Ltd. biomass coupling and regeneration project environmental impact assessment second public notice" was published on September 9. Ltd. plans to take advantage of the clean, efficient and environmental protection of the coal engine boiler of Huaneng Jinling Power Plant to implement the sludge coupling project and give full play to the role of the stock unit of Huaneng Jinling Power Plant in urban sludge emission reduction, harmless, resourcefulness and mold disposal.
In January 2022, Huaneng International Power Jiangsu Energy Development Co., Ltd. located at No. 8, Jiangxian Avenue, Qixia District, Nanjing, Jiangsu Province, and Nanjing Water Group Resource Recycling Technology Co., Ltd. jointly invested to establish Zilai Recycling Technology (Nanjing) Co.
Purple, as the main body of the construction and operation of the biomass coupling and recycling project, leases the site of the current sludge water sedimentation pond of Huaneng Jinling Power Plant, and after removing the sludge water sedimentation pond, takes advantage of the technological leadership of the clean and efficient coal-fired generating units of Huaneng Jinling Power Plant to establish a sludge receiving and pre-treatment system to cooperate with the sludge generated by Nanjing Wastewater Treatment Plant to achieve comprehensive treatment and utilization of urban pollutants.
The disposal scale of this project is 500 tons/day in the near future and 800 tons/day in the long-term planning. The power plant boiler mixed with municipal sludge can not only use the original hot smoke or steam of the power plant as dry heat source, but also use the existing combustion and pollutant treatment system to save the investment and operation cost of sludge treatment.
The wastewater treatment plant sludge disposed of by the project is mainly collected from Tiebei, Chengdong and Xianlin. River sludge comes from the rivers in Nanjing. The disposal capacity of this project is 500t/d, which can partially fill the gap of sludge disposal capacity in Nanjing.
The project adopts the sludge pre-drying carbonization treatment technology of coal-fired power plant, and is equipped with the treatment capacity of 2 sets of 250t/d sludge comprehensive processors. After the completion of the project, Zilai Renewable Resources Technology (Nanjing) Co., Ltd. has 500t/d municipal sludge harmless disposal capacity and is expected to treat 150,000 tons of sludge per year (of which sewage treatment sludge accounts for 90-95% and river mud accounts for 5-10%). The transportation of sewage treatment sludge and river mud is done by the third-party units entrusted by each sewage treatment plant and river management government departments. Sewage treatment sludge and river mud are stored in the engineering sludge warehouse with mixed storage.
The integrated processor is connected to the boiler through the furnace flue pipe.1. 1 and 2 units of Huaneng Jinling Power Plant, configured with 1 Purple Recycling Technology (Nanjing) Co. Biomass Coupling and Recycling Project Environmental Impact Report 1000 units m3. In the wet sludge warehouse storage, the sludge is transported to the integrated processor through a plunger pump arranged at the bottom of the sludge warehouse. The high temperature furnace smoke extracted from the boiler tail flue is used to dry and crush the sludge in the integrated processor. After the sludge is processed, it enters the furnace for combustion through the sludge burner. The combustion products are treated by the tail flue gas purification facility to meet emission standards.
Sludge source
The sewage jurisdiction of Nanjing Water Group Co., Ltd. includes 8 sewage collection and treatment systems, including Jiangxinzhou, Chengbei, Tiebei, Chengdong, Xianlin, Qiaobei, Chengnan, Baguazhou, and is responsible for the management and maintenance of all sewage facilities in the "District Junction Node Well" sewage treatment plant. According to the actual operation data provided by Jinling Environment, the average daily sludge production of the nine sewage treatment plants in 2019-2021 is shown in Table 4.2-1.
According to Nanjing Water Group "Fourteen Five" strategic development plan and sewage special planning, will be in the north of the bridge, south of the city, Xianlin project will be in the north of the bridge, south of the city line expansion "Fourteen Five" is expected to the end of 2025, the total scale of sewage treatment will reach 2.22 million m3 / d .
According to the Urban Drainage Engineering Planning Code (GB50318-2017), the sludge yield of sewage treatment plants can predict the actual mud production rate of the local built sewage treatment plants, and can also be estimated according to the sewage water quality, slurry age, process and other factors to treat m³ sewage product water content 80% sludge 6-9%t. In addition, according to the "Nanjing urban domestic sewage treatment plant sludge treatment and disposal special planning (2018-2035)", taking into account the gradual completion of the upgrading of rainwater and sewage treatment plants in Nanjing, the full implementation of actions to improve the quality and efficiency of urban domestic sewage treatment will increase the concentration of influent pollutants and tons of water pollutants reduction, the sludge production in the medium term to 2025 can reach 7%.5t/10000m³ (water content 80%). Therefore, combined with the actual operational data provided by Golden Environment, the sludge production forecast here is 7.5 and 8.5t/million m³ (water content 80%) comparing the two parameters and calculating the average daily sludge production of 1665 and 1887t/d (water content 80%) for the 10 wastewater plants in 2025.2-2.
The sludge incineration (mixed) disposal agreement signed by Nanjing Water Group Co., Ltd. will expire at the end of 2023 or early 2024, and it is unclear whether the agreement will be renewed. Nanjing Water Group invested in the construction of the Nanjing Sludge Treatment Center project Phase I treatment scale of 400t/d (water content 80% sludge) + at present, the overall completion of the incineration treatment process more than 70%, is expected to be basically completed and enter the commissioning phase by the end of 2022.
In summary, the total sludge disposal capacity is expected to be only 400 by 2025, and without considering the renewal of the sludge incineration (blending) disposal agreement t/d, the sludge disposal gap is analyzed as follows:
(1) If the sludge production is projected at 7.5t/million m³ (water content 80%), the average daily sludge production in 2025 is 1665t/d sludge treatment gap is 1265t/d (water content 80%)
(2) If the sludge production is projected at 8.5t/million m³ (water content 80%), the average daily sludge production in 2025 is 1887t/d sludge treatment gap is 1487t/d (water content 80%).
Therefore, the sewage treatment plant sludge disposed of in this project is mainly collected from Tiebei, Chengdong and Xianlin. River sludge comes from the rivers in Nanjing. The disposal capacity of this project is 500t/d, which can partially fill the gap of sludge disposal capacity in Nanjing.
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