桩西联采油废水氧化塘的逗留时间分布研究

Sojourn Time Distribution of Oilfield Produced Wastewater in Two Oxidation Ponds in Series at Zhuangxi Gathering/Treating Plant

胜利油田桩西采油厂桩西联合站采油污水外排前经串联的两座长 333m ,宽 12 5m ,底部起伏很大的氧化塘处理至符合二级排放标准。采用NO-3 N(NaNO3 )作为示踪剂 ,从入口一次性投放 ,连续 16 6h定时测定出口污水中NO-3 N质量浓度 ,由平均流量求得污水在串联两氧化塘内逗留时间分布密度J′(t)和分布函数J(t) ,进一步求出逗留时间tM=75h ,扩散因素d =1.32 8传质准数Pe=1/d =0 .75 3<5。这些数据表明该氧化塘显著偏离理想反应池。

The produced wastewater at oil gathering/water treating plant of Zhuanxi, Shengli, is treated additionally in two oxidation ponds in series to meet the requirements specified by drainage Standard of the 2nd class and then discharged into environment. The ponds are of 333 m long and 125 m wide each with fluctuate uneven bottom surfaces. Using NO - 3 N(NaNO 3) as tracer and after introducing it into inlet to the 1st pond, the mass concentration of NO - 3 N in wastewater at outlet of the 2nd pond is regularly determined over 166 hrs and from these data and average flow rate the sojourn time distibution density J′(t) and distribution function J(t) are obtained and from these it is found that the sojourn time t M=75 hrs, diffusion factor d=1.328 , and Péclet number for mass transfer Pe=1/d=0.753<5 . These results show that the two oxidation ponds in series under study observably deviate from the ideal reaction pond and present a basis for constructing mathmatical models of such ponds.