生物流化床反应器脱氮技术的研究与应用进展

生物流化床技术是废水处理中常采用的生物技术之一。作者介绍了生物流化床脱氮技术的最新研究进展与应用,详细分析了影响生物流化床脱氮效率的主要因素,指出了生物流化床脱氮技术存在的一些急需解决的问题,提出了生物流化床技术今后的发展方向。     

生物流化床用于废水处理的研究

生物流化床技术是普通活性污泥法和生物膜法相结合的废水生化处理技术,因其具有处理效率高、容积负荷大、传质速度快、应用范围广等优点而受到广大研究者的关注.介绍了现阶段几种主要的生物流化床--内循环生物流化床、外循环三相流化床及厌氧-好氧复合式生物流化床等,并总结了其在各种废水处理中的应用研究情况,指出了生物流化床技术目前主要存在的问题及今后的发展方向.     

生物流化床技术在水处理领域的研究进展

生物流化床有机结合了生物膜法与活性污泥法的优点,容积负荷大、处理效率高、应用范围广,在废水处理领域有良好的发展前景。介绍了生物流化床技术研究现状,综述了新型流化床工艺的发展情况,包括厌氧-好氧组合工艺、三相逆流化床、与生物膜结合以及芬顿Fenton流化床等新方向,展望了生物流化床技术的发展趋势。     

生物技术及其应用进展

介绍了生物技术在微生物采油、生产化学品、生物补救技术、烟气脱硫、油品生物脱硫等领域的应用进展以及磁化流化床生物转化技术的开发现状     

生物流化床在废水处理中的应用进展

介绍了生物流态化技术在废水处理方面的应用历史与发展概况,对近年来出现的一些新型生物流化床反应器的操作原理和结构特点作了介绍。指出生物流化床应向着降低能耗、适应不同水质的处理需要方向发展。     

好氧生物流化床技术探讨

对好氧生物流化床的特点及工作原理进行了综述,总结了好氧生物流化床的研究现状和好氧生物流化床系统的实际应用,并对好氧生物流化床未来的发展方向进行了分析。     

水处理中生物填料的研究进展

概述了生物填料在5种生物膜法污水处理技术——生物滤池、生物转盘、生物接触氧化法、生物流化床、移动床生物膜反应器中的研究进展和应用现状,并探讨了生物填料的发展方向。     

生物流化床污水处理技术进展与展望

生物流化床是一种高效的、适应性广的新型污水处理技术,它是一个分布参数、非线性、时变、大滞后和多变量耦合的复杂系统,难以建立精确的数学模型,生物流化床的自动控制已经成为其推广的重要障碍之一。本文在简要介绍生物流化床污水处理技术的工艺特点及发展状况基础上,着重从控制方案、策略方面对其他流化床的控制方法进行总结,并提出生物流化床控制思路,最后分析生物流化床的发展前景,针对目前生物流化床存在的问题,提出未来的发展方向。     

生物流化床的类型及特点

介绍了各种用于废水处理的生物流化床,对其结构组成、特点、适用范围及处理效果进行了分类阐述,重点总结了好氧流化床与厌氧流化床的发展概况,并指出了今后进一步研究与应用生物流化床的努力方向。     

生物三相流化床处理废水特性的基础性研究

1.概 论 废水处理生物三相流化床是将生物、化工与水处理技术有机结合应用于有机废水处理的一种新型装置,它的特点是微生物浓度高、传质速度快,因此具有体积负荷大、反应时间短、处理能力大的优点。日本有关专利已报道了生物三相流化床水处理设备的实际应用情况。国内的研究也非常活跃。这一技术很有可能作为一种脱氮、脱磷新工艺技术而取代其它生物处理技术,它的优越性是:将自然环境水净化加以高密度化组合的净化方法,可以实现系统小型化,降低设备费用;载体的比表面积大,生物浓度高,可     

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.     

Novel polyurethane coating technology through glycidyl carbamate chemistry

Glycidyl carbamate chemistry combines the excellent properties of polyurethanes with the crosslinking chemistry of epoxy resins. Glycidyl carbamate functional oligomers were synthesized by the reaction of polyfunctional isocyanate oligomers and glycidol. The oligomers were formulated into coatings with several amine functional crosslinkers at varying stoichiometric ratios and cured at different temperatures. Properties such as solvent resistance, hardness, and impact resistance were dependent on the composition and cure conditions. Most coatings had an excellent combination of properties. Studies were carried out to determine the kinetics of the curing reaction of the glycidyl carbamate functional oligomers with multifunctional and model amines. Detailed kinetic analysis of the curing reactions was also undertaken. The results indicated that the glycidyl carbamate functional group is more reactive than a glycidyl ether group. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, on October 27–29, 2004, in Chicago, IL.     

Highly moisture-proof polysilsesquioxane coating prepared via facile sol-gel process

A highly moisture-proof polysilsesquioxane coating was obtained from a new bis-silylated precursor, which was synthesized from 3-aminopropyltriethoxysilane (APTES) and m-xylylene diisocyanate (m-XDI) in tetrahydrofuran (THF) and verified by ¹H MAS NMR. For direct comparison purposes, an SiO₂ coating was also prepared by the Stöber method using tetraethoxysilane (TEOS) as the reactant. Interestingly, the coating obtained from the polysilsesquioxane sol exhibited a much higher moisture resistance capability than its counterpart, which was attributed to its more compact feature between nanoparticles as characterized by N₂ absorption experiment and transmission electron microscopy (TEM). Furthermore, its high transparency of about 92% showed potential for application in the protection of optical crystals.     

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.