Membrane fouling behavior and microbial community succession in a submerged membrane bioreactor treating harbor oily wastewater

A membrane bioreactor (MBR) was established for treating harbor oily wastewater. It showed good removal performance for chemical oxygen demand (COD), oil content, suspended solids (SS), and other pollutants. However, serious membrane fouling occurred. It was recognized that the extracellular polymeric substances (EPS) accumulated on the membrane surface, especially the proteins, were of great importance for the transmembrane pressure (TMP) increment and membrane fouling. The MBR was optimized via improving aeration rate and reducing the ratio of A_r/A_d (A_r and A_d are the cross-sectional areas of the riser and the downcomer of the MBR). The increasing rate of TMP was slowed, indicating that the optimization strategy could effectively mitigate membrane fouling. Microbial community evolution was monitored and analyzed by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE), cloning, and sequencing of 16S ribosomal ribonucleic acid (rRNA) fragments. Results revealed that low community shift occurred during the whole operational period. Geobacter sp. and Rhodocyclales sp., which have also been identified by other studies in a petroleum refinery wastewater MBR or an infiltration basin receiving highway runoff, dominated in the MBR system throughout. Comamonas sp. was thought to accommodate the lower aeration rate in this study, while Rhodocyclales sp. preferred the higher aeration rate. In addition, during the operational time under high organic loading rate, a few species were present in abundance, and may have been responsible for the good removal performance at this time.     

颗粒填料复合式膜生物反应器（HMBR）技术研究

膜污染是制约膜生物反应器（MBR）工程化应用的瓶颈。针对现有MBR存在的缺点,本文提出了新型的颗粒填料复合式膜生物反应器（HMBR）,并介绍了HMBR在工业废水处理中的应用。通过分析悬浮颗粒物在膜表面的沉积条件,从流体力学、微生物学、水处理工艺学、亚微观动力学等方面对HMBR的性能和特点进行了详细阐述,表明颗粒填料可以有效地减缓膜污染和提高膜生物反应器过滤性能。     

复合式膜生物反应器处理城市污水中水力停留时间的确定

本文在以复合式膜生物反应器系统为基础,以模拟城市污水为处理对象。通过运行条件优化研究,综合脱氮除磷效果及经济因素,将复合区水力停留时间控制在7h左右。此时系统总去除率为:CODcr≧96.28%、NH3-N≧97.54%、TN≧74.87%、TP≧74.34%,出水可以稳定保证在CODcr≦14.35mg/L、NH3-N≦0.74mg/L、TN≦9.02mg/L、TP≦1.05mg/L。效果较好。     

Distribution of extracellular polymeric substances in pilot-scale membrane bioreactor

The spatial distribution of extracellular polymeric substances （EPS） in a pilot-scale membrane bioreactor （MBR） was studied. The sampling points on top of and inside the membrane module were measured and analyzed by the experimental variant function. The content of EPS was spatially interpolated by ordinary Kriging method, and il- lustrated with SURFER software. A case study was carried out in an MBR with membrane aperture of 0.4 ~tm and handling capacity of 120 ma/d in Jizhuangzi sewage treatment plant, Tianjin. From the visualization of EPS distribu- tion, it is seen that on the horizontal plane, the content of EPS was the lowest at the center; and on the vertical plane, the content of EPS decreased with the increase of depth. The shearing force caused by aeration of perforated pipe and the influent mode are the main influencing factors for this distribution.     

Time-dependent sediment transport subjected to downward seepage

Experiments were conducted using cohesionless sand particles with median diameter of 0.48 mm to investigate the time variation of sediment transport rate under the influence of local downward seepage.The experimental results show that the bedload transport rate in terms of volumetric sediment transport rate per unit width increased rapidly with time in the presence of suction,eventually reaching a peak beyond which it started to decrease.The trend of reduction was significantly reduced beyond 8 400 s after the test started.The analytical expression was derived in terms of dimensionless sediment transport rate and dimensionless time.The hypothesized relationships were compared with the experimental data,indicating a good agreement with each other.     

Distribution of Extracellular Polymeric Substances in Pilot-Scale Membrane Bioreactor

The spatial distribution of extracellular polymeric substances (EPS) in a pilot-scale membrane bioreactor (MBR) was studied. The sampling points on top of and inside the membrane module were measured and analyzed by the experimental variant function. The content of EPS was spatially interpolated by ordinary Kriging method, and illustrated with SURFER software. A case study was carried out in an MBR with membrane aperture of 0.4 μm and handling capacity of 120 m3/d in Jizhuangzi sewage treatment plant, Tianj...     

Operation Characteristics of Treating Surface Water with Polyvinylchloride Hollow Fiber Ultrafiltration Membrane

Ultrafiltration (UF) technique is prospective asalternative for conventional processes such as coagula-tion, flocculation, sedimentation and/or flotation,rapid and slowsand filtration[1]. Recentdevelopmentsin reducing energy consumption by (semi) dead-endfiltration and prevention of membrane fouling by back-washing (combined with chemicals), make UF moreand more an interestingoption forthe treatmentof sur-face water on a large scale[2]. At present, UF full-scale applications are evenlyspread…     

Amniotic membrane transplantation for porous sphere orbital implant exposure

Objective： This study is aimed at describing the clinical outcome of amniotic membrane transplantation for exposure of porous sphere implants. Methods： A retrospective review of consecutive cases of porous sphere orbital implant exposure was carried out. Eight cases were presented between May 2004 and Oct. 2006 （5 males, 3 females; mean age 44.5 years）. Six had enucleation and two had evisceration. Exposure occurred in two primary and six secondary. Orbital implant diameter was 22 mm in seven cases and 20 mm in one case. Six patients are with hydroxyapatite and two with high-density porous polyethylene （Medpor） orbital implants. The mean time from implantation to exposure was 1.1 months （range 0.8-2 months）. All patients required surgical intervention. Results： The time of follow-up ranged from 3.0 to 28.0 months （mean 16.5 months）. Amniotic membrane grafting successfully closed the defect without re-exposure in all of these patients. The grafts were left bare with a mean time to conjunctiva of about 1 month （range 0.8-1.5 months）. Conclusion： Exposed porous sphere implants were treated successfully with amniotic membrane graft in all of patients. The graft is easy to harvest. This technique is useful, dose not lead to prolonged socket inflammation and infection, and it is valuable application extensively.     

Treating Opaque Beer Wastewater Using a Novel Internal Circulation Membrane Bioreactor

An innovative internal circulation membrane bioreactor(ICMBR) treating traditional opaque beer brewery wastewater was introduced. Beer wastewater from Tianjin Huarun Brewhouse was taken as the influent. The removal efficiency of suspended solid, chemical oxygen demand, total nitrogen and ammonia nitrogen were studied with the changeable hard real time design method, organic loading rate and nutrition elements. The average percentage reduction in chemical oxygen demand achieved 90%. The total nitrogen and ammonia nitrogen were also reduced by 90% and 95%, respectively. The results indicate that the outlet of ICMBR meets the requirements of the environment landscape recycling use.     

Implications of membrane fouling toward the removal of the pharmaceutical sulfamethoxazole by nanofiltration processes

The influence of membrane fouling on the retention of the trace organic contaminant sulfamethoxazole by a nanofiltration (NF) process was investigated. Organic fouling caused a severe flux decline possibly due to pore blocking and adsorption directly after the commencement of the fouling layer development. Such membrane-foulant interactions were absent for colloidal fouling, which resulted in a more gradual flux decline. Membrane charge played a significant role in the separation process of inorganic salts, where the retention was the highest in a caustic environment (high pH) due to more swollen membrane material caused by the higher negative charge on the membrane. Organic fouling and a combination of colloidal and organic fouling led to a significant increase in the membrane negative charge. The influence of membrane fouling on solute retention was dependent on the fouling behaviour and the physicochemical properties of the model foulants, where the model foulants probably contributed to an increase in the retention of charged solutes due to enhanced electrostatic interactions. Organic fouling caused an increase in the retention of inorganic salts and sulfamethoxazole due to pore blocking. In contrast, colloidal fouling caused a decrease in the retention of inorganic salts due to cake-enhanced concentration polarisation. However, the presence of a colloidal fouling layer did not reduce the retention of sulfamethoxazole. A mixture of colloidal and organic matter improved the retention of inorganic salts. A similar conclusion can be inferred for sulfamethoxazole at pH 4 when the compound exists in a neutral form.     

电催化氧化降解含酚工业废水实验研究

采用价廉的涤纶滤膜作为电解体系隔膜,利用阴、阳极同时作用降解含酚工业废水,在反应时间80min,曝气量1.2L/min,电流密度30mA/cm2的最佳条件下,含酚废水COD去除率可达到80%,阴极室COD去除率高于阳极室。     

Removal of aqueous phenol compound by vacuum membrane distillation

1.IntroductionPhenolisanimportantchemicalindustrymaterial,butitalsoaboundswithserioushazardtoenvironmentandthreatstohumanhealth.Rigidruleshavebeenmadeoutonthephenoldischargeconcentration.Researchesonthetreatmentofphenolwastewaterwerecarriedoutinvariouscountries[1-5].Membraneseparationmethodsincludingreverseosmosis,ultrafiltrationandpervaporationhaveattractedmuchattentionforphenolwastewatertreatment,withcelluloseacetate(CA)membraneemployedmostly[6].Membranedistillationisanewmembraneseparation…     

闭式引流配合榄香烯乳、顺铂治疗恶性胸腔积液疗效观察

目的观察闭式引流配合榄香烯乳、顺铂治疗恶性胸腔积液的近期疗效及毒性。方法行胸腔闭式引流后，向胸腔内灌注榄香烯乳300mg，顺铂60mg 1次／周，连用1—3周。结果恶性胸腔积液完全缓解率为68．4％，总有效率为92．1％。副作用为轻度恶心，一过性胸痛、发热。结论闭式引流配合榄香烯乳、顺铂治疗恶性胸腔积液效率高．毒副反应小．值得临床推广。     

遮光对光皮桦苗木存活率及生长效应分析

本研究设遮光度40％、60％、80％和ck（全光照）4种处理,探讨光因子对光皮桦苗木存活率、适合度和生长的影响。研究表明,全光照条件下,死亡最高时期出现在播种后第11～60d（6月11日～7月30日）,死亡率高达84．5％,适合度仅为0．0358。遮光度40％和60％两种处理,死亡最高时期出现时间相近,死亡率前者高于后者,分别达71．1％和62．0％,适合度分别达0．1329、0．1740。当遮光度达到80％时,死亡最高时期出现时闻不明显,死亡期延续时间较长,其苗木死亡率（62．8％）、适合度（0．1700）与60％遮光度处理差异不明显。随遮光度增大,苗高、地径、生物量等主要生长指标亦明显增大。生产中采用60％～80％遮光度给光皮样幼苗遮荫可有效地提高光皮桦的苗木存活率和生长规格。     

溶胶-凝胶浸渍法制备氧化铝膜的形貌表征

Alumina membranes without pinholes and cracks were prepared by the sol-gel process using anunordum aluminium sulphate as the starting material. The effects of different preparing conditions on morphology characteristics of the membrane were investigated by scanning electron microscopy and 3D rotational microscopy. The preparing conditions include the amounts of drying control chemical additives （DCCA）, sintering procedure and sol-gel concentration. The results showed that PVA is a good crack-preventing reagent and the morphology of supported membranes was affected by ninny factors, including Al2O3 concentration, PVA/Al2O3 ratio, heating rate, membrane thickness and intrinsic defects of the substrate surface.     

Morphological characterization of Al_2O_3 membrane fabricated by sol-gel dip-coating method

1 Introduction Alumina membrane has received considerable atten-tion for its thermal ,chemical and mechanical stabilityin filtration applications .Alumina membraneis usuallyprepared by sol-gel process ,in which uniform nano-meter-sized particles can be pr…     

渗透胁迫对玉米幼苗膜脂过氧化及过氧化氢酶活性的影响

本实验以三个玉米品种新实多2号、东单7号、中原单32为实验材料,采用PEG 6000模拟土壤干旱条件,研究渗透胁迫下不同玉米品种M DA(丙二醛)含量、CAT(过氧化氢酶)活性以及膜相对透性间的相互关系,结果表明,渗透胁迫下三个玉米品种M DA含量和质膜相对透性均随胁迫强度的增加而增加,而CAT活性则随胁迫强度的增加而减少,CAT活性与M DA含量、质膜相对透性均呈显著或极显著负相关关系,且品种间存在差异,通过分析比较,可初步判断三个玉米品种幼苗的抗渗透胁迫能力为新实多2号优于中原单32和东单7号.     

液膜法分离富集废水中邻硝基酚的研究

采用乳状液膜法分离富集药厂未处理废水中的邻硝基酚(OPN),探讨了液膜中表面活性剂用量、膜增强剂用量、内水相浓度、乳水比、油内比以及乳水混合转速和时间参数之间的最佳组合方案:煤油95mL,Span80为5mL,内水相浓度为2.5%.油内比2∶1,乳水比1∶3,乳水混合速度100r/min,混合时间25min.实验结果表明:采用本实验室制备的乳状液膜分离富集废水中的邻硝基酚,n=6时,邻硝基酚的平均富集率为98.58%,RSD为0.22%.     

内江市城区大气污染状况研究

运用实地调查和定量定性分析的研究方法,针对内江市城区大气中的三大主要污染物SO2、NOx、总悬浮颗粒物的环境质量监测数据,分析其污染因素：生活污染、工业污染、交通污染、农业污染和其他污染,并由此提出污染防治的措施和建议：控制污染源,合理规划城市建设,改变能源结构,加大植树造林力度．     

男大学生中长跑运动员训练过程生理生化指标研究——心率恢复率、血乳酸清除率变化情况

通过实验室研究方法、文献资料法、数理统计法、综合分析法等研究方法对业余男中长跑运动员在不同训练阶段的血乳酸清除率、心率恢复率等指标进行测定,得出了不同训练阶段运动员的运动强度安排、间歇时间安排应不同的结论.运动员在训练初期运动强度要小些,间歇时间为9min左右;训练三个月后训练强度可适当加大,间歇时间调整为8min左右;当系统训练半年后由于运动员的血乳酸清除率和心率恢复率都达到了一个较高的水平,可以采用较大的训练强度,适当地缩短训练时间,将间歇时间调整为7min左右.