中进周出二沉池的改造.ppt

案例分析—天津某污水处理厂Verticel工艺 Case study—Verticel process in a Tianjin WWTP 工程概况 天津某污水处理厂总处理规模为45万吨/天，共分5个系列运行，每个系列的处理规模为9万吨/天。原工艺为：除磷型AO工艺，执行GB18918-2002 二级排放标准。 The total flowrate of a tianjin WWTP is 450000CMD. There are 5 trains, the flowrate of each train is 90000CMD. The original process is AO with phosphorus removal and the effluent standard is class2. 单系列参数介绍：曝气池为9个廊道，总池容为：34,300 m3 ；总水利停留时间为： 9.2 hrs The parameters of each train: there are 9 passes; the total volume is 34,300 m3 ; the HRT is 9.2 hrs. 设计进水水质influent quality： COD：300mg/l ； BOD5：165mg/l；TSS:165mg/l ； NH3-N：45mg/l；总氮：60mg/l；PH:7-8。 设计出水水质effluent quality：生物处理系统出水氨氮和总氮执行GB18918-2002一级A标准，其余指标执行GB18918-2002一级B标准. TN and NH3-N meet class1A and other items meet class1B。 系统改造 system retrofit 采用Siemens BNR/Verticel工艺对现有生化池进行改造。 保留原有生化池主要结构尺寸不变，进行内部局部修改，其中前两个廊道改为VLR 立环氧化沟 ，其余廊道略微改变曝气量，使系统形成0、1、2mg/L的溶解氧梯度模式。 The proposed up-grade requires no changes in the dimensions of the bio-reactor; all up-grading works are carried out inside the tank where the first two passes are converted into VLR reactors followed by seven passes with fine-bubble diffused aeration. The DO in different pass is change from0,1to2mg/l. 改造效果——氨氮去除率对比图the contrast of the ammonia removal rate 分析analyze Verticel系列已稳定实现了硝化过程。取得了氨氮远远好于一级A的排放标准。而对比的原系列虽然在部分时段内也能较好地实现硝化过程。但出水效果不稳定。在一半以上的时间内氨氮均不能满足出水一级A的排放要求。 Nitrification is very good in Verticel system and the effluent is far more better than the effluent requirement standard. Only less than 50% effluent ammonia data meet class 1A in the contrastive train. It means nitrification in the contrastive train is still not stable enough. TN总氮去除与碳氮比的关系 the relationship between TN removal rate and BOD/TN 目前系统总氮还没有满足一级A的排放标准，但通过以下曲线图可见TN去除率与原水中BOD/TN的比值基本有统一的变化趋势，当BOD/TN的比值偏高时去除率也略好，且由于原水中的BOD/TN的总体比值偏低基本小于3，下一步可通过降低初沉池排泥和部分超越初沉池等措施来增加碳源来逐步提高TN去除率。Up to now the TN does not meet class1A. From below curve we can know the TN removal rate has the similar variability with the ratio of BOD