大气颗粒物PM_(2.5)监测技术研究进展及展望

大气颗粒物已经成为中国的首要大气污染物,其中PM2.5污染越来越受到政府和相关部门关注,本文综述了国内外对大气颗粒物PM2.5的几种监测方法的研究进展,重点比较了各种监测方法的优缺点,并通过实例对比说明了β-射线法的可靠性及用膜片反演方法提高精确度的可行性,同时就加强国内PM2.5监测技术研究提出相关建议及展望。     

Biological sulfate removal from acrylic fiber manufacturing wastewater using a two-stage UASB reactor

A two-stage UASB reactor was employed to remove sulfate from acrylic fiber manufacturing wastewater. Mesophilic operation (35±0.5℃) was performed with hydraulic retention time (HRT) varied between 28 and 40 hr. Mixed liquor suspended solids (MLSS) in the reactor was maintained about 8000 mg/L. The results indicated that sulfate removal was enhanced with increasing the ratio of COD/SO₄^2-. At low COD/SO₄^2-, the growth of the sulfate-reducing bacteria (SRB) was carbon-limited. The optimal sulfate removal efficiencies were 75% when the HRT was no less than 38 hr. Sulfidogenesis mainly happened in the sulfate-reducing stage, while methanogenesis in the methane-producing stage. Microbes in sulfate-reducing stage performed granulation better than that in methane-producing stage. Higher extracellular polymeric substances (EPS) content in sulfate-reducing stage helped to adhere and connect the flocculent sludge particles together. SRB accounted for about 31% both in sulfate-reducing stage and methane-producing stage at COD/SO₄^2- ratio of 0.5, while it dropped dramatically from 34% in sulfate-reducing stage to 10% in methane-producing stage corresponding to the COD/SO₄^2- ratio of 4.7. SRB and MPA were predominant in sulfate-reducing stage and methane-producing stage respectively.     

长江原水臭氧-生物活性炭挂膜中试研究

为了探究面向长江水源的臭氧-生物活性炭深度处理工艺的挂膜技术,进行了长江原水常州段的臭氧-生物活性炭挂膜中试研究.结果表明,在挂膜前期,由于炭柱的物理吸附作用逐渐饱和,炭柱对DOC(溶解性有机碳)、UV_(254)和COD_(Mn)(高锰酸盐指数)的去除率逐渐降低,对氨氮几乎没有去除,在挂膜中后期,由于活性炭上生物膜逐渐成熟,生物降解起主导作用,有机物和氨氮去除率升高并趋于稳定.90 d后,炭柱对DOC、UV_(254)和COD_(Mn)这3个有机物指标的去除率分别稳定在30.64%、57.50%和30.00%以上,氨氮去除率稳定在88.93%左右,认为挂膜成功.扫描电镜图显示活性炭表面出现丰富的菌胶团,同时高通量测序也验证了活性炭中丰富多样的微生物群落结构.     

Study of metabolites from the degradation of polycyclic aromatic hydrocarbons (PAHs) by bacterial consortium enriched from mangrove sediments

The PAH metabolites produced during degradation of fluorene, phenanthrene and pyrene by a bacterial consortium enriched from mangrove sediments were analyzed using the on-fiber silylation solid-phase microextraction (SPME) combining with gas chromatography–mass spectrometry (GC–MS) method. Seventeen metabolites at trace levels were identified in different PAH degradation cultures based on the full scan mass spectra. In fluorene degradation cultures, 1-, 2-, 3- and 9-hydroxyfluorene, fluorenone, and phthalic acid were detected. In phenanthrene and pyrene degradation cultures, various common metabolites such as phenanthrene and pyrene dihydrodiols, mono-hydroxy phenanthrene, dihydroxy pyrene, lactone and 4-hydroxyphenanthrene, methyl ester, and phthalic acid were found. The detection of various common and novel metabolites demonstrates that SPME combining with GC–MS is a quick and convenient method for identification as well as monitoring the real time changes of metabolite concentrations throughout the degradation processes. The knowledge of PAH metabolic pathways and kinetics within indigenous bacterial consortium enriched from mangrove sediments contributes to enhance the bioremediation efficiency of PAH in real environment.     

农户经济行为方式对农村环境的影响

农户经济行为方式的不同,必然导致不同的环境后果。文章在调查研究的基础上,认为微观上农户的职业选择对于我国广大农户的生产方式和生活方式具有重要影响,从而间接影响到我国的农村环境状况。我国目前的农村环境状况之所以呈现出种种不同的现状和发展方向,最直接的原因,是由于不同的农户经济行为方式选择所造成的。因此,进行农村环境保护,离不开对农户生存状态的认识和研究,只有从根本上提高和改善农户的生存状态,才能达到持续利用与保护农村环境的最终目标。     

传统生存方式变迁对农村环境的影响

随着农村社会经济的发展,农户的生存方式开始逐步由传统的生存方式逐步转变为现代的生存方式。在具体的案例研究过程中,我们既可以看到传统生存方式的环境友好的一面,也可以看到传统生存方式变迁过程中农户经济行为变化对于农村环境的不利影响。与此同时,社会经济发展过程中,新的现代生产生活要素的介入,在不断使农户的生活逐步走向现代化的同时,也带来了种种环境问题。总之,农村环境问题的产生既有传统生存方式本身存在的问题,也来自于生存方式变迁过程中新的外部物质的介入,因此,对于农村环境的改善需要同时从这两方面着手,在改善农户生存方式的同时,更要从根本上控制外部的污染物质的介入。     

微絮凝-直接过滤工艺在城市污水深度处理中的应用研究

微絮凝 -直接过滤工艺是一种将混凝反应、沉淀截留集中在同一滤柱内同步完成的高效水处理工艺。该工艺应用于城市污水的深度处理中 ,通过絮凝剂的加入 ,具有同步去除PO3 -4 P、SS和部分COD的功能。本文研究了该工艺对二级处理出水中PO3 -4 P、SS和COD的去除效果及其规律。研究表明 :采用聚合氯化铁 (PFC)作为絮凝剂 ,当Fe/P摩尔比为 2∶1时 ,水中PO3 -4 P的去除率达 98.8% ,浓度可降至 0 .1mg/L以下 ,同时SS、COD去除率也有明显提高。与传统的混凝、沉淀除磷工艺相比 ,该工艺具有操作简单、结构紧凑、占地面积小、污泥量少等优点 ,是一种更为经济和简单的处理单元 ,适用于现有城市污水处理厂的除磷和进一步提高水质的深度处理     

深床过滤机理及其在水处理中的应用研究与进展

深床过滤既有过滤功能,又具生物处理作用,具有良好的应用前景;本文阐述了深床过滤的最新研究动向,深床过滤过程的数学模型的构建方法,国内外利用深床过滤技术处理微污染水源水、城市生活污水及污水深度处理的实验研究状况.     

盘式曝气器的结构优化设计

盘式曝气器是目前城市污水处理厂主要采用的曝气设备之一.但目前盘式曝气器存在充氧能力低、阻力损失大、使用寿命短等技术问题,增加了城市污水处理厂运行成本,降低了运行效能.针对这些问题,对盘式曝气器进行了结构优化设计.通过结构优化,既改善了曝气器的抗撕裂性和自闭性,同时又提高了充氧能力,降低了曝气阻力损失.     

可张孔曝气器曝气能耗试验研究

通过试验研究,总结出可张孔曝气阻力损失的影响因素,以优化产品的结构设计参数,降低产品在工程应用中的能耗,获取更好的经济效益。