氨氮对低碳高氮垃圾渗滤液短程硝化效能影响试验研究

研究以开发低碳高氨氮质量浓度的老龄化垃圾渗滤液自养脱氮技术为目标,探讨高NH3-N质量浓度对其短程硝化效能的影响.结果表明,在温度为30℃,DO质量浓度为2.5mg-L-1,进水pH为8.0,NH3-N负荷为3.0kg·m-3·d-1的条件下,SBBR反应器短程硝化能承受的进水NH3-N质量浓度为3000mg·L-1,相应FA抑制质量浓度为179.56mg·L-1,系统的NH3-N去除率为56.7%.     

高氮垃圾渗滤液SBBR生物脱氮工艺特性研究

应用序批式生物膜反应器(SBBR)处理实际垃圾渗滤液,在DO质量浓度分别为0.45mg·L-1和1.19mg·L-1的条件下,研究了系统的有机物、氨氛和总氮的去除特性以及游离氨(FA)、DO对系统同步硝化反硝化(SND)类型的影响.经过250d试验研究表明,SBBR系统能够稳定高效地同步去除渗滤液内高浓度有机物和高浓度氨氮.在初始COD为122～2 385 mg·L-1的情况下,出水COD为23～390 mg·L-1,具有平均86.8%的去除率,有机物最大去除速率为20.44 kgCOD·m-2载体·d-1.在初始NH4+-N质量浓度为40～396.5 mg·L-1的情况下,出水NH4+-N质量浓度为0～41.2 mg·L-1,最大硝化速率为2.87 kgN·-2载体·d-1,SBBR系统内发生了明显的SND现象,TN平均去除率分别为73.8%(p(DO)=0.45 mg·L-1)和30%(p(DO)=1.19 mg·L-1)左右.当FA质量浓度在1.5～1 1.6 mg·L-1范围内时,系统中共存有硝酸型SND和亚硝酸性SND;当FA从18.6 mg·L-1增加到56 mg·L-1,系统中形成稳定的亚硝酸SND.FA是影响系统SND类型的主要因素,DO可促进亚硝酸性SND向硝酸型SND的转化.     

A/A/O氧化沟中DO对SND脱氮的影响研究

采用A/A/O氧化沟反应器处理低碳源城市污水,考察了DO浓度对硝化及反硝化过程的影响,分析DO浓度与同步硝化反硝化(SND)脱氮反应速率的关联性。研究发现,较适宜的DO浓度范围为1.0~1.5 mg/L,DO浓度降低会影响氨氮降解,硝化效果急剧变坏的临界溶解氧浓度范围为0.8~1.5 mg/L,而DO浓度过高则不利于主反应区SND脱氮,同时较多的溶解氧内回流至缺氧区会破坏其脱氮环境。当DO<2.0 mg/L时,NO-3-N生成速率与NH+4-N氧化速率之比与DO之间线性关系较好;SND随着DO浓度的升高而受到抑制,当DO>2.0 mg/L时,NO-3-N生成速率与NH+4-N氧化速率之比与DO之间基本不呈线性关系,系统中基本不发生SND反应。     

短程硝化耦合厌氧氨氧化工艺处理低C/N比生活污水

为快速实现低C/N比生活污水高效低耗稳定脱氮,在常温条件下,对短程硝化-厌氧氨氧化工艺的启动及脱氮性能进行研究,在常温,高DO(2.5 mg·L-1)条件下,采用实时控制结合神经网络模型预测控制可快速启动短程硝化,亚硝积累率达到95%以上。由于生物膜的独特结构可为厌氧氨氧化(Anammox)菌提供良好的厌氧环境,因此选用生物滤池来实现厌氧氨氧化,启动期间克服了温度变化的影响,第173天后,NH4+-N和NO2--N去除率达到90%以上,TN去除率达到80%,Anammox滤池成功启动。后续将短程硝化与厌氧氨氧化耦合,通过逐步提高滤速启动耦合系统,Anammox滤池滤速可提高到0.5 m·h-1,总氮容积负荷达到0.75 kg·m-3·d-1。系统出水TN平均浓度为8 mg·L-1,实现了短程硝化耦合厌氧氨氧化工艺稳定高效地处理生活污水。     

O1/A1/O2/A2工艺处理焦化废水试验研究

通过对短程硝化反硝化工艺的研究,开发了好氧/厌氧/好氧/缺氧(O1/A1/O2/A2)生物脱氮新工艺并用于焦化废水的处理。考察了NH4+-N、COD、TN对反应器运行效果影响。结果表明,当进水COD平均为3 012.9 mg/L,NH4+-N、TN、挥发酚、总氰平均质量浓度分别为590.5、608.4、361.8、34.5 mg/L;出水COD平均为81.7 mg/L,出水NH4+-N、TN、挥发酚、总氰的平均质量浓度分别为0.1、9.9、0.1、0.1 mg/L,出水指标达到国家污水综合排放一级标准,A/O工艺处理这种焦化废水TN偏高,而用O1/A1/O2/A2工艺可以解决这一问题,实现了TN脱除。考察了温度、DO、pH对短程硝化影响。结果表明,在DO质量浓度为1.0～1.5 mg/L、温度在30～35℃、pH 7.5～8.0,系统能够进行稳定短程硝化反硝化。     

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。     

复合铁酶促活性和普通活性污泥系统低温启动对比研究

对比研究了＜15℃的低温条件下复合铁酶促活性污泥和普通活性污泥系统的启动过程.结果表明,向2个平行试验装置投加等量的接种污泥,两系统在以下工况条件经32 d均成功启动:HRT为20 h,污泥龄30d,进水体积流量与回流污泥体积流量比200％,DO的质量浓度2.0～4.0 mg·L-1;培养过程中,复合铁酶促活性污泥系统比普通活性污泥系统污泥含量更高,系统启动速度快;对COD、NH3-N、PO43--P的平均去除率较普通活性污泥系统分别提高6.10.11个百分点;脱氢酶活性、NH3-N硝化速率、吸磷速率分别提高了5.20 μg·mg-1·h、3.15 mg·L-1.h-1、2.0mg·L-1·h-1,表明复合铁活性污泥系统在低温条件下较普通活性污泥系统具有更高的微生物活性.     

生活污水不同生物脱氮过程中N_2O产量及控制

利用好氧-缺氧SBR反应器和全程曝气SBBR反应器处理生活污水,分别实现了全程、短程和同步硝化反硝化脱氮过程,研究了不同脱氮过程中N2O的产生及释放情况,同时考察了不同DO条件下同步脱氮效率及N2O产生量。结果表明,全程、短程生物脱氮过程中N2O主要产生于硝化过程,反硝化过程有利于降低系统N2O产量。全程、短程、同步硝化反硝化脱氮过程中N2O产量分别为4.67、6.48和0.35mg.L-1。硝化过程中NO2-N的积累是导致系统N2O产生的主要原因。部分AOB在限氧条件下以NH4+-N作为电子供体,NO2-N作为电子受体进行反硝化,最终产物是N2O。不同DO条件下同步硝化反硝化过程中N2O的产生表明:控制SBBR系统中DO浓度达到稳定的同步脱氮效率可使系统N2O产量最低。     

HMBR处理生活污水实现短程硝化反硝化研究

在DO质量浓度为1.5 mg/L、温度为28℃等条件下,NO2--N积累率>50%,系统实现短程硝化。硝化率为77.35%,反硝化率83.25%,SND率64.74%,HMBR实现同步短程硝化反硝化。COD平均去除率为91.61%,NH3-N去除率77.34%,TP去除率45.13%,且膜对COD、TP有截留作用。在系统实现耦合作用后对有机物有去除效果。     

啤酒废水同步脱氮除磷工艺影响因素研究

通过SBR短程硝化反硝化同步脱氮除磷工艺处理模拟啤酒生产综合废水,为达到稳定的COD、NH4+-N和TP的去除及NO2--N的积累,对该工艺的影响因素进行了研究.结果表明,工艺的稳定运行是由进水COD、pH、DO、温度和MLSS等因素共同作用的结果,其中控制较低的DO的质量浓度(＜0.5 mg·L-1)是实现NO2--N积累的关键因素之一;过低或过高的进水pH、COD均会影响该工艺的正常运行.温度及MLSS含量会影响氨氧化过程与反硝化过程的反应速率,但不是系统稳定运行的决定因素.当DO的质量浓度为0.3～0.5 mg·L-1、进水COD低于1 100 mg· L-1、pH为7.2～8.4,在12～25℃可获得稳定的NO2--N积累.     

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.     

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。     

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.     

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.     

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.     

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.