出水水头对自生生物动态膜过滤性能的影响

增加出水水头不利于自生生物动态膜(SFDM)的恢复.随着恢复期出水水头的增加,SFDM的稳定出水通量逐渐达到一个极限通量,约为35L·(m²·h)^-1.继续增大出水水头,稳定出水通量甚至有降低的趋势在相同的出水通量下,动态膜的稳定运行时间随着恢复期出水水头的增加而显著降低.当恢复期出水水头为0.5cm时,稳定运行的时间＞10d,当恢复期出水水头为10cm时,稳定运行时间＜5h.研究了产生上述现象的原因,并提出使每个过滤周期从出水水头为0处开始的操作策略.     

乳状液膜法处理含柠檬酸工业废水的研究

本文研究了以LMA-1为表面活性剂,正三辛胺为流动载体,Na_2CO_3溶液为内相试剂.煤油为膜溶剂所组成的液膜体系处理柠檬酸废水,考察了搅拌速度、表面活性剂种类和用量.载体用量、乳水比、油内比对废水中COD去除率的影响,结果表明:当LMA-1为3g·100ml~(-1)煤油,R_(?)=1:10,R_(?)=1:1.搅拌速度为300r·min~(-1)时.废水中COD的去除率可达99%.     

SEMIPERMEABLE MEMBRANE DEVICES USED TO ESTIMATE BIOCONCENTRATION OF POLYCHLORINATED BIPHENYLS1

ABSTRACT: Aquatic organisms passively accumulate hydrophobic organic compounds, such as polychlorinated biphenyls, even when ambient water concentrations of the contaminant are below analytical detection limits. However, contaminant concentrations in tissue samples are subject to an inherently high level of variability due to differences in species, life stage, and gender bioconcentration potentials. Semipermeable membrane devices (SPMDs) were used to sample Aroclor 1254, a mixture of readily bioconcentrated polychlorinated biphenyls (PCBs), in a contaminated wetland near Flat Top, WV. The devices consisted of triolein, a lipid found in fish, enclosed in a polyethylene membrane. SPMDs were deployed in the water column and in direct contact with wetland sediments along a previously identified concentration gradient of PCBs. The devices were retrieved after a 25-day exposure period. Analytes were recovered by dialyzing the devices in nanograde hexane. Hexane dialysates were condensed and analyzed by gas chromatography. All deployed devices sequestered quantifiable amounts of Aroclor 1254. Water-column SPMDs accumulated PCBs far in excess of ambient water concentrations. The devices contacting sediments accumulated PCBs at all sites, though accumulated concentrations did not exceed concentrations in sediment. Patterns of PCB concentration in the devices corresponded to the identified gradient at the site. Results from the water-column SPMDs were used to estimate the concentration of the dissolved, bioavailable fraction of PCBs present in the water column. These concentrations ranged from 0.01 to 0.09 μg/L of bioavailable Aroclor 1254.     

厌氧膜生物反应器处理高浓度食品废水的应用

采用由完全混合的厌氧生物反应器和板杠式超滤膜组成的膜生物反应器对高浓度食品放心水进行处理,考察了厌氧膜生物反应器的处理效果及其对负荷、水力停留时间等的稳定性,膜组件装填面积为０．６４ｍ＾２,膜材质为聚醚砚（ＰＥＳ）,膜截贸分子量为２００００。结果表明：ＣＯＤ负荷在２～３ｋｇ／（ｍ＾３．ｄ）时,膜出水ＣＯＤ去除率可达８０％～９０％,当ＣＯＤ负荷超过４．５ｋｇ（ｍ＾３．ｄ）时,混合液ＶＦＡ出现积累,Ｃ     

错流膜生物反应器水力清洗特性研究

采用外压管式聚砜－聚丙烯腈共混超滤膜进行错流膜生物反应器水力清洗特性研究,结果表明,清洗时采用高膜面流速、低操作压力和限制透过液对流传递作用有利于错流膜生物反应器通量的恢复,这符合膜藏去除过程中的传质机理;适宜的膜面流速应稍大于临界流速ｖｋ＝１．９２ｍ／ｓ,清洗时间应控制在１０ｍｉｎ,适宜的清洗操作压力为０．０７ＭＰａ。     

Salinity exchange between seawater/brackish water and domestic wastewater through electrodialysis for potable water

● Present a general concept called “salinity exchange”. ● Salts transferred from seawater to treated wastewater until completely switch. ● Process demonstrated using a laboratory-scale electrodialysis system. ● High-quality desalinated water obtained at ~1 mL/min consuming < 1 kWh/m ³ energy. Two-thirds of the world’s population has limited access to potable water. As we continue to use up our freshwater resources, new and improved techniques for potable water production are warranted. Here, we present a general concept called “salinity exchange” that transfers salts from seawater or brackish water to treated wastewater until their salinity values approximately switch, thus producing wastewater with an increased salinity for discharge and desalinated seawater as the potable water source. We have demonstrated this process using electrodialysis. Salinity exchange has been successfully achieved between influents of different salinities under various operating conditions. Laboratory-scale salinity exchange electrodialysis (SEE) systems can produce high-quality desalinated water at ~1 mL/min with an energy consumption less than 1 kWh/m³. SEE has also been operated using real water, and the challenges of its implementation at a larger scale are evaluated.     

Ceramic membrane fouling mechanisms and control for water treatment

● The fouling is summarized based on ceramic membrane performance and pollutants. ● The current research methods and theoretical models are summarized. ● The membrane fouling control methods and collaborative technology are reviewed. Membrane separation, as an important drinking water treatment technology, has wide applications. The remarkable advantages of ceramic membranes, such as chemical stability, thermal stability, and high mechanical strength, endow them with broader prospects for development. Despite the importance and advantages of membrane separation in water treatment, the technique has a limitation: membrane fouling, which greatly lowers its effectiveness. This is caused by organics, inorganic substances, and microorganisms clogging the pore and polluting the membrane surface. The increase in membrane pollution greatly lowers purification effectiveness. Controlling membrane fouling is critical in ensuring the efficient and stable operation of ceramic membranes for water treatment. This review analyzes four mechanisms of ceramic membrane fouling, namely complete blocking, standard blocking, intermediate blocking, and cake filtration blocking. It evaluates the mechanisms underlying ceramic membrane fouling and summarizes the progress in approaches aimed at controlling it. These include ceramic membrane pretreatment, ceramic membrane surface modification, membrane cleaning, magnetization, ultrasonics, and nanobubbles. This review highlights the importance of optimizing ceramic membrane preparation through further research on membrane fouling and pre-membrane pretreatment mechanisms. In addition, combining process regulations with ceramic membranes as the core is an important research direction for ceramic membrane-based water treatment.     

滤膜过滤 微波干燥法快速测定水中悬浮物

采用滤膜过滤微波干燥技术,建立了水中悬浮物的快速测定方法。以0.45μm硝酸乙酸纤维素(CN-CA)滤膜为过滤介质,采用变功率连续加热模式,空白湿滤膜在10 min内恒重(900 W/5 min+500 W/5 min),附有悬浮物的湿滤膜在13 min内恒重(900 W/8 min+500 W/5 min)。选择不同质量浓度的高岭土标准样品和不同类别的实际样品进行方法性能测试,结果表明,该方法检出限为5 mg/L,相对标准偏差(RSD)为2.7%~7.1%,相对误差为2.0%~5.0%,采用该方法与采用标准方法《水质悬浮物的测定重量法》(GB 11901—89)测定实际样品的结果吻合。该方法显著缩短了水中悬浮物测定的分析时间,精密度和准确度能够满足分析要求,可用于地表水及一般工业排放废水中悬浮物质量浓度的快速测定。     

室内空气净化技术

概述了室内空气污染的类型 ,全面介绍了目前各种室内空气净化技术及其进展 ,并且分析了各技术的优缺点。此外 ,提出将膜分离与光催化技术相结合 ,能克服当前各种技术的局限性的构想。这一组合技术可能成为今后该领域研究的一个重要方向     

生物膜接触氧化法处理苯胺废水

以AN3菌和硝化类细菌构成的复合生物膜降解苯胺 ,研究挂膜过程中苯胺代谢产物的变化情况、生物膜内异养菌与硝化类细菌生态分布情况 ,以及水质条件对苯胺代谢速率的影响 .结果表明 ,挂膜期间苯胺中的氮首先被降解成氨 ,然后进一步生成亚硝酸根或硝酸根 .反应器内的稳定生物膜主要由AN3菌构成 ,但靠近出水位置生物膜中的硝化类细菌密度较进水位置高 10 0倍以上 .生物膜代谢的最佳pH值范围是 6 9— 7 5 .重金属离子 ,尤其是Hg2 ,通常会对生物膜的代谢活性产生抑制作用