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1.
为探究表面流人工湿地设计参数对水力性能和净化效果的影响,分析设计参数与水力性能指标和净化效果指标之间的关系性,优选综合考虑水力性能和净化效果的设计参数组合,对表面流人工湿地设计参数(长宽比、水深、植物间距、流量、进出口布置、植物种类)开展正交试验。结果表明:设计参数对净化效果有显著的影响,各水力性能指标之间、以及净化效果指标之间均存在极显著的相关性,水力性能指标与净化效果指标之间存在一定的相关性。长宽比、水深和植物间距是影响表面流人工湿地水力性能和净化效果的主要设计参数,尤其以长宽比的影响最为显著。在试验条件下,表面流人工湿地最优设计参数组合为长宽比4∶1、水深30 cm、植物间距20 cm、流量0.55 m3/h、进出口中进中出布置、水生植物水葱。 相似文献
2.
采用环境流体动力学模型(environmental fluid dynamics code,EFDC)建立表面流人工湿地水动力-水质耦合模型,研究隔板长度与湿地长度比值(简称隔长比)对表面流人工湿地水力性能及净化效果的影响规律,优选适宜的隔长比。结果表明:1)率定和验证的12组结果中,水动力模型模拟评价结果为中等及以上,即相关系数0.7、纳什系数0.4、相对误差20%,的有7组,水质模型模拟评价结果为中等及以上,即相对误差20%,的有10组。2)表面流人工湿地适宜隔长比随长宽比的增加而增大,当长宽比由1、2、4变为4、8、16时,对应的适宜隔长比分别为0.675、0.850、0.938。3)表面流人工湿地主要水力指标随适宜隔长比的增大而增加,对净化效果指标的提升不明显。4)在适宜隔长比不变的情况下增加湿地的表面积能明显提升水质净化效果(50%)。研究可为表面流人工湿地实际工程设计提供依据。 相似文献
3.
《水土保持学报》2014,(3)
通过3年(2011-2013年)的系统性试验,主要考察水平潜流以及复合流(波形)人工湿地对城市雨水径流的净化效果。分别研究2种人工湿地在不同水深(350,550,750mm)下,水力停留时间(24,36,48,72h)、运行间隔天数(1,3,5,7,10,15d)等的最佳组合工况,最后对3种水深下的净化效果进行对比。结果表明:一般工况下,水平潜流人工湿地对污染物浓度去除率和负荷削减率均值分别为53.62%和57.37%,复合潜流人工湿地净化效果比水平流高出7%左右。2组人工湿地在3种水深下的最佳水力停留时间为48h,最佳运行间隔天数为7~10d,此时水平潜流人工湿地对污染物浓度去除率和负荷削减率均值分别为64.46%和68.45%,复合潜流人工湿地净化效果比水平流高出6.2%左右。750mm水深时水平潜流人工湿地对污染物的浓度去除率比350mm和550mm水深时分别高出32.21%和5.88%,负荷削减率分别高出31.60%和5.92%;复合流湿地浓度去除率比前2种水深时分别高出26.14%和5.06%,负荷削减率分别高出25.89%和5.07%。设计的2组人工湿地系统净化效果良好,复合流人工湿地净化效果优于水平潜流,均可用于城市面源污染控制和雨水利用。 相似文献
4.
在自行建造的IVCW系统模型上,通过对富营养化湖库水体的处理试验,研究水力负荷对富营养化水体净化效果的影响,进而为人工湿地系统构建提供参考依据. 相似文献
5.
双向对冲流滴灌灌水器是1种可形成急转流、正反双向流、以及对冲混掺流等加大能量耗散效果的新型灌水器。为研究灌水器的水力性能以及流道几何参数对水力特性的影响,取灌水器几何参数作为因素,采用正交设计安排25组试验方案,开展水力性能测试,计算流道的局部损失系数,同时对正交试验结果进行直观和方差分析,建立几何参数与流态指数的回归模型。结果表明,灌水器流态指数为0.432～0.464,其水力性能良好。单元流道的局部损失系数为6.698～19.130,显示优越的消能效果。挡水件与分水件最大过水通道宽度对流态指数的影响最大。建立的几何参数与流态指数之间的回归模型R2=0.94,且验证表明其估算值与试验值相对误差小于5%,可可靠地估算流态指数。研究可为双向对冲流滴灌灌水器水力性能预研和评估、结构优化提供参考。 相似文献
6.
研究了新型复式潜流人工湿地对生活污水的净化效果。在不同水力负荷、季节、曝气方式等条件下经过小试试验,分析了该湿地对污染物净化效果的影响。结果表明,该系统出水水质稳定,达到《城镇污水处理厂污染物排放标准》(GB 18918—2002)的一级A标准。在水力负荷184 mm·d-1条件下COD、NH3-N去除率最大分别可达87.2%、68.9%。冬季低温条件下对各类污染物去除率仍大于20%。正交试验分析得知,最佳运行条件是气温28.6℃、水力负荷0.184 m3·m-2·d-1、水力停留时间2.4 d。对比试验表明,采用预曝气方式对湿地净化效果明显优于厌氧处理。 相似文献
7.
垂直流人工湿地处理生活污水的试验 总被引：3，自引：1，他引：3
通过将强化混凝引入到垂直流人工湿地水质净化系统,从而提高了人工湿地的处理效率。试验证明,该预处理装置的设置降低了湿地负荷,提高了人工湿地对污水的净化效率,特别是对有机污染物有较好的去除效果。改良后的湿地系统对生活污水污染物净化具有良好效果,且运行成本低,适用于土地资源比较丰富、资金紧张的地区。 相似文献
8.
双向对冲流灌水器水力性能和消能机理模拟与验证 总被引：2，自引：2，他引：0
为研究双向对冲流灌水器的水力性能和消能机理,安排25组试验方案,开展流量测试与模拟计算,选取模拟精度较高的湍流模型计算不同压力区间的流态指数、正反向水流流量比,分析正反向水流分布情况。结果表明,RNG k-ε模型的流量计算值与实测值的相对误差为1.656%~3.151%,与其他模型相比,RNG k-ε模型的相对误差较小;灌水器的流态指数为0.414~0.483,水力性能良好,尤其在低压区间,流态指数为0.414~0.456,正反向水流流量比趋近于1,水力性能更加突出;随压力的增大,反向水流的流量增幅较快,流量比减小,水力性能降低;正反向水流在挡水装置的齿尖形成对冲与混掺是消能的核心,而水流分布不均会影响灌水器的消能效果;在灌水器边壁增加多个改变流向的挡水装置,可优化双向水流配比,提高水力性能,从而验证不同压力区间、不同流量比与水力性能的内在关系。研究可对灌水器结构优化、水力性能提高提供参考。 相似文献
9.
同等条件下开展了3种不同类型人工湿地（垂直流、潜流和表面流人工之地）对洞庭湖水质净化效果的研究。结果表明:（1）洞庭湖水体中NH4+-N,TN,TP,高锰酸钾指数,BOD5和CODCr的进水浓度与3种不同类型人工湿地出水浓度季节变化规律保持一致,冬季明显高于夏季,洞庭湖进水中NH4+-N,TN,TP,高锰酸钾指数,BOD5和CODCr浓度均高于3种不同类型人工湿地出水浓度,相同时期,3种不同类型人工湿地出水水质NH4+-N,TN,TP,高锰酸钾指数、BOD5和CODCr浓度基本表现为表面流 > 潜流 > 垂直流;（2）3种类型人工湿地对TN,TP,高锰酸钾指数、BOD5和CODCr的去除率依次表现为垂直流 > 潜流 > 表面流,而对NH4+-N的去除率依次表现为垂直流 > 表面流 > 潜流,其中以BOD5的去除效果最好（去除率最高）,但3种类型人工湿地对BOD5的去除率差异均不显著（p > 0.05）;（3）3种类型人工湿地植物地上和地下生物量均表现为垂直流 > 潜流 > 表面流,差异均显著（p < 0.05）,垂直流人工湿地植被N含量、P含量、N积累量和P积累量均显著高于潜流和表面流（p < 0.05）;（4）3种不同类型人工湿地植物的N,P积累量分别与生物量、N含量、P含量均呈显著的线性关系（p < 0.01）,人工湿地植物生物量对N,P积累量的影响大于植物体内N,P含量的影响,可以通过生物量来评价人工湿地植物对N,P去除效果。 相似文献
10.
多级串联表面流人工湿地净化生活污水效果 总被引：2，自引：2，他引：0
农村生活污水已经成为农业面源污染的主要来源之一。为了研究如何在经济发展水平不高的农村建立能有效治理农村生活污水,且建设成本低、运行维护简单的人工湿地系统,该文通过在桂林市青狮潭灌区构建了多级串联的表面流人工湿地系统,研究分析了不同子系统的水质净化效果及相关检测指标浓度的沿程变化规律。研究结果表明,湿地系统对氮磷的去除效率总体呈现出随时间推移逐渐下降的趋势,同时湿地的表面积越大,其对氮磷的去除率越高。研究还发现,该湿地系统对高浓度进水具有快速、稳定的去除效果,而对低浓度进水的营养盐去除则表现得较为平缓和持久。通过对湿地系统沿程氮磷浓度衰减的拟合及回归分析,建立了与湿地系统进口浓度有关的TN、NH4+-N和TP浓度的沿程衰减模型,相关分析表明其最佳的拟合模型均为指数衰减模型。该湿地系统在整个试验时期内均表现出了良好的净化效果,有效地减轻了农村生活污水对外界水环境的破坏,指数衰减模型的建立也为后续湿地设计及排水水质预测提供了理论分析依据。 相似文献
11.
【目的】以富士（Fuji）、 秦冠（Qinguan）嫁接在平邑甜茶（Malus hupehensis Rehd.）上的当年生盆栽苗为试验材料,采用砂培方法,研究了缺氮胁迫和干旱对富士和秦冠生长情况、 光合参数、 植株各部位氮磷钾含量及氮素利用效率的影响,分析比较了低氮干旱条件下富士和秦冠生长及氮素利用的差异,以期为果树生产高效肥水利用提供理论指导。【方法】试验共设四个处理: 正常氮正常水（ZZ）、 低氮正常水（DZ）、 正常氮干旱（ZG）、 低氮干旱（DG）。氮素和水分均设置两个水平,分别为正常氮（6 mmol/L NO-3-N）、 低氮（0.3 mmol/LNO-3-N）、 正常供水（保持盆中砂子相对含水量为饱和含水量的80%~85%）、 干旱处理（保持盆中砂子相对含水量为饱和含水量的60%~65%）。【结果】富士和秦冠的生物量（茎和叶）、 株高茎粗等生长指标以及光合速率、 气孔导度、 蒸腾速率均为正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）,并且相对应处理下秦冠的以上指标均高于富士;正常供水下,缺氮处理使富士、 秦冠的根冠比比正常氮处理均有所增加,富士提高了2.05%,秦冠提高了22.40%。富士和秦冠的氮、 磷、 钾含量均表现出正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）; 氮、 钾元素含量在植株各部位的分布顺序依次是叶＞根＞茎,磷元素则是根＞叶＞茎;光合氮素利用效率（PNUE）和氮素利用效率表现为秦冠处理之间差异极显著,富士处理之间差异不显著;秦冠的PNUE和NUE明显高于富士,在低氮正常水（DZ）处理下,秦冠氮肥利用率比富士高42.07%,在低氮干旱（DG）处理下高64.14%;低氮胁迫下富士和秦冠的NUE显著提高,并且秦冠提高的幅度高于富士。【结论】施用氮肥能够显著提高富士与秦冠的干物质量,同等水肥条件下,秦冠生长优于富士;水分亏缺会减少叶片对氮的吸收,干旱条件下适度增施氮肥,可提高果树的抗旱能力;低氮干旱胁迫下秦冠的生长指标、 光合指标及氮素利用效率指标均优于富士,表现出较强的抗低氮干旱胁迫的能力。 相似文献
12.
Kyle Devey Michael Mucalo Gordon Rajendram Joseph Lane 《Communications in Soil Science and Plant Analysis》2015,46(4):72-80
Laser-induced breakdown spectroscopy (LIBS) is a new technique for the analysis of plant material. This study investigates the application of LIBS to pasture-based plant samples. The LIBS measurements were obtained from pelletized pasture samples (100 samples) that had been also analyzed by inductively coupled plasma–optical emission spectroscopy (ICP-OES) following microwave digestion for calibration and comparison purposes. Comparisons for elements sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), boron (B), phosphorus (P), and sulfur (S) showed that LIBS could be used for almost all the standard profile total elements with concentrations down to low mg/kg levels (observed error of Na: 0.024 percent, K: 0.18 percent, Mg: 0.016 percent, Ca: 0.073 percent, P: 0.017 percent, Mn: 31 mg/kg, Fe: 150 mg/kg, Zn: 6.6 mg/kg, and B: 1.1 mg/kg). Elemental analysis at less than mg/kg levels was not possible using LIBS. The elements S and Cu were particularly difficult to analyze with reliability using LIBS at the concentration levels found in the plant samples. Replacing microwave digestion and subsequent ICP analysis with a direct analysis of dried plant samples using LIBS has the potential to improve the productivity and reduce the cost of testing. 相似文献
13.
《中国生态农业学报》2014,(8)
正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology, 相似文献
14.
M.A. Callaham Jr. J.M. BlairT.C. Todd D.J. KitchenM.R. Whiles 《Soil biology & biochemistry》2003,35(8):1079-1093
The responses of tallgrass prairie plant communities and ecosystem processes to fire and grazing are well characterized. However, responses of invertebrate consumer groups, and particularly soil-dwelling organisms, to these disturbances are not well known. At Konza Prairie Biological Station, we sampled soil macroinvertebrates in 1994 and 1999 as part of a long-term experiment designed to examine the effects and interactions of annual fire, mowing, and fertilization (N and P) on prairie soil communities and processes. For nearly all taxa, in both years, responses were characterized by significant treatment interactions, but some general patterns were evident. Introduced European earthworms (Aporrectodea spp. and Octolasion spp.) were most abundant in plots where fire was excluded, and the proportion of the total earthworm community consisting of introduced earthworms was greater in unburned, unmowed, and fertilized plots. Nymphs of two Cicada genera were collected (Cicadetta spp. and Tibicen spp.). Cicadetta nymphs were more abundant in burned plots, but mowing reduced their abundance. Tibicen nymphs were collected almost exclusively from unburned plots. Treatment effects on herbivorous beetle larvae (Scarabaeidae, Elateridae, and Curculionidae) were variable, but nutrient additions (N or P) usually resulted in greater densities, whereas mowing usually resulted in lower densities. Our results suggest that departures from historical disturbance regimes (i.e. frequent fire and grazing) may render soils more susceptible to increased numbers of European earthworms, and that interactions between fire, aboveground biomass removal, and vegetation responses affect the structure and composition of invertebrate communities in tallgrass prairie soils. 相似文献
15.
Grete Skrede Berit Karoline Martinsen Anne-Berit Wold Stein-Erik Birkeland Kjersti Aaby 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(3):193-208
Abstract A 3-year study was carried out to investigate quality parameters in 14 tree fruit and berry species grown in southern Norway. The species were blueberry, apple, aronia, sour cherry, sweet cherry, red raspberry, strawberry, blackcurrant, gooseberry, red currant and elderberry, harvested along with wild bilberry, cloudberry and lingonberry. Significant differences between species were identified for all quality parameters. The coefficient of variation between species was lowest for pH (12.5%), dry matter (18.9%) and soluble solids (25.3%), followed by titratable acids (59.3%), total phenolics (83.8%), antioxidant capacity FRAP (85.7%) and antiradical power by the DPPH-assay (97.8%), total monomeric anthocyanins (132%) and ascorbic acid (137%). Average coefficient of variation within species were lower and ranged from 4 (pH) to 62% (ascorbic acid). Only the FRAP values were significantly affected by harvesting year with lower levels in 2004 than in 2005 and 2006. There were significant interactions between species and harvesting year for dry matter, soluble solids, pH, ascorbic acid and FRAP. The results indicate generic ranges in composition within species independent upon growing location and climate, and the composition of the tree fruits and berries is not likely to deviate from these ranges. It is concluded that desirable composition of tree fruits and berries and their products should primarily be achieved by selection among species rather than searching fors broadened variation within individual species. 相似文献
16.
《Communications in Soil Science and Plant Analysis》2012,43(7):865-877
Potassium (K) fixation and release in soil are important factors in the long-term sustainability of a cropping system. Changes in K concentration and characteristics of K fixation and release in rhizosphere and nonrhizosphere soils in the rapeseed (Brassica napus L.)–rice (Oryza sativa L.) rotation were investigated using a rhizobox system. The concentrations of different forms of K in both rhizosphere and nonrhizosphere soils decreased with plants compared to without plants, regardless of K fertilizer application. Potassium uptake by crops mainly came from the rhizosphere soil. In the treatment without K fertilizer (–K), the main form of K supplied by the soil to the crops was 1.0 mol L?1 nitric acid (HNO3) nonextractable K, followed by nonexchangeable K, and then exchangeable K. In the treatment with K fertilizer (+K), the main K forms supplied by the soil to the crops were exchangeable K and nonexchangeable K. The amount and rate of K fixation after one cycle of the rapeseed–rice rotation was greater in rhizosphere soil than in nonrhizosphere soil. The amount and rate of K fixation of soil in the +K treatment were significantly less than in the –K treatment. The cumulative amounts of K released with 1.0 mol L?1 ammonium acetate (NH4OAc) and 1.0 mol L?1 HNO3 extraction increased with the increasing numbers of extractions, but the K-releasing power of soil by successive extraction decreased gradually and finally became almost constant. The release of K was less in rhizosphere soil than in nonrhizosphere soil. The release of K in the +K treatment was similar to that in the –K treatment in rhizosphere soil, but the K release in nonrhizosphere soil was greater with the +K than the –K treatment. Overall, the information obtained in this study will be helpful in formulating more precise K fertilizer recommendations for certain soils. 相似文献
17.
Electron donor and pH relationships for biologically enhanced dissolution of chlorinated solvent DNAPL in groundwater 总被引：3，自引：0，他引：3
Biologically enhanced dissolution offers a method to speed removal of chlorinated solvent dense non-aqueous-phase liquid (DNAPL) sources such as tetrachloroethene (PCE) and trichoroethene (TCE) from aquifers. Bioremediation is accomplished by adding an electron donor to the source zone where fermentation to intermediates leading to acetic acid and hydrogen results. The hydrogen and possibly acetic acid are used by dehalogenating bacteria to convert PCE and TCE to ethene and hydrochloric acid. Reductive dehalogenation is thus an acid forming process, and sufficient alkalinity must be present to maintain a near neutral pH. The bicarbonate alkalinity required to maintain pH above 6.5 is a function of the electron donor: 800 mg/L of bicarbonate alkalinity is sufficient to achieve about 1.2 mM TCE dechlorination with glucose, 1.7 mM with lactate, and a much higher 3.3 mM with formate. Laboratory studies indicate that in mixed culture, formate can be used as an electron donor for complete conversion to ethene, contrary to pure cultures studies indicating it cannot. Various strategies can be used to add electron donor to an aquifer for DNAPL dehalogenation while minimizing pH problems and excessive electron donor usage, including use of injection-extraction wells, dual recirculation wells, and nested injection-extraction wells. 相似文献
18.
Aleš Lebeda Ivana Doležalová Eva Křístková Barbora Mieslerová 《Genetic Resources and Crop Evolution》2001,48(2):153-164
Staff members of the Department of Botany of Palacký University in Olomouc and Gene Bank Department – Workplace Olomouc, Research Institute of Crop Production in Prague, Czech Republic, conducted an expedition in seven European countries (Austria, Czech Republic, France, Germany, Italy, the Netherlands, Switzerland) in August/September 1999 to collect wild Lactuca spp. germplasm and study its geographic distribution, ecology and biodiversity. During the mission, more than 600 locations were visited resulting in the collection of 602 seed samples (accessions) of wild Lactuca species and 13 seed samples of related genera (Chondrilla and Mycelis). Lactuca serriola f. serriola, L. serriola f. integrifolia, L. saligna and L. viminea subsp. chondrilliflora were prevalent in southern Europe (Italy, France), however, only L. serriola was common in central and western Europe (Austria, Czech Republic, Germany, Netherlands, Switzerland). The greatest diversity of Lactuca species was found in France, where also the most seed samples (165) were collected. The most characteristic habitats with a high density of Lactuca spp. populations were observed along roads and highways, grassy ditches, ruderal communities, and dust-heaps. Natural infections by powdery mildew (Erysiphe cichoracearum) and downy mildew (Bremia lactucae) on some wild Lactuca spp. were observed. Recent observations concerning the geographic distribution, population structure, habitats, and natural occurrence of diseases of Lactuca spp. are discussed. This assemblage of genetic resources of Lactuca spp. can serve as the basis of future studies of species diversification, spatial population structure, plant microevolution, domestication processes, and genetic variability of host-parasite interactions. 相似文献
19.
Y. Bashan J. J. Bustillos L. A. Leyva J.-P. Hernandez M. Bacilio 《Biology and Fertility of Soils》2006,42(4):279-285
Inoculation of wheat seedlings with the plant growth-promoting bacterium Azospirillum brasilense Cd was immobilized in alginate microbeads and, without applying any stress, significantly increased the quantity of several
photosynthetic pigments, such as chlorophyll a, chlorophyll b, and the auxiliary photoprotective pigments violaxanthin, zeaxanthin, antheroxanthin, lutein, neoxanthin, and β-carotene.
This resulted in greener plants with no apparent visible stress. After monitoring the quantity of photosynthetic pigments
for 4 weeks, we observed that inoculated plants had higher quantities of pigments in shoot and stem. The greatest difference
in the quantity of all pigments between inoculated and noninoculated plants occurred in the first week of growth. Regardless
of treatment, the quantity of pigments in stems was three to four times less than the quantity of these pigments in shoots.
Application of Azospirillum, either as liquid inoculant or as alginate microbeads, did not alter the positive effect of the bacteria on pigment production
or the positive response of the plants towards A. brasilense Cd inoculation. 相似文献
20.
Three slow-growing legume trees used for desert reforestation and urban gardening in the Sonoran Desert of Northwestern Mexico
and the Southwestern USA were evaluated whether their growth can be promoted by inoculation with plant growth-promoting bacteria
(Azospirillum brasilense and Bacillus pumilus), unidentified arbuscular mycorrhizal (AM) fungi (mainly Glomus sp.), and supplementation with common compost under regular screenhouse cultivation common to these trees in nurseries. Mesquite
amargo (Prosopis articulata) and yellow palo verde (Parkinsonia microphylla) had different positive responses to several of the parameters tested while blue palo verde (Parkinsonia florida) did not respond. Survival of all tree species was over 80% and survival of mesquite was almost 100% after 10 months of cultivation.
Inoculation with growth-promoting microorganisms induced significant effects on the leaf gas exchange of these trees, measured
as transpiration and diffusive resistance, when these trees were cultivated without water restrictions. 相似文献