曝气策略调控CANON工艺降温降基质稳定运行

Stable operation of CANON system during temperature and substrate decreasing process via aerobic regime adjustment

通过调整曝气策略,研究了降温降基质(氨氮)运行过程中实现全程自养脱氮(CANON)序批式生物膜反应器(SBBR)稳定运行的可行性.结果表明,在中温(35℃)高基质[(446.47±43.77)mg NH 4^+-N/L]曝气/停曝=60min/60min条件下,反应器稳定运行223d,总氮去除负荷(TNRR)和总氮去除率(TNRE)分别为(0.49±0.07)kg N/(m^3 d)和(84.3±4.6)%.温度降至20~23℃,根据一个运行周期内NO^-2-N积累速率和去除速率之比调整曝气工况为曝气/停曝=40min/80min,运行69d后TNRR和TNRE分别降至(0.43±0.04)kg N/(m 3 d)和(69.5±5.7)%.而后逐步梯度降低基质至(105.6±16.1)mg NH 4^+-N/L,采用相同策略分别调整曝气/停曝时间为40min/80min、30min/90min和8min/32min,运行93d后TNRR降至(0.16±0.02)kg N/(m 3 d),TNRE升至(71.5±7.5)%.高通量测序结果从群落组成角度证实了降温和降基质过程中实施的曝气调控策略维持了CANON系统脱氮功能菌的主导地位,亚硝酸盐氧化菌NOB相对丰度一直被控制在0.1%以下.

The feasibility of the stable operation of a sequencing biofilm batch reactor(SBBR)for completely autotrophic nitrogen removal over nitrite(CANON)was investigated using aeration condition adjusting strategy,along with decreasing temperature and influent substrate(anammonia).The SBBR operated steadily for 223 days at 35°C and high substrate[(446.47±43.77)mg NH4+-N/L]with the aeration regime of aeration/non-aeration=60min/60min;the total nitrogen removal rate(TNRR)and total nitrogen removal efficiency(TNRE)reached(0.49±0.07)kg N/(m^3.d)and(84.3±4.6)%,respectively.After temperaute decreasd to 20~23°C,the intermittent aerobic condition was changed to aeration/non-aeration=40min/80min based on the ratio of NO2--N accumulation rate to NO2--N removal rate in the single-cycles.The TNRR and TNRE decreased to(0.43±0.04)kg N/(m^3 d)and(69.5±5.7)%for 67days of operation,respectively.With gradual decreasing ammonia to(105.6±16.1)mg NH4^+-N/L,the aeration/non-aeration time was regulated to 40min/80min,30min/90min and 8min/32min in sequence.For 67days operation,the TNRR decreased to(0.16±0.02)kg N/(m^3.d);nevertheless,the TNRE increased to(71.5±7.5)%.High-throughput sequencing results confirmed that the regulation strategy applied herein ensured the dominance of nitrogen removal functional bacterias in CANON system during decreasing temperature and substrate while the relative abundance of nitrite oxidizing bacteira was always below 0.1%.