emission control will be included in the review of cleaner production, clean production transformation of enterprises in key industries will be carried out, advanced and applicable technology and equipment will be adopted, and solid waste generation will be reduced at source.

For example, Xuzhou City in Jiangsu Province clearly "encourages industrial park areas and enterprises to undertake industrial solid waste utilization and share infrastructure; Enterprises should adopt advanced processes and equipment, promote cleaner production, and promote source reduction."

-- Practicing a green lifestyle. Continue to promote the classification of domestic waste, and establish and improve classification, collection, transportation, and treatment systems.

As a typical tourism city, since being selected as the first batch of "waste free city" construction pilot cities in 2019, Sanya City, Hainan Province, has achieved negative growth in the total amount of solid waste such as domestic waste, focusing on creating a "waste free" cultural atmosphere led by the tourism industry, and has created three batches of 38 "waste free hotels" and 13 "waste free scenic spots".

-- Promoting green agricultural production. We will further implement actions to reduce the amount of fertilizers and pesticides and increase their efficiency, and strengthen the prevention and control of non-point source pollution in the planting industry. We will appropriately develop multi-level and integrated aquaculture models, such as integrated rice-fishery farming, integrated fish-light farming, and fish-vegetable co-development, and promote energy conservation and emission reduction of fishing vessels and fishing machines.

Xunshan Group Co., Ltd. is a national key leading enterprise of agricultural industrialization in Rongcheng City, Weihai City, which mainly focuses on the breeding, breeding and processing of seafood treasures. Over the years, the company has created a unique "multi-nutrient level ecological farming model", changing the status quo of single farming kelp or shellfish in the past, implementing mixed farming of algae, filter-feeding shellfish, and feeding fish, and farming in accordance with the ratio of 7:2:1.

"This model forms a virtuous cycle of mutual promotion between aquaculture organisms and ecological environment, which plays an important role in reducing the total amount of carbon dioxide, controlling the eutrophication of coastal and near-shore waters, and improving the ecological environment of aquaculture waters." Xianshan Group Allen Bay national Marine ranch operations manager Bian Dapeng said.

Secondly, take the resource utilization of solid waste as a breakthrough to promote the saving and efficient use of resources and energy.

-- Strengthening the utilization of industrial solid waste as raw materials and energy. Promote the utilization of coal gangue, fly ash, tailings, smelting slag and other industrial solid wastes in the extraction of valuable components, production of building materials, road construction, ecological restoration, soil treatment and other fields.

-- Strengthening the resource utilization of domestic solid waste. Promote the resource utilization technology of food waste, and use food waste to produce biodiesel, biogas, soil amendments and other products.

In the workshop of Celeb Environmental Technology Co., LTD., located in Huancui District of Weihai City, the reporter saw a kitchen waste treatment equipment "swallow" food kitchen waste in the equipment through solid-liquid separation, oil-water separation and automatic sorting device, and in a moment can "spit" out waste oil, table leftover food and debris.

"The waste oil can be used as raw materials for aviation oil and biodiesel after deep processing, and the leftover food from the table can be used as feed materials for Marine organisms and other omnivores after sterilization, deodorization, energy saving, dehydration and harmless treatment." "Said Zhou Benliu, the company's chairman.

-- Promoting comprehensive utilization of agricultural solid waste. Improve the utilization level of straw fertilizer, fuel, feed, raw material and base material, and strengthen the control of straw incineration. We will improve the utilization of livestock and poultry waste as resources and energy, and promote the development of biomass energy in rural areas.

-- Promoting the recycling of construction waste. Encourage the application of recycled aggregates and products of construction waste in construction projects and road projects. Promote the large-scale use of treated construction waste in the fields of earthwork balance, forestry soil, and environmental governance.

Take the harmless treatment of solid waste as the key point, and cooperate to reduce greenhouse gases and pollutants.

By continuously promoting the capacity building of domestic waste incineration treatment, reducing the landfill treatment of domestic waste, and jointly promoting the prevention and control of domestic waste pollution and carbon emission reduction.

At Rongcheng Solid Waste Comprehensive Treatment and Application Industrial Park Co., LTD., in Weihai City, garbage trucks are unloading domestic garbage collected from all over the city to the garbage pond through the garbage discharge platform. "The waste is fermented and dehydrated in a closed waste storage pit before being sent to an incinerator." The company manager Wang Xiaoming introduced.

"The flue gas produced by waste incineration is treated by the purification system and discharged into the atmosphere, and all flue gas emission indicators meet the national standards." "The slag produced can be treated and used as subgrade filler or building material," Mr. Wang said.

"In recent years, Weihai has achieved 'all incineration and zero landfill' of domestic waste in the whole region." Song Jijiang, chief economist of the urban management center of Weihai City Housing and Construction Bureau, introduced that the current waste incineration treatment capacity of the city has reached 3800 tons/day, which can ensure that the daily daily incineration treatment of domestic waste is clear, and the harmless treatment rate and incineration treatment rate are 100%.

Address the three major challenges

The ultimate goal of "waste free city" construction is to form a "waste free society". Next, the construction of "waste free city" needs to deal with three major challenges.

-- Improving systematic solutions. Solid waste treatment and disposal is reflected in the source reduction, classification and recycling, collection and transportation, resource utilization, harmless disposal and other links, which are connected with each other and have a clear division of labor, and jointly constitute a complex system. However, in reality, the construction of "waste free cities" in some places still lacks a systematic and comprehensive overall plan for solid waste treatment and disposal, and the comprehensive utilization rate of solid waste is low.

Wen Zongguo, a professor at the School of Environment of Tsinghua University, suggested a comprehensive survey of the sources, types, flow directions and how to deal with the current situation of urban solid waste;

The concept of "waste free city" is formulated into a clear and quantifiable construction target according to the index system.

Plan and implement the key areas and indicator system of the national "waste free city", and propose specific and operable solutions for different types of solid waste;

From the whole process of solid waste generation, classification, collection and transportation, resource utilization and harmless disposal, comprehensive consideration is given to infrastructure construction, recycling and treatment mode, commercial construction and operation mode. According to the characteristics of the city, according to the characteristics of solid waste classification policies, to form a systematic plan for the construction of "waste free city".

-- Exploring diversified financing methods. Cities with complete solid waste hardware facilities and high management levels should work hard on optimization and improvement and move forward to fine management. Cities with large hardware gaps and relatively low management levels need to speed up the shortcomings of solid waste disposal facilities and improve the comprehensive management level.

Wen Xuefeng, deputy director of the Department of Solid Waste and Chemicals of the Ministry of Ecology and Environment, believes that the effective investment and financing model is the engine of the construction of "waste free city", which can solve the problem of local government funding sources to a certain extent, avoid increasing local debt, and also stimulate local investment, supplement the shortcomings of solid waste infrastructure, and promote high-quality development.

"It is suggested that we can focus on the support of CDB policy banks and explore diversified financing methods." For example, Wen Xuefeng said that the circular economy industrial park construction project of Xuzhou City cooperated with CDB to pilot the construction of more than 2,200 acres of circular economy industrial park, innovatively proposed the "three overall planning" financing model of overall construction content, overall repayment sources, and overall credit increase methods, explored the "going out" promotion and replication path, and obtained a 20-year, 4.55 billion yuan credit loan.

-- Establishing and improving long-term mechanisms. In recent years, the national, provincial, urban linkage, provinces and cities have also strengthened the guidance and help of the construction of "waste free city" in the region.

For example, Zhejiang Province carried out the pilot work of "waste free city" digital reform; The mine ruins of Weihai City, Shandong Province reappear the "Huaxia city model" of green mountains and water; Jiangsu Province to carry out the construction of "waste free canal" and "waste free park"; Hubei Province carried out the whole chain control of phosphogypsum pollution; Manganese residue pollution control system was carried out in Chongqing. Yunnan Province to promote the agricultural organic waste collection and transportation of integrated multi-use "Shunfeng Erhai" model.

In the next step of "waste free city" construction, in addition to playing the role of the relevant departments of the state and provinces and cities to achieve accurate guidance and help, it is also necessary to encourage the active participation of relevant industries and enterprises. Such as encouraging industry associations to undertake the exploration of common problems in the construction of "no waste city"; Support industry associations, leading enterprises and specialized new enterprises to play a platform role to solve local projects but lack of technology, capital and other problems.

On the other hand, establish a scientific evaluation mechanism. Duan Lizhe, deputy director and senior engineer of the Comprehensive Office of the Asia-Pacific Regional Center of the Basel Convention, suggested that we should explore a scientific evaluation mechanism, regularly evaluate the progress of the construction of a "waste free city" intelligent supervision platform, summarize experiences and problems, and constantly optimize the implementation path of China's "waste free city" to "waste free society".

 Source:https://mp.weixin.qq.com/s/8R8toXyI7PKJSPtJQ5EQ8g