Type 0092丝状菌污泥微膨胀在短程硝化中的实现

Realization of Limited Filamentous Bulking with Type 0092 Filamentous Bacteria as the Dominant Filamentous Bacteria in Shortcut Nitrification

利用Type 0092丝状菌不易引发污泥恶性膨胀的特点,本实验采用实际生活污水,以SBR反应器接种短程硝化污泥,考察了短程硝化状态下启动Type 0092丝状菌污泥微膨胀的特性,研究了系统启动与维持期间的污泥沉降性能、亚硝酸盐积累率(NAR)、污染物去除特性以及污泥菌群结构变化情况.结果表明控制DO为0. 3~0. 8 mg·L^-1,F/M(以COD/MLSS计)=0. 24 kg·(kg·d)^-1,按照交替缺氧/好氧模式运行(单周期3次,缺氧∶好氧=20 min∶60 min),能够启动Type 0092丝状菌污泥微膨胀与短程硝化耦合,系统SVI值维持在180 m L·g^-1左右,NAR一直维持在99%左右,COD和TN去除率能够分别提高约13%和5%,相较于传统全程硝化非微膨胀状态曝气量能节省约62. 5%.当交替缺氧/好氧模式变为单周期交替6次,缺氧∶好氧=10 min∶30 min,亚硝酸盐氧化菌(NOB)的活性会恢复,使短程硝化被破坏;低溶解氧、交替缺氧/好氧、低负荷是实现Type 0092丝状菌污泥微膨胀的关键因素,当负荷(以COD/MLSS计)大于0. 25 kg·(kg·d)^-1时,仅靠低溶解氧和间歇曝气无法维持污泥微膨胀状态.

Type 0092 filamentous bacteria generally do not result in excessive sludge bulking.To take advantage of this,domestic sewage was used to inoculate shortcut nitrification sludge in a sequencing batch reactor (SBR).Sludge settleability,the nitrite accumulation ratio (NAR),pollutant removal characteristics,and the dynamic variation of microbial communities during the system startup and maintenance were investigated. The results indicated that limited filamentous bulking (LFB) with Type 0092 filamentous bacteria combined with shortcut nitrification could be achieved under alternating anoxic and aerobic (four times/cycle;the ratio of anoxic /aerobic was 20 min /60 min) with low dissolved oxygen (DO) content (0. 3-0. 8 mg·L^-1) and a low food /microorganism (F/ M) ratio [0. 24 kg·( kg·d)^-1,COD/MLSS.The removal rate of COD and total nitrogen (TN) were increased by 13% and 5% when the sludge volume index (SVI) and NAR were maintained at approximately 180 mL·g^-1 and 99%,respectively,and aeration consumption was reduced by 62. 5% compared to general whole-run nitrification. When the ratio of anoxic /aerobic changed to be 10 min /30 min as alternating times increased to 6 times per cycle,the activity of the nitrite oxidizing bacteria (NOB) recovered,causing shortcut nitrification to be destroyed.In addition,low DO,alternate anoxic /aerobic modes,and low loading rates were the key factors in achieving LFB with Type 0092 filamentous bacteria as the dominant filamentous bacteria. Limited filamentous bulking could not be maintained under low DO and alternating anoxic /aerobic conditions with loading rates above 0. 25 kg·(kg·d)^-1,COD/MLSS.