DO和HRT对连续流MBBR亚硝酸型SND影响

Influence of DO and HRT on nitrite type simultaneous nitrification and denitrification in MBBR

为探讨亚硝酸型同步硝化反硝化SND过程中的生物脱氮特性,以实际生活污水为对象,通过连续运行移动床生物膜反应器MBBR系统,研究了溶解氧质量浓度DO和水力停留时间HRT对亚硝酸型SND的影响.试验结果表明,化学需氧量COD在200 mg/L左右,HRT为14 h,水温为15-27℃,pH值为6.24-6.98的相对稳定条件下,控制DO在2.9-5.0mg/L的过程中MBBR反应器均能实现亚硝酸型SND,平均亚硝酸盐氮NO2-—N积累率为75.96%;当DO为（4.5±0.3）mg/L时,平均总氮TN去除率达62.89%,取得了最好的TN去除效果,而该条件下NO2-—N的积累率达最小值51.23%,DO过高或过低都会影响系统亚硝酸型SND的进行;当COD在220 mg/L左右,pH值为6.14~7.47,水温为26~31℃,控制溶解氧在（4.5±0.3）mg/L,随HRT的延长,氨氮NH4＋—N和TN的去除率明显增大,但NO2-—N的积累率减小,系统的亚硝酸型SND效果逐渐减弱.

To research the biodenitrification characters of nitrite type simultaneous nitrification and denitrification SND.By treating municipal waste water,the effects of dissolved oxygen DO and hydraulic retention time HRT on nitrite type SND in moving-bed biofilm reactor MBBR system with continuous-flow are studied in this paper.The experiment results show that when chemical oxygen demand COD is 200 mg/L,HRT is 14 h,the water temperature is 15～27 ℃ and pH value is 6.24～6.98,the phenomenon of nitrite type simultaneous nitrification and denitrification took place and the average nitrite nitrogen accumulated rate is 75.96 % in the MBBR by controlling DO from 2.9 mg/L to 5.0 mg/L.While DO is controlled at（4.5±0.3） mg/L,the removal ratio of total nitrogen TN reach the climax about 62.89 %,but nitrite nitrogen accumulated rate reach the minimum about 51.23%,and too high or too low DO values of the system would have a detrimental effect on nitrite type SND.Under the condition that COD is about 220 mg/L,pH value is 6.14～7.47,the water temperature is 26～31 ℃ and DO is（4.5±0.3） mg/L,the removal rates of ammonia nitrogen NH4＋—N and TN went up obviously along with the HRT extending,but nitrite nitrogen accumulated rate brought down accordingly,and the effect of nitrite type SND about the MBBR system is gradually weakened.