\"Enhanced version\" for high-concentration wastewater treatment in coal chemical industries: enables near-zero emissions and reduces costs by over 20%

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\"Enhanced version\" available for high-concentration wastewater treatment in coal chemical industries: near-zero emissions achievable with over 20% cost reduction. Author/Source: Date: 10-13-2016. Clicks: 9. On October 10, reporters learned from Nanjing University of Technology that China’s first enhanced treatment technology for high-concentration wastewater generated in coal gasification processes has, after more than half a year of continuous operation and optimization, completed its pilot test at the Datang International’s coal-to-natural gas project in Keshiketeng Banner, Inner Mongolia, on the eve of National Day. The high-concentration wastewater resulting from phenol and ammonia recovery is treated using a newly developed, enhanced integrated process, enabling the effluent to consistently meet the requirements for feeding it into subsequent membrane separation units: COD ≤ 50 ppm, total phenols ≤ 1.5 ppm, volatile phenols ≤ 0.5 ppm, ammonia nitrogen ≤ 5 ppm, total nitrogen ≤ 30 ppm, and total oil ≤ 10 ppm. 　 This technology was jointly developed by Nanjing University of Technology and Datang International, and it passed the evaluation of its achievements organized by the China Petroleum and Chemical Industry Federation on July 20. Experts unanimously agree that this technology addresses the key technical challenges associated with the enhanced treatment of high-concentration wastewater generated in coal gasification processes, as well as those related to near-zero emissions. It provides an effective and economical solution for such wastewater treatment, and its technical achievements are at an internationally advanced level, making it highly valuable for widespread adoption in the industry. At present, Datang International and other domestic coal chemical enterprises that use pressurized coal gasification are actively discussing with Nanjing University of Technology to jointly advance the industrialization of this project. According to Xu Yanhua, dean of the School of Environment at Nanjing Tech University and director of the National Laboratory for Water Conservation and Emission Reduction in the Clean Conversion of Coal in the petroleum and chemical industry, addressing the issues such as high concentration, strong toxicity, and difficulty in treatment associated with the high-concentration wastewater generated by coal gasification, the research team developed an enhanced pre-treatment combination technique that enables the selective catalytic degradation of refractory organic compounds in this wastewater ； To address the challenges posed by residual toxic substances in biochemical wastewater and the difficulty in treating recalcitrant biological metabolites, which can affect the stable operation of subsequent membrane systems, an efficient and low-consumption ozone-catalyzed secondary oxidation technology was developed through dual-circulation enhanced mass transfer and the creation of multimetal-doped catalysts. This technology improves the removal efficiency in the subsequent secondary biochemical treatment process, ensuring that the wastewater meets the quality requirements for further advanced treatment. On this basis, the R&D team also developed an integrated treatment process featuring enhanced pretreatment + single-stage biochemical treatment (two-stage A/O) + high-efficiency and low-consumption secondary oxidation + secondary biochemical treatment (A/O-MBR). The operation of this process system is not only impact-resistant and efficient, but also low-cost with minimal secondary pollution, enabling it to consistently meet the water quality requirements for the subsequent reverse osmosis membranes. According to experts, once this technological achievement is put into industrial use, it is expected to completely solve the problem of water pollution in coal chemical industries, significantly increase the rate of recycled wastewater, achieve nearly zero wastewater discharge on a consistent basis, and also reduce the overall operating costs associated with wastewater treatment by more than 20%. For existing projects, applying these technical advancements for optimization can **release the processing capacity of the existing wastewater treatment facilities**