焦化废水生物脱氮技术研究进展

焦化废水是一种氨氮和有机物浓度较高的难生化降解的有机废水,本文介绍了近年来焦化废水生物脱氮处理技术的特点及研究进展,包括传统的硝化反硝化工艺及新型的短程硝化反硝化、同时硝化反硝化以及厌氧氨氧化工艺,最后指出目前生物脱氮研究的主要方向。     

新型污水脱氮工艺研究进展

阐述了污水脱氮的反应工艺,综述对比了厌氧氨氧化(ANAMMOX)工艺、短程硝化反硝化(SHARON)工艺、限氧自养硝化-厌氧反硝化(OLAND)工艺、短程硝化-厌氧氨氧化(SHARN-ANAMMOX)工艺和单相CANON(SHARON-ANAMMOX)这五种生物脱氮工艺工作原理,脱氮效果和工艺的优缺点。     

污水生物脱氮除磷新技术

首先简单阐述了生物脱氮除磷机理,然后重点介绍了目前几种污水生物处理新技术:厌氧/缺氧/好氧MBR工艺、短程硝化反硝化工艺和倒置A2/O工艺等,最后对污水生物脱氮除磷技术的发展进行了展望,并提出了一些建议。     

焦化污水生物脱氮装置回流比的选择

目前,国内采用的焦化污水生物脱氮工艺,从循环方式来看,可分为内循环法和外循环法两种。从工艺形式上分有Ａ－Ｏ法、Ａ－Ａ－Ｏ法、ＳＢＲ法以及最新发展起来的Ａ－Ｏ－Ｏ法等。但无论采用那种脱氮工艺,都需要将硝化后含高浓度ＮＯｘ－Ｎ的上清液或泥水混合液回流到反硝化段进行脱氮,而这种回流量与处理水量之比就是生物脱氮工艺中的回流比,通常以Ｒ表示。根据理论,在完全进行反硝化的情况下,回流比与系统总氮去除率有如下关系：η＝Ｒ／（１＋Ｒ）,见图１。从图１可看出,回流比直接影响着系统的总氮去除率。回流比越大,系统的总…     

回流比对厌氧氨氧化与反硝化耦合脱氮性能的影响

为提高厌氧氨氧化与反硝化耦合系统的脱氮性能,试验开展了回流比对厌氧氨氧化与反硝化耦合脱氮的影响研究。试验通过设置回流比分别为0%、100%、150%、200%和300%,测定反应系统氨氮、硝氮去除率,确定厌氧氨氧化与反硝化耦合工艺运行的最佳回流比。结果表明:回流比为150%为最适回流比,此时氨氮去除率达36%,硝氮去除率达50%,耦合系统运行平衡稳定。     

高回流比对序批式生物膜反应器脱氮性能的影响

硝化液回流是污水生物脱氮工艺实现前置反硝化脱氮的重要手段，通常回流比为200%～400%。本文研究了高回流比对序批式生物膜反应器(SBBR)脱氮性能的影响，结果表明，在回流比为300%、1 000%、3 000%三种条件下回流比为3 000%的总氮去除率最高，稳定运行期间TIN平均去除率为98.69%±0.81%，同时也使NH₄⁺-N得以完全氧化。推测在高回流比引起的强对流环境下，生物膜内传质效率得以加强，从而提高了同步硝化反硝化(SND)效果。本研究结果对集成分散式污水处理装置的研发及改善市政污水处理生物脱氮效率具有重要意义。     

超低碳氮比污水脱氮除磷技术控制与研究

传统的AAO生物脱氮除磷工艺处理超低C/N比城市污水时,其脱氮除磷效果很差,考察了低温环境下启动短程硝化反硝化的可行性,交替AAO短程硝化反硝化工艺为超低C/N的城市污水处理提供了一种崭新的生物脱氮除磷工艺.同时为进一步解决进水COD严重不足的情况,在原厂不增设构筑物的前提下,充分挖掘优先利用污水处理厂内碳源技术,通过采用回流活性污泥(RAS)侧流水解发酵进一步补充碳源.     

新型生物脱氮工艺中N_2O产生及释放研究进展

N_2O是重要的温室气体之一,微生物作用是大气中N_2O的主要产生源.大量污水脱氮工艺的研究及应用表明,生物脱氮过程中N_2O主要产生于微生物的硝化和反硝化代谢过程.近年来,许多新型生物脱氮工艺已逐步应用到实际污水处理中.本文阐述了硝化、反硝化阶段N_2O的产生机理,并分析了传统生物脱氮工艺及同步硝化反硝化、 短程硝化-反硝化、厌氧氨氧化、反硝化除磷等新型工艺中N_2O的产生量及其影响因素,提出在追求高脱氮效率的同时,优化系统运行条件及种群结构,可在一定程度上降低系统N_2O的产量及危害,为新型生物脱氮工艺实际运行过程中降低N_2O的产量提供参考.     

污水生物脱氮新技术研究现状与发展方向

综述了国内外生物脱氮领域最近开发出的短程硝化反硝化、同步硝化反硝化和厌氧氨氧化等新技术,指出了这些新技术的特点以及存在的不足.重点论述了目前实现短程硝化反硝化生物脱氮技术的方法,如控制温度、溶解氧浓度和pH值,并提出应用序批式反应器(SBR)实现短程硝化-反硝化生物脱氮工艺今后研究的发展方向和开发应用的前景.建议加强同步硝化反硝化和厌氧氨氧化生物脱氮工艺反应机理方面的研究.     

生物脱氮除磷新技术进展

近年来研究发现了突破传统脱氮除磷原理的同时硝化反硝化现象、反硝化除磷现象、短程硝化反硝化脱氮工艺、厌氧氨氧化工艺。这些新技术和工艺克服了传统污水生物脱氮除磷技术所存在的不能使脱氮和除磷同时达到最佳效果的缺点。重点从新技术的基本原理及其体现出来的优势以及相关工艺等几方面综述这四种新技术和工艺。     

Sapindaceae,cyanolipids, and bugs

Scentless plant bugs (Heteroptera: Rhopalidae) are so named because adults of the Serinethinae have vestigial metathoracic scent glands. Serinethines are seed predators of Sapindales, especially Sapindaceae that produce toxic cyanolipids. In two serinethine species whose ranges extend into the southern United States,Jadera haematoloma andJ. sanguinolenta, sequestration of host cyanolipids as glucosides renders these gregarious, aposematic insects unpalatable to a variety of predators. The blood glucoside profile and cyanogenesis ofJadera varies depending on the cyanolipid chemistry of hosts, and adults and larvae fed golden rain tree seeds (Koelreuteria paniculata) excrete the volatile lactone, 4-methyl-2(5H)-furanone, to which they are attracted.Jadera fed balloon vine seeds (Cardiospermum spp.) do not excrete the attractive lactone. Loss of the usual heteropteran defensive glands in serinethines may have coevolved with host specificity on toxic plants, and the orientation ofJadera to a volatile excretory product could be an adaptive response to save time.Mention of a commercial product does not consititute an endorsement by the USDA.     

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.     

Many Drugs of Abuse May Be Acutely Transformed to Dopamine,Norepinephrine and Epinephrine In Vivo

It is well established that a wide range of drugs of abuse acutely boost the signaling of the sympathetic nervous system and the hypothalamic–pituitary–adrenal (HPA) axis, where norepinephrine and epinephrine are major output molecules. This stimulatory effect is accompanied by such symptoms as elevated heart rate and blood pressure, more rapid breathing, increased body temperature and sweating, and pupillary dilation, as well as the intoxicating or euphoric subjective properties of the drug. While many drugs of abuse are thought to achieve their intoxicating effects by modulating the monoaminergic neurotransmitter systems (i.e., serotonin, norepinephrine, dopamine) by binding to these receptors or otherwise affecting their synaptic signaling, this paper puts forth the hypothesis that many of these drugs are actually acutely converted to catecholamines (dopamine, norepinephrine, epinephrine) in vivo, in addition to transformation to their known metabolites. In this manner, a range of stimulants, opioids, and psychedelics (as well as alcohol) may partially achieve their intoxicating properties, as well as side effects, due to this putative transformation to catecholamines. If this hypothesis is correct, it would alter our understanding of the basic biosynthetic pathways for generating these important signaling molecules, while also modifying our view of the neural substrates underlying substance abuse and dependence, including psychological stress-induced relapse. Importantly, there is a direct way to test the overarching hypothesis: administer (either centrally or peripherally) stable isotope versions of these drugs to model organisms such as rodents (or even to humans) and then use liquid chromatography-mass spectrometry to determine if the labeled drug is converted to labeled catecholamines in brain, blood plasma, or urine samples.     

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.     

2008～2009年世界塑料工业进展

收集了2008年7月～2009年6月世界塑料工业的相关资料,介绍了2008～2009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、环氧树脂、不饱和聚酯树脂)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。