电除尘器比电阻软件测算研究与应用

为了进一步提高静电除尘器的收尘效率、降低能耗,对粉尘比电阻这一重要影响因素进行了研究。依据粉尘比电阻值定义,建立了收尘极板上粉尘层压降模型,提出了利用压降模型和伏安拟合特性曲线数学表征式来在线测算真实工况下粉尘层比电阻的实现方法。以480C型阳极板、RS芒刺阴极线极配形式进行了模拟验证实验,结果表明测算所得的比电阻数值与实际值相符。最后对现有电除尘控制系统中基于比电阻值的反馈控制方法做了简要介绍。     

植物混种原位修复多环芳烃污染农田土壤

通过比较实验前后土壤微生物主要类群数量、PAHs降解菌数量、土壤PAHs含量和植物不同部位PAHs含量变化,评价植物单种和混种野外原位修复多环芳烃(PAHs)污染农田土壤的效果。结果显示,150 d天生长期内,黑麦草/小麦混种及黑麦草/蚕豆混种修复效果最好,对土壤PAHs总量的降解率分别达到了59.4%和64.8%。同时,这2个混种处理土壤细菌、真菌和PAHs降解菌数量分别显著高于相应的小麦、蚕豆和黑麦草单种处理。植物不同部位PAHs含量高低次序为根部>茎叶≈籽粒。混种模式下,蚕豆和小麦不同部位PAHs含量比单种模式的不同程度降低,特别是籽粒部。植物混种模式不仅显著提高了土壤PAHs的降解率,还降低了农作物体内PAHs含量,实现了边生产边修复,在污染农田土壤修复领域有着广阔的应用前景。     

Evaluation of the mobility of c14‐labelled pesticides in soils by thin layer chromatography using a linear analyser

Abstract

The mobility of seven pesticides in a chromic cambisol soil was studied by soil thin layer chromatography. Pesticide mobilities were determined by means of conventional autoradiographs of the chromatograms, as well as from sequential series of curves and images of the pesticide spots provided by a linear analyser. The R _f values obtained from the autoradiographs and those provided by the linear analyser were quite consistent. Based on such values, pesticide mobility decreased in the following order: acephate > fluometuron > atrazine > ethofumesate > metolachlor > diazinon > glyphosate. According to the mobility scale proposed by Helling and Turner (1968), acephate is highly mobile; atrazine, fluometuron, ethofumesate and metolachlor are moderately mobile; diazinon is slightly mobile; and glyphosate is immobile. The images provided by the linear analyser allow to determine the R _f values for the zones of maximum activity in the pesticide spots (R _f ^max), as well as the activities of different spot zones and those corresponding to R _f and R _f ^max. The results obtained show the image analyser to provide more expeditious R _f measurements from the chromatograms and open up new prospects for using soil TLC to investigate pesticide mobility.     

混合液回流比对MSBR工艺强化生物脱氮的影响

针对二级城镇污水处理厂提标改造时出水氮、磷指标很难同时达到一级A标准（GB18918-2002）的情况,提出了改良式序批式反应器（MSBR）的强化生物脱氮运行模式,并通过生产性实验研究了MSBR工艺混合液回流比（6单元回流至5单元）对出水COD、TP、NH4＋-N及TN的影响。实验结果表明,MSBR工艺混合液回流比对COD、NH4＋-N去除基本上没有影响,但对TN和TP去除有影响。当回流比从0提高1和1．5时,TP去除效率分别降低了5．85％和4．06％;而TN去除效率分别提高了10．46％和7．87％,同时出水TN可稳定达到一级A标的要求。从控制运行能耗和脱氮效果的角度综合考虑,该污水厂强化生物脱氮的混合液回流比控制在1是比较合适的。     

Take your swimsuit along: the value of improving urban bathing sites in the metropolitan area of Berlin

Many inhabitants of Berlin enjoy bathing in lakes and rivers during the summer. However, so far no data exist about who goes bathing and what quality bathers expect from bathing sites. In an online survey conducted during the summer of 2007 respondents were presented with a choice experiment concerning various attributes of bathing sites such as water quality or cleanliness of the beach. Applying both random parameter logit models as well as a latent class model reveals that unobserved taste heterogeneity is present among bathers, i.e. not all bathers would benefit equally from improving bathing sites. A test concerning preference consistency reveals high internal validity.     

ABR+活性污泥法在番茄废水中的应用

以奇台太极华力食品有限公司番茄废水处理工程实例为依据,介绍了采用ABR厌氧+完全混合活性污泥法工艺在处理番茄加工废水的设计、调试及运行情况。经过2年运行,其进水COD在700~1 500mg/L之间,最大处理水量达到4 000m3/d;出水COD在40~70mg/L之间,COD去除率达到97%。处理出水可以稳定达到污水综合排放二级标准。ABR+完全混合活性污泥法工艺具有启动快,调试时间短,工程造价低的优点,尤其适宜处理番茄等间歇时间长工作时间短的季节性生产污水。     

复配介质去除地下水中腐殖酸

以模拟地下水为研究对象,进行了复配介质去除地下水中腐殖酸的实验研究。探讨了配比、粒径、固液比、pH和温度对腐殖酸去除效果的影响。腐殖酸的浓度通过紫外分光光度法测定。结果表明:在不加活性炭的条件下,H物质∶X物质∶Q物质=1∶8∶8时,其硬度较好;在初始pH=6.34、反应时间为4 h时,去除率可达到95%以上;当反应时间≤1 h时,去除率随粒径增大而减小,而当反应时间为2～6 h时,小粒径和中等粒径复配介质对腐殖酸去除率略高于大粒径;一定浓度范围内,腐殖酸的去除率与固液比呈正相关,但固液比增大时,并不能无限提高去除率,当固液比为1∶200～1∶50时,去除率呈现平台;pH对复配介质去除效果影响不大,而温度对腐殖酸的去除有显著影响,较低温度(16.8℃)下的去除率比较高温度(35.0℃)下的去除率高5%。该复配介质去除地下水中腐殖酸是有效可行的,可作为PRB(permeable reactive barrier,渗透反应格栅)的潜在反应介质。     

Review of advances in the thin layer chromatography of pesticides: 2006–2008

Applications of thin layer chromatography and high performance thin layer chromatography for the separation, detection, qualitative and quantitative determination, and preparatire isolation of pesticides and their metabolites are reviewed for the period from July 1, 2006 to November 1, 2008. Analyses are described for a variety of sample types and pesticide classes. In addition to references on residue and formulation analysis, studies such as pesticide-structure relationships, identification and characterization of plant pesticides, metabolism, degradation, mobility, and lipophilicity are covered. Future prospects for pesticide thin layer chromatography are also considered.     

MBR污泥混合液特性变化及膜污染关系研究

考察了长期运行不排泥情况下膜生物反应器(MBR)中的污泥混合液特性变化,并结合Darcy公式探讨污泥性质与膜污染的关系.研究表明,在130 d的运行期间,随着污泥龄(SRT)的增加,污泥浓度增大,混合液粘度增大,污泥的平均粒径从51.56 μm增加到92.57μm后略有减小;对比上清液和出水的分子量分布特征发现,膜组件...     

杉木拟赤杨混交林土壤肥力的研究

通过对杉木拟赤杨混交林及杉木纯林土壤团聚体结构、土壤养分状况及酶活性的研究表明,与杉木纯林相比,混交林土壤结构性能得到改善,供肥和保肥能力加强,各种土壤酶活性提高,土壤肥力较好。表明杉木拟赤杨混交林具有良好的培肥土壤功能,对杉木人工林的地力维持和提高有重要意义。