A comparable study of microbial community in aerobic granular sludge and activated sludge for wastewater treatment

Effect of ammonia at different concentrations on aerobic granular sludge and activated sludge was investigated in this study. Meanwhile, bacterial diversity variation and ammonia oxidizing bacterium （AOB） quantification within both kinds of sludge were monitored by terminal restriction fragment length polymorphism （T-RFLP） and real-time PCR （RT-PCR） technique, respectively. The results showed that the COD removal of both kinds of sludge changed slightly when the ammonia removal efficiency decreased gradually with the ammonia concentration increased from 100 mg L^-1 to 500 mg L^-1 Furthermore, activated sludge demonstrated higher ammonia removal ability than that of aerobic granular sludge （10%- 16%）. As revealed by T-RFLP, activated sludge was of higher ammonia removal ability and more abounding bacterial diversity than that of aerobic granular sludge, suggesting that the bacterial diversity was probably relevant to the ammonia removal. The RT-PCR results indicated that the AOB population size of activated sludge and aerobic granular sludge were 2.80× 10^4-3.44× 10^4cells （g dried sludge）^-1 and 7.83×10^4-1.18×10^5cells （g dried sludge）^-1, respectively. There is no obvious positive correlation between the ammonia removal ability and number of AOB in both kinds of sludge.

Resistance to salt stresses by aerobic granular sludge:sludge property and microbial community

Saline wastewater is regarded as a challenge for wastewater treatment plants because high-salinity conditions negatively affect on traditional biological technologies.Aerobic granular sludge(AGS)has gained attention as a promising technology for saline wastewater treatment because of its compact structure and the ability to withstand toxic loadings.Therefore,this study investigated the saltresistance performance,sludge properties and microbial community of AGS under low-salinity and high-salinity conditions,with the saline concentrations ranging from 0 to 50 g/L.The results showed that AGS could withstand long-term saline stresses,and the maximum salinity reached 50 g/L within 113 d.Under salinities of 10,30,and 50 g/L,the chemical oxygen demand(COD)removal efficiencies were 90.3%,88.0%and 78.0%,respectively.AGS also its maintained strength and aggregation at salinities of 10 and 30 g/L.Overproduction of extracellular polymeric substances(EPS)by non-halophilic bacteria that enhanced sludge aggregation.The compact structure that ensured the microorganisms bioactivity helped to remove organic matters under salinities of 10 and 30 g/L.At a salinity of 50 g/L,moderately halophilic bacteria,including Salinicola,Thioclava,Idiomarina and Albirhodobacter,prevailed in the reactor.The dominant microbial communities shifted to moderately halophilic bacteria,which could maintain aerobic granular stabilization and remove organic matters under 50 g/L salinity.These results in this study provide a further explanation for the long-term operation of AGS for treating saline wastewater at different salinities.It is hoped that this work could bring some clues for the mystery of salt-resistance mechanisms.

Effect of seed sludge on characteristics and microbial community of aerobic granular sludge

Aerobic granular sludge was cultivated by using different kinds of seed sludge in sequencing batch airlift reactor. The influence of seed sludge on physical and chemical properties of granular sludge was studied; the microbial community structure was probed by using scanning electron microscope and polymerase chain reaction-denaturing gradient gel electrophoresis （PCR-DGGE）. The results showed that seed sludge played an important role on the formation of aerobic granules. Seed sludge taken from beer wastewater treatment plant （inoculum A） was more suitable for cultivating aerobic granules than that of sludge from municipal wastewater treatment plant （inoculurn B）. Cultivated with inoculum A, large amount of mature granules formed after 35 days operation, its SVI reached 32.75 mL/g, and SOUR of granular sludge was beyond 1.10 mg/（g.min）. By contrast, it needed 56 days obtaining mature granules using inoculum B. DGGE profiles indicated that the dominant microbial species in mature granules were 18 and 11 OTU when inoculum A and B were respectively employed as seed sludge. The sequencing results suggested that dominant species in mature granules cultivated by inoculum A were Paracoccus sp., Devosia hwasunensi, Pseudoxanthomonas sp., while the dominant species were Lactococcus raffinolactis and Pseudomonas sp. in granules developed from inoculum B.

Isolation and characterization of a strain with high microbial attachment in aerobic granular sludge

Aerobic granule is a special microbial aggregate associated with biofilm structure.The formation of aerobic granular sludge is primarily depending on its bacterial community and relevant microbiological properties.In this experiment,a strain with high microbial attachment was isolated from aerobic granular sludge,and the detailed characteristics were examined.Its high attachment ability could reach 2.34(OD600 nm),while other low attachment values were only around 0.06-0.32,which indicated a big variation among the different bacteria.The strain exhibited a very special morphology with many fibric fingers under SEM observation.A distinctive behaviour was to form a spherical particle by themselves,which would be very beneficial for the formation and development of granular sludge.The EPS measurement showed that its PN content was higher than low attachment bacteria,and 3 DEEM confirmed that there were some different components.Based on the 16 S rRNA analysis,it was identified to mostly belong to Stenotrophomonas.Its augmentation to particle sludge cultivation demonstrated that the strain could significantly promote the formation of aerobic granule.Conclusively,it was strongly suggested that it might be used as a good and potential model strain or chassis organism for the aerobic granular sludge formation and development.

The key role of inoculated sludge in fast start-up of sequencing batch reactor for the domestication of aerobic granular sludge

Two types of inoculated sludges, granular sludge that had been stored at-20°C and activated sludge, were investigated for the domestication of aerobic granular sludges(AGSs in sequencing batch reactors(SBRs). The results showed that using the stored granular sludge as inoculation sludge could effectively shorten the domestication time of AGS and yielded mature granular sludge after 22 days of operation. The AGS domesticated by stored granular sludge had better biomass and sedimentation properties; its MLSS and SVI reached8.55 g/L and 35.27 mL/g, respectively. The removal efficiencies for chemical oxygen demand(COD), ammonium nitrogen(NH_4^+-N) and total phosphorus(TP) reached 90.76%, 97.39% and 96.40%, respectively. By contrast, 54 days were needed to obtain mature granules using activated sludge. The microbial community structure was probed by using scanning electron microscopy(SEM) and high-throughput sequencing. The results showed that the diversity of the microbial community in mature granules was reduced when stored granular sludge rather than activated sludge was employed as inoculation sludge, and the dominant microbes were changed. The dominant species in mature granules domesticated using stored granular sludge were Zoogloea, Acidovorax and Tolumonas at the genus classification level, while the dominant species were Zoogloea and TM7-genera in granules developed from activated sludge.

The biological effect of metal ions on the granulation of aerobic granular activated sludge

As a special biofilm structure,microbial attachment is believed to play an important role in the granulation of aerobic granular activated sludge（AGAS）.This experiment was to investigate the biological effect of Ca^2＋,Mg^2＋,Cu^2＋,Fe^2＋,Zn^2＋,and K＋which are the most common ions present in biological wastewater treatment systems,on the microbial attachment of AGAS and flocculent activated sludge（FAS）,from which AGAS is always derived,in order to provide a new strategy for the rapid cultivation and stability control of AGAS.The result showed that attachment biomass of AGAS was about 300%higher than that of FAS without the addition of metal ions.Different metal ions had different effects on the process of microbial attachment.FAS and AGAS reacted differently to the metal ions as well,and in fact,AGAS was more sensitive to the metal ions.Specifically,Ca^2＋,Mg^2＋,and K＋could increase the microbial attachment ability of both AGAS and FAS under appropriate concentrations,Cu^2＋,Fe^2＋,and Zn^2＋were also beneficial to the microbial attachment of FAS at low concentrations,but Cu^2＋,Fe^2＋,and Zn^2＋greatly inhibited the attachment process of AGAS even at extremely low concentrations.In addition,the acylated homoserine lactone（AHL）-based quorum sensing system,the content of extracellular polymeric substances and the relative hydrophobicity of the sludges were greatly influenced by metal ions.As all these parameters had close relationships with the microbial attachment process,the microbial attachment may be affected by changes of these parameters.

同步硝化内源反硝化除磷好氧颗粒污泥的储存与恢复

针对好氧颗粒污泥颗粒化时间慢等问题,进行了同步硝化内源反硝化除磷好氧颗粒污泥常温储存及活性恢复实验研究.结果表明,好氧颗粒污泥经过60d的常温储存后,颗粒的结构基本能保持稳定,但是颗粒污泥的活性大幅度降低,污染物去除率仅有储存前的30%~40%.将常温储存的颗粒污泥接种到反应器中,经过一定的调控手段,可以在60d内恢复好氧颗粒污泥的功能及活性.此外,经过储存与恢复,好氧颗粒污泥的群落结构也发生了明显变化.大部分的微生物的相对丰度变化可逆,经过储存和恢复可以恢复至储存前的状态(包括Defluviicoccus(GAOs)和Flavobacterium(PAOs)),重构同步脱氮除磷的微生物群落结构.

氧化锌纳米颗粒和四环素复合胁迫对好氧颗粒污泥处理低碳源废水的影响

为明确新污染物氧化锌纳米颗粒(ZnO NP)和四环素抗生素(TCA)复合胁迫对好氧颗粒物污泥处理低C/N废水的影响,构建了小试规模的颗粒污泥反应器,探究了ZnO NP和TCA复合影响对AGS处理低C/N废水的影响,分析了出水水质、污泥特征及微生物群落特征的变化,揭示了ZnO NP和TCA复合胁迫对AGS的影响机制。结果表明,ZnO NP和TCA复合胁迫对AGS处理低C/N废水具有拮抗作用。ZnO NP和TCA复合暴露组别内,出水COD和溶解性磷酸盐(SOP)浓度分别为42.8~53.4 mg/L和1.95~2.36 mg/L,对应去除效率分别下降至75.1%~78.5%和70.3%~75.6%,远低于ZnO NP和TCA单一暴露组别。ZnO NP和TCA复合胁迫降低了AGS污泥浓度总固体(TS)至5.5~5.8 g/L,挥发性固体/TS至0.61~0.64,但刺激胞外聚合物(EPS)含量至91.6~93.4 mg/g。此外,ZnO NP和TCA复合胁迫提高了EPS内蛋白质(PN)和多糖(PS)含量,并提高PN/PS。酶活性分析表明ZnO NP和TCA复合胁迫降低了与污染物和营养盐去除相关的关键酶活性。微生物群落结构分析ZnO NP和TCA复合胁迫降低了属水平上与反硝化相关的Tsukamurella、unclassified f_Comamonadaceae、Micropruina和Microbacterium的相对丰度。ZnO NP和TCA复合胁迫产生的生态毒性对AGS具有严重影响。研究结果为理解新污染物ZnO NP和TCA复合胁迫的环境风险具有一定的理论意义。

进水底物对好氧颗粒污泥特性及微生物群落的影响

为了研究进水底物对好氧颗粒污泥(AGS)特性的影响,通过接种絮状污泥于序批式反应器(SBR)中以生活污水和模拟生活污水作为进水底物,对AGS形成过程中的污泥特性和微生物群落展开研究。研究表明:以模拟生活污水为进水底物,发现颗粒污泥内部以丝状菌为框架,通过对污泥的截留逐渐形成AGS,污泥沉降性能良好。随着AGS的形成胞外聚合物(EPS)组分中蛋白质(PN)含量增加显著,PN/PS由1.77上升至5.80,促进了AGS的形成和稳定性,且EPS含量与Zeta电位、污泥沉降指数呈负相关。连续投加Fe(OH)_(3)胶体抑制了NOB菌的活性,导致生活污水阶段污染物的去除效果较差;AGS形成后污染物的去除效果明显上升,特别是氮、磷污染物。生活污水阶段Candidatus_Microthrix菌属引起了系统内丝状菌膨胀,同时微生物群落丰富度、多样性逐渐降低。模拟生活污水阶段具有疏水性和分泌EPS功能的菌属丰度占比持续上升,例如:unclassified_o__Saccharimonadale(33.%→22.0%)、Zoogloea(3.0%→6.0%)、unclassified_f__Sphingomonadaceae(0.87%→3.1%)菌属等;促进了污泥颗粒化;同时随着污泥颗粒化程度提高,具有反硝化和除磷功能的菌属丰度占比持续上升,保证了AGS系统高效的脱氮除磷性能。

微塑料对颗粒污泥运行效能的影响

微塑料(MPs)作为新污染物的环境行为得到广泛关注。然而,MPs对好氧颗粒污泥(AGS)处理低C/N废水过程中颗粒化进程、营养盐去除规律及微生物种群特征的影响至今鲜有探究。因此,本论文以苯二甲酸乙二醇酯MPs和AGS为探究对象,在室温环境下,探究了MPs粒径对AGS处理城镇低C/N废水的影响,并解析相关作用机制。结果表明,MPs存在加速了AGS颗粒化,提高了污泥浓度,促进了胞外聚合物(EPS)分泌,且MPs粒径越大,颗粒化进程越显著。MPs存在降低了AGS对COD和营养盐的去除,且MPs粒径越大,营养盐去除抑制越显著。MPs粒径在150μm时,COD、NH_(4)^(+)-N及TN的去除效率下降至81.6%~84.1%、82.3%~86.5%和61.6%~62.8%,均远低于空白组。MPs粒径越大,其在AGS内去除效率越低。大粒径MPs提高了Proteobacteria的相对丰度至59.6%,但降低了具有有机质分解能力的Bacteroidota的相对丰度。本论文丰富了MPs在水环境的影响行为,为日后MPs污染控制提供一定的理论依据。

好氧颗粒污泥处理长链二元酸发酵废水性能及微生物特征研究

采用序批式好氧颗粒污泥反应器处理长链二元酸废水,研究结果表明采用逐步降低废水稀释比的运行方式,40 d可完成反应器启动。成熟颗粒污泥的粒径大、稳定性高,颗粒完整性系数和粒径>0.9 mm的污泥比重分别达99.68%和75.5%。颗粒污泥具有丰富的有机物降解菌毛单胞菌属和氧化硫奥托氏菌属,以及具有分泌EPS的除磷菌,可实现95.1%的COD和69.9%的总磷去除。该工艺在去除长链二元酸废水有机污染物和总磷方面具有优势,有良好的应用前景。

污泥生物炭对低C/N废水好氧颗粒污泥长期运行稳定性的影响

将污泥生物炭作为载体培养好氧颗粒污泥,研究培养成熟的好氧颗粒污泥在碳氮比(C/N)由10降为4条件下的长期运行稳定性.结果表明,通过添加生物炭培养成熟的好氧颗粒污泥颗粒结构更紧密,不易解体.虽然丝状菌Thiothrix大量增殖,但是好氧颗粒沉淀性能良好,SVI_(30)始终维持在50mL/g左右;系统COD去除效率达到90%以上,TN去除率为70%左右.高通量测序分析表明,加炭系统微生物多样性有所降低,但具有反硝化功能的细菌数量增加,提升了系统脱氮性能.添加污泥生物炭培养成熟的好氧颗粒污泥具有更好的脱氮性能和长期运行稳定性,有利于低C/N条件下的高氨氮废水处理.

布洛芬对好氧颗粒污泥的影响及其去除机理

探索了布洛芬(IBP)对好氧颗粒污泥(AGS)的影响机制,分析了AGS系统去除IBP的效能及机理.结果表明,IBP的存在对AGS体系的氨氮去除率几乎没有影响,对有机物、总氮和磷的去除轻微抑制.AGS系统对0.5mg/L的IBP具有较强抗性,而1.0~5.0mg/L IBP会减少EPS分泌,降低污泥沉降性能,影响功能菌富集,从而不利于AGS系统的稳定.连续120d的测试结果表明,AGS可以通过吸附和降解去除0.5~5.0mg/L的IBP.吸附等温线模型表明AGS主要通过多层吸附作用吸附IBP.IBP的降解途径包括脱羧和羟基化.IBP的长期存在增强了耐药性微生物的增殖,但改变了群落结构,降低了微生物多样性和丰富度,尤其是丝硫菌属(Thiothrix)成为优势属.AGS技术用于处理含抗炎药物(IBP)污水具有良好的应用前景,但高浓度的IBP对AGS系统的性能产生了较大的不利影响,需要引起重视.

盐度对好氧颗粒污泥处理畜禽养殖废水的影响机制探究

以好氧颗粒污泥(AGS)和畜禽养殖废水为探究对象,在室温环境下探究了盐度对AGS处理畜禽养殖废水的影响,并分析了不同盐度环境下AGS的污泥特征及微生物群落结构,揭示了相关机制。结果表明,低盐度(低于1.0 g/L)利于AGS去除污染物和营养盐,而高浓度盐度降低了营养盐去除,提高了胞外聚合物(EPS)的分泌。当盐度为0.2 g/L时,COD、NH_(4)^(+)-N、TN和PO_(4)^(3-)-P的去除效率高达94.6%~95.2%、94.6%~96.8%、70.6%~72.1%和88.5%~92.1%,然而当盐度超过1.0 g/L,污染物及营养盐去除效率显著下降。盐度能影响AGS污泥特征,并提高蛋白质的分泌。盐度有效提高了AGS污泥沉降性。微生物学机制分析表明0.2 g/L盐度作用下AGS内与有机质降解及氮磷去除相关微生物的相对丰度提高。

好氧颗粒污泥处理锅炉脱硫废水的性能及机制探究

为了探究好氧颗粒污泥(AGS)对锅炉脱硫废水处理效能及作用机制,以AGS和锅炉脱硫废水为探究对象,构建了AGS和传统A~2/O工艺,在中温条件下比较了AGS和传统A~2/O工艺对锅炉脱硫废水处理效能的影响,并解析相关作用机制。结果表明,相较于传统A~2/O工艺,AGS处理锅炉脱硫废水具有更优的污染物和营养盐去除,在AGS工艺内,化学需氧量(COD)、NH_(4)^(+)-N和总氮(TN)的去除率分别高达94.6%~97.8%、94.3%和74.3%。AGS工艺内胞外聚合物(EPS)含量高于传统A~2/O工艺。在内聚物聚羟基脂肪酸酯(PHA)富集方面,AGS展示出更大富集量,可高达5.87 mmol/g,但糖原质的代谢水平下降。AGS内微生物群落主要是Proteobacteria、Bacteroidetes、Firmicutes,其中Bacteroidetes和Nitrospirae的相对丰度显著高于传统A~2/O工艺。研究结果为锅炉脱硫废水的高效处理提供一定的技术支撑。

溶解氧浓度对好氧颗粒污泥形成及微生物群落演变的影响

曝气头深度与系统内的溶解氧(DO)浓度有关,而DO浓度对好氧颗粒污泥中微生物处理废水性能具有重要意义。采用高径比为7.5的序批式反应器(SBR)C0~C3,内接冷藏颗粒污泥,进水为混合废水,以SBR底部为起点曝气头分别设置在SBR的0H(有效高度简写为H)、1/3H、1/2H和H处,产生的DO分别为3、4、5、6 mg/L,分析SBR系统中污泥特性、污染物去除性能及微生物群落的动态变化规律。结果表明:60 d时,C0~C3中颗粒污泥中值粒径分别为952、1 325、1 020、725μm,悬浮固体质量浓度分别为3.99、6.74、3.18、6.90 g/L,胞外聚合物质量浓度分别为125.12、135.14、128.05、114.81 mg/g;对污水中COD、氨氮、总磷平均去除率均高达79%、74%和65%以上;富集了具有固氮的拜叶林克氏菌属(Beijerinckia)、脱氮的丛毛单胞菌属(Comamonas)和降解芳香烃的新鞘氨醇菌属(Novosphingobium)。通过调控曝气头深度,实现了不同功能微生物的富集,对好氧颗粒污泥的稳定运行有实际应用价值。

好氧颗粒污泥的形成机理

本文综述了几种比较流行的好氧颗粒污泥的形成机理,并进行了分析讨论。同时,总结了各种条件下形成好氧颗粒污泥的理化特性、培养条件及其形态。

序批式反应器的好氧颗粒污泥特性研究

对序批式反应器中好氧颗粒活性污泥的形成过程、处理性能和颗粒分布特性进行了研究。结果表明,不同操作条件下产生了结构形态不同的颗粒污泥,沉降时间是颗粒污泥形成的主要因素,有机负荷对颗粒污泥的结构有一定影响。颗粒污泥反应器对溶解性COD的去除率可达90%,对氨氮的去除率为24%。颗粒污泥在反应器中分布不均匀,反应器底部MLSS高达8 g/L,SVI为34 mL/g,随着反应器高度的增加则MLSS值降低、SVI值提高;此外较大的颗粒污泥聚集在反应器的底部,较小的颗粒污泥和絮体分布在反应器的中上部。

降解五氯酚的微好氧颗粒污泥的培养及其微生物种群分析

在微好氧的条件下培养出颗粒污泥并用含五氯酚(PCP)的废水对颗粒污泥进行驯化,研究了培养过程中颗粒污泥的MLSS、SVI、粒径以及对COD和PCP处理能力的变化.颗粒污泥培养成熟后,PCP和COD的去除率分别达到85.3%和86.1%.用扫描电镜观察了颗粒污泥的结构,颗粒污泥内细菌种群丰富,大多数为短杆菌和球菌.同时采用聚合酶链式反应-变性梯度凝胶电泳(PCR-DGGE)技术对培养出的微好氧颗粒污泥以及用PCP驯化后的颗粒污泥中微生物的种群进行了初步分析和对比,用PCP驯化后的微生物种群发生了较明显的动态变化,新增了某些菌群,如不动杆菌(Acinetobacter)、变形杆菌(Proteobacterium)和硫酸盐还原菌等.

好氧颗粒污泥的形成及其性质

综述了好氧颗粒污泥的研究进展 ,包括好氧颗粒污泥的基本特征和微生物相、好氧颗粒污泥形成的主要条件及其颗粒化过程、好氧颗粒污泥反应器等 .好氧颗粒污泥是近几年发现的在好氧条件下自发形成的细胞自身固定化颗粒 ,具有良好的沉淀性能、较高的生物量和在高容积负荷条件下降解高浓度有机废水的良好生物活性 .颗粒化过程是一个多阶段的过程 ,取决于废水组成、操作条件和适当的选择压等因素 .SBR反应器 (SequencingBatchReactor)