游离氨(FA)协同曝气时间对活性污泥沉降性能的影响

摘要

Three sequencing batch reactors (SBRs) (R0:aeration stopped when nitrification completed exactly;R0-30:aeration stopped 30 min ahead of when nitrification completed;R0+30:aeration stopped 30 min exceeded when nitrification completed) were operated to investigate the synergetic effect of free ammonia (FA) and length of aeration phase on the sludge settleability by controlling the conditions of three FA concentrations (0.5,5.1,10.1 mg/L) combined with three aeration time (t0:when nitrification completed exactly;t0-30:30 min ahead of when nitrification completed;t0+30:30 min exceeded when nitrification completed).The results showed that:The average NH4+-N removal rate of R0 and R0 +30 system was 98.6％ and 99.3％,respectively throughout the whole experimental period,while the R0-30 system was just 72.3％ under the same initial FA concentration;under the lower FA(0.5 mg/L,5.1 mg/L),with aeration time increasing,settling velocity(SV30) and sludge volume index(SVI) values reduced gradually,the sludge settleability was improved;under a higher FA (10.1 mg/L) concentration,with the increase of the operating cycle,the sludge settleability was improved gradually,and the average SVI values of system was in the sequence of R0-30 ＞ R0 +30 ＞ R0 with the value of 165.1,152.5,134.5 mL/g,and the average activity coefficients of sludge were in the order of fR0-30 ＞fR0 ＞fR0+30 with the values of 0.77,0.70 and 0.65.It was found that sludge activity reduced when increasing aeration time under higher FA(10.1 mg/L) concentration.%采用3个序批式反应器(SBR)(R0:硝化结束时停曝气;R0-30:硝化结束提前30min停曝气;R0+30:硝化结束延迟30 min停曝气),控制3种游离氨(FA)浓度梯度(0.5,5.1,10.1 mg/L)协同3种曝气时间(t0:硝化结束时停曝气;t0-30:硝化结束提前30 min停曝气;t0+30:硝化结束延迟30 min停曝气)的条件下,研究了FA协同曝气时间对活性污泥沉降性能的影响.结果表明:整个试验过程,在初始FA浓度相同条件下,R0和R0+30系统NH4-N平均去除率分别为98.6％和99.3％,而R0-30系统NH4+-N平均去除率仅为72.3％.在较低FA浓度(0.5,5.1 mg/L)条件下,随着曝气时间增加,活性污泥的污泥沉降比(SV30)值和污泥体积指数(SVI)值均逐渐降低,污泥沉降性能趋好.在较高FA浓度(10.1 mg/L)条件下,随着运行周期的增加,污泥沉降性能逐步变好,R0-30系统的SVI平均值最大,R0+30系统次之,R0系统最小,其值分别为165.1,152.5,134.5 mL/g,且污泥活性f平均值大小顺序fR0-30＞fR0＞fR0+30,其值分别为0.77、0.70和0.65.这表明在较高FA浓度(10.1 mg/L)条件下,曝气时间延长,导致污泥活性降低.