SBBR工艺中亚硝酸型同步硝化反硝化的过程控制

采用序批式生物膜反应器（SBBR）,在生物膜培养驯化初期实现了亚硝酸盐硝化,通过调节曝气量控制系统内的溶解氧浓度,实现了SBBR工艺中的亚硝酸型同步硝化反硝化生物脱氮,出水中亚硝酸盐累积率（NO2^--N／NO2^--N）达到90％左右,TN低于8mg·L^-1,去除率为71．4％～85．6％。为了实现SBBR工艺中亚硝酸型同步硝化反硝化的过程控制,考察了亚硝酸型同步硝化反硝化生物脱氮过程中DO、pH和ORP的变化规律。试验结果表明,DO、pH和ORP的变化规律与反应器内COD的降解和“三氮”的转化有良好的相关性,并在不同温度条件下的亚硝酸型同步硝化反硝化硝化过程中具有良好的重现性,可以依据DO、pH和ORP在变化曲线上的特征点作为SBBR法亚硝酸型同步硝化反硝化的过程控制参数。     

溶解氧对膜生物反应器硝化反硝化的影响

实验采用一体式膜生物反应器处理生活污水，考察了溶解氧对膜生物反应器同步硝化反硝化作用的影响，同时对膜生物反应器中同步硝化反硝化机理进行了详细的分析。结果表明，反应器对NH3-N、TN的去除率受DO的影响较大，当HRT为6h，进水pH值为7．0～8．5，反应器温度为7-13℃，DO为1.5mg／L左右时，系统对NH3-N、TN的去除率分别在97％和92％以上，达到了同步硝化反硝化的运行条件。     

溶解氧和游离氨对短程硝化启动的影响及调控

通过连续流反应短程硝化过程中溶解氧和游离氨对亚硝酸盐积累的影响研究,采用两组平行反应器进行对比。结果表明连续流工艺在城市生活污水的处理中,常温（25℃）低氧（1.5～2.5 mg/L）条件下能够快速启动短程硝化,FA质量浓度在20～40 mg/L对硝酸菌形成抑制,对亚硝酸菌的生长没有抑制,DO质量浓度调控在0.5～1.0 mg/L左右适宜范围内,可以实现亚硝酸盐积累并能获得较高的氨氮去除率。为连续流短程硝化同步反硝化的运行和调控提供了理论基础。     

移动床生物膜反应器中同步硝化反硝化的实现及动力学分析

以低COD/N人工模拟废水为基质,研究移动床生物膜反应器(MBBR)内同步硝化反硝化(SND)过程。进水COD和NH4+-N的质量浓度分别为200 mg/L和40 mg/L,以K1型填料为载体(填充率为40%),DO控制在3~4mg/L,20 d后有稳定的生物膜形成。生物膜完全成熟后,每个填料上平均生物膜量为33.5 mg,出水COD和NH4+-N去除率平均分别达86.68%和97.25%,NO2--N基本无累积,NO3--N的质量浓度均保持在5 mg/L以下,TN去除率在后期最高达90.6%,计算得到SND率达91.66%,结果证实在单一反应器内实现了良好的同步硝化反硝化过程。动力学模拟得出同步硝化反硝化过程中的NO3--N饱和常数为5.83 mg/L,大于单级反硝化过程中的硝酸盐氮饱和常数。     

低能耗条件下紊动床生物膜法与活性污泥法的效果比较

研究了在相同的较低能耗条件下紊动床生物膜反应器与活性污泥反应器的运行效果。结果表明：当负荷（1．2kgCOD／m^3·d，0．12kgNH^＋4-N／m^3·d）相同时，在保证2个反应器内2-3mgDO／L的相同曝气量条件下，紊动床生物膜反应器的COD平均去除率为90．6％，接近活性污泥法的91．5％；但氨氮去除率不稳定且平均仅为51．3％，低于活性污泥反应器的97、8％。其原因可能是由于生物膜内DO限制导致的硝化过程受阻，以及生物膜脱落导致的紊动床反应器内悬浮与附着生物量浓度周期性的变化。另一方面，紊动床生物膜反应器内污泥的表观产率为0．22kgVSS／gCOD，低于活性污泥反应器的0．45kgVSS／gCOD，因而剩余污泥量明显少于后者。     

不同曝气控制方式对SBR短程硝化特性的影响

分别采用恒定鼓风量[0.4m_(空气)~3/(m_水~3·h)]和恒定DO(0.5mg/L)的连续曝气控制方式,通过控制温度为30±1℃、pH值为7.9~8.2,研究两种曝气控制方式对于低C/N城市污水短程硝化的特性。结果表明:恒定曝气量[0.4m_(空气)~3/(m_水~3·h)]实现稳定短程硝化的时间明显快于恒定DO(0.5 mg/L)的曝气控制方式,而且恒定曝气量实现稳定的亚硝酸盐积累率达95%以上,明显地高于恒定DO(0.5 mg/L)的曝气控制方式的NO_2-N积累率85%,恒定曝气量[0.4 m_(空气)~3/(m_水~3·h)]的控制方式短程硝化的曝气控制时间宜控制为4 h,而恒定DO(0.5 mg/L)的控制方式短程硝化的曝气控制时间宜控制为3 h。     

复合式膜生物反应器内的同步硝化反硝化研究

研究了半软性填料膜生物反应器内的同步硝化反硝化现象及机理,考察了DO,C/N对有机物和氨的去除效果以及对同步硝化反硝化的影响。试验结果表明,反应器内存在较好的同步硝化反硝化效果。进水COD为800mg／L左右,pH为7．0-8．0,HRT为10h,温度为25℃时,DO为2．5mg／L左右,C／N为20左右的条件下同步硝化反硝化效果最好,且COD,NH4^＋-N,TN去除率都可以达到90％以上。     

亚硝酸型半硝化影响因素的试验研究

在成功完成亚硝酸型半硝化反应器启动的基础上,初步研究了pH、温度、FA、有机质及DO等对亚硝酸型半硝化反应过程的影响程度并确定各因素的最佳控制范围,得出亚硝酸型半硝化反应pH在8．0-8．5、温度范围为25-30℃、C／N为1．96、溶解氧浓度小于0.4mg／L时反应达到最佳状态,这为今后亚硝酸型半硝化一厌氧氨氧化脱氮技术深入的研究创造了条件。     

短程硝化反硝化影响因素分析

通过介绍短程硝化反硝化的脱氮机理,分析了温度、DO浓度、游离氨浓度、游离亚硝酸浓度、pH值、泥龄及有机物浓度7个方面对于短程硝化反硝化的影响,探讨如何控制这些影响因素来达到亚硝酸盐的积累,最终实现短程硝化反硝化。提出了一些常用脱氮工艺进行短程硝化反硝化的控制参数,并展望了今后研究的发展方向。     

基于DO和ORP的短程硝化SBR控制方法研究

对在污水处理过程中,短程硝化-反硝化面临着亚硝酸氧化菌(NOB)增殖导致系统运行问题,研究运行了一个短程硝化-反硝化序批式活性污泥反应器(SBR),以溶解氧(DO)含量和氧化还原电位(ORP)作为控制参数,利用控制系统调节好氧硝化和缺氧反硝化的反应时间,以实现氮的去除并抑制NOB的生长。结果表明,在实验条件下(温度29～30℃,pH为8～9,污泥停留时间14 d),处理的高NH4+-N含量(质量浓度500～750 mg/L)的废水经过2个月的运行,成功地抑制了NOB的生长,并启动了短程硝化-反硝化SBR。SBR出水中NH4+-N的质量浓度低于1 mg/L,NO2--N的积累率(NAR)维持在98%以上。     

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.     

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。     

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.