Effects of an Experimental Enrichment of Instream Habitat Heterogeneity on the Stream Bed Morphology and Chironomid Community of a Straightened Section in a Sandy Lowland Stream

A straightened stream stretch with poor habitat heterogeneity was divided into a “control” section with a low amount of submerged woody debris and an experimentally “wood-enriched” downstream section to study the effect of enhanced habitat diversity on the benthic invertebrate community. The downstream section was enriched by fixing 25 wood packages constructed from 9–10 branches on the stream bottom. Succession processes occurring in the two stream sections were compared by chironomid exuviae drift from July to November 2000 and from April to August 2001. During the first sampling period, more drifting chironomid exuviae (medians of control vs. wood-enriched: 446 vs. 331, no significant difference) and total number of taxa (44 vs. 36, Wilcoxon signed-rank test P = 0.019) were recorded for the control section. Although species compositions of both stream sections were highly similar (Sørensen index: 0.83) the diversity in the wood-enriched section was distinctly lower compared to the control section (Shannon–Weaver index: 1.19 vs. 1.50). During the second sampling period, exuviae numbers remained higher in the control section (median: 326 vs. 166), but total numbers of taxa were nearly equal (51 vs. 49), as well as species diversity (Shannon–Weaver index: 1.67 vs. 1.64). The lower chironomid diversity observed during the first sampling period coincided with a gradual but significant change of the streambed morphology in the wood-enriched section. There, the initially more U-shaped profile (V/U = 0.81 ± 0.37) had turned into a pronounced V shape (V/U = 1.14 ± 0.21), whereas the control section retained its unaltered U shape (V/U = 0.62–0.75). This small-scale study on experimental of woody debris in sandy lowland streams showed that the negative impact of increased hydraulic disturbance of the existing streambed more than outweighed any positive impact resulting from the increase in woody debris.     

pH值及碱度对焦化废水处理效果的影响

采用SBR工艺处理焦化废水,探讨了pH值及碱度对有机物降解及生物脱氮的影响。试验结果表明,pH值8.5~9.2时,COD和NH3-N去除率均较高。出水NO2-积累,生物脱氮以短程硝化—反硝化的途径进行,NO2-对COD浓度的贡献值得重视。好氧反硝化脱氮约占总氮去除率的30.3%。     

未来绿色竞争力——工业污染防治水平

早在手工业时代,工业污染就已引起人们的警觉;而随着生产力的发展,工业污染加剧.20世纪50年代,工业生产和其他方面排放的有害物质,大大超过自然净化能力,环境恶化并出现了一系列重大的耳熟能详的公害事件(如1952年的伦警烟雾事件,50年代的日本水俣病事件等),这才引起世界各国的普遍关注.     

乡村振兴视域下的生态产品价值实现模式路径研究

全面推进乡村振兴,加快农业农村现代化建设,已成为中国全面建成小康社会后的重大战略.作为乡村振兴的主战场,也是绿水青山和自然资源的集中分布区域,中国广大农业农村地区蕴含着丰富的生态产品.在乡村振兴和农业农村现代化建设新形势下,如何通过推动生态产品价值的实现,从而促进乡村振兴成为目前的重要课题,尤其是实现模式路径的研究更是...     

苯乙炔铜协同PMS光催化降解磺胺二甲嘧啶的机理研究

基于过一硫酸盐(PMS)的高级氧化技术(SR-AOPs)在废水处理中引起广泛关注.本工作成功合成苯乙炔铜(PhC₂Cu)光催化剂并构建新型的PhC₂Cu/PMS体系,并进行可见光下降解磺胺二甲嘧啶(SMT)的机理研究.紫外-可见漫反射光谱、荧光发射光谱和光电化学测试表明PhC₂Cu具有良好的光电化学特性.PhC₂Cu光催化活化PMS可以产生多种活性物种,并且PMS捕获电子能提高PhC₂Cu界面电荷传输效率和光生载流子的分离效率,进而来提高PhC₂Cu/PMS体系的光催化性能.值得注意的是,PhC₂Cu/PMS体系在低功率蓝色LED灯下使SMT的降解率在30 min内高达97.65%,其反应速率分别是PhC₂Cu添加PMS(无光照)情况下的7.70倍和PhC₂Cu光照下(无添加PMS)的5.62倍.通过一系列环境影响因素(pH、离子、实际水体等)实验表明PhC₂Cu/PM...     

紫外增强KMnO4氧化电镀废水中铜-有机络合物

高锰酸钾(KMnO₄)是一种氧化性能很强且环境友好的氧化剂.本文探究了紫外(UV)增强KMnO₄处理氧化铜-乙二胺四乙酸有机络合物(Cu-EDTA)的动力学和机制,考察了KMnO₄浓度、初始溶液pH及水体中常见离子等影响因素对该体系的影响,确认了主要活性物种,并推导了Cu-EDTA的氧化路径和KMnO₄的作用机理.结果表明:相比单独UV或KMnO₄的作用,UV/KMnO₄能够显著增强Cu-EDTA的氧化效果.在初始pH=3.2、最佳氧化剂和污染物比例为1.2、反应时间为20 min的条件下,Cu的去除效率可以达到92%.随着KMnO₄浓度在0.09～0.9 mmol·L^-1范围内增加,Cu去除率随之增加.粹灭实验表明,与HO·相比,活性锰物种(RMnS)是UV/KMnO₄氧化Cu-EDTA的主要活性物种.采用超高效液相色谱-质谱联用技术分析Cu-EDTA的降解产物,表明其降解遵循脱羧反应.不...     

试论二十一世纪高校体育师资的素质问题

二十一世纪高校体育师资的综合素质提出了更新、更高、更全面的要求,体育老师要跟上时代的步伐,适应现代体育改革与发展的需要就必须进一步提高自身的素质,这是未来高校体育工作的基础和关键.     

用水指标和排水指标的统计计算

通过实例说明一些常见设备的用水指标和排水指标如何统计计算。     

曝气在煤矿酸性矿井水石灰石中和处理中的作用

煤矿酸性矿井水的处理包括三个方面：（１）中和游离的Ｈ２ＳＯ４；（２）驱溶于水的ＣＯ２；（３）除去Ｆｅ、Ａｌ等金属硫酸盐。本文针对目前应用较多的中和塔工艺中存在的问题进行研究、试验，提出了曝气流化床工艺实现酸性矿吉水达标排放的改进措施。