沉淀池自动排泥装置

<正> 沉淀池的排泥关系到沉淀效果和操作管理。排泥周期太长,池底被压实的泥渣流通性差,排除困难,如果池底积泥过多,将会影响沉淀池的正常运行,排泥周期短,又会增加管理上的麻烦。特别是目前广泛采用斜板斜管沉淀池,随着沉淀效果的提高,池中截留的泥渣量也相应的增多,为了及时排除沉淀池中的泥渣和减少操怍管理上的麻烦,实现沉淀池的排泥自动化是必要的。     

平流式沉淀池排泥智能化控制的生产性应用研究

论文将虹吸排泥改进为泵吸智能化排泥,并且通过在线质量流量仪的污泥读数控制排泥泵的运行,可节约排泥水量84%,降低沉淀池排泥能耗约72%,同时解决了沉淀池排泥管道易阻塞及排泥自动化的难题。     

双层平流沉淀池的设计与应用

该文介绍了双层平流沉淀池在国内的应用,并通过工程实例详细介绍了双层平流沉淀池的主要设计内容。与普通平流沉淀池相比,双层沉淀池的处理效率更高、占地面积较省,但整体池深较深、排泥系统相对复杂,本文根据双层沉淀池的特点,介绍和分析了该池型的设计参数,絮凝区与沉淀区的设计,以及上下层排泥系统的设计,为同行业相关设计提供借鉴和参考。     

水厂沉淀池改造方法与应用分析

针对传统沉淀工艺在水厂运行中存在的问题,通过总结沉淀池改造成功案例,得出改造方案。完善进水区以降低进水流速,提高布水均匀性;通过延长排泥车行程等方式改造排泥系统以解决"跑矾"现象;针对不同的水质问题,可考虑平流-斜管组合池、浮沉池、水平管沉淀技术等来提高水处理效果。通过进水口、排泥系统以及沉淀池型3方面改造可有效提高沉淀池进水稳定性,解决排泥不畅的问题,增强对低温低浊水以及含藻水的适应性。在未来,沉淀池改造仍应以进水口、排泥系统以及沉淀池型3方面改造为主,并适当借鉴国外的高效沉淀技术,以提高对原水的处理效果。     

PC机在虹吸式行车排泥机上的全自动控制

排除积泥是平流式沉淀池生产运行中的重要环节，排泥机的工作情况直接关系到沉淀池的可靠运行和生产效率。虹吸式排泥机能有效地排除池底沉泥，但其自身用水量约为制水量的5％。在水资源日见馈乏的今天，能确保水质的前提下，节省排泥机的自身用水具有十分重要的意义。闵行水厂一车间自95年开始，采用PC机对排泥机进行技术改造，现已在全自动状态下经济运行，实测排泥机用水量可节约60％。1.排泥机工作情况闵行水厂一车间的平流式沉淀池，如图1所示，总长74米，排泥机以1米／分的速度在沉淀池两端间作固定程式往复运行，往返一次需时2.5小…     

关于如何改善虹吸式排泥机工作的探讨

上海闵行自来水厂有两个制水车间，各有独自制水工艺流程。制水一车间於一九九二年将原土沉淀池（建於一九五八年）改建成折板反应平流式钢筋混凝土沉淀池，日产水量7.7万吨。采用桁车式虹吸排泥机连续往返运行排泥。1.排泥机原设计与工作状况平流式沉淀池沉淀区长74.0米。排泥机以1（米／分）速度作连续运行，往返一次需2.5小时。一天24小时，池底每个排泥断面可排泥10次左右。排泥机由6根DN40排泥管沿地宽均匀分布，垂直下伸至距沉淀池底部15～20厘米处，并装有吸泥喇叭口。每根排泥管都固定在排泥机梁架上，向外延伸至池外侧排泥明渠上…     

往复式底部刮泥机在矩形沉淀池中的设计与应用

介绍了往复式底部刮泥机的特点,结合工程实例就该刮泥机在各类矩形沉淀池中的适用性做了详尽分析,同时,对往复式底部刮泥机与气力松动、气力输送辅助排泥系统的联合应用做了详细介绍。研究认为往复式底部刮泥机适用于绝大部分的矩形沉淀池,具有运行稳定、排泥效率高、排泥浓度高,生产水耗低等优点,具有良好的适用性和广阔的市场前景。     

高密度沉淀池污泥量估算及设备选型设计

石灰混凝澄清工艺中高密度沉淀池末端会产生大量的污泥。沉淀池终端污泥系统设计中,污泥量计算正确与否将直接影响到高密度沉淀池配套污泥处理设备的合理选型。文中介绍了工程设计中高密度沉淀池污泥量的计算方法和相应污泥设备配置选型方法。通过对高密度沉淀池排泥量的准确估算,选择适合的污泥处理统设备,最终能保证高密度沉淀池系统的稳定运行。     

气吹式沉淀池表面浮泥清理技术研究

沉淀池中污泥会因为没有及时排泥等原因都会导致沉淀后的污泥上浮,上浮的污泥会导致沉淀池的出水水质变差,提高沉淀池表面浮泥的去除效果,不仅关系到污水处理工艺的效果和成本,在保护环境等方面也具有十分重要的意义。本文主要阐述了一种气吹式沉淀池表面浮泥清理装置的研究,该装置通过气体吹扫管对沉淀池表面的浮泥进行清除,该装置不仅效率高、能耗低,而且能够彻底清除沉淀池表面浮泥。     

浅谈某城镇污水处理厂二沉池翻泥问题及措施

本文论述了造成二沉池翻泥的原因,并以某污水处理厂为例,探讨了该厂二沉池翻泥问题的思路和方法。结合该厂实际情况,通过采取降低污泥浓度、辅助投加絮凝剂、改变曝气模式等措施,解决了活性污泥沉降性差的问题,对防止二沉池翻泥具有积极意义。     

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。