Shanghai continuously improves the capacity of harmless disposal and resource utilization of garbage, making domestic garbage ＂turn waste into treasure＂ at the end of the chain 2023-05-31 Source： Jief

Reporter Yan Yingpu

Have you ever wondered if you have worked so hard to sort out the good garbage, and will it be mixed up when you get to the garbage treatment plant? What did it eventually become? The disposal link at the end of the chain is the key for the whole people to develop the habit of garbage sorting. People need to know that their efforts in sorting have not been in vain, and the sound harmless disposal and resource utilization ability at the end is the silent but most powerful response.

Shanghai is about to enter the fourth year of promoting the construction of the whole process classification system of domestic waste. Today, in the electricity and natural gas used by people, in the benches where people sit and rest, and in the special feed for breeding, there is a way out for turning Shanghai domestic garbage into treasure.

"one point to the end"

Laogang Eco-environmental Protection Base is the largest garbage disposal site in Shanghai, and now its territory has been expanded. The third phase of Shanghai Bioenergy Reuse Center is under construction. After it is put into operation, Laogang can add 2,000 tons of wet waste treatment capacity every day, making it the largest deep resource utilization base of wet waste in the world.

After the domestic garbage is put into different categories, such as dry garbage, wet garbage, recyclable garbage and harmful waste, corresponding factories need to deal with them. Since 2019, Shanghai has begun to increase the construction of terminal disposal facilities, constantly filling in shortcomings and filling in blanks.

Shanghai Bioenergy Reuse Center is an exploration to fill the "blank" of wet waste disposal in Shanghai. At present, the first and second phases of Shanghai Bioenergy Reuse Center have been fully operated, with a total scale of 2,500 tons/day of wet garbage treatment.

Dry garbage also enjoys a special "housekeeper" service. According to the person in charge of Laogang Branch of Shanghai Environment Group Renewable Energy Operation Management Company, Laogang Renewable Energy Utilization Center has the "world’s best" waste incineration plant, and the eight incineration lines in the second phase of the project are around the clock, with a daily capacity of 6,000 tons of waste. If the first phase of the project is added, a total of 3 million tons of domestic garbage will be disposed of every year, accounting for about 1/3 of the total garbage generated by Shanghai residents.

The reporter learned from Shanghai Chengtou, which undertakes the task of transferring and disposing 80% of domestic waste in Shanghai, that at present, it has built and operated 11 domestic waste incineration plants in the city, with a daily domestic waste incineration capacity of more than 18,500 tons, accounting for more than 60% of the total domestic waste incineration capacity in Shanghai. The incineration system adopts the internationally advanced grate furnace, and the flue gas emission indexes all reach or exceed Shanghai landmarks and EU standards. Five wet waste plants have also been built and operated, accounting for 50% of the total capacity of wet waste recycling in Shanghai.

The premise of turning waste into treasure is "one point to the end", not only the hardware facilities should be distinguished, but also the whole process management should be strictly classified. Taking Shanghai Chengtou as an example, it has built and operated 12 domestic waste collection and transportation transfer stations in the city. The on-site operation procedures, dynamic establishment of compressed berths and the construction of special containers for kitchens have all been optimized, and classification signs have been added to ensure that dry and wet garbage are not mixed.

Xupu, Hulin and Laogang solid waste container transfer bases have also updated and configured more than 2,000 containers to meet the requirements of classified transportation, and the automatic allocation system has been applied to realize classified garbage transfer. At the same time, the operation flow of classified transshipment is explored in practice, and the classification operation standard is formed. Through hardware transformation and software upgrade, all aspects of collection, compression, transit and water transport are fully sealed, so as to realize "no odor outflow and no liquid leakage".

Relying on this, Shanghai not only exerts its strength in the source delivery, but also links the classified transit, classified transportation and classified disposal with closed-loop management after the classified delivery, forming the "Shanghai Model" for the classified treatment of domestic waste refined and summarized by the National People’s Congress, and promoting it to the whole country.

turn waste into treasure

There is a "black technology factory" in Laogang. Stepping into it, I saw layers of metal baskets stacked up to form a "small high-rise", which hatched black hydra larvae. According to the person in charge, these black hydra larvae make a living by eating wet garbage. If the production line runs at full capacity, they can eat 50 tons of wet garbage a day.

The black hydrangea is a microcosm of the diversification of garbage recycling in Shanghai. In recent years, Shanghai has formed a "point-station-field" operation system for recycling renewable resources, and almost every kind of garbage has a corresponding outlet-dry garbage can be burned to generate electricity; Wet garbage can be used for biogas generation and biogas residue utilization; Even hard construction waste is transformed into recycled aggregate and backfill material after special process, which is used to make recycled bricks and cement mortar.

The resource utilization for recyclables is more detailed. At present, six regions, including Jiading, Qingpu, Xuhui, Huangpu, Pudong and Jing ‘an, are promoting the integration of the two networks and the construction of recycling system of renewable resources, with a total of 5,210 recycling points, 6 open demonstration sites along the street, 35 transfer stations and 3 distribution centers.

By May 2023, a total of 46,350.33 tons of recyclable materials such as glass, clothing, plastics, paper and gold had been recovered in these areas. According to the standards of the International Solid Waste Association, the annual carbon emissions of waste paper recovered by resource companies can be reduced by about 43,942 tons, that of waste plastics by 14,194 tons and that of waste glass by 9,890 tons.

For recyclable materials with complex components, such as plastic and aluminum foil composite materials such as milk cartons, the disposal production line in Laogang has solved the problem: waste paper-based composite packages such as milk cartons and tetra pak are recycled and cleaned, and then they are directly crushed and extruded into "plastic wood" new materials through low-temperature and high-temperature hot pressing. The paper, plastic and aluminum foil in paper-based composite packages are more closely combined and become plastic wood products belonging to the category of industrial boards. At Chongming Flower Expo, a flower viewing bench made of discarded milk boxes became online celebrity in one fell swoop.

Precision does not miss.

Different from the past, garbage disposal operators are no longer sweating, but "go upstairs" and sit in the office. On the third floor of the second phase of Laogang Renewable Energy Utilization Center, front-line staff can be seen through the glass window of the central control room. On the big screen, combustion data, emission data and power generation data are scrolling and jumping, and employees are burying their heads in data analysis and operation scheduling, which is orderly.

In the face of the multiplication of the difficulty coefficient of municipal solid waste treatment, the complexity of the original production process and management mode has increased several times compared with before, and the production management cost has increased greatly, so the crowd tactics can not cure the problem. It is necessary to rely on digital technology for efficient management of the "last mile" of garbage classification.

"The automation degree of the second phase project of Laogang Renewable Energy Utilization Center has reached 100%. All the data produced on site can be received, automatically analyzed and automatically fed back in the central control room, and finally all the on-site equipment can be automatically controlled." The person in charge introduced.

This kind of intelligent control is not only at the "point" of the old port, but covers the whole city. The reporter learned from Shanghai Chengtou that the "digital environment" management information system has realized that the data of domestic waste classification, removal and disposal in 16 administrative districts can be collected in real time, and the domestic waste can be traced back to the source; The middle-end logistics is clear, realizing the identification of box numbers, box types and box sources of 2,300 and 4 types of garbage containers, and cooperating with the terminal disposal requirements for intelligent scheduling and accurate distribution; Terminal disposal, realize the intelligent operation of the old port base, make the solid waste disposal operation visual and transparent, establish a closed loop of real-time data acquisition, analysis and application, and promote the coordinated optimization of production equipment and facilities in the base and the recycling of resources and energy.

The change brought about by this is that the transfer of domestic waste is like express delivery, and the logistics is accurate and traceable, ensuring the daily production of domestic waste in the central city of Shanghai. What if garbage is mixed? With the help of artificial intelligence technology, we can solve the problem, and through real-time analysis and processing of images and videos of domestic waste, we can accurately judge unqualified foreign bodies mixed in them.

The data shows that the performance indicators of this AI system, such as the capture rate, detection rate, accuracy and misidentification rate, are in the leading position in the industry, which effectively reduces the complexity of wet waste quality supervision, and is conducive to forcing the classification operation of the upstream garbage delivery and removal links, improving the quality of garbage classification and maximizing the resource utilization of supporting garbage.