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针对微污染水中浊度及COCMn超标的情况,试验采用石英砂过滤-活性炭吸附过滤的方式进行了连续流微污染水净化研究.过滤前投加混凝剂后采用纤维球进行助凝,混凝剂采用聚合氯化铝.试验结果证明,石英砂过滤加活性炭吸附过滤工艺在运行初期对微污染水中的浊度及CODMn有较好的去除效果,出水浊度及CODMn达到国家农村饮水安全的要求.但运行后期,该工艺对微污染水中的CODMn去除率较低,且反冲后其活性炭的吸附能力不能得到有效恢复,因此,活性炭的有效再生是活性炭用于净化微污染水的必要条件. 相似文献
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供水流程中的摇蚊污染影响水厂生产和自来水水质，S市水厂进行的摇蚊污染特征调查结果表明，污染水厂的摇蚊优势种是花翅摇蚊，水厂孳生的摇蚊来源于进厂原水，摇蚊主要孳生分布在水厂沉淀池。水厂沉淀池形成摇蚊污染的主要原因有：原水的悬浮物和丰富的藻类，沉淀池的温度、溶解氧、pH值，摇蚊幼虫对氯离子和混凝剂浓度的较强耐受性。 相似文献
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供水流程的摇蚊污染影响水厂生产和自来水水质， S市水厂进行了摇蚊污染特征调查表明，污染水厂的摇蚊优势种是花翅摇蚊。水厂孳生的摇蚊来源于进厂原水，摇蚊主要孳生分布在水厂沉淀池。水厂沉淀池形成摇蚊污染的主要原因有：原水的悬浮物和丰富的藻类；沉淀池的温度、溶解氧、pH值，摇蚊幼虫对制水工艺中的氯离子和混凝剂浓度具有较强的耐受性。 相似文献
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研究固定化微生物技术处理微污染水的运行效果，分析载体、微生物、原水高锰酸盐指数等影响因素对固定化微生物技术的净水效能的影响。试验结果表明：工程菌人工固定化形成的生物活性炭对微污染水中有机物去除率较高，并且稳定，高锰酸盐指数去除率平均40%；出水高锰酸盐指数<2.5mg/L，浊度<1.0NTU，细菌总数<100（cfu/mL），总大肠菌群未检出。 相似文献
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近年来,超滤技术已经成为全球饮用水处理领域研究的热点,同时也为其应用于农村饮水安全工程提供了很好的选择。选取浸没式聚偏氟乙烯(PVDF)中空纤维超滤膜作为过滤材料,分别以高岭土、腐殖酸配水模拟农村地表水源中季节性的浊度、天然有机物(NOM)污染,研究了中空纤维超滤膜的处理效果及膜污染特性。结果表明,浸没式超滤膜对原水浊度有较高的耐受负荷,直接超滤时出水有机物浓度与进水有机物浓度成正比,且跨膜压差随进水有机物浓度的增加呈指数增长,投加混凝剂可以延缓膜污染进程,混凝-超滤出水水质符合国家饮用水卫生标准要求。浸没式中空纤维超滤膜适用于农村饮水安全工程。 相似文献
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介绍周口市二水厂针对微污染原水所作的技改实例。该实例将现有的虹吸滤池改为气浮式虹吸滤池，使水处理流程由混凝──沉淀──过滤变为混凝──沉淀──气浮──过滤，从而强化了水处理系统的整体性能及其对原水水质的适应能力。 相似文献
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高锰酸盐复合药剂预氧化处理受污 总被引：3，自引：0，他引：3
水库水因藻类的污染产生嗅味、色度和有机物质含量极大升高；烧杯搅拌试验和生产性试验表明，高锰酸盐复合药剂可显著提高对藻类含量高、有机污染严重且嗅味明显的水库水的处理效果；并且高锰酸盐复合药剂与混凝剂的投加顺序对混凝效果有一定影响，混凝剂后投加高锰酸盐复合药剂效果更好，且存在最佳投量1.5mg/L。 相似文献
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以微囊藻为优势藻的R水库原水及柱孢藻为优势藻的J水库原水为研究对象,分别进行预氧化混凝试验.采用二氧化氯与次氯酸钠作为预氧化剂,按照0:1、1:1及2:1的质量浓度比搭配硫酸铝混凝剂,分析预氧化混凝对藻类及有机物的去除效果,建立合适的预氧化加药策略.结果表明,3种组合均可以提升混凝除藻效果.对于R水库原水,不建议使用二... 相似文献
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利用沸石-活性炭组合填料生物滤池对黄河兰州段微污染原水预处理效果进行了试验研究。采用上向流方式,原水经沸石-活性炭组合填料生物滤池,通过自然挂膜的方法,使生物膜附着生长在填料表面,经比较试验,在不同水力停留时间下,检测污染物的去除效果。进而在气水比、水力停留时间一定的条件下,观察其耐冲击负荷能力,并对沸石-活性炭组合填料滤池与沸石生物滤池和活性炭生物滤池的除污效果进行比较。结果表明：水力停留时间为40 m in,气水比为1∶1,水温在25-30℃的试验条件下,组合填料生物滤池对NH3-N,CODcr,UV254,浊度和锰的平均去除率分别为94.77%,39.92%,10.17%,70.10%,91.30%。因此,沸石-活性炭组合填料生物滤池相对于沸石生物滤池而言,其对微污染原水的预处理效果较明显,且具有较强的耐冲击负荷能力。 相似文献
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对三球悬铃木(俗称法国梧桐)落叶酸碱预处理及其同步糖化发酵产氢工艺进行实验研究,利用修正的冈珀茨模型(Gompertz model)对产氢曲线加以拟合,以累积产氢量和产氢速率为考察指标,研究不同酸碱预处理方法(添加质量分数为2%、4%、6%、8%的H2SO4和Ca(OH)2)对三球悬铃木落叶光合生物产氢性能的影响规律,优化出最佳酸碱预处理工艺条件为:稀酸预处理后的落叶试样的产氢性能优于氢氧化钙预处理后的落叶试样,其中H2SO4质量分数为4%时处理效果最佳,发酵产气中的氢气最大体积分数达66.34%,累积产氢量为369 m L,最高产氢速率11.03 m L/h。稀酸处理液可以实现3次有效回收利用。 相似文献
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M. Galbignani M. C. Merli E. Magnanini F. Bernizzoni I. Talaverano M. Gatti S. Tombesi A. Palliotti S. Poni 《Irrigation Science》2016,34(2):105-116
Testing of new rootstocks for drought tolerance targets traditionally rain-fed districts where supplemental irrigation is more frequently needed due to the pressures of global warming. A seasonal evaluation of gas exchange and water-use efficiency (WUE) of cv. Sangiovese grafted to the new drought-tolerant genotype M4 in a dry-down trial against the commercial SO4 stock is reported. The experiment was conducted in 2014 on twelve 2-year-old, non-fruiting potted Sangiovese grapevines grafted on M4 and SO4 stocks and assigned to SO4-WW (well-watered), SO4-WS (water-stressed), M4-WW and M4-WS treatments. Progressive water deficit was imposed by reducing water supply to 70, 50 and 30 % of whole-canopy demand derived from concurrent measurements of transpiration in WW. Unlike SO4, M4 showed slower stress progression, as highlighted by pre-dawn leaf water potential, and retained higher whole-canopy net CO2 exchange rates (NCER) and transpiration rates per unit of leaf area at all replenishment levels as well as exhibiting higher canopy WUE at both 50 and 30 % WW. Although single-leaf assessment was in partial disagreement with data recorded on the whole-canopy basis, robust data were acquired to confirm that the M4 stock performs better than SO4 at any water replenishment level in terms of higher NCER/leaf area and/or canopy WUE. Findings feed expectations that grafting Sangiovese to the M4 rootstock should result in a problem-solving tool for rain-fed areas subject to temporary summer drought. 相似文献
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温度及矿化度对土壤持水性能的影响 总被引：2，自引：0，他引：2
采用离心机法测定了不同矿化度(1、3、5、10g/L)的NaCl和Na2SO4溶液在不同温度条件下(5、10、20、30℃)对土壤水分特征曲线及其van Genuchten方程参数的影响。结果表明,温度与θs、α均呈现显著的负相关,相关系数分别为-0.83、-0.99;θs与α呈极显著的正相关关系,与n呈极显著的负相关关系,α与n呈极显著的负相关关系。溶液的盐分类型对土壤水分特征曲线的影响在不同的吸力段影响不同,在近饱和段影响比较明显,且对参数α值也有显著影响,其中Na2SO4的影响较NaCl明显。溶液矿化度对土壤水分特征曲线参数(θs,α,n)的影响均不显著。 相似文献
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Soil water movement under a single surface trickle source 总被引：5，自引：0，他引：5
Under a trickle source, the flow of water in unsaturated soil takes place from a disc source having a radius changing with time due to change in the rate of infiltration. To predict the wetting pattern below an emitter placed on the soil surface, an unsteady, non-linearised numerical model has been developed in an oblate spheroidal coordinate system. Using this coordinate system, the problem involving disc source geometry having radius changing with time, is simplified, as the disc is a degenerate case of an oblate spheroid. The results of the proposed model are in close agreement with the experimental results of [Taghavi, S.A., Marino, M.A., Rolston, E., 1984. Infiltration from a trickle irrigation source. J. Irrig. Drain. Eng. ASCE 110 (4), 331–341] and the numerical model of [Bresler, E., 1978. Analysis of trickle irrigation with application to design problems. Irrig. Sci. 1, 3–17] developed in cylindrical coordinates. The applicability of the model has been analysed for special conditions of trickle irrigation e.g. large time water application, redistribution of soil water after discharge is cut off or reduced, and basin irrigation with restriction of surface water flow. 相似文献
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Summary Water stress was imposed upon soybean [Glyxine max (L.) Merr. cv. Williams] and maize [Zea mays (L.) cv. Pioneer 3377] plants grown under controlled-environment conditions during a growing period of several irrigation cycles. Transpiration rates of individual plants were measured with a calibrated heat-pulse method and correlated to the rate of water loss obtained from successive weighings of the pots containing irrigated or water-stressed plants. Transpiration rate was reduced in the stressed plants of both species, but the reduction was not linear with decreasing soil matric potential. Transpiration rates declined rapidly at high soil matric potential, and dropped more slowly as the soil dried. Although measured transpiration rate declined by nearly 30% following a reduction of soil matric potential to -0.1 MPa, differences in leaf water potential and CO2 assimilation rate were small and less than the sensitivity of the measurement techniques used. Total system resistance to water flow increased as the soil dried. 相似文献
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对有机化学品的定量结构-生物降解性相关(QSBR)研究可节约试验量,并快速对环境行为未知的化学品进行生态风险评估,实现有毒有害化学品污染管理的"预先防范原则"。通过生物降解试验测定黄河细菌对17种取代酚的一级降解动力学常数K,并分别采用量子化学法和基团贡献法利用SPSS19.0软件进行了QSBR研究。结果表明,所得模型相关系数平方的校正值Radj2分别为0.853和0.848。模型显示,Mw和ELUMO可以很好地描述黄河细菌对取代酚的生物降解性,位阻效应是影响黄河包头段细菌对酚类生物降解的主要因素,化合物分子对电子的亲和能力对其生物降解性也有一定影响;不同官能团对取代酚的生物降解性抑制作用不同,其强弱顺序为:[Cl][NO2][C2H5][OCH3][CH3][OH]。 相似文献
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微灌砂滤料的表层过滤和气水反冲洗试验研究 总被引：1，自引：0，他引：1
采用砂过滤器模型,在3种滤料粒径的条件下进行了过滤和气水反冲洗试验研究。根据在不同的过滤速度、原水颗粒质量分数、粉煤灰粒径条件下测得的滤层表面的压力,判断各因素与发生表层过滤的关系。以出水浊度随时间的变化,对比3种加气模式以及单纯水洗的效果。试验结果表明,原水颗粒质量分数和煤灰粒径是发生表层过滤的主要影响因素,且砂滤料的粒径越小,越容易发生表层过滤,在一定速度范围内过滤速度的影响最小。反冲洗以出水浊度为指标,气冲-气水混冲-水冲与气水混冲-水冲要优于气冲-水冲和单纯水洗的效果。 相似文献
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[Objective]The objective of this paper is to experimentally investigate the responsive change in yield and water use efficiency of cotton to irrigation frequency after soil loosening.[Method]The experiment was conducted from 2016 to 2017 after deeply loosening soil. By keeping the irrigation amount the same, we compared three irrigation frequencies: Irrigating once in each 4 day (D4), 7 days (D7) and 10 days (D10) respectively. The associated irrigation times were 17, 10 and 7 respectively. In each treatment, we measured soil moisture, dry matter accumulation, water consumption, water use efficiency and the yield of the crop.[Result]After deep loosening, keeping irrigation frequency at a moderate level (D7) significantly enhanced water-holding capacity of the 0~ 20 cm soil, thereby facilitating distribution of dry matter to different organs in the bud and boll and consequently improving the water use efficiency (WUE). Compared to D4 and D10, D7 increased WUE by 15.5% and 10.5% in 2016 and 16.5% and 9.2% in 2017, respectively. Increasing irrigation frequency promoted vegetative growth and reduced distribution of the dry matter to organs in the bud and boll. In contrast, reducing irrigation frequency reduced the accumulation of total dry matter, storage of water in the top soil and water consumption. Compared to D4 and D10, D7 increased the yield by 13.8% and 7.0% in 2016, and 17.3% and 6.1% in 2017. The main mechanism underlying in yield increase in D7 was the increase in boll number and average weight of the bolls in each plant. [Conclusion]Irrigating once after each 7 days, together with deep soil loosening, can effectively promote vegetative growth and organ production from dry matter, thereby facilitating the conversion of dry matter to organs and improving cotton yield and its water use efficiency. © 2019 TEST-ZL Publishing, LLC. All rights reserved. 相似文献