脉冲曝气方式下活性污泥降解特征分析

研究了脉冲曝气方式对活性污泥降解模拟生活污水的影响。结果表明:脉冲曝气时,总有机碳去除率与连续曝气下的去除率相当,均在85%左右,氨氮去除率比连续曝气时的去除率低4%~5%,总氮去除率比连续曝气时的高3%~4%,溶解性微生物产物的产出浓度比连续曝气下的低2 mg/L左右。     

BPAC-UF组合工艺去除微污染原水中嗅味物质的工艺条件优化

采用正交试验设计方法对BPAC-UF去除微污染水源水中嗅味物质的工艺条件进行优化。根据组合工艺要求和单因素预试验的结果,确定炭池曝气强度、污泥回流间隔、炭池PAC更新率和膜池曝气方式这4个试验因素,每个因素设置3个水平,共设计9组工况进行试验,并将嗅昧物质(二甲基三硫醚、2-甲基异茨醇、β-紫罗兰酮)及氨氮的去除率,跨膜压差的增长速率作为评价工艺运行效果和膜污染程度的指标。试验所得的最优工艺条件:炭池曝气强度为30 L/h,污泥回流间隔为0.5 h,PAC更新率为15%,膜池曝气方式为连续曝气。     

微纳米曝气强化碳纤维生态浮床水处理效果研究

采用微纳米曝气与微孔曝气对比的方式,研究了碳纤维湿地式人工浮床在以上2种曝气方式下净化水质效果及规律。结果表明,在相同HRT(1 d)和气水体积比(6:1)的条件下,微纳米碳纤维浮床比传统曝气浮床对水体中COD、NH4+-N和TP去除率分别提高7%、10%、9%,并且能够在更短的时间内完成碳纤维填料的挂膜过程,说明微纳米曝气对碳纤维人工浮床具有更好的强化去除效果。2种曝气方式下,COD的去除受HRT变化最小,NH4+-N、TP的去除均随着HRT的增加而增加,并且微纳米曝气条件下对各污染物的去除率始终优于传统曝气     

膜材料对膜曝气生物膜反应器性能影响的比较

选择聚偏氟乙烯(PVDF)和聚丙烯(PP)中空纤维曝气膜作为膜曝气生物膜反应器(MABR)的膜组件材料,比较两种膜材料由于亲疏水性能、表面形态、生物相容性等性质的差别,对MABR挂膜启动速度、生物附着量、脱氮除碳及膜污染等性能的影响。研究显示,运行末期PVDF和PP膜纤维生物附着量分别为35.62 g·m^-2和30.63 g·m^-2。通过场发射扫描电子显微镜观察两种膜表面生物污染情况,PVDF膜纤维表面呈鱼鳞状结构,有效保护了膜孔不被微生物完全堵塞。在90 d的运行周期内以PVDF为曝气膜材料的MABR获得了90%以上的COD去除率和78%的TN去除率;而以PP为曝气膜的MABR由于运行后期曝气膜纤维污染严重仅得到了76.5%的COD去除率和49.1%的TN去除率。因此,PVDF曝气纤维更适于作膜曝气生物膜反应器的曝气膜。     

两种运行方式对曝气生物滤池的影响

通过动态模拟试验,考察了两种运行方式对曝气生物滤池的影响。试验结果表明,上流式曝气生物滤池的挂膜时间略少于下流式曝气生物滤池,两种运行方式的生物相丰富;上流式与下流式曝气生物滤池在40cm和60cm对有机污染物的去除率分别为62．3％和67．8％,沿水流方向的COD去除率趋于稳定;两种运行方式的曝气生物滤池在填料高度40cm处。对SS的去除率较高,分别为76．7％和74．3％,而上流式曝气生物滤池出水的SS的去除率高于下流式曝气生物滤池,分别为96．5％和92．1％。上流式曝气生物滤池的操作方式优于下流式曝气生物滤池。     

运行方式对曝气生物滤池的影响研究

通过动态模拟试验,考察两种运行方式对曝气生物滤池的影响。试验结果表明,上流式曝气生物滤池的挂膜时间略少于下流式曝气生物滤池,两种运行方式的生物相丰富;上流式与下流式曝气生物滤池填料高度在40cm和60cm时对有机污染物的去除率分别为62.3%和67.8%,沿水流方向的COD去除率趋于稳定;两种运行方式的曝气生物滤池在填料高度40cm处对SS的去除表现出较高的去除率,分别为76.7%和74.3%,而上流式曝气生物滤池出水的SS的去除率高于下流式曝气生物滤池,分别为96.5%和92.1%。上流式曝气生物滤池的操作方式优于下流式曝气生物滤池。     

曝气-强化混凝-陶瓷膜微滤组合工艺处理含油废水

以某港口含油污水处理厂二级气浮出水为研究对象,探究曝气-高锰酸钾强化混凝-陶瓷膜微滤组合工艺对含油废水中油和有机物(COD)的去除效能,重点考察曝气时间、高锰酸钾投加量、投加方式等因素对处理效果的影响。结果表明,最佳曝气时间为40 min,高锰酸钾投加量2 mg/L,投加方式为在混凝剂PAC前投加;组合工艺对油和COD总的去除率可达到91%~94%;此外,曝气和高锰酸钾强化混凝处理过程能够减缓跨膜压差的增长速率,延长陶瓷平板膜的使用寿命。     

全通量陶瓷膜去除自来水中总铁和Zn2+的研究

通过以自来水为原水的连续试验,记录有效压差和对应出口流量的数据,推导出全通量即一次过水率达98%以上陶瓷膜的过膜压力(TMP);在不同流量条件下,全通量陶瓷膜对Fe、Zn2 金属离子去除率基本保持稳定,说明全通量陶瓷膜对运行负荷变化有一定的适应性;在不同有效压差情况下,全通量陶瓷膜对Fe、Zn2 金属离子去除率有较大变化,说明有效压差和Fe、Zn2 金属离子去除率之间存在较好的匹配关系。     

优化曝气方式对减缓SMBR一体式反应器中膜污染的影响

在相同运行条件下,研究了改进型曝气方式（膜出水时气水比为20：1,停止抽吸时气水比为40：1）和传统曝气方式（采用气水比40：1连续曝气）一体式膜生物反应器下SMBR的运行情况。试验结果表明：改进曝气方式的SMBR中胞外聚合物（EPS）和溶解性微生物产物（SMP）浓度以及料液粘度都低于传统的SMBR,减轻了膜污染,直观表现为具有较低的跨膜压力（TMP）;两种曝气方式的膜阻力均以沉积层阻力为主,改进曝气方式的SMBR沉积层阻力所占比例高于传统的SMBR,后者膜孔吸附及堵塞阻力所占比例远高于前者,因此后者膜清洗费用高;此外改进型曝气方式由于其阶梯式曝气强度降低了能耗。     

一体式A/O接触反应器处理农村生活污水启动研究

采用连续曝气预启动-逐步延长停曝时间的方式启动一体式A/O接触反应器,研究该工艺挂膜启动特征,并就间歇曝气与连续曝气处理效果进行比较。结果表明,反应器运行15 d后完成连续曝气预启动,COD、NH4+-N和TN的去除率分别达到80%、75%和40%,且生物相稳定。逐步延长停曝时间至15 h/d和16 h/d,COD、NH4+-N和TN去除率在停曝时间为12 h/d时迅速下降,而后又上升,最终能达到85%、70%和54%,间歇曝气启动成功,整个启动过程历时98 d。综合分析,8 h曝气/16 h停曝的间歇曝气运行方式更为经济有效。     

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.     

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.     

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。