两级A/O工艺处理偏高氮废水中试及其运行策略研究

Treatment for Relatively High Nitrogen Wastewater by Two-stage A/O Process and Its Operation Strategy

采用模拟青吉污水厂两级A/O工艺的中试系统进行了4个工况的试验。结果表明,在进水COD和TN分别为600 mg/L和70 mg/L左右时,控制污泥回流比为100%,混合液回流比先后调整为200%或150%,出水TN均不会超过20 mg/L。在进水TN浓度进一步提高、进水COD基本不变的情况下,必须采取增加MLSS、提高混合液回流比和外加碳源等措施,出水TN方能不大于20 mg/L。在分析总结中试结果的基础上,提出了对应于不同进水TN的两级A/O工艺出水TN达标排放的各工况运行参数组合及其碳源投加量估算方法,可用于指导污水厂运行。

A pilot plant system was used to treat four different conditions by simulation of two-stage A/O process in Qingji wastewater treatment plant.The experimental results show that when influents COD and TN are approximately 600 mg/L and 70 mg/L,respectively,the sludge return ratio is 100%,the internal recycle ratio is adjusted successively to 200%or 150%,and the effluent TN is less than 20 mg/L.When the influent TN is larger than 70 mg/L,some measures,such as increasing MLSS,increasing internal recycle ratio,and adding exotic carbon source,have to be adopted,so that the effluent TN would be less than 20 mg/L.On the basis of analysis and summary of pilot test results,a method to estimate proper combination of different parameters and carbon source dosage was proposed to treat different influent TN conditions by two-stage A/O process.The method can be used to guide the operation of sewage plants to meet the standard in terms of effluent TN discharge.