污水污泥热消化工艺的研究进展

污水污泥的资源化利用(土地利用等)已经成为国内外处置污泥的重要发展方向,利用污泥热消化技术可以使污泥达到资源化利用的标准.在分析中,重点介绍了污泥热消化工艺的特点、污泥热消化工艺的类型,包括对污泥自热高温好氧消化工艺、厌氧分级高温消化工艺、两段高温好氧/中温厌氧消化工艺的介绍,并简要阐述了这些污泥热消化工艺的基本应用情...     

自热高温好氧消化工艺中污泥监测指标的变化规律研究

自热高温好氧消化工艺（ATAD）是目前处理城市污泥较为新颖的一种技术,该技术处理污泥效果好,处理成本低,处理15 d左右,基本可使污泥达到无害化的标准。对自热高温好氧消化工艺进行了介绍,并对工艺运行时污泥的挥发性有机物（VSS）、脱氢酶活性（DHA）、病原菌的灭活情况、总氮（TN）、总磷（TP）、蛋白质的变化进行监测,分析了这些指标的变化规律,以期为污泥后续资源化利用研究提供参考。     

超声波-缺氧/好氧消化与传统好氧消化效果的比较研究

为考察超声波-缺氧/好氧消化对污泥降解的效果,通过实验室中试对比试验,研究了污泥超声波-缺氧/好氧消化对传统好氧消化的比较优势。研究结果表明,经过25 d的消化后,超声波-缺氧/好氧消化污泥TSS和VSS的去除率分别达到了35.77%和50.02%,比好氧消化污泥分别提高了3.90%和8.99%;超声波-缺氧/好氧消化污泥稳定时间比好氧消化污泥缩短了近6 d;超声波-缺氧/好氧消化污泥的TN去除率为40.8%,远高于传统好氧消化,并且超声波-缺氧/好氧消化污泥上清液中氨氮和硝态氮浓度却远低于传统好氧消化,因而降低了上清液回流氨氮和硝态氮对污水处理系统的负荷压力。     

预热自热高温好氧消化过程中污泥各项性能指标的变化研究

对预热自热高温好氧消化过程中污泥各项性能指标的变化进行了研究,研究项目包括污泥的p H值、氧化还原电位(ORP)、总氮(TN)、氨氮(NH4+-N)、总磷(TP)、蛋白质、挥发性有机酸(VFA)和总有机碳(TOC)。结果表明,以上研究指标均有不同程度的变化,反应了消化后污泥性质的变化,为研究消化后污泥的用途提供了有益的参考。     

邻苯二甲酸二(2-乙基己基)酯对污泥好氧消化的影响

对邻苯二甲酸二(2-乙基己基)酯(DEHP)对污泥好氧消化的影响进行了研究,以期为污泥的安全资源化利用提供一定的基础资料。结果表明,对于污泥好氧消化,当进泥中DEHP投加量为20mg/L时,对VSS去除率没有明显影响;当DEHP投加量为100mg/L以上时,随DEHP投加量的增加,VSS去除率下降,同时反应器污泥中DEHP的残留浓度随之增大。     

低压直流电促进污泥好氧消化的性能研究

为了提高污水厂的剩余污泥好氧消化效率,在剩余污泥好氧消化过程中施加低压直流电场,研究不同电场条件下污泥中有机物(以MLSS表征)、总磷和沉降性(以SV表征)变化情况,探讨电场对污泥好氧消化效率的影响。结果表明:在直流电压为5 V条件下,间歇通电12 d后,通电1、2、3 h/d组,污泥的MLSS去除率分别达到39.50%、44.50%、44.75%,与未通电组相比,分别提高了33.90%、50.85%、51.69%。并且研究发现在1 h/d的电场条件下,一定周期内污泥的脱氢酶活性与细菌总数高于未通电组。实验表明低压直流电对污泥好氧消化性能有促进作用。     

城市污水处理厂污泥减量试验研究

采用单纯好氧消化和生物促生好氧消化对污泥减量及CODCr降解进行对比分析。结果表明:经过38 d的好氧消化,污泥量最终从16.02 g/L下降到7.48 g/L,污泥去除率已大于50%,污泥去除率呈上升趋势最终达到53.3%;CODcr由60 mg/L降低到43.6 mg/L,接近城镇污水处理厂一级排放标准。使用生物促生技术后,反应6 d,MLSS由12.34 g/L迅速降低到6.12 g/L,污泥浓度已降至50%以下,其去除率迅速上升达到50.41%;CODCr由60 mg/L降低到32.6 mg/L,达到并优于城镇污水处理厂一级排放标准。     

污泥热消化试验研究

污泥是污水处理的产物,成分复杂,如果处置不当会引起二次污染。污泥热消化可以使污泥达到稳定化和无害化。实验比较了在不同污泥浓度下,污泥高温好氧消化的效果,并且对污泥高温好氧消化和高温厌氧消化、高温厌氧消化和常温厌氧消化进行了比较,得出结果:低浓度的污泥(含水率约91.5%,VSS=38.6 mg/L)更有利于污泥的高温好氧消化,经过12 d的高温好氧消化,污泥各项指标:COD、VSS的降解率分别达到76.58%和50.2%,热消化中的高温(约50℃)可以去除污泥中的病原菌、病毒等,可以使污泥达到农用的标准;高温好氧消化和高温厌氧消化(都在低浓度污泥条件下)均可以使污泥达到稳定化,但经高温厌氧消化后的污泥有臭味;高温厌氧消化无论是在杀菌、杀病毒方面还是在产甲烷和氢气的速率方面等都要优于常温厌氧消化。     

剩余污泥“水解/好氧消化”减量化工艺探讨

结合剩余污泥好氧消化和厌氧消化工艺的优缺点,从理论和实验研究上分析了剩余污泥＂水解/好氧消化＂减量化工艺的可行性。     

曝气量对自热式高温好氧消化污泥减量的影响

采用批式自热高温好氧消化(ATAD)工艺进行污泥稳定化处理,对TSS、VSS、温度、脱氢酶、细菌总数、pH和氧化还原电位(ORP)、停留时间等指标进行了测定,探讨不同曝气量对悬浮固体浓度去除率、反应器自升温、污泥减量及稳定化处理效果的影响.试验发现,曝气量过高会引起散热作用,使反应器温度下降;过低会影响微生物活性,反应器升温慢,停留时间长,两种情况都会引起TSS、VSS去除率降低.在搅拌强度为450 r/Min条件下,对VSS为49g/L的混合污泥(生活污泥与剩余污泥体积比为1:8)的最佳曝气量为45 mL/8,此时VSS的去除率可达到53.98%,结果达到了污泥稳定的目的.     

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。