进水配比对煤气化废水厌氧段处理效能影响

在温度35℃pH值7.0左右,HRT为30 h的厌氧反应器中,研究了厌氧氨氧化与反硝化的耦合作用.进水氨氮为70～120 mg/L左右,COD为800～1200 mg/L左右条件下,将含亚硝酸盐和硝酸盐浓度人工配水按厌氧进水配比引入反应器中,氨氮、亚硝态氮进水浓度分别为75.43 mg/L、99.87 mg/L时,总氮负荷为233.82 mg/(L·d),考察不同进水配比R(0～100％)对厌氧反应器的脱氮除碳效能影响.实验结果表明,在进水配比为75％条件下,系统氨氮、亚硝态氮去除率达55.71％、63.65％,TN去除率最高达64.56％,COD去除率达80％左右.结果表明,适当的进水配比,不仅可以达到稀释厌氧进水的作用,还可以促使厌氧氨氧化与反硝化的协同脱氮除碳效果.     

厌氧氨氧化反应器启动和影响因素实验研究

采用自制的UASB(升流式厌氧污泥床)反应器,接种产甲烷颗粒污泥,以自配含有氨氮和亚硝态氮的水为进水,来研究厌氧氨氧化反应的启动和影响因素。实验结果表明:反应器运行150后,氨氮(NH~+_4-N)和亚硝态氮(NO~-_2-N)的去除率稳定在50%左右,硝态氮(NO~-_3-N)有明显增加,表明厌氧氨氧化反应启动成功;在温度为30～35℃,pH为7～7.5,水力停留时间为24 h, COD为100～200 mg/L,NH~+_4为89.3 mg/L,NO~-_2为100 mg/L,即NH~+_4:NO~-_2=1:1.12时,厌氧氨氧化反应速率最快。     

水力负荷与低温对厌氧氨氧化与反硝化协同反应器的影响

采用一套3.2L具有填料的上流式厌氧污泥床反应器,在固定进水氨氮、亚硝氮和COD浓度的基础上,通过对进水负荷4个阶段的调节,考察其对厌氧氨氧化与反硝化协同反应器运行的影响。经试验发现,在低水力负荷条件下,氨氮、亚硝氮、COD的平均去除率分别达到了94.1%、97.2%和89.4%,出水硝氮的生成量为4.35mg/L;而在高水力负荷条件下,氨氮、亚硝氮和COD的去除率下降较为明显,为54.2%、73.9%和81%,硝氮的生成量为9.97mg/L。通过再次调低水力负荷,协同脱氮效果基本上能够恢复到之前的水平,表明反应器具备了一定的抗负荷冲击能力。同时低温会对反应器产生较大影响,但反应器内的菌群具备抵御低温并较快恢复的能力,保证了反应器二次启动的成功。     

低基质厌氧氨氧化SBBR反应器启动研究

采用SBBR反应器,接种普通污水厂剩余污泥,以人工配制含NH4+-N和NO2--N的低氨氮废水为进水,NH4+-N、NO2--N分别为24.3~32.0 mg/L、31.9~37.5 mg/L,p H为7.60~7.75,水温为(32±1)℃,考察低基质条件下厌氧氨氧化反应器启动及稳定运行特征。结果表明:经100余天后,SBBR厌氧氨氧化反应器成功启动。进水TN为60.8~68.7 mg/L时,平均去除率为88.3%,NH4+-N和NO2--N的去除率均达到95%以上。稳定运行期间,NH4+-N去除量、NO2--N去除量和NO3--N生成量的质量浓度之比为1∶1.37∶0.27,出水p H略高于进水,稳定在7.95左右。     

硝化-厌氧氨氧化组合反应器的运行和评价

利用硝化-ANAMMOX组合反应器处理具有高氨氮、低有机质特点的城市厌氧消化污泥滤液。反应器稳定运行后,进水氨氮和亚硝态氮的质量浓度分别达到约360和400mg/L,水力停留时间为30h,总氮容积负荷达到493.4mg/(L·d)时,出水氨氮和亚硝态氮的质量浓度分别为73.6和69.2mg/L。实验中ANAMMOX反应器的启动和运行基本取得了成功。     

部分亚硝化-厌氧氨氧化联合工艺处理含氮废水的研究

部分亚硝化-厌氧氨氧化联合工艺是一种新型的废水脱氮工艺。实验采用模拟废水,进水氨氮浓度为600 mg/L。亚硝化SBR反应器在温度为30℃、HRT为24 h、DO≈0.2 mg/L的运行条件下,将废水中的一部分氨氮氧化成亚硝氮,并使得亚硝化SBR反应器出水中NH4+-N和NO2--N比值接近1∶1.32后,再作为厌氧氨氧化SBR反应器进水;厌氧氨氧化SBR反应器在温度为37℃、HTR为24 h的运行条件下,将氨氮和亚硝氮转化为N2。实验结果表明,部分亚硝化-厌氧氨氧化联合工艺脱氮效果较好,废水中氮的去除率可达94.44%。     

厌氧氨氧化工艺在处理腈纶废水过程中的应用研究

厌氧序批式活性污泥法,即厌氧序批式反应器(ASBR)是一种以序批间歇运行操作为主要特征的废水厌氧生物处理工艺,依赖于形成沉降性能良好的生物体,采用单个反应器完成处理的序列操作,即进水、反应、沉降和排水。实验的设计方案是将ASBR工艺与厌氧氨氧化(ANAMMOX)技术组合应用于处理腈纶厂排放的不能够达标排放的高浓度有机废水。其中,ANAMMOX技术具有良好的有机污染物分解去除效果,氨氮(NH4+-N)的进水浓度为283.2 mg/L,经ANAMMOX技术和ASBR工艺处理后的腈纶废水出水NH4+-N浓度为20 mg/L,去除率达95%;亚硝态氮(NO2--N)的进水浓度为300 mg/L左右,经ANAMMOX技术和ASBR工艺处理后的腈纶废水出水中NO2--N未检出(NO2--N浓度为0 mg/L),去除率达100%;化学需氧量(CODcr)的进水浓度为306.3 mg/L,经ANAMMOX技术和ASBR工艺处理后的腈纶废水出水CODcr值为44 mg/L,去除率达85%。从污水处理工程应用角度看,ANAMMOX过程比传统硝化-反硝化脱氮方式具有明显优势,能够达到企业清洁生产的要求与目的。     

无机碳源对一体化厌氧氨氧化反应器脱氮性能的影响研究

通过在进水中投加无机碳源(碳酸氢钠),研究无机碳源(IC)对一体化厌氧氨氧化反应器脱氮性能的影响。结果发现,进水IC含量对一体化厌氧氨氧化反应器脱氮性能有显著的影响。当进水IC的质量浓度为1.5 g/L时,反应器运行状况良好,NH_3-N去除率高达98.8%,TN去除率达到87%;当其质量浓度降低至1.0 g/L时,NH_3-N去除率降至85%,TN去除率降至75%;当其质量浓度降至0.5 g/L时,NH_3-N去除率仅为69%,TN去除率降至61%。当进水IC的质量浓度恢复至1.5 g/L后,出水的NH_3-N的质量浓度迅速降低至3 mg/L左右,去除率恢复至98.8%,TN去除率也上升至87%,说明IC含量对一体化厌氧氨氧化反应器的抑制作用具有可恢复性。较高IC含量有利于提高一体化厌氧氨氧化反应器的脱氮性能。     

好氧-SNAD-MBBR工艺处理煤气化废水

研究了同步亚硝化、厌氧氨氧化和反硝化(SNAD)-生物移动床(MBBR)工艺对煤气化废水脱氮的处理效果。结果表明,通过控制低DO含量和低污泥停留时间(SRT)的方法防止了好氧反应器中硝化菌的积累,为后续SNAD反应器提供了合适的进水。煤气化废水经好氧反应器去除COD后进入SNAD MBBR进行脱氮,控制SNAD反应器温度为30～33℃,DO的质量浓度为0.5～0.8 mg/L,p H为7.5～7.7,HRT为24 h。TN去除率达到90.7%,出水TN、NH_4~+-N的质量浓度分别低于20、5 mg/L,COD去除率达到89.6%,出水COD低于60 mg/L。运行25 d后,SNAD反应器中厌氧氨氧化菌的种类由接种时的Candidatus Brocadia变为Candidatus Kuenenia。     

亚硝化-厌氧氨氧化组合工艺处理煤气化废水的研究

为了实现煤气化废水的经济有效脱氮，分别研究了单独亚硝化及其与厌氧氨氧化组合工艺对实验室模拟废水和实际煤气化废水的脱氮性能，分析了废水中苯酚对亚硝化反应器运行的影响及其自身转化。结果表明：质量浓度为7～50 mg/L的苯酚对亚硝化系统首先产生抑制，但随着运行时间延长，系统性能逐渐恢复。在处理实际煤气化废水时，逐渐增加进水中煤气化废水的比例，废水中毒性物质对亚硝化过程的影响能够被克服，亚硝化反应器可以实现稳定运行。在亚硝化反应器中，亚硝态氮积累率达90%左右，COD去除率达98%，反硝化脱氮对总氮的去除率达到60%左右；组合工艺中亚硝化反应器和厌氧氨氧化反应器均能够稳定运行，厌氧氨氧化脱氮率维持在70%左右；实际煤气化废水亚硝化-厌氧氨氧化全程氮去除率平均达到86%。     

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.     

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.     

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.