生物除锰技术研究进展与应用

文章简要阐述了生物除锰的机理,重点介绍生物除锰的工艺流程和应用,包括以生物滤池为核心的单极/多级工艺、复合MF/UF中空纤维膜工艺以及用于处理矿山废水的人工湿地工艺;同时介绍了国内外生物除锰的研究动态,如:同时去除NH4+、Fe、Mn的研究、生物滤池运行模式的研究等。分析了目前存在的问题,并对今后生物除锰的研究方向提出了一点看法。     

Enhanced atrazine removal using membrane bioreactor bioaugmented with genetically engineered microorganism

Bioaugmentation with genetically engineered microorganisms (GEMs) in a membrane bioreactor (MBR) for enhanced removal of recalcitrant pollutants was explored. An atrazine-degrading genetically engineered microorganism (GEM) with green fluorescent protein was inoculated into an MBR and the effects of such a bioaugmentation strategy on atrazine removal were investigated. The results show that atrazine removal was improved greatly in the bioaugmented MBR compared with a control system. After a start-up period of 6 days, average 94.7% of atrazine was removed in bioaugmented MBR when atrazine concentration of influent was 14.5 mg/L. The volumetric removal rates increased linearly followed by atrazine loading increase and the maximum was 65.5 mg/(L·d). No negative effects were found on COD removal although carbon oxidation activity of bioaugmented sludge was lower than that of common sludge. After inoculation, adsorption to sludge flocs was favorable for GEM survival. The GEM population size initially decreased shortly and then was kept constant at about 10⁴–10⁵ CFU/mL. Predation of micro-organisms played an important role in the decay of the GEM population. GEM leakage from MBR was less than 10² CFU/mL initially and was then undetectable. In contrast, in a conventionally activated sludge bioreactor (CAS), sludge bulking occurred possibly due to atrazine exposure, resulting in bioaugmentation failure and serious GEM leakage. So MBR was superior to CAS in atrazine bioaugmentation treatment using GEM.     

好氧颗粒污泥膜生物反应器的研究进展

综述了好氧颗粒污泥膜生物反应器(MBR)在废水生物处理中的研究进展,着重介绍了MBR中好氧颗粒污泥的特性、好氧颗粒污泥对氨氮的去除特性及其对膜污染控制的特性,并在此基础上展望了好氧颗粒污泥MBR技术的发展方向。     

烷基膦酸载体液膜中Cd(II)的传输

采用内耦合大块液膜分离技术,通过考察料液相pH值、温度、载体浓度以及解析相组成对Cd(II)迁移速率的影响,研究了以烷基膦酸为流动载体的液膜中镉的迁移规律,并建立了渗透系数与pH值、温度以及载体浓度之间的关系方程.结果表明,Cd(II)以CdR22HR(Kex值为3.58106)配合物形式在液膜中传输,增加载体浓度或升高温度,迁移速率明显升高.最佳传质条件为料液相pH值4.5～5.1、载体浓度5.0%～7.5%、温度298～308K.     

UF膜与混凝粉末活性炭联用处理微污染原水

采用混凝、粉末活性炭和UF膜分离的联用技术对黄浦江原水进行试验 ,结果表明 ,混凝、粉末活性炭可有效地去除溶解性有机物 .混凝处理主要去除大分子量的有机物 ,粉末活性炭主要去除低分子量的有机物 .混凝、粉末活性炭还能有效地去除三氯甲烷生成潜能 (THMFP) ,对于低分子量的THMFP ,混凝去除效果很差 ,而粉末活性炭去除很好 .试验还表明 ,混凝、粉末活性炭还可大大降低膜的滤饼层阻力 ,当混凝剂投加量为 4mg/L时 ,膜的滤饼层阻力最小 .     

活性炭-纳滤膜工艺去除饮用水中总有机碳和Ames致突变物

分别以地表水和地下水为水源的水厂出水为研究对象 ,探讨活性炭 纳滤膜工艺对饮用水中总有机碳和Ames致突变物的去除效果及机理 .结果表明 ,活性炭的吸附作用受其本身性质和有机物特性影响较大 ,去除能力有限 ,但它可作为纳滤的预处理 ,确保膜进水符合要求 ;纳滤则可将水中总有机碳和Ames致突变物大部分去除 ,使TA₉₈及TA₁₀₀菌株在各试验剂量下的MR值均小于 2 ,Ames试验结果均完全呈阴性 ,确保了饮用水的安全性 .两者的组合是获得优质饮用水的有效处理工艺 .     

膜萃取处理水溶液中镉、锌离子的工艺

以P204+正庚烷为萃取剂,将中空纤维膜萃取技术用于处理水溶液中镉离子、锌离子.研究了两相流速、初始浓度及溶液pH等因素对传质系数和萃取率的影响,计算了膜萃取器的传质单元高度(HTU)_w,同时还研究了萃取剂的再生问题.实验结果表明,在低浓度下(＜500 mg/L),平衡分配系数较大,传质阻力主要是在水相;在初始浓度较高时(＜2000mg/L),由于分配系数较小,三项传质阻力均不可忽略;在初始浓度很高时(＞2000mg/L),传质由有机相和膜相阻力控制.实验还表明通过膜器串联可以实现萃取剂的再生.对于稀溶液(＜200mg/L),中空纤维膜萃取可以使水溶液中金属离子浓度减小2个数量级,通过计算,中空纤维膜萃取器(HTU)_w在15～30cm之间,大大低于传统的萃取塔.     

Changes in fetal heart rate pattern after intrauterine paracentesis in one twin with meconium peritonitis

We report a case of in utero paracentesis of ascites in a fetus with meconium peritonitis due to volvulus at 34 weeks which resulted in the correction of an abnormal fetal heart rate pattern and enabled vaginal delivery by preventing abdominal dystocia. The intrauterine intervention also helped to establish the diagnosis and potentially reduced the respiratory compromise after birth. Copyright © 2001 John Wiley & Sons, Ltd.     

First-trimester fetal sex determination in maternal serum using real-time PCR

An Erratum has been published for this article in Prenatal Diagnosis 22(13) 2002, 1241. Fetal sex prediction can be achieved using PCR targeted at the SRY gene by analysing cell-free fetal DNA in maternal serum. Unfortunately, the results reported to date show a lack of sensitivity, especially during the first trimester of pregnancy. Therefore, determination of fetal sex by maternal serum analysis could not replace karyotype analysis following chorionic villus sampling. A new highly sensitive real-time PCR was developped to detect an SRY gene sequence in maternal serum. Analysis was performed on 121 pregnant women during the first trimester of pregnancy (mean gestational age: 11.8 weeks). Among them, 51 had at least one previous male-bearing pregnancy. Results were compared with fetal sex. SRY PCR analysis of maternal serum was in complete concordance with fetal sex. Among the 121 pregnant women, 61 were bearing a male fetus and 60 a female fetus. No false-negative results were observed. Furthermore, no false-positive results occurred, even though 27 women carrying a female fetus during the current pregnancy had at least one previous male-bearing pregnancy. This study demonstrates that a reliable, non-invasive sex determination can be achieved by PCR analysis of maternal serum during the first trimester of pregnancy. This non-invasive approach for fetal sex prediction should have great implications in the management of pregnant women who are carriers of an X-linked genetic disorder. Prenatal diagnosis might thus be performed for male fetuses only, avoiding invasive procedures and the risk of the loss of female fetuses. Copyright © 2001 John Wiley & Sons, Ltd.