冷冻PN/A颗粒污泥快速活化过程中的污泥形态与菌群演化特征分析

接种颗粒污泥是快速启动高性能自养脱氮反应器的有效方法之一.为建立污泥活化与反应器效能的响应关系,在连续流反应器中接种冷冻储存的颗粒污泥,并采用高负荷和高水力选择压的调控策略,在34 d内成功启动了部分亚硝化/厌氧氨氧化(PN/A)一体化系统.反应器总氮去除率大于83％,总氮去除负荷稳定在1.67 kg·(m3·d)-1...     

表层附着累枝虫的好氧颗粒污泥特性

在序批式反应器(SBR)中处理实际生活污水,并接种城市污水处理厂活性污泥,培养出表层附着大量累枝虫的好氧颗粒污泥.运行120 d时,颗粒污泥浓度可达4482 mg·L-1,污泥容积指数(SVI)为55 m L·g-1左右,颗粒的粒径主要在1.6~2.5 mm之间,平均沉速为55.4 m·h-1,累枝虫密度可达30450 ind·m L-1.CODCr和NH+4-N的平均去除率分别为87.9%和91.8%.采用直接免疫荧光法证实累枝虫可吞食游离细菌,能有效减少出水SS,且出水SS与累枝虫的密度变化整体呈相反趋势.表层附着生长的累枝虫略微降低了颗粒污泥的沉速.结构分析可看出累枝虫根植于颗粒表层,柄的部分成为颗粒污泥的"骨架",有利于颗粒污泥结构强度和稳定性.     

ABR耦合CSTR一体化工艺好氧颗粒污泥亚硝化性能调控及稳态研究

本研究将厌氧折流板反应器(ABR)末端两隔室分别改为曝气池与沉淀池,使其成为厌氧耦合好氧一体化工艺,探索连续流条件下好氧颗粒污泥亚硝化实现条件.分别在厌氧区和好氧区接种厌氧颗粒污泥和好氧颗粒污泥,控制好氧区沉淀时间为1 h,好氧区C/N比由1逐渐降低至0.4,并逐步提高进水氨氮容积负荷[由0.89 kg·(m3·d)-1提高至2.23 kg·(m3·d)-1].经45 d的运行,在好氧区成功培养出成熟的亚硝化颗粒污泥,其外观呈黄色,结构密实、边缘清晰,出水亚硝酸盐积累率稳定在80%左右.游离氨(FA)和游离亚硝酸(FNA)共同抑制作用是实现稳定亚硝酸盐积累的关键因素.运行初期部分好氧颗粒污泥出现解体现象,好氧区产生大量絮体;但后期絮体逐步转化为小粒径颗粒污泥,表明一定数量的有机碳源有利于絮体颗粒化,而大量富集慢速生长的硝化细菌对颗粒的稳定维持起重要作用.     

实际污水培养好氧颗粒污泥及其特性研究

采用实际城市污水在序批式反应器(SBR)中试装置中成功培养出好氧颗粒污泥.颗粒污泥的沉降速率>21 m·h-1,显示了良好的沉降性能.颗粒污泥对化学需氧量(COD)、氮(N)、磷(P)具有同步去除的能力.在3 h的运行周期中,反应器出水COD<50 mg·L-1,氨氮(NH+4-N)<5.0 mg·L-1,总氮(TN)<15 mg·L-1,对TN和总磷(TP)的去除率达到50%.采用共聚焦激光扫描显微镜(CLSM)对好氧颗粒污泥的结构分析表明,好氧颗粒污泥的胞外多聚物(EPS)在整个颗粒污泥中均匀地分布,构成颗粒污泥的骨架.对颗粒污泥的X射线衍射(XRD)分析显示,在好氧颗粒污泥的内部存在许多无机矿物质,在颗粒污泥形成初期,废水中的无机成分可能具有"晶核"的作用.     

厌氧氨氧化启动过程及微生物群落结构特征

采用UASB反应器以体积比1∶2接种实验室培养的具有厌氧氨氧化(ANAMMOX)功能的厌氧污泥和城市污水厂的好氧污泥,耗时17 d成功启动ANAMMOX反应,启动阶段分为菌体水解期、活性提高期和稳定运行期.稳定运行后,逐步提高反应器容积负荷富集厌氧氨氧化菌,当容积负荷由0.10 kg·(m~3·d)~(-1)增至0.44 kg·(m~3·d)~(-1)时,总氮(TN)去除负荷也随之由0.09 kg·(m~3·d)~(-1)提高到0.42 kg·(m~3·d)~(-1),反应器污泥逐渐由浅红色加深,粒径大于0.2 mm的污泥所占比例由10.90%增至38.37%.采用高通量测序对接种污泥和负荷提高期的污泥进行检测,其中绿曲挠菌门(Chloroflexi)、变形菌门(Proteobacteria)、WWE3门、放线菌门(Actinobacteria)、浮霉菌门(Planctomycetes)等占据主导.随着厌氧氨氧化菌富集程度的增大,脱氮功能菌中的变形菌门所占比例逐渐减少,从21.60%降至14.20%,而浮霉菌门随之增多,相对丰度由0.73%升至15.50%.当反应器的容积负荷增到0.44 kg·(m~3·d)~(-1)时,浮霉菌门中,Candidatus Brocadia属、Candidatus Jettenia属和Candidatus Kuenenia属是主要菌属,Candidatus Brocadia属占13.40%,是主要的厌氧氨氧化菌属.     

好氧亚硝化颗粒污泥中硝化细菌群落结构分析

在小试好氧上流式污泥床(AUSB)反应器中,实现了由厌氧颗粒污泥到好氧硝化污泥再到亚硝化颗粒污泥的转化,AUSB反应器的亚硝化率稳定在90%以上.利用FISH、荧光实时定量PCR等技术,考察了AUSB反应器中好氧颗粒污泥中硝化菌群的生态分布.结果表明:好氧亚硝化颗粒污泥呈层状结构,氨氧化细菌(AOB)主要分布在颗粒污泥表层,亚硝酸盐氧化细菌(NOB)多分布在内层,颗粒内核则无活性细胞;随反应器氨氮负荷逐渐提高,颗粒污泥中AOB的相对含量逐渐升高,当NH₃-N负荷分别为0、0.4、1、     

PN-ANAMMOX一体化反应器处理电子行业PCB废水

利用已经启动成功并达到稳定脱氮效能的部分亚硝化-厌氧氨氧化一体化反应器,研究碱性印制电路板(PCB)废水自养生物脱氮的可行性及运行特性.结果表明,将进水NH+4-N浓度维持在220 mg·L-1时,经过80 d的运行,一体化反应器出水NH+4-N、NO-2-N浓度降低并稳定在4.0 mg·L-1和9.8 mg·L-1左右,脱氮效能最高达到1.29 kg·(m3·d)-1.同时出水总氮小于50 mg·L-1,满足接管排放标准.一体化反应器内好氧区NO-2-N产生速率最高为2.05 kg·(m3·d)-1,厌氧区的厌氧氨氧化菌最高脱氮效能为2.91 kg·(m3·d)-1,说明各功能菌在相应区域得到稳定地增长.一体化反应器适用于无机含氨的碱性PCB废液自养生物脱氮处理.     

Biodegradation of p-cresol by aerobic granules in sequencing batch reactor

The cultivation of aerobic granules in sequencing batch reactor for the biodegradation of p-cresol was studied. The reactor was started with 100 mg/L of p-cresol. Aerobic granules first appeared within one month of start up. The granules were large and strong and had a compact structure. The diameter of stable granules was in the range of 1-5 mm. The integrity coefficient and granules density was found to be 96% and 1046 kg/m³, respectively. The settling velocity of granules was found to be in the range of 2× 10^-2-6× 10^-2 m/sec. The aerobic granules were able to degrade p-cresol upto 800 mg/L at a removal efficiency of 88%. Specific p-cresol degradation rate in aerobic granules followed Haldane model for substrate inhibition. High specific p-cresol degradation rate up to 0.96 g p-cresol/(g VSS. day) were sustained upto p-cresol concentration of 400 mg/L. Higher removal efficiency, good settling characteristics of aerobic granules, makes sequencing batch reactor suitable for enhancing the microorganism potential for biodegradation of inhibitory compounds.     

Nitrification and denitrification in biological activated carbon filter for treating high ammonia source water

Since the ammonia in the effluent of the traditional water purification process could not meet the supply demand, the advanced treatment of a high concentration of NH₄ ⁺-N micro-polluted source water by biological activated carbon filter (BACF) was tested. The filter was operated in the downflow manner and the results showed that the removing rate of NH₄ ⁺-N was related to the influent concentration of NH₄ ⁺-N. Its removing rate could be higher than 95% when influent concentration was under 1.0 mg/L. It could also decrease with the increasing influent concentration when the NH₄ ⁺-N concentration was in the range from 1.5 to 4.9 mg/L and the dissolved oxygen (DO) in the influent was under 10 mg/L, and the minimum removing rate could be 30%. The key factor of restricting nitrification in BACF was the influent DO. When the influent NH₄ ⁺-N concentration was high, the DO in water was almost depleted entirely by the nitrifying and hetetrophic bacteria in the depth of 0.4 m filter and the filter layer was divided into aerobic and anoxic zones. The nitrification and degradation of organic matters existed in the aerobic zone, while the denitrification occurred in the anoxic zone. Due to the limited carbon source, the denitrification could not be carried out properly, which led to the accumulation of the denitrification intermediates such as NO₂ ⁻. In addition to the denitrification bacteria, the nitrification and the heterotrophic bacteria existed in the anoxic zone. __________ Translated from Environmental Science, 2006, 27(1): 69–73 [译自: 环境科学]     

不同恢复方式对硝化颗粒污泥活性的影响

利用SBR反应器培养的成熟好氧硝化颗粒污泥,进行了硝化颗粒污泥临界活性以及不同氨氮浓度及曝气时间对储存的好氧硝化颗粒污泥活性恢复的影响研究.结果表明,储存不同时间的硝化菌活性(SOUR,O2/VSS)差别较大,储存前硝化颗粒污泥硝化菌SOUR为13.15 mg·(g·h)-1,储存20 d的硝化菌SOUR下降了1.26 mg·(g·h)-1,恢复运行了5个周期,氨氮去除率已经达到95%以上,恢复后活性为13.87 mg·(g·h)-1.但储存30 d的硝化菌SOUR降了11.63 mg·(g·h)-1,恢复运行51个周期后,氨氮去除率才达到92.64%,恢复后活性为14.92 mg·(g·h)-1,同时这种储存方法恢复时间较长,因此提出硝化颗粒污泥的临界活性为当硝化菌SOUR开始下降时,进行活性恢复.在临界活性的基础上,采用当硝化菌SOUR下降到临界活性时实施恢复,之后进入下一个储存周期,这种储存方式即为动态储存.当进水氨氮浓度分别为20、30、40 mg·L-1时,进行颗粒污泥活性恢复,进水氨氮浓度为40 mg·L-1恢复后硝化菌活性最高,经过3次动态储存后,其活性保持良好.当曝气时间分别为1、2、3 h时,进行颗粒污泥活性恢复,曝气时间为1 h时恢复后硝化菌活性最高,在动态储存过程中其活性一直保持较高水平.     

高盐高碱环境下硝化反硝化过程及N2O产生特征

采用稳定运行在高盐高碱环境厌氧/好氧/缺氧(A_n/O/A)模式下的序批式生物膜反应器(SBBR),考察在不同碳氮比(C/N)条件下,硝化反硝化过程及N_2O产生特征.结果表明,在C/N为5、2和对照组(C/N=0)时,总氮去除率分别为(98. 17±0. 42)%、(65. 78±2. 47)%和(44. 08±0. 27)%; N_2O的产生量分别为(32. 07±2. 03)、(21. 81±0. 85)和(17. 32±0. 95) mg·L~(-1); N_2O转化率(N_2O产生量在去除总氮中的比例)分别为(29. 75±0. 93)%、(30. 04±2. 17)%和(41. 69±0. 80)%.高盐高碱条件下,亚硝酸盐氧化菌(NOB)受到很强的抑制作用,硝化过程基本停留在亚硝酸盐阶段.由于高盐高碱环境对N_2O还原酶活性的抑制,使得异养反硝化过程产生了大量N_2O,随着碳氮比的增大,有更多的碳源用于反硝化过程,因而总氮去除率和N_2O产生量均随之增加.随着碳氮比的增大,N_2O转化率随之降低,这可能是由于异养反硝化过程氮素还原酶对电子的竞争所形成的,碳氮比越高,电子竞争越弱.高通量测序表明:在SBBR中,氨氧化细菌(AOB)被富集,而几乎不存在NOB;优势异养反硝化菌属主要是Thauera、Azoarcus和Gemmobacter.     

启动三级PN/A颗粒污泥反应器处理高浓度氨氮废水

为将部分亚硝化-厌氧氨氧化技术(PN/A)应用于高浓度氨氮废水的处理,本研究以经破碎后的全自养脱氮颗粒污泥为种污泥,通过协同控制进水氨氮负荷(NLR)、各格室溶解氧(DO)水平和游离氨(FA)浓度等参数,在106 d内成功启动了三级连续流反应器.结果表明,颗粒污泥在启动初期呈现明显的亚硝化功能.反应器采用高NLR和限制曝气的控制策略,能够有效控制亚硝酸氧化菌增殖,并避免DO对厌氧氨氧化菌的抑制作用,有利于颗粒密实度和脱氮活性的提升.当进水氨氮浓度升至350 mg·L-1时,通过调节进水p H和碱度投加量,可以消除前端格室内高FA浓度对功能菌活性的不利影响.反应器最终实现了7. 2 kg·(m~3·d)-1的总氮去除负荷,较传统活性污泥法高出50～100倍.模拟不同曝气强度的序批次实验也证明,各格室污泥的脱氮活性持续增强,且格室1中颗粒污泥的成熟度最高.期间,胞外聚合物含量与比总氮去除速率呈现良好的线性相关(R2 0. 97),这意味着颗粒密实度的改善对提升反应器性能具有积极意义.     

微氧水解酸化处理石化废水的生物降解特性

本研究采用微氧水解酸化技术处理石化废水,以抑制硫酸盐的还原,减少硫化氢的产生.同时,通过与厌氧水解酸化的对比试验,研究了微氧水解酸化的生物降解特性.微氧反应器的ORP控制在(-290±71)m V,厌氧反应器的ORP为(-398±31)m V.反应器运行近7个月的结果表明,在进水COD为202~514 mg·L-1、硫酸根浓度为350~650 mg·L-1及HRT为12 h时,微氧水解酸化反应器COD的平均去除率为31.2%,高于厌氧水解酸化的26.4%.厌氧出水的VFA浓度((2.34±0.60)mmol·L-1)高于微氧出水((1.89±0.48)mmol·L-1).微氧出水的平均比紫外吸收值(UV254/DOC)为0.017,显著低于厌氧出水(0.025),表明微氧环境可以提高兼性水解酸化菌的生理代谢功能,强化难降解芳香有机物和含共轭双键大分子化合物的去除.微氧水解酸化出水的硫离子浓度((0.11±0.04)mg·L-1)显著低于厌氧出水((1.27±1.22)mg·L-1).454焦磷酸测序结果表明:微氧水解酸化菌群中,变形菌门、绿弯菌门和放线菌门菌群丰度(所占比例分别为39.7%、20.3%、1.9%)高于厌氧水解酸化菌群(分别为36.9%、17.5%、1.3%),对难降解大分子有机物的去除效果好;厌氧水解酸化菌群中拟杆菌门和酸杆菌门所占比例较大,酸化效果更好.在属的水平上,微氧水解酸化污泥中鉴定出的硫酸盐还原菌的种群多样性和丰度均低于厌氧污泥,这与其出水较低的硫离子浓度一致,表明微氧环境能够有效抑制硫酸盐还原菌的活性.上述研究结果表明,微氧水解酸化是一种很有前途的石化废水预处理技术.     

Effects of nitrite on phosphate uptake in anaerobic-oxic process

An anaerobic-oxic (A/O) biological phosphorus removal reactor was operated to study the effect of nitrite on phosphate uptake. The phosphorus uptake profile was determined under different operating conditions. The results indicated that in addition to oxygen and nitrate (DPB_Na, nitrate denitrifying phosphorus removal), to some extent, nitrite could also serve as an electron acceptor to achieve nitrite denitrifying phosphorus removal (DPB_Ni). The quantity and rate of phosphorus uptake of DPB_Ni, however, were evidently lower than that of DPB_Na. The experiment results revealed that nitrite would bring toxic action to phosphate-accumulating organisms (PAOs) when NO₂ ⁻-N ⩾ 93.7 mg/L. The nitrite existing in the anoxic reactor made no difference to the quantity and rate of denitrifying phosphorus removal, but it could reduce the consumption of nitrate. Moreover, the data showed that the aerobic phosphate uptake of DPB_Ni was lower than that of anaerobic phosphorus-released sludge in a traditional A/O process. However, there was not much difference between these two kinds of sludge in terms of the total phosphorus uptake quantity and the effluent quality. Translated from Environmental Science, 2006, 27(4): 701–703 [译自: 环境科学]     

Nitrifying population dynamics in a redox stratified membrane biofilm reactor (RSMBR) for treating ammonium-rich wastewater

Nitrogen removal performance and nitrifying population dynamics were investigated in a redox stratified membrane biofilm reactor (RSMBR) under oxygen limited condition to treat ammonium-rich wastewater. When the NHt₄⁺-N loading rate increased from 11.1±1.0 to 37:2 ± 3:2 gNHt₄⁺-N·m⁻²·d⁻¹, the nitrogen removal in the RSMBR system increased from 18.0±9.6 mgN·d⁻¹ to 128.9±61.7 mgN·d⁻¹. Shortcut nitrogen removal was achieved with nitrite accumulation of about 22:3 ± 5:3 mgNO₂⁻-N·L⁻¹. Confocal micrographs showed the stratified distributions of nitrifiers and denitrifiers in the membrane aerated biofilms (MABs) at day 120, i.e., ammonia and nitrite oxidizing bacteria (AOB and NOB) were dominant in the region adjacent to the membrane, while heterotrophic bacteria propagated at the top of the biofilm. Real-time qPCR results showed that the abundance of amoA gene was two orders of magnitude higher than the abundance of nxrA gene in the MABs. However, the nxrA gene was always detected during the operation time, which indicates the difficulty of complete washout of NOB in MABs. The growth of heterotrophic bacteria compromised the dominance of nitrifiers in biofilm communities, but it enhanced the denitrification performance of the RSMBR system. Applying a high ammonia loading together with oxygen limitation was found to be an effective way to start nitrite accumulation in MABs, but other approaches were needed to sustain or improve the extent of nitritation in nitrogen conversion in MABs.     

好氧颗粒污泥处理制糖工业废水厌氧出水的除磷特性研究

制糖工业废水经厌氧生物处理后,COD大幅下降,但是出水中N、P含量仍然较高,严重破坏水体生态平衡.利用好氧颗粒污泥对制糖工业废水的厌氧出水进行脱氮除磷处理,讨论了其除磷过程.经复合底物(乙酸盐、丙酸盐、丁酸盐)培养的好氧颗粒污泥直径1.7 mm,SVI为38.43 mL.g-1,TP去除率达90.9%,出水磷含量仅为1.3 mg.L-1,单位COD释磷率为0.571,厌氧条件下磷的释放速率达到5.73 mg.(g.h)-1,好氧颗粒污泥表现出较好的沉淀性能和较高的除磷活性.由于底物中丙酸盐、丁酸盐含量增加,使得聚磷菌在反硝化过程中NO3--N的利用率增加,即消耗单位质量的NO3--N可以吸收更多的磷.好氧颗粒污泥及其胞外聚合物中P元素的含量与其中Mg、Ca、Fe元素的含量表现出很高的相关性,胞外聚合物对P的吸附使得体系除磷能力进一步增强.通过对污泥反硝化除磷的研究发现,反硝化聚磷菌占总聚磷菌的61.9%,其吸磷量与消耗硝酸盐的比值[m(P)/m(NO3--N)]为1.14.     

新型填料A/O生物滤池处理低碳氮比农村污水脱氮

针对低碳氮比导致低污染农村污水生物处理时出水总氮(total nitrogen, TN)质量浓度高不能满足排放标准的问题,以普通砾石A/O生物滤池为对照组(1号),采用芦竹和活性炭分别作为缺氧段和好氧段填料的A/O生物滤池(2号)处理人工模拟农村污水并研究其脱氮效果.结果表明,当进水化学需氧量(chemical oxygen demand, COD)、氨氮(ammonia nitrogen, NH~+_4-N)和TN质量浓度分别为(79.47±14.21)、(34.49±2.08)和(34.73±3.87)mg·L~(-1)时,两套装置对COD、NH~+_4-N和TN的去除率分别为(88.00±7.00)%和(89.00±10.00)%、(90.00±2.00)%和(97.00±7.00)%、(37±15)%和(68±7)%,表明添加新型填料芦竹和活性炭能显著增强A/O生物滤池对NH~+_4-N和TN的去除.高通量测序结果显示, 1号装置中参与硝化过程的微生物主要为Proteobacteria(变形菌门), 2号则是变形菌门和Nitrospirae(硝化螺旋菌门)共同作用;1号装置缺氧段中发挥反硝化作用的主要细菌门类包括Chloroflexi(绿弯菌门)、变形菌门、Bacteroidetes(拟杆菌门)和Planctomycetes(浮霉菌门),而2号缺氧段中则主要是拟杆菌门、变形菌门、Firmicutes(厚壁菌门)和Patescibacteria.实时荧光定量聚合酶链式反应(quantitative real time polymerase chain reaction, qPCR)结果表明, 2号装置中生物膜的硝化功能基因(amoA和Nitrospira 16S rDNA)、反硝化功能基因(narG、nosZ、nirS和nirK)和厌氧氨氧化功能基因(ANAMMOX)丰度均高于1号装置,除narG和nosZ基因外,其余几种都有1～2个数量级的差别.     

O池溶解氧水平对石化废水A/O工艺污染物去除效果和污泥微生物群落的影响

以实际石化废水为处理对象,研究溶解氧浓度对A/O反应器生物降解特性的影响.A、B两组反应器平行运行以进行对比,O段的溶解氧浓度分别控制在2~3 mg·L-1和5~6 mg·L-1.反应器稳定运行近半年的结果表明:在HRT为20 h时,A组反应器出水的COD(72.5 mg·L-1±14.8 mg·L-1)略高于B组(68.7 mg·L-1±14.6 mg·L-1),COD平均去除率分别为67.0%和68.8%;出水氨氮的平均浓度和去除率为0.8 mg·L-1和95%左右.出水的BOD5均低于5 mg·L-1.表明A/O反应器对有机物的生物降解比较彻底,溶解氧浓度对其没有显著影响.对O段污泥进行454高通量测序结果表明:变形菌门、浮霉菌门和拟杆菌门细菌所占比例较高,在A、B组反应器中的比例分别为58.7%和59.2%、14.7%和12.7%以及10.8%和12.4%.高溶解氧运行的反应器B具有较高的菌群丰度和多样性,氨氧化菌Nitrosomonas、亚硝酸氧化菌Nitrospira和专性好氧菌如Planctomyces的比例较高.厌氧反硝化菌如Azospira和Acidovora在反应器A中的含量较高.在属的水平,鉴定出的Novosphingobium、Comamonas、Sphingobium和Altererythrobacter属细菌具有降解多环芳烃、氯代硝基苯、农药和石油化合物的功能,有利于石化废水的降解.     

亚硝氮停供及恢复供给对Anammox反应器中氮去除的影响

在Anammox-UASB反应器中研究了亚硝氮停供及恢复供给后不同进水亚硝氮/氨氮比(R_I)对Anammox系统脱氮的影响,对Anammox系统停供亚硝氮培养后的污泥微生物群落进行了分析.结果表明,Anammox反应器在长期停供亚硝氮培养后,微生物多样性增加,氨氧化菌(Nitrosomonas)和Anammox菌都大量增殖,这两种微生物通过协同作用使得部分氨氮得以去除,NH_4~+-N最大去除速率可达68.77 mg·L~(-1)·d~(-1),出水p H低于进水.反应器恢复亚硝氮供给后,脱氮效果快速恢复.Anammox反应器中存在的氨氮"超量去除"现象是由氨氧化菌作用引起的,氨氧化菌活性易受亚硝氮浓度抑制.氨氮"超量去除"量占氨氮总去除量的百分比与R_I呈负相关关系.当R_I为0.17时,氨氮"超量去除"量占氨氮总去除量的百分比高达68.83%;当R_I增加到1.30∶1后,氨氮"超量去除"现象基本消失.     

Aerobic granulation of pure bacterial strain Bacillus thuringiensis

The objective of this study is to cultivate aerobic granules by pure bacterial strain, Bacillus thuringiensis, in a sequencing batch reactor. Stable granules sized 2.0–2.2 mm were formed in the reactor after a five-week cultivation. These granules exhibited excellent settling attributes, and degraded phenol at rates of 1.49 and 1.19 g phenol/(g VSS?d) at 250 and 1500 mg/L of phenol concentration, respectively. Confocal laser scanning microscopic test results show that Bacillus thuringiensis was distributed over the initial small aggregates, and the outer edge of the granule was away from the core regime in the following stage.