焦化废水特征有机污染物反硝化降解速率特征分析

Characteristics analysis of degradation rate in denitrification of characteristic organic pollutants in coking wastewater

以焦化废水特征有机污染物苯酚、喹啉、吡啶和吲哚为碳源,研究了不同C/N(COD/NO-3-N)比值进水条件下,反硝化过程中NO-2-N积累特征及反硝化动力学特征。结果表明,进水C/N比在2.5~17的条件下,均会出现NO-2-N积累的现象。当C/N比值为2.5时,NO-2-N出现稳定积累。基于完全反硝化且COD去除率最高的进水条件为,进水C/N比为6。随着C/N比值从2.5增至17,达到NO-2-N的最大积累量时间从140 min降至60 min,NO-2-N的最大积累率从51.7%降至23.1%。相同进水C/N比条件下,在NO-2-N积累阶段,NO-3-N比还原速率大于NO-2-N比还原速率,导致NO-2-N积累;在NO-2-N还原阶段,NO-3-N比还原速率小于NO-2-N比还原速率。不同进水C/N比条件下,在NO-2-N积累阶段,NO-2-N比积累速率基本不变,为0.072 g N/(g VSS·d)左右。不同进水C/N比值条件下,NO-2-N积累阶段的表观碳氮比均大于NO-2-N还原阶段的表观碳氮比。

With phenol,quinoline,pyridine and indole which were characteristic organic pollutants of coking wastewater as carbon sources,the NO-2-N accumulation characteristics and denitrification kinetics parameters under initial influent limitation of different C /N(COD /NO-3-N) ratio were studied. The results showed that NO-2-N accumulation were observed under different ratios of C /N. The NO-2-N accumulation was stable when C /N ratio was 2. 5. Based on complete denitrification,the best C /N ratio of the highest COD removal rate was 6.As the C /N ratio increased from 2. 5 to 17,the time reaching the max NO-2-N accumulation amount reduced from 140 min to 60 min,and the max accumulation rate of NO-2-N reduced from 51. 7% to 23. 1%. Under the condition of same C /N ratio,specific NO-3-N reduction rate was faster than specific NO-3-N reduction rate in the NO-2-N accumulation phase,causing the accumulation of NO-2-N. In NO-2-N reduction phase,specific NO-3-N reduction rate was slower than specific NO-2-N reduction rate. Under different C /N ratio condition,specific NO-2-N reduction rate basically remained unchanged in the phase of NO-2-N accumulation,it was about 0. 072 g N /(g VSS·d),while apparent C /N in NO-2-N accumulation stage was bigger than that of NO-2-N reduction phase.