水车驱动好氧生物转盘附载填料挂膜的特性及处理效果

以缺氧调节-好氧-经济型人工湿地生物生态组合工艺中好氧单元技术——水车驱动好氧生物转盘为研究对象,选择毛毡、碳毡、无纺布3种挂膜填料,对比其污染物去除性能和微生物富集特性,从而确定最适填料.结果表明,无纺布填料生物转盘硝化效果和生物亲和性优于其余两种填料,对CODCr、氨氮的平均去除率分别为84.3％和80.5％....     

水车驱动式生物转盘氧传质模型的构建

水车驱动式生物转盘将生物转盘与跌水充氧相结合,实现高效充氧。经理论分析与试验校核,为水车生物转盘建立氧传质模型。将水车生物转盘充氧过程简化为跌水过程充氧和盘片转动充氧两部分,对两部分分别建立模型。跌水过程以双膜理论为基础,从物料平衡角度建立氧传质模型。盘片转动过程以体积修正系数为基础,对Kim&Molof模型进行修正,建立充氧模型。二者结合,经理论推导与试验校正得出最终的水车生物转盘充氧模型。模型结果显示,水车生物转盘充氧能力与初始溶解氧浓度、跌水高度、盘片转速、装置尺寸及温度有关。此模型的建立为其他改进型生物转盘的氧传质模型的建立提供了有效依据和参考。     

异波折流板反应器水力特性试验研究

以Cl~-为示踪剂,采用停留时间分布法(RTD)研究在清水和有污泥稳定运行条件下,HRT对异波折流板反应器和平板折流板反应器水力特性的影响,并进行了对比分析.结果表明,进水为清水、HRT为2～8 h,HRT对平板折流板反应器的水力特性的影响比异波折板反应器更为显著,异波折板反应器的流动模式处于平推流和完全混合的"中间状态".相同HRT条件下异波折板反应器的死区率小于平板折板反应器,异波折板反应器内接种污泥后,死区比清水反应器时有所增加,生物死区成为死区大小的主要贡献者.     

复合式厌氧折流板反应器启动中的相分离特性

采用复合式厌氧折流板反应器(HABR)处理模拟啤酒废水,考察了其快速启动过程中的处理效能及相分离特性。结果表明:HABR可在33 d内完成启动,对COD的去除率92%;pH值在反应器前后端分别呈酸性和中性,促进了产酸菌和产甲烷菌的分离;厌氧系统内挥发性脂肪酸(VFAs)质量浓度的变化可以用于判断产酸作用和产甲烷作用之间是否处于动态平衡状态;HABR的产气量和末端出水VFAs质量浓度呈负相关关系,证明产甲烷菌的代谢活性逐渐增强。在快速启动过程中,HABR表现出了明显的生物相的选择和分离现象。     

厌氧折流板反应器处理制糖废水的启动试验研究

对厌氧折流板反应器(ABR)处理制糖废水的启动过程及其微生态进行了研究.结果表明:在水温为33℃,水力停留时间为24h的条件下,进水COD由1 200 mg/L逐步提升到2 400 mg/L,经过68 d,ABR对COD的去除率可达到92％以上.启动过程中第1隔室的抗冲击性最大,挥发酸浓度最高达22.69 mmo1/L.微生态情况第1隔室以杆菌为主,第2隔室中由杆菌组成的链状结构较为明显,第5隔室则出现了比较成熟的球菌.第5隔室颗粒污泥的辅酶F420含量最高,为1.25 μmo1/g,具有较好的产甲烷活性.小瓶静态批量试验表明ABR具有较好的抗冲击负荷能力.     

分段进水式厌氧折流板反应器的启动试验

在SABR反应器内以颗粒污泥接种,各格室按5∶4∶3∶2∶1的比例进水.在COD有机负荷2.13 kg·m-3·d-1,HRT=24 h,运行30d后在COD有机负荷2.66 kg· m-3·d-1,HRT=72h下运行50d.在启动运行80d时,COD去除率平均保持在90％以上,SABR反应器启动成功.     

活性炭改性及对生物转盘挂膜性能的影响

借助化学分析、表面形态分析等表征方法,研究了经化学氧化-铁离子覆盖技术和氢氟酸处理后活性炭（AC）的表面形貌、表面官能团含量、比表面积及其亲水性的变化情况。结果表明,采用化学氧化-铁离子覆盖技术改性处理后的活性炭同未处理的活性炭相比,其表面孔径分布均匀、细密,孔结构呈规则的蜂窝形状,酸性官能团含量增加0.116 meq/g,比表面积增加415.80 m²/g,平衡含水率增加19.28%。将两种表面氧化处理过的活性炭分别制作成两组生物转盘Ⅰ、Ⅱ,用其来处理油田污水,对比分析两种改性方法对生物转盘挂膜性能的影响,转盘Ⅱ微生物含量为2.60×10⁹ cfu/g,生物膜干重达到16.9096 g/m²,在盘片转速4 r/min、水温20 ^oC、水力停留时间（HRT）为6 h、pH值为6~8时,三级生物转盘各级化学需氧量（COD）去除率均在80%以上,最高达到了92.36%,并且生物转盘Ⅱ的去除效果好于转盘Ⅰ。     

2套组合折流板反应器系统处理生活污水的启动运行

以厌氧污泥为种泥,采用2套填充不同填料的兼氧-厌氧组合ABR为反应器,考察了填充不同填料组合系统处理生活污水的启动运行。结果表明,当温度在25～35℃时,进水体积流量约为0.40 m3/d、HRT为24 h时,连续运行65 d后,组合单元中2种填料表面均形成一层均匀而致密的深褐色菌膜;稳定运行时,填充悬浮球型填料的组合ABR和填充组合填料的ABR对生活污水中COD的平均去除率分别为66.5%和70.1%,对SS的平均去除率分别为90.9%、92.0%,出水COD和SS含量均达到GB 18918-2002二级排放要求,且填充组合填料的系统对COD、SS、TN及TP的去除率效果均优于填充悬浮球填料的系统。     

A~2/O工艺反应器水力流态研究

为了研究中试A2/O工艺反应器在不同流量条件下的实际HRT、死水区比例及反应器推流及混合效果,采用脉冲示踪法,以NaCl作示踪剂,测试了对反应器的水力流态分布。结果表明,进水流量分别为610、780、1 150 L/h时,厌氧池、缺氧池死水区比例在40%以上,整个生物反应器的死水区比例为20%,反应器在运行过程中,串联级数最高可达8,该反应器有较好的推流作用。     

厌氧折流板反应器处理退浆废水的启动研究

对采用厌氧折流板反应器(ABR)处理难降解退浆废水的启动过程进行了研究.实验结果表明:经过90 d的运行,反应器在32～34℃、上流速度8 m/h、水力停留时间6 d、COD容积负荷1.80 kg/(m3·d)的条件下,COD去除率达到55%以上,启动成功.出水COD稳定在4 500 mg/L左右,碱度约为700～850 mg/L.运行情况表明,启动初期反应器各隔室的pH变化较大,有效控制pH是系统启动成功的关键.启动后期,各隔室pH稳定在6.8～7.3之间,挥发性脂肪酸(VFA)质量浓度为300～500mg/L.随着隔室的横向推移,污泥的SS、VSS和SS/VSS不断增大,推测反应器中厌氧微生物相分离现象显著.     

新型生物转盘两种挂膜方式的比较研究

采用两种挂膜方式(自然挂膜法和流量递增式挂膜法)对新型生物转盘的启动进行对比研究,重点考察了COD去除率及盘片生物量的变化情况。研究结果表明,自然挂膜法需要24天才能完成挂膜,COD去除率较低,盘片生物量较少;流量递增式挂膜法15天即可完成挂膜,COD去除率达75%以上,盘片生物量较多,A、B两段盘片上的生物量分别达到2.76×109 cfu/g、2.44×109 cfu/g;流量递增式挂膜法更适合该新型生物转盘的启动。     

新型生物转盘处理工业废水的启动挂膜试验研究

为评估某新型生物转盘处理工业废水的可行性,调节生物转盘进水流量为10 L/min,转速为3 r/min,配水比为2∶1,在连续进水的情况下,通过对挂膜时间,挂膜期间COD、NH3-N、微生物含量、生物相变化的分析,结果表明该生物转盘挂膜周期短(只需13天),生物量大,AB段分别达到了2.76×109 cfu/g和2.36×109 cfu/g,生物相变化明显,COD去除率达到了65%以上,适用于工业废水的处理。     

高含固率污泥厌氧消化系统的启动方案与试验

高含固污泥厌氧消化技术是目前国内外的研究热点。该文以上海市白龙港污水处理厂脱水污泥稀释而成的含固率为10%的污泥作为研究对象,对高含固污泥厌氧消化技术进行了初步的探讨。试验结果表明,厌氧消化系统的进泥含固率升高至10%后,每投入1 m3的污泥产气约16~18 m3沼气,远高于现有浓缩污泥厌氧消化系统的产气率(8~10 m3沼气/m3污泥)。高含固率污泥厌氧消化系统推荐采用清水启动策略,即消化罐内介质的初始状态为清水(二沉池出水),之后以不同投配率投加原污泥,避免系统启动过程中的VFA的积累,尤其是丙酸含量的积累。该研究成果不仅可为该污水处理厂现有污泥厌氧消化系统未来的扩建改造服务,而且可为国内同类工程提供借鉴和示范。     

Discovery and Biological Characterization of the Auromomycin Chromophore as an Inhibitor of Biofilm Formation in Vibrio cholerae

Bacterial biofilms pose a significant challenge in clinical environments due to their inherent lack of susceptibility to antibiotic treatment. It is widely recognized that most pathogenic bacterial strains in the clinical setting persist in the biofilm state, and are the root cause of many recrudescent infections. The discovery and development of compounds capable of either inhibiting biofilm formation or initiating biofilm dispersal might provide new therapeutic avenues for reducing the number of hospital‐acquired, biofilm‐mediated infections. We detail here the application of our recently reported image‐based, high‐throughput screen to the discovery of microbially derived natural products with inhibitory activity against Vibrio cholerae biofilm. Examination of a prefractionated library of microbially derived marine natural products has led to the identification of a new biofilm inhibitor that is structurally unrelated to previously reported inhibitors and is one of the most potent inhibitors of V. cholerae reported to date. Combination of this compound with sub‐MIC concentrations of a number of clinically relevant antibiotics was shown to improve the inhibitory efficacy of this new compound compared to monotherapy treatments, and provides evidence for the potential therapeutic benefit of biofilm inhibitors in treating persistent biofilm‐mediated infections.     

Femtosecond Laser Patterning of the Biopolymer Chitosan for Biofilm Formation

Controlling microbial growth is crucial for many biomedical, pharmaceutical and food industry applications. In this paper, we used a femtosecond laser to microstructure the surface of chitosan, a biocompatible polymer that has been explored for applications ranging from antimicrobial action to drug delivery. The influence of energy density on the features produced on chitosan was investigated by optical and atomic force microscopies. An increase in the hydrophilic character of the chitosan surface was attained upon laser micromachining. Patterned chitosan films were used to observe Staphylococcus aureus (ATCC 25923) biofilm formation, revealing an increase in the biofilm formation in the structured regions. Our results indicate that fs-laser micromachining is an attractive option to pattern biocompatible surfaces, and to investigate basic aspects of the relationship between surface topography and bacterial adhesion.     

Suggestion of a New Correlation for the Height of Shallow Dispersion Bed Formed in a Rotating Disc Contactor

A rotating disc contactor (RDC) was designed and constructed. The obtained experimental results for the heights of shallow dispersion beds formed in the separation zone of the extraction column, suggested a new correlation. It was found that any increase in dispersed phase flow rate or rotor speed caused an increase in the dispersion height. Also, the results revealed the profound effect of the continuous phase viscosity on the height of the bed. Within the ranges of experimental results, the proposed correlation was in good agreement with the data of shallow beds compared to previous proposed relations.     

Assessment of di-(2-ethylhexyl)phthalate (DEHP) Removal in a Rotating Biological Contactor and Activated Sludge Process Treating Domestic Wastewater

Di-(2-ethylhexyl)phthalate (DEHP) is one of the most representative persistent micro-pollutants detected in the sewage sludge. In the present study, the presence of DEHP and its removal in various treatment units of a sewage treatment plant (STP) including an attached growth biological system i.e., a rotating biological contactor (RBC) and a suspended growth biological system i.e., activated sludge process (ASP) were investigated. Representative samples of sewage and sludge were collected at each stage of the STP for 2 years to explore the DEHP flow in the dissolved (DEHP_d) and adsorbed (DEHP_a) phases. The combination of RBC with a final clarifier was responsible for 50.4 and 58.2% of DEHP_d and DEHP_a removals, respectively. Both DEHP_d and DEHP_a removals were greater in RBC compared to ASP, demonstrating that an attached growth biological system is more efficient in the removal of DEHP compared to the suspended growth biological system. A good correlation between DEHP and organic matter removal was observed by using Pearson-correlation matrix approach.     

Environmental Stimuli Shape Biofilm Formation and the Virulence of Periodontal Pathogens

Periodontitis is a common inflammatory disease affecting the tooth-supporting structures. It is initiated by bacteria growing as a biofilm at the gingival margin, and communication of the biofilms differs in health and disease. The bacterial composition of periodontitis-associated biofilms has been well documented and is under continual investigation. However, the roles of several host response and inflammation driven environmental stimuli on biofilm formation is not well understood. This review article addresses the effects of environmental factors such as pH, temperature, cytokines, hormones, and oxidative stress on periodontal biofilm formation and bacterial virulence.     

船用一体化生物活性炭装置选炭挂膜及运行优化

采用一体化生物活性炭中试装置,探究4.0 mm和1.5 mm的柱状炭对污染物去除性能,择优选择作为装置目标炭进行人工挂膜。挂膜成功后,探究不同气水比条件下,装置污染物去除效果。结果表明,2种活性炭均有较高的COD去除率,且4.0 mm柱状活性炭运行稳定,无跑炭现象,利于生物膜的形成,为此次实验的目标炭。启动挂膜阶段,装置污染物去除率呈现先降低后逐步升高,最后趋于稳定;气水体积比2:1条件下,装置污染物去除效率较高,COD、NH4+^-N的平均去除率分别为79.5%、10.7%。NH4^+-N去除率均不高,可能与硝化细菌生长受限有关。