序批式气升环流反应器处理硝基苯废水

Treatment of nitrobenzene-containing wastewater by a sequencing internal loop airlift reactor

采用序批式气升环流反应器(SAR)处理硝基苯废水,研究了硝基苯浓度和COD/N对处理过程的影响,分析了缺氧段COD和硝基苯降解动力学。结果表明,硝基苯在缺氧段被还原为苯胺,而苯胺在好氧段得到快速降解。硝基苯与基质(葡萄糖-COD)最佳质量比为1∶35~1∶25,该条件下反应器对硝基苯和COD去除率分别可达99%~100%和92%~94%。由于受传质限制,进水需要维持106 mg/L的氨氮(葡萄糖-COD/N比值为100∶10)以满足缺氧段微生物对氨氮的营养需要。缺氧段COD的降解符合二级动力学,反应速率常数k2为2.7×10-4L·mg/h;硝基苯的降解符合一级动力学,反应速率常数k1为0.14 h-1。研究表明,序批式气升环流反应器可作为一种简单而有效的反应器用于处理硝基苯废水。

A sequencing internal loop airlift reactor( SAR) was employed to investigate the effects of nitrobenzene( NB) concentration and COD /N ratio on treatment of NB-containing wastewater. The degradation kinetics of COD and NB during the anoxic stage was analyzed. The results showed that NB was effectively reduced to aniline( AN) during the anoxic stage and the AN was then efficiently degraded during the aerobic stage in the reactor. A removal efficiencies of 99% ~ 100% and 92% ~ 94% were obtained for NB and COD,respectively,as the optimal NB /substrate( glucose-COD) ratio on a mass basis varied between 1 ∶ 35 and 1 ∶ 25. An ammonia concentration of 106 mg /L( glucose-COD /N ratio 100 ∶ 10) should be maintained to meet the need of microorganisms for ammonia as nutrient in the anoxic stage. In the anoxic stage,the COD removal followed the pseudo second-order kinetics and k2 was determined as 2. 7 × 10-4L·mg /h; the NB removal fit the pseudo first-order kinetics and k1 was determined as 0. 14 h-1. It suggested that the SAR can provide an effective yet simple method for treatment of NB-containing wastewater.