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51.
52.
喀斯特峡谷区工程性缺水原因及解决途径——以贵州省花江峡谷示范区为例 总被引:3,自引:0,他引:3
喀斯特峡谷区河深坡陡,地下水深埋,水资源利用难度大,加之经济和水利工程薄弱,是贵州省工程性缺水的典型区域。通过对花江峡谷示范区工程性缺水的原因剖析,提出一系列解决工程性缺水问题的措施,如雨水收集、表层喀斯特水和基岩裂隙水的开发利用、节水、加强对水利工程设施的管理和维护、加大水利投入以及提高植被覆盖率等,这对解决喀斯特峡谷及类似区域的工程性缺水问题有一定的指导和参考意义。 相似文献
53.
54.
将活性污泥培养及驯化后接种于生物滴滤塔中,挂膜启动后处理模拟氯苯废气(简称氯苯废气),考察了生物滴滤塔在挂膜启动阶段及稳定运行阶段的性能。实验结果表明:接种41 d后生物滴滤塔成功挂膜,此时氯苯去除率稳定在90%以上;生物滴滤塔稳定运行阶段,随着进气中氯苯质量浓度由303.82 mg/m3逐渐增至1 489.05 mg/m3,氯苯去除率从85.1%降至70.1%。处理氯苯废气适宜的工艺条件为:空塔停留时间超过45 s,喷淋液流量31.8 mL/min,氯苯负荷23.97~128.01 g/(m3·h)。生物滴滤塔对喷淋液的酸性环境有较好的适应性,喷淋液pH的变化对氯苯去除率无显著影响。 相似文献
55.
研究了混凝一气浮工艺对不同分子量区间三卤甲烷生成势(trihalomethanes formation potential,THMFP)的去除效果及絮体形态对THMFP去除效果的影响。结果表明,混凝一气浮工艺以去除大分子量区间THMFP为主,对小分子量区间THMFP的去除效果较差。UV254值与THMFP值的线性相关系数为0.9449,UV254值可以较好地反映THMFP的含量。絮体的分形维数为1.17~1.2时,孔隙率较大,可增加絮体对THMFP的活性吸附空间,且絮体相对密度较小,可增强同向絮凝作用,增加絮体和THMFP的接触概率,有利于气浮对THMFP的去除。 相似文献
56.
Jan Bernd Barhorst Roland Kubiak 《Environmental science and pollution research international》2009,16(5):582-589
Background, aim and scope The use of sodium hypochlorite (HYP) in viticulture results in effluents which are contaminated with halogenated substances.
These disinfection by-products (DBPs) can be quantified as group parameter ‘adsorbable organic halogens’ (AOX) and have not
been determined in effluents of viticulture yet. The substances that are detected as AOX are unknown. The AOX can be composed
of harmless substances, but even toxic contaminants. Thus, it is impossible to assess ecological impacts. The aim of this
study is to determine the quantification of AOX and DBPs after the use of HYP. This will be helpful to reduce environmental
pollution by AOX.
Materials and methods The potential of HYP to generate AOX was determined in laboratory-scale experiments. Different model solutions were treated
with HYP according to disinfection processes in viticulture and conditions of AOX formation in effluents were simulated. AOX
were quantified using the flask-shaking method and identified DBPs were investigated by gas chromatography–mass spectrometry.
Results Treatment with HYP resulted in the formation of AOX. The percentage conversion of HYP to AOX was up to 11%. Most important
identified DBPs in viticulture are chloroform, dichloroacetic acid and trichloroacetaldehyde. In addition, the formation of
carbon tetrachloride (CT), 1,1,1-trichloropropanone, 2,4-dichlorobenzoic acid and 2-chloro-/2,4-dichlorophenylacetic acid
was investigated. It was demonstrated that reaction temperature, concentration of HYP and type of organic matter have important
influence on the formation of chlorinated DBPs.
Discussion The percentage conversion of HYP to AOX was similar to other published studies. Although a correlation of single compounds
and AOX is difficult, chloroform was the predominant AOX. Generation of the volatile chloroform should be avoided due to possible
adverse effects. The generation of dichloroacetic acid is of minor importance on account of biodegradation. Trichloroacetaldehyde
and 1,1,1-trichloropropanone are weak mutagens and their formation should be avoided.
Conclusions The generation of AOX and chlorinated DBPs can be minimised by reducing the concentrations of the organic materials in the
effluents. The removal of organic matter before disinfection results in a decreased formation of AOX. HYP is an effective
disinfectant; therefore, it should be used at low temperatures and concentrations to reduce the amount of AOX. If possible,
disinfection should be accomplished by the use of no chlorine-containing agents. By this means, negative influences of HYP
on the quality of wine can also be avoided.
Recommendations and perspectives Our results indicate that HYP has a high potential to form AOX in effluents of viticulture. The predominant by-products are
chloroform, dichloroacetic acid and trichloroacetaldehyde. In further research, wastewaters from a winery and the in- and
outflows of two sewage treatment plants were sampled during vintage and analysed. These results will be discussed in a following
paper. 相似文献
57.
城市污水处理厂第二沉淀池出水的污染物浓度较低,经过矿化及灭菌等深度处理后可以回用,从而减轻对淡水资源的需求。本实验采用溶胶-凝胶法制备了负载TiO2的浮石光催化剂,对城市污水处理厂第二沉淀池出水进行了矿化及灭菌处理研究。采用低压汞灯对处理水样照射2h,有机物降解率可以达到50%,灭菌效率达到100%。处理后的水可以作为农作物灌溉、城市绿化和娱乐用水。负载在浮石表面的TiO2薄膜经过10次的光催化循环实验后,没有明显破损,可以再次循环使用。TiO2浮石具有质轻、机械性能好和价格低等优点,该方法处理废水的适用浓度低,可以广泛应用于微污染水和城市污水处理厂出水的深度处理。 相似文献
58.
Tim S. Nawrot Nino Kuenzli Jordi Sunyer Tingming Shi Teresa Moreno Mar Viana Joachim Heinrich Bertil Forsberg Frank J. Kelly Muhammad Sughis Benoit Nemery Paul Borm 《Atmospheric environment (Oxford, England : 1994)》2009,43(30):4595-4602
We assessed the extent to which constituents of PM2.5 (transition metals, sodium, chloride) contribute to the ability to generate hydroxyl radicals (OH) in vitro in PM2.5 sampled at 20 locations in 19 European centres participating in the European Community Respiratory Health Survey. PM2.5 samples (n = 716) were collected on filters over one year and the oxidative activity of particle suspensions obtained from these filters was then assessed by measuring their ability to generate OH in the presence of hydrogen peroxide. Associations between OH formation and the studied PM constituents were heterogeneous. The total explained variance ranged from 85% in Norwich to only 6% in Albacete. Among the 20 centres, 15 showed positive correlations between one or more of the measured transition metals (copper, iron, manganese, lead, vanadium and titanium) and OH formation. In 9 of 20 centres OH formation was negatively associated with chloride, and in 3 centres with sodium. Across 19 European cities, elements which explained the largest variations in OH formation were chloride, iron and sodium. 相似文献
59.
This study reports on the effect of microwave radiation for inactivation of Ascaris lumbricoides eggs in 25 g of soil compared to ultraviolet irradiation and ozone expose. Microwave radiation at 700 W with 14% water content (w/w) achieved approximately 2.5 log inactivation of eggs in soil within 60 s. On the other hand, UV irradiation at 3 mW cm−2 with and without shaking soil for 3600 s achieved approximately 0.32 and 0.01 log inactivation of eggs, respectively. In ozone treatment, 0.13 log inactivation of eggs was achieved with 5.8 ± 0.7 mg L−1 of dissolved ozone dose for 30 min in a continuous diffusion reactor. In addition, the inactivation of eggs by three disinfection techniques was conducted in water in order to compare the inactivation efficiency of eggs in soil. The inactivation efficiency of microwave radiation was found to be no significant difference between in soil and water. However, the inactivation efficiency of UV irradiation was significantly increased in water while in ozone expose there was no significant difference between in soil and water. Microwave treatment thus proved to be the most efficient method in controlling A. lumbricoides eggs in soil. 相似文献
60.
污水处理中紫外消毒方法与传统消毒方法相比之下具有不需要投加化学药剂、不产生有毒有害副产物、消毒效率高、操作简单、便于运行管理等特点。本文着重介绍了目前用于消毒的紫外灯的种类,并阐述了浊度、微生物种类、光复活性能等影响紫外消毒效果的因素,最后对未来紫外消毒方法发展的前景做出了分析。 相似文献