Landfill leachate treatment by MBR： Performance and molecular weight distribution of organic contaminant

A membrane bioreactor (MBR) with an air-lift bioreactor and gravity flow is applied to treating landfill leachate. More than 99% of BOD5 (biochemical oxygen demand for five days) removal effi-ciency is achieved with less than 35 mg/L of BOD_5 in the effluent at less than 1.71 kg BOD5/m~3·d of BOD_5 loading rate. When DO (dissolved oxygen) is maintained at the range of 2.3―2.8 mg/L and the loading rate of NH_4~ -N (ammonium nitrogen) is kept at 0.16― 0.24 kg NH_4~ -N/m~3·d, the NH_4~ -N in the effluent is less than 15 mg/L. However, compared with high removal rates of BOD_5 and NH_4~ -N, the removal effi-ciency of soluble chemical oxygen demand (SCOD) varies between 70% and 96%. The investigation of molecular weight (MW) distribution has been carried out by the gel permeation chromatography (GPC) so as to understand the fate of organic matters in the MBR treating of landfill leachate. Results indicate that organic matters of the landfill leachate are composed of a high MW fraction (MW of the peak, MWp = 11480―13182 Da) and a low MW fraction (MWp = 158―275 Da). The high MW fraction is not biode-gradable, but can be decreased with microfiltration membrane. The most of the low MW fraction is bio-degradable, but the residue of the low MW fraction is able to permeate through the membrane, thus re-sulting in high SCOD in the effluent of the MBR.     

浸没板式膜MBR处理生活污水的试验研究

采用浸没板式膜生物反应器(MBR)中试系统针对学生宿舍与食堂混合排水进行处理.系统采用A/O工艺,日处理污水4 m3.当进水BOD5和CODCr分别为90~450 mg.L-1,120~900 mg.L-1时,出水BOD5和CODCr分别为5~25 mg.L-1,8~45 mg.L-1,均得到了90%以上的去除率.同时对出水色度去除以及膜污染进行了全面实验研究,采用活性炭吸附可有效去除处理水色度,被污染的膜采用机械及药物方法清洗后可有效恢复通量.研究结果认为浸没板式膜生物反应器适用于中小规模的生活及产业有机废水的处理,具有广阔的应用前景.     

Pilot Study on Drinking Water Advanced Treatment by GAC-MF System

The pilot pedomance of the combined GAC-MF membrane process for drinking water advanced treatment was described. In the process of GAC adsorption, under the conditions of 20min HRT and 6 m/h filtration rate, the removal efficiencies of UV254 and trichloromethane could reach 40% and 50% respectively and the UV254 and trichloromethane in system effluent was less than 0.015cm^-1 and 5 μg/L respectively. Inthe post MF membrane process, MF membrane effectively retained the particles and bacteria in raw water. The effluentturbidity was less than 0.2 NTU and no bacteria were detectedat all in permeate. A computer-controlled system was employedto control this system. The mcmlrane operating parameters of backwash interval, dtration and flux were studied. The backwash interval of 10-min, 20-min and 60-min wasresearched respectively, and the variation of trans-membrane pressure was also analyzed. Comequently short backwash interval was recommended under the same water consume.     

内支撑结构MBR处理高浓度有机废水实验研究

采用新型内支撑结构板式MBR对高浓度有机废水进行处理,并分别对CODCr,氨氮以及出水色度等处理效果进行了评价.为保证MBR正常运行,系统采用UASB作为预处理手段.当UASB出水CODCr和NH4+-N分别为1000～2000mg/L和50～300mg/L时,MBR最终出水CODCr和NH4+-N分别为87.8～309.6mg/L和8～38.4mg/L,平均去除率分别达到86.41%和90.11%,处理效果良好.同时针对MBR出水色度的去除,试验采用活性炭吸附处理,可以有效地去除出水的色度.     

生物强化膜生物反应器处理洗车废水

洗车废水用水量大，而且回用水质要求较高，采用膜生物反应器(MBR)处理以保证回用水的水质，同时可缓解水资源短缺的问题．利用生物强化技术针对性强、应用灵活和效率高等特点，将高效菌生物强化技术与MBR结合处理洗车废水．在相同运行条件下运行两个MBR，其中一个MBR中投加高效菌，并对两者的处理效果进行比较．试验结果表明，用高效菌强化的MBR出水水质良好，出水的色度、化学需氧量(COD)、氨氮(NH3-N)和阴离子表面活性剂(LAS)等均优于普通污泥-MBR出水．     

Fabrication and morphology of NbCx-C composite three-dimensinal netted fibers

The raw materials were commercial powders of Nb₂O₅ (99.95%), reactive carbon (99.99%), NaCI (99.95%) and sucrose (99.94%). By the carbothermal method, the NbC_x (x= 0.98)-C composite three-dimensional netted fibers were prepared in graphite resistance furnace in 0.1 MPa/N₂ ambient atmosphere at temperature from 970 to 1 120°C. The diameters of composite three-dimensional netted fibers are 12–38 μm, the hole circumferences of netted fibers are 0.22–2.2 mm and the hole diameters are 70–701 μm. The process conditions for fabricating NbC_x-C composite three-dimensional netted fibers and related morphology, composition and crystal structure of NbC_x-C composite netted fibers were investigated in detail.     

基于曝气生物滤池工艺处理老龄垃圾渗滤液

分别在小试和工业化规模上系统研究了基于曝气生物滤池(BAF)的工艺对老龄垃圾渗滤液的处理效果.在实验室中,对比传统生化处理工艺,BAF单元对COD的去除率提高了20%.将基于BAF的组合工艺(厌氧+BAF+膜生物反应器MBR+反渗透RO)应用于深圳某填埋场渗滤液处理,取得了较好的处理效果.BAF单元对COD、氨氮的去除率分别达到31%和94.2%.生物处理单元(包括BAF和MBR)对铜、锌的去除率达到70%以上,而对镍、铬、铅的去除率小于50%.RO膜对重金属的去除率均高于生物处理单元.该组合工艺既保证了生物降解的持续进行,又保证了RO膜的稳定运行.利用GC-MS对生物处理单元有机污染物成分进行了分析,并对其降解机理进行了初步探讨.     

MBR处理丁基黄药废水启动期好氧活性污泥特性

探讨利用膜生物反应器(MBR)处理丁基黄药(简称黄药)废水时的启动期及好氧活性污泥驯化过程的运行特征,分析其好氧活性污泥的形成过程、形态特征、性质及对污染物的去除机制.以啤酒污水处理曝气池污泥为接种污泥,以乙酸钠和黄药为碳源,培养及驯化絮体污泥.结果表明,MBR系统经过35 d启动及驯化即可达到正常运行状态,絮体污泥的SVI为100 mL/g,MLVSS/MLSS为0.75,生物量大且沉降性良好,COD及黄药去除率分别可以达到80%和90%.絮体污泥的形成及膜的高效截留增强了MBR运行的稳定性,为黄药废水的高效降解提供了保证.     

好氧颗粒污泥膜生物反应器处理畜禽废水

采用好氧颗粒污泥膜生物反应器处理畜禽废水,分别对COD、NH4 -N、NO2--N、NO3--N的去除效果和对膜通量的影响进行了研究。结果表明:在水力停留时间(HRT)为8h,进水COD浓度为600mg/L,NH4 -N浓度为40mg/L的条件下,出水COD、NH4 -N的浓度分别为46.6和4.8mg/L。NO2--N和NO3--N的去除率也可达90%以上。并且好氧颗粒污泥的加入减缓了膜的污染。     

Occurrence of sulfonamide antibiotics in sewage treatment plants

The occurrence of sulfonamide antibiotics （SAs） was investigated in the six sewage treatment plants （STPs） of Beijing, China. Of the 13 objective antibiotics, suIfamethoxazole, suIfapyrldine, suIfamerazine, sulfadiazine and suIfamethizol were detected in the influents with the average concentrations of 1.2 ± 0.45, 0.29 ± 0.25, 0.048 ± 0.012, 0.35 ± 0.52 and 0.33 ± 0.21 μg·L^-1, respectively, and those in the effluents were 1.4 ± 0.74, 0.22 ± 0.19, 0.021 ± 0.008, 0.22 ± 0.21and 0.01± 0 μg·L^-1, respectively. SuIfamethoxazole was the predominant compound detected, and was found in all wastewater samples with the other two compounds sulfapyridine and suIfamerazine. It should be noted that suIfadiazine was first reported in wastewatera, and the concentration levels of all detected compounds except for suIfamethizol （detected once in the effluent samples） in the influents were observed to be similar to those in the effluents. From the dsts in this study, it can be found that suIfamethoxazole, suIfapyridine, suIfamerazine and suIfadiazine could be partly removed in anoxic and aerobic treatment unit and vice versa in anaerobic process, which led to their low or even negative removal rates in the effluents. The increase on the concentrations of suIfamethoxazole and suIfapyridine in the effluents was found probably due to the biotransformation of their acetylated forms in anaerobic treatment unit. In addition, it was observed that the biodegradation of suIfamethoxazole and suIfapyridine could partly occur during the anoxic and aerobic process, while suIfamerazine was partly eliminated in the anaerobic and anoxic units.     

缺氧-好氧膜生物反应器处理高氨氮废水的研究

采用缺氧-好氧MBR组合工艺对高氨氮废水处理进行试验研究,结果表明:该工艺处理效果优良,系统对浊度、COD、氨氮的平均去除率分别为99.8%、95.3%、97.2%,在回流比为3的情况下,总氮的去除率可达72.7%.该系统具有较强的抗冲击负荷的能力.     

PVB超滤膜污染特性及其在MBR中的应用

采用连续制膜技术制备了平片式聚乙烯醇缩丁醛(PVB)超滤膜。该膜室温下平均纯水通量为0.02 L/(m2.h.Pa),对牛血清白蛋白(BSA)的平均截留率为25.0%(BSA水溶液质量浓度0.5 g/L)。通过终端过滤实验,以活性污泥混合液为处理对象,分析了PVB超滤膜过滤过程中的膜污染特性。结果表明:沉积层阻力占总过滤阻力的70%以上,是PVB膜过滤活性污泥混合液过程中污染阻力的主要组成部分;将制备的PVB超滤膜应用于好氧膜生物反应器(MBR)处理生活污水中,PVB-MBR系统在膜通量12 L/(m2.h)条件下运行105 d,期间未对膜进行任何人为清洗,系统抽吸压力能够在-16~-22 kPa间维持稳定,且系统出水的主要水质指标完全符合国家城镇污水处理厂污染物排放一级A的标准。     

膜生物反应器净化污水的抗冲击性能

比较了膜生物反应器(MBR)和传统活性污泥工艺(CAS)在相同运行条件下处理生活污水的抗冲击性能.结果表明:MBR系统出水、上清液以及CAS出水COD浓度均随进水COD容积负荷增加而线性递增,但递增的速率前者仅分别为后两者的42.1%和37.1%;MBR的COD容积负荷是CAS的3倍;进水NH3-N容积负荷、温度和pH值冲击对MBR出水水质影响不大,但低温会加速膜污染进程.MBR抗污染物负荷、pH值、温度的冲击能力显著优于CAS工艺.     

Porosity and permeability evolution and evaluation in anisotropic porosity multiscale-multiphase-multicomponent structure

Based on the hybrid hypersingular integral equation-lattice Boltzmann methods (HHIE-LBM), the porosity and permeability evolution and evaluation process in anisotropic saturated porosity multiscale-multiphase-multicomponent (ASP-MS-MP-MC) structures under ultra high temperature and pressure conditions was analyzed on parallel CPU and GPU platforms. First, virtual physical models at multi-spatial scales (2 μm, 5 μm and 10 μm) were restructured by computerized microtomography technology and data. Second, using HHIE-LBM methods, the anisotropic porosity and permeability tensor at core level and pore level under ultra high temperature and pressure conditions were calculated. Third, the evolution and evaluation process of the porosity and permeability as a function of multi temporal spatial scales was investigated. Finally, the relationship between porosity and permeability and ASP-MS-MP-MC structures (micro-meso-macro-scale) was explored.     

超微滤膜去除工程纳米粒子的可行性——以聚苯乙烯纳米颗粒为例

 工程纳米粒子的广泛应用导致其直接或间接进入水环境,对生物和人类造成健康风险。为研究超微滤膜去除水体中工程纳米粒子的可行性,选用3种不同孔径的中空纤维膜对聚苯乙烯纳米颗粒进行截留,并系统考查膜对聚苯乙烯纳米颗粒的去除效果及影响因素。研究结果表明：超微滤膜能够有效去除水体中工程纳米粒子。在进水压力25~125 kPa、进水切线流速0.12~0.59 m·s^-1,以及纳米颗粒质量浓度在25~100 mg·L^-1之间,超滤膜对聚苯乙烯纳米颗粒的截留率均在90%以上;压力与纳米颗粒物质量浓度的提高导致膜对聚苯乙烯的截留率也相应提高,而进水流速对截留率的影响不明显。纳米颗粒粒径与膜孔径的比在小于1时,对截留率影响较大,膜分离10 min时的实验截留率值与Nakao模型预测值较接近。     

The template preparation and characterization of three new shapes of titania nanometer-array systems

Nano-structure systems such as nano-structure de- vices and quantum devices have become a hot spot[1] in the materials science. Recently, the synthesis and the preliminary exploration of the properties of novel nano-structures or nanometer constitutional …     

Fast formation of NaA zeolite membrane in the microwave field

NaA zeolite membrane was successfully synthesized on the porous α-Al₂O₃ support by microwave heating. The synthesis of NaA zeolite membrane in the microwave field only needs 15 min and the synthesis time is 10 times shorter than that by conventional heating. SEM characterization indicates that the zeolite crystals in the NaA zeolite membrane synthesized by microwave heating are uniform in size; the membrane thickness is about 4 μm and is thinner than that of the NaA zeolite membrane synthesized by conventional heating. Gas permeation studies indicate that the permeances of the NaA zeolite membrane synthesized by microwave heating are 3–4 times higher than those of the NaA zeolite membrane synthesized by conventional heating, while their permselectivities are comparable.     

MBR与二段式SBR处理酱油废水的对比分析

通过MBR与SBR处理酱油废水对比分析发现,MBR的出水COD优于二段式SBR,而二段式SBR＋气浮出水COD优于MBR. SBR工艺对色度基本没有去除作用. MBR出水色度低于两段式SBR＋气浮工艺.以日处理水量400 m^3的现场工程为例,对SBR和MBR的工程总投资和运行费用进行了对比分析,MBR的运行费用比SBR低22%. 但MBR的制水成本较高,使其难以推广应用.随着自来水费与排污费的提高、膜组件价格下降及寿命延长,该技术会有更快的发展. 将MBR与SBR工艺进行组合,是解决MBR现存问题的有效途径.     

Determination of copy number for 5S rDNA and centromeric sequence RCS2 in rice by Fiber-FISH

The copy number of 5S rDNA and centromeric sequence RCS2 was determined by extended DNA fiber based fluorescence in situ hybridization (Fiber-FISH) in rice (Oryza sativa ssp. indica cv. Guangluai No. 4) genome. In order to determine the copy number, it is necessary to know the basepair number that a given length DNA fiber contains under a microscope. Therefore, the length of two DNA fragments, in which the basepair number had been already known, was measured. The insert sequence of the tested BAC 38D17 was 136 kb and its extended DNA was 56.4 μm long, 2.41 kb/μm on average, while that of the tested BAC 44B4 was 144.5 kb in total and 55.7 μm long, 2.60 kb/μm on average under the microscope. They were very close to the theoretical value of B-DNA in the Watson-Crick DNA model, which is 2.97 kb/μm. According to the average value of basepair number per μm of the two samples mentioned above, that is, 2.51 kb/μm, it could be estimated that the copy number was about 686 for 5S rDNA and 286-1121 for the centromere sequence RCS2.     

Salt glands inGlycine soja L. China

A scanning electron microscope observation is carried out on Glycine soja L., which grows around the estuary of the Yellow River, in Kenli County, Shandong Province. It is first discovered that there are salt glands, in the shape of balls, on the surface of the stems and leaves of G. soja L., and distributed at the intercellular layer. With a handle at the base, the salt glands are not equal in size, and show a layer-upon-layer structure. They have a diameter of 21.6 μm, a handle length of 1.2 μm, their secretory pore's diameter is 5.6 μm. There are two ways to secrete salt ions: younger glands secrete salt ions through the secretory pore, and mature glands by breaking themselves.