电极生物膜处理地下水中的硝酸盐氮实验研究

采用电极生物膜法研究处理含硝酸盐氮的地下水.结果表明,温度过低威过高,对反硝化细菌的活性都有一定抑制;m(C)/m(N)为1时能实现总氮与总碳的同时去除,与理论计算的最经济m(C)/m(N)为1.07相近;电流的刺激作用可以提高异养反硝化菌的脱氮效率,其脱氮率和电流之间有大的关系,同时硝酸盐氮的负荷越大,电流要求越高;HRT越长,硝酸盐的去除率越高.     

OAO水生蔬菜型人工湿地工艺对农村无序排放污水中氮磷的去除效果

为了考察OAO水生蔬菜型人工湿地对村落无序排放污水中氮磷的净化效果,户外自然条件下,采用人工模拟试验的方法,在不同水力负荷、进水浓度和C/N比及氮源形式的单因素影响条件下,对湿地进出水中氮磷浓度进行监测。试验结果表明:当水力负荷从0. 1 m~3/(m~2·d)提高到0. 5 m~3/(m~2·d)时,氮磷的去除率呈下降趋势,去除负荷先升高后降低。综合考虑,选取该湿地最佳水力负荷为0. 3 m~3/(m~2·d),此时氨氮、硝态氮、总氮和总磷的去除率分别为70. 17%、88. 48%、69. 13%和75. 33%,相应的去除负荷分别为1. 22、0. 52、1. 5 g/(m~2·d)和0. 098 g/(m~2·d)。在一定的浓度范围内,氨氮、硝态氮、总氮和总磷的去除率随着进水浓度的增加而增加,当超过一定的浓度后,去除率会趋于稳定甚至有所下降。当进水中的C/N由2增加到8时,总氮去除率由35%提高到65%;而当C/N由8增加到20时,总氮去除率仅由65%提高到80%,增加幅度相对较小。当进水中的硝氮比例增加时,总氮的去除率较高。冬季时,湿地对氮磷的去除率有所降低,氮的去除效果降低明显,对磷的去除影响较小。     

蜂窝填料三相流化床去除城市污水中的总氮特性研究

在好氧条件下,构建了蜂窝填料三相流化床,研究了三相流化床去除城市污水中总氮的效果以及氨态氮、亚硝酸盐和硝态氮转化规律.结果表明,当HRT为3h时,三相流化床对总氮去除率为52.61％.氨氮去除率为45.71％,进、出水中的亚硝酸盐和硝酸盐氮质量浓度均较低(进水低于1.12 mg/L,出水低于4.52 mg/L).对剥落...     

竹屑载体生物膜-活性污泥一体化SBR集成工艺的脱氮性能

采用竹屑作为微生物载体构建生物膜-活性污泥一体化系统,系统置于两段进水脉冲式SBR内运行,对低C/N生活污水的脱氮特性进行研究.研究了不同温度、C/N、水力停留时间(HRT)等参数对系统的脱氮性能影响.结果表明,温度为25℃、C/N=4.0、HRT=12 h时,CODCr、总氮、氨氮质量浓度分别从155.35、35.7...     

新型一体式膜生物反应器处理高氨氮、低C/N废水的研究

采用新型一体式膜生物反应器处理高氨氮,低C/N废水.考察了高氨氮、不同进水C/N条件下,反应器对污染物的处理效果,研究了水力停留时间(HRT)和温度对系统稳定性的影响情况.结果表明,当进水氨氮质量浓度为 98.0～150.0mg·L-1,COD/TN为0.8～5.7时,COD、氨氮、TN去除率均随进水C/N的增加而升高,且对TN的去除效果影响最大;温度和HRT都对系统稳定性有一定的影响,低温和较短的HRT都不利于污染物的去除.     

高效反硝化菌株的分离鉴定及功能验证

本实验室通过富集筛选得到一株反硝化细菌LSD1,通过形态观察、生化实验、16Sr DNA序列分析及进化树比对,鉴定该菌株为假单孢菌(Pseudomonas veronii)。该反硝化细菌的最佳碳源为甲醇,初始C/N比为6时脱氮效果最佳。连续进水实验结果显示,该菌株需要6～15 d完成菌种驯化,驯化完成后,进水总氮负荷可提高至500 mg/L,总氮去除率提高至95%以上,出水总氮小于10 mg/L,最优C/N比为3.08。由于该菌株具有高效反硝化能力,因此在富营养化水体及废水处理中具有较好应用前景。     

碳管膜曝气膜生物反应器处理高浓度氨氮污水的研究

对以煤基微孔碳管为组件的碳膜曝气膜生物反应器(MABR)处理高浓度氨氮污水进行了实验研究。碳膜同时起到生物膜载体和无泡曝气的双重作用。氧气和营养物分别从生物膜的两侧进入膜内。本实验进行150d,分阶段对不同溶解氧(DO)条件,不同进水浓度和不同水力停留时间(HRT)下,MABR的硝化、反硝化同时去除COD的性能进行研究。研究表明,在溶解氧为0.8 mg/L的条件下,TN有最佳去除效果,NH3-N、TN和COD去除率分别为87.88%、86.5%和87.64%。NH3-N的去除率随DO的升高而增大,去除率可达99.7%,但更高的溶解氧(>1.6 mg/L)对去除率影响甚微。高进水负荷实验于16d内,进水NH3-N浓度增大4倍,至214.25 mg/L,去除率仍保持92%以上。HRT由20h逐渐降低至8h时,去除率略有降低,但去除负荷增长2倍以上。说明该MABR装置有良好的脱氮能力和较高负荷下的污水处理能力。     

倒置A~2/O工艺生活污水脱氮效果研究

采用倒置A2/O工艺处理生活污水中的氮,研究进水C/N、溶解氧、回流比这三个因素对倒置A2/O工艺脱氮效果的影响;分析好氧段、缺氧段、厌氧段各阶段,总氮、氨氮、硝酸盐氮、亚硝酸盐氮的转化情况,以确定实现最佳脱氮的效果。结果表明:最佳进水C/N比为400,好氧段溶解氧为2.0mg/L,污泥回流比为75rad时,脱氮效果最好。通过对不同格室氮形态的研究表明,亚硝酸盐主要在缺氧段去除,而在厌氧段和好氧段出现了亚硝酸盐的累积;对于氨氮的去除主要发生在好氧段,其去除率可占到总去除率的70%以上。     

影响膜生物反应器处理效果的因素研究

通过连续运行MBR研究了DO、HRT、C／N对膜生物反应器处理效果的影响。试验结果表明：当CODMn在2．1—12．8mg／L范围内,C／N为10：1,HRT为5h时,当DO为1mg／L时,TN的去除率达到最大值56．43％,而DO过高或过低都会影响同步硝化反硝化的进行;控制DO为1mg／L,其余操作条件不变,当HRT为4h,TN的去除率达到最大值57．29％;C／N为20：1时,MBR对水中的CODMn、NH3-N和TN等的去除率均达到较好的处理效果;因此,膜生物反应器的最佳操作条件是DO为1mg／L,HRT为4h,C／N为20：1。     

三种MBR脱氮工艺与稳定运行性能的比较

对比春夏季时AO-MBR、AO-MBR(长HRT)、AAO-MBR在处理实际生活荇水时对污染物的处理能力和膜污染情况。结果表明,三个工艺对COD的去除均维持在较高水平,能够很好地抵抗进水的冲击负荷对系统的影响,出水COD_(Cr)始终能够维持在50 mg/L以下。在对氮的去除方面,发现在春夏季,长HRT的AO-MBR和AAO-MBR均能得到更好的脱氮效果,在进水TN为30~60 mg/L时,出水TN能够维持在10 mg/L以下;说明延长HRT能够有效提高MBR的脱氮效率。     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.     

2007～2008年世界塑料工业进展

收集了2007年7月～2008年6月世界塑料工业的相关资料,介绍了2007～2008年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况.按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯·硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、不饱和聚酯树脂、环氧树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍.     

2005～2006年国外塑料工业进展

收集了2005年7月～2006年6月国外塑料工业的相关资料,介绍了2005—2006年国外塑料工业的发展情况。提供了世界塑料产量、消费量及全球各类树脂生产量以及各国塑料制品的进出口情况。作为对比,介绍了中国塑料的生产情况。按通用热塑性树脂（聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂）、工程塑料（聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚）、通用热固性树脂（酚醛、聚氨酯、不饱和树脂、环氧树脂）、特种工程塑料（聚苯硫醚、液晶聚合物、聚醚醚酮）的品种顺序,对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。