Abstract:

China is one of the countries with water shortage， and wastewater recycling is an important way to alleviate water shortage. According to the requirements of the Action Plan for Prevention and Control of Water Pollution， industrial production should give priority to the use of reclaimed water. After a coal chemical company replaced the water source for production from reservoir water to the tailwater of the wastewater treatment plant， the quality of produced water deteriorated continuously. Through analysis of the process design and operating conditions， it was determined that the residual organic pollutants and ammonia nitrogen in the tailwater of the wastewater treatment plant were the main cause of the system’s poor operation. For the industrial water treatment unit， BAF tanks and high-efficiency sedimentation tanks were installed to eliminate the negetive effects of organic pollutants and ammonia nitrogen. For the demineralized water treatment unit， an UF-RO system was added to improve the pretreatment effect of demineralized water and reduce the system burden of ion exchange unit. After the optimization， the system effluent COD was≤30 mg/L， ammonia nitrogen was≤5 mg/L， Na⁺ was≤10 μg/L， conductivity （25 ℃）≤0.2 μS/cm， and the system could operate continuously and stably to meet the production demand of the plant. The project realized the high quality reuse of the tailwater of wastewater treatment plant in coal chemical enterprises， and made a useful exploration for the design optimization of reclaimed water reuse in coal chemical industry.

Key words: tailwater, desalinated water, coal chemical industry, reclaimed water reuse

摘要：

我国是全球水资源短缺的国家之一，污水再生利用是缓解水资源短缺的重要途径。根据《水污染防治行动计划》的要求，工业生产要优先使用再生水。国内某煤化工有限公司将生产用水的水源由水库水更换为污水处理厂尾水后，水处理系统的产水水质不断恶化。通过对系统的工艺设计及运行状况进行调研分析，确定污水处理厂尾水中残余的有机污染物、氨氮等物质是导致系统运行不良的主要原因。针对工业水处理单元，增设了BAF池、高效沉淀池，以消除有机污染物、氨氮对系统的不利影响；针对除盐水处理单元，增设超滤-反渗透系统，提高了除盐水系统的预处理效果，减轻离子交换除盐水装置的系统负担。改造后，系统出水中COD≤30 mg/L，氨氮≤5 mg/L，除盐水系统出水Na⁺≤10 μg/L，电导率（25 ℃）≤0.2 μS/cm，系统可连续稳定运行，满足工厂的正常生产需求。该工程实现了污水处理厂尾水在煤化工企业的高质量回用，为煤化工行业的中水回用设计优化作出了有益探索。

关键词: 尾水, 除盐水, 煤化工, 再生水回用

CLC Number: 

• X703