乙醇型发酵法生物制氢中COD浓度变化对发酵厌氧活性污泥产氢系统的影响

以糖蜜废水为底物,利用连续流搅拌槽式反应器(CSTR)作为反应装置,通过实验在乙醇型发酵情况下,维持其他参数不变,改变反应器内COD浓度,对糖蜜废水厌氧发酵生物制氢进行了研究.结果表明在一定范围内,反应器的产氢产气量随着COD浓度变化成正比,超过某一范围系统即崩溃.     

两相厌氧工艺处理合成制药废水的启动试验研究

设计了两相厌氧系统,以生活污水厂好氧污泥为种泥,对合成制药废水进行启动试验研究。控制水温在(35±1)℃,产酸反应器进水pH在5.5~6.5、产甲烷相进水pH在7.0±0.3,通过交替提高进水COD与增大进水流量提高系统容积负荷(VLR)。经过51 d的启动运行,系统的VLR达到4.7 kg/(m3·d),HRT为36 h,COD去除率达到89.5%。产酸和产甲烷反应器均培养出足量的适于处理该废水的厌氧污泥,表明两相厌氧反应启动成功。     

金银花蒸馏残液中温厌氧发酵试验

采用自制中温厌氧反应器对金银花蒸馏残液进行中温厌氧发酵试验,系统考察了金银花蒸馏残液COD及产甲烷量随厌氧反应时间的变化情况。结果表明,在(37±1)℃的中温反应条件下,经8 h连续运行,产甲烷势较高为0.272 L/g,但COD去除效果不理想,仅为49.5%;向反应器中加入少量铁屑后最终废水COD去除率达到76.6%,但加入铁屑累计产甲烷量变化不大;对4种不同处理条件下的废水厌氧产甲烷过程进行动力学分析,得到最佳反应条件为添加微量元素铁屑,调节p H为中性。可为金银花中药废水处理及资源化利用提供工程设计参考,同时为我国每年多达数百万吨(含水分)中药渣处理提供思路。     

水稻秸秆渗滤床半固态厌氧发酵性能研究

以水稻秸秆为原料，利用自行设计的渗滤床反应器，对比研究了不同温度（20、25、30和35℃）及不同预处理方式（NaOH、生物试剂和沼液）对秸秆厌氧发酵产气性能、物能转化率、发酵后沼液性能和产气成本等方面的影响。实验结果表明：发酵后总固体（TS）质量分数稳定在13%~15%之间，属于半固态厌氧发酵，同时累积产气量与温度、发酵后COD及NH₃-N的变化量均呈极显著正相关。相同温度（20~30℃）条件下，经预处理后的水稻秸秆TS产气率较空白均有所提高；其中沼液预处理效果最为明显，35℃条件下，TS产气率及挥发性固体（VS）产甲烷率分别为154.0和55.2 mL/g，较空白样品分别提高25.1%和52.5%。同时，沼液预处理可显著提升厌氧发酵产气中的甲烷体积分数。各预处理样品TS产甲烷率及VS产甲烷率呈随温度（20~30℃）上升而增加的趋势，但产甲烷提升率随温度的上升而逐渐下降，将系统温度从20℃提升至25℃，各处理产甲烷率可提高90%以上。考虑到沼气工程罐体增温及产能收支平衡等因素，温度控制在25℃是经济性最好的策略模式。从产气成本上分析，自产沼液具有较佳的处理效果和较低的生产成本，每生产1 m³沼气的可变成本1.62元。     

磷酸预处理对芦苇秸秆与牛粪混合厌氧发酵的影响

为研究酸预处理对芦苇秸秆-牛粪混合厌氧发酵的影响,采用6%磷酸对芦苇秸秆进行预处理,并与牛粪混合进行厌氧发酵制沼气实验,同时对酸预处理组和对照组在厌氧发酵过程中产气量、p H、COD以及发酵前后混合原料木质纤维素变化情况进行分析。结果表明,酸预处理提高混合原料发酵的产气量,其总产气量为97.24 m L/g,比对照组的产气量13.69 m L/g高出610.3%;酸预处理组p H更接近中性,表明该系统具有更好的抵御酸化能力和稳定性;酸预处理提高了发酵体系COD的含量,促进发酵原料的降解。研究表明,芦苇秸秆可以作为发酵原料进行再利用,且磷酸预处理可以提高发酵系统缓冲能力和原料利用效率。     

ABR作为产甲烷反应器的两相厌氧工艺的启动特性

用厌氧折流板反应器(ABR)作为两相厌氧工艺的产甲烷反应器进行了启动研究,寻求快速启动的办法。采取先快速提高进水COD浓度,后提高进水量的方式,使产酸相尽快维持在酸性最佳条件下,调节产甲烷相进水pH值在6.8～7.2之间,从而保证产甲烷相在最佳条件下,经过35 d的启动过程,分别在产酸反应器和产甲烷反应器中出现了性能良好的絮状活性污泥和厌氧颗粒污泥。启动后第35天,当两相反应器水力停留时间为14 h,COD负荷为36.48 kg/(m3.d)时,系统整体COD去除率达到98.0%。     

复合式厌氧折流板反应器启动中的相分离特性

采用复合式厌氧折流板反应器(HABR)处理模拟啤酒废水,考察了其快速启动过程中的处理效能及相分离特性。结果表明:HABR可在33 d内完成启动,对COD的去除率92%;pH值在反应器前后端分别呈酸性和中性,促进了产酸菌和产甲烷菌的分离;厌氧系统内挥发性脂肪酸(VFAs)质量浓度的变化可以用于判断产酸作用和产甲烷作用之间是否处于动态平衡状态;HABR的产气量和末端出水VFAs质量浓度呈负相关关系,证明产甲烷菌的代谢活性逐渐增强。在快速启动过程中,HABR表现出了明显的生物相的选择和分离现象。     

厌氧发酵停滞后主动曝气效果研究

本研究发现发酵体系一般停滞在两个阶段,水解酸化阶段和产甲烷高峰结束之后。对两个停滞期进行主动曝气,可以再次启动厌氧发酵产甲烷,同时提高产气量和发酵基质的降解率。分别讨论了水解酸化阶段主动曝气的效果和产甲烷高峰期后主动曝气的效果。结果表明:对水解酸化阶段停滞期进行主动曝气产气量增加了3066~3826 m L,提高了187%~272%;对产甲烷高峰期后停滞期进行主动曝气,产气量增加了879~1080 m L,提高了13%~16%。发酵停滞前产气效果好的,主动曝气后产气量增幅不显著,发酵停滞前产气效果差的,主动曝气后产气的增量占累积产气量的65%~73%。     

中温厌氧工艺处理豆制品废水实验研究

采用自制的中温厌氧反应器对豆制品废水进行处理,系统考察了豆制品废水COD及产甲烷量随厌氧反应时间的变化情况。结果表明,在35~37℃的中温反应条件下,经12 h连续运行,废水的COD去除率达到89.49%,产甲烷势为0.133 L.(g COD)-1。同时,还考察了向反应器中加入铁屑以形成内电解对厌氧反应参数的影响。结果发现,加入少量铁屑后反应12 h废水的COD去除率达到91.56%,比不加铁屑时提高了2.07%。可为豆制品加工企业的废水处理及反应器的工程设计提供可行的途径和有益的参考。     

pH值对苦荞渣厌氧发酵性能的影响

以苦荞渣为原料,设置不同总固体（TS）质量分数的发酵液进行厌氧发酵,探究TS质量分数对发酵产气量及发酵液酸化的影响。并通过对发酵液添加缓冲溶液探究整个厌氧发酵过程中挥发性脂肪酸的变化情况。结果表明：当TS质量分数为4%时,产气情况良好;当TS质量分数超过4%时,系统就会发生酸化,酸化的原因是由于过量的丁酸积累所导致。通过使用缓冲溶液（30% NaOH溶液）调节pH值进行联合产氢产甲烷联合发酵,可促进丁酸向乙酸的转化,有效解决酸积累问题并提高能源转化效率。相同TS质量分数下,产氢产甲烷联合组（4^#和5^#）的能源转化效率分别是未处理组（2^#和3^#）的10.8倍和12.8倍。酸化后使用缓冲溶液调节pH值不仅可以快速恢复产气,恢复产气率也相比其他恢复方式的产气率更高,TS产气率达到1 267 mL/g。使用Modified Gompertz方程进行拟合发现,相关系数（R）均在0.99以上,拟合结果较好。     

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.     

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.     

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。     

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.