多阶段生活垃圾接种堆肥水溶性有机物荧光特性表征研究

为提高堆肥效率，采取多阶段接种技术（MSIC）进行城市生活垃圾堆肥实验，并运用荧光分析技术，对不同堆肥阶段样品提取出的水溶性有机物（DOM）的变化进行跟踪分析。荧光同步光谱分析显示：堆肥过程中类蛋白峰发生红移，且在堆肥后期出现了类腐殖质峰，且类腐殖质荧光峰与类蛋白荧光峰荧光强度的比值‰‰不断增大，T2处理增长幅度最大。发射光谱分析显示：254nm激发波长下发射光谱中后1／4波段与前1／4波段的荧光强度积分面积之比A435-450/A300-345、465nm激发波长下发射光谱中470～640nm范围内荧光积分面积A协枷均不断增大，表明堆肥腐殖化程度不断增强，且T2处理在堆肥各阶段腐殖化程度均高于其他处理，T2处理物质结构最为复杂，腐殖化程度达到最高。三维荧光光谱显示：随着堆肥的进行，与蛋白质类物质有关的类蛋白峰荧光强度持续降低，而与腐殖质类物质产生的类富里酸荧光峰强度却不断增强；紫外区与可见区类富里酸峰荧光强度的比值r（A，C）随着堆肥的进行总体呈下降趋势；T2处理DOM中有机成分发生最为显著的变化，各阶段类蛋白荧光峰的发射波长明显发生红移，并且紫外、可见区域内类富里酸荧光强度明显高于其他处理，促进堆肥DOM中类富里酸物质数量的积累。结果表明：MSIC能够有效促进堆肥腐殖化进程，提高堆肥效率，是一种更加优良的堆肥技术。     

新疆内陆河城市段涉水环境风险重点企业三维荧光光谱特征分析

为获得排污企业稳定的三维荧光光谱特征(荧光峰类型、强度、位置等),利用三维荧光技术分析西北某内陆河流城市段主要工业企业污水的荧光光谱特征。研究结果表明:各企业未处理的污水均存在类色氨酸T峰(Ex/Em=225～237/320～380 nm及Ex/Em=275/320～380 nm),大部分存在类腐殖质荧光峰A峰(Ex/Em=237～260/400～500 nm,300～370)和C峰(Ex/Em=300～370/400～500 nm),酵母产品加工企业与乳制品企业有类络氨酸B峰(Ex/Em=260～290/300～310 nm及Ex/Em=275/310 nm);各企业处理后水体的DOM荧光峰和荧光强度均明显下降,污水处理前、后各荧光峰位置也发生了变化。城镇生活污水厂从进水到曝气环节水体DOM以类蛋白荧光峰为主,出水以类腐殖酸荧光峰为主;经过水解酸化后T峰强度提高,在曝气阶段各峰荧光强度明显下降;水体中COD、TN、NH_3-N以及TOC等指标与DOM中类蛋白荧光组分具有较好的相关关系。     

秦岭落叶松及油松凋落物可溶性有机碳含量及其紫外-可见光谱特征

森林凋落物分解过程中可溶性有机碳含量的变化对研究森林凋落物在生态养分循环中凋落物分解快慢及其养分释放机制有着重要的作用。通过秦岭太白县境内落叶松林、油松林不同分解阶段(L-F-H)凋落物室内10d恒温(25℃)浸提实验,初步分析了凋落物分解过程中可溶性有机碳(DOC)含量分布特征及其紫外-可见光谱特征。实验结果表明:凋落物DOC含量L层F层H层;DOC_(油松林)DOC_(落叶松);浸提液紫外-可见光谱自200nm到800nm吸光度值趋于减小,L层、F层浸提液谱线呈现明显的单波峰,H层谱线存在端吸收,各谱线的波峰或端吸收都出现在200nm附近;肩峰出现在240～280nm范围内,推测样品中有芳香环结构存在。凋落物不同分解阶段浸提液DOC含量与200nm处吸光度值呈现较强相关性(R~20.9)。     

水面实测遥感光谱数据的叶绿素a反演模型构建—以太湖为例

叶绿素a遥感反演的关键是建立遥感数据和叶绿素含量的定量关系。本文根据2007年11月在太湖实测的水体反射光谱及实验室分析得到的叶绿素浓度数据，对太湖水体反射光谱特征与叶绿素浓度之间的关系进行分析和建模。研究结果表明：687nm附近反射峰位置对叶绿素浓度有很好的指示作用，在太湖水体叶绿素浓度的估测模型中，反射峰位置的指数模型要优于线性模型；叶绿素a浓度与684nm和633nm附近的一阶微分有很好的相关性，利用R’684和R’633所建叶绿素a浓度反演模型的估算精度R2分别达到0.89和0.91。     

蒽醌染料活性艳蓝KN-R的化学氧化脱色和矿化

研究了使用NaClO化学氧化处理活性艳蓝KN-R模拟染料废水。分别以592nm、380nm、255nm波长处的吸光值为主要指标,跟踪染料的脱色降解。考察了NaClO投加量、染料浓度、温度和13H值等主要因素对模拟废水脱色的影响。结果表明：用NaClO化学氧化处理0．1mmolL^-1的活性艳蓝KN-R模拟染料废水,当NaClO与染料的摩尔比为18,T=30℃,13H值为7时,反应30分钟,脱色率可达到100％。pH值对脱色和TOC的去除有很大影响,酸性或中性条件下,染料快速脱色,30分钟后吸光值基本恒定,反应6个小时TOC的去除仍不明显;碱性条件下,染料缓慢脱色,但反应6个小时TOC的去除率可以达到40％左右。     

钡盐沉淀法处理纳米银工业废水

液相化学还原法制备纳米银是近些年的研究热点之一,但工艺过程产生的工业废水处理问题未有关注。首次采用钡盐沉淀法处理纳米银工业废水,考察了反应温度、p H值、钡盐种类等因素对废水COD (化学需氧量)及色度去除率的影响。其最佳工艺条件如下:反应温度15℃,初始p H值10. 5,反应时间1h,每100mL废水投加二水氯化钡8g;废水COD去除率为85. 6%,色度去除率高达97. 1%。傅里叶变换红外光谱(FT-IR)、X射线衍射(XRD)等表明:纳米银工业废水中存在醌-氢醌类化合物,此羟基醌类化合物可与溶液中的钡离子反应生成沉淀而得以去除;另外,新生成的硫酸钡细微颗粒带正电,絮凝沉降过程对废水中的羟基醌类化合物存在吸附作用。     

氨基酸型甲醛吸附材料制备及净化效果研究

通过浸渍法制备出氨基酸型甲醛吸附净化材料,并考察了甲醛气体浓度及流速、温度、不同甘氨酸浸渍液浓度、p H值等对模拟甲醛污染空气的净化效果,发现甘氨酸溶液浸渍时间不同制备的吸附净化材料对甲醛的去除率影响不大,净化效果均可达80%以上;净化温度升高不利于甲醛的去除;甲醛去除率随甘氨酸p H值的增加而增加。研究成果有一定应用价值。     

蒙脱石对溶液中镍和铜的吸附特性研究

采用镍和铜作为溶液中的吸附质,探讨了蒙脱石对这2种重金属的吸附性能。通过实验研究了p H值、吸附剂用量、反应时间、浓度等因素对吸附Ni2+和Cu2+的影响。根据实验结果可知,蒙脱石对金属离子的吸附效率随溶液p H值、吸附剂用量、反应时间的增加而增加,但随着金属离子浓度的增加而降低。吸附动力学研究表明,蒙脱石对Ni2+和Cu2+的吸附过程符合准2级动力学模型。     

土壤pH对东南景天修复镉污染土壤的影响研究

东南景天是一种镉和锌的超积累植物,改变土壤p H能否有效提高其吸收镉的效率,需要进一步验证。采用盆栽实验研究不同土壤p H下东南景天吸收和积累Cd的差异以及对Ca Cl2提取有效态镉的影响。结果表明,降低土壤p H值显著提高了土壤镉的有效态含量。弱酸性土壤即p H接近5.5时东南景天生物量及累积镉的量最大,土壤镉去除率也最高,达6.6%。强酸性即当p H接近4时,虽然植物地上与地下镉含量均最高,但生物量最小,植物去除率较其他处理低。研究证实降低土壤p H是提高植物提取效率的有效办法,这为进一步利用东南景天修复镉污染土壤,提高修复效率提供了科学依据。     

钒钛磁铁矿尾矿锰、铁元素浸出规律研究

以攀西地区钒钛磁铁矿尾矿为研究对象,通过设置浸出实验,从酸类、p H、温度、反应时间4个方面探讨尾矿中Mn、Fe元素的迁出规律。结果表明,Mn在草酸中的浸出浓度远大于在醋酸和盐酸中的浸出浓度。随着p H的增大,Mn的浸出浓度整体呈减小趋势,有机酸做浸提剂时,Mn的浸出浓度在p H=2或3时达到最大值;无机酸做浸提剂时,Mn的浸出浓度在p H=1时达到最大值。Fe在草酸中的浸出浓度大于在醋酸和盐酸中的浸出浓度,随着p H增大,Fe的浸出浓度逐渐减小并趋于稳定。另外,温度升高、反应时间延长都有利于Mn、Fe从尾矿中浸出。各变量对Mn、Fe浸出的影响效果为p H酸类温度反应时间。本研究可以对尾矿浸出液的安全使用提供初步指导。     

A numerical model for drying of spherical object in an indirect type solar dryer and estimating the drying time at different moisture level and air temperature

A numerical model for simultaneous heat and mass transfer was developed for solar drying of spherical objects and the object considered is green peas. Solar collector outlet temperature is assumed as drying chamber temperature and justified through energy balance equations. Assumptions are imposed on heat and mass transfer governing equations without losing the physics of the problem. Discretization is performed by finite difference method with implicit scheme. To generalize, the governing equation and boundary conditions are non-dimensionalized. The set of finite difference equations was solved by Tridiagonal Matrix Algorithm and a computer code in MATLAB was developed to solve them. The drying curves showed two stages of drying, initial, and secondary drying stage. At all drying temperatures and drying time, the center moisture was maximum and it was minimum at the boundary. A percentage of 85.67 surface moisture content and 25.33% center moisture was eliminated in the first 1 hr at 348 K. The product should be dried up to 7.45, 4.74, and 3.74 hr at air drying temperatures of 318, 333, and 348 K respectively, to maintain 10% of the product’s initial moisture content. The result is compared with the experimental result from literature and they are found to be in good agreement.     

An Assessment of Changes in Kunzea ericoides var. microflora and Other Hydrothermal Vegetation at the Wairakei–Tauhara Geothermal Field, New Zealand

Hydrothermal ecosystems are of high conservation and scientific value, but they are sensitive to external perturbations that result from development. This study examines the composition of vegetation at four plots at the Wairakei-Tauhara geothermal field, New Zealand, using the Scott height-frequency method, ground temperatures at 0.1- and 1-m depth, soil pH, and photographic surveys. It highlights the response of plant communities, in particular that of Kunzea ericoides var. microflora, in terms of composition, structure, and biomass index values, measures changes in ground temperature, as well as provides baseline data against which to compare future changes. It was found that optimal growing conditions for K. ericoides var. microflora are at temperatures above background conditions with a slightly acidic pH. Plots with cooler, less acidic conditions support more diverse plant communities, which also promote the establishment of invasive species. This suggests that the largest threats to thermotolerant vegetation in New Zealand, including K. ericoides var. microflora, are further decreases in ground temperature because the establishment of invasive species may result in thermolerant vegetation being out-competed in hydrothermal ecosystems. Recognising and understanding the ecological diversity and dynamics of hydrothermal ecosystems, as well as acknowledging the competing interests between development and conservation, is key to the management and protection of these areas.     

PERFORMANCE OF A NEW POLYMERIC WATER DISINFECTANT1

ABSTRACT: A new insoluble N-halamine polymeric disinfectant material has been tested in a water filter application to determine (1) its tendencies to leach undesirable decomposition products, (2) its range of potential applicability, and (3) its regenerability. In flowing water tests, poly-1,3-dichloro-5-methyl-5-(4‘-vinylphenyl)hydantoin (Poly-I) leached only small amounts of total organic carbon, free and total chlorine, anions, and volatile organics such as trihalomethanes. Furthermore, Poly-I provided bactericidal efficacy over the pH range 4.5 to 9.5 and at temperatures as high as 37°C. Poly-I is deactivated by reducing agents such as sodium thiosulfate and by ethanol; following deactivation, it can be regenerated by exposure to flowing aqueous free chlorine. Poly-I appears suitable for use as a biocidal filter for small potable and recreational waters, for it is effective over a wide pH and temperature range and is readily regenerable. It would not be useful, however, for disinfection of large bodies of water such as in city treatment plants because of its cost and the large amount of the material that would be necessary.     

Thermal Pollution Mitigation in Cold Water Stream Watersheds Using Bioretention

This study examines the use of bioretention as a strategy to reduce the thermal impact associated with urban stormwater runoff in developing cold water stream watersheds. Temperature and flow data were collected during 10 controlled runs at a bioretention facility located in Blacksburg, Virginia. It was determined that bioretention has the ability to reduce the temperature of thermally charged stormwater runoff received from an asphalt surface. Significant reductions in peak and average temperatures (p < 0.001) were observed. However, this facility was unable to consistently reduce the temperature below the threshold for natural trout waters in Virginia. The ability of bioretention to reduce runoff volume and peak flow rate also serves to reduce the hydrothermal impact. An average thermal pollution reduction of nearly 37 MJ/m³ was calculated using an adopted threshold temperature of 20°C. Based on the results of this study, it was concluded that properly designed bioretention systems have the capability to reduce the thermal impact of urban stormwater runoff on cold water stream ecosystems.     

HP6890色谱柱用于环境空气中微量恶臭硫化物的检测

利用HP6890型气相色谱仪进行环境空气中微量恶臭硫化物分析,实验结果表明:分离效果、峰形都很好,实验采用4种柱箱初始温度及升温程序,分别由初始温度70℃升温至90℃、120℃、130℃及由初始温度150℃,最后升温至190℃,相应分析一个样品的时间依次为:130.515min、63.419min、56.359min及11.116min,样品分析时间大大缩短,可提高分析效率。     

Effect of Climate Warming and Drought on Urban Stream Temperatures in a Semiarid,Seasonal System

Stream temperatures are key indicators for aquatic ecosystem health, and are of particular concern in highly seasonal, water‐limited regions such as California that provide sensitive habitat for cold‐water species. Yet in many of these critical regions, the combined impacts of a warmer climate and urbanization on stream temperatures have not been systematically studied. We examined recent changes in air temperature and precipitation, including during the recent extreme drought, and compared the stream temperature responses of urban and nonurban streams under four climatic conditions and the 2008–2018 period. Metrics included changes in the magnitude and timing of stream temperatures, and the frequency of exceedance of ecologically relevant thresholds. Our results showed that minimum and average daily air temperatures in the region have increased by >1°C over the past 20 years, warming both urban and nonurban streams. Stream temperatures under drought warmed most (1°C–2°C) in late spring and early fall, effectively lengthening the summer warm season. The frequency of occurrence of periods of elevated stream temperatures was greater during warm climate conditions for both urban and nonurban streams, but urban streams experienced extreme conditions 1.5–2 times as often as nonurban streams. Our findings underscore that systematically monitoring and managing urban stream temperatures under climate change and drought is critically needed for seasonal, water‐limited urban systems.     

安徽砀山水果产区近十年气候变化的R/S分析

基于1996—2005年的地面气象资料,应用R/S方法对砀山近十年平气温、降水和日照量等气候要素进行了分析。结果表明,砀山年平均气温、极端最高气温和极端最低气温均呈下降趋势,年降水量呈上升趋势,年日照量变化和缓,且具有较强的持续性。气候要素年际季节变化趋势表现为:冬、夏季平均温差减小,气温年较差有减小的趋势;降水夏季增加,其他各季节平均降水变率减小,各季节平均日照量变率减小。     

STREAM TEMPERATURE INCREASES AND LAND USE IN A FORESTED OREGON WATERSHED1

ABSTRACT: The Salmon Creek Watershed drains 325 km² of forested terrain in the Cascade Mountains of western Oregon. Over a 30–year period (from 1955 to 1984) average daily maximum and minimum stream temperatures, calculated from the 10 warmest days of each year, have risen 6°C and 2°C, respectively. In contrast, a small decrease in maximum air temperatures was found over the same period. Regression analysis indicated a highly significant (p < 0.01) relationship between a cumulative index of forest harvesting and maximum stream temperatures. Maximum temperatures also tended to increase for several years following major peak flow events. The interaction between harvest activity (logging and road construction), changing forest and riparian management practices and the occurrence of natural hydrologic events (peak flows and associated mass soil movements) tend to obscure specific cause-and-effect relationships regarding long-term changes in maximum stream temperature.     

Analysis of Extreme Summer Rainfall Using Climate Teleconnections and Typhoon Characteristics in South Korea1

Abstract: It is now widely acknowledged that climate variability modulates the frequency of extreme hydrological events. Traditional methodologies for hydrologic frequency analysis are not devised to account for variation in the exogenous teleconnections. Flood frequency analysis is further plagued by the assumptions of stationary in the causal structure as well as ergodicity. Here, we propose a dynamical hierarchical Bayesian analysis to account for exogenous forcing that govern the summer season rainfall. The precursors for Korean summer rainfall at different frequencies are identified utilizing wavelet and independent component analyses. The sea surface temperatures, the ensemble of rainfall predictions by General Circulation Model, in addition to the typhoon attributes were found to have direct correlation with extreme rainfall events and were used as inputs to the logistic regression model. The model parameters are estimated using Markov Chain Monte Carlo and the resulting posterior distributions associated with individual inputs are analyzed to advance our understanding of the spatiotemporal impact of the teleconnections. Eight rainfall stations throughout Korea are considered in this analysis. We demonstrate that the probability of occurrence of extreme events could be successfully projected at a 90% rate of correct classification of extreme events.     

水中二氧化氯静态膜分离的研究

利用二氧化氯在360nm处有一最大吸收峰以及二氧化氯能够通过微孔性聚四氟乙烯膜的特性进行了静态膜分离的研究。通过研究温度和二氧化氯的浓度对分离效果的影响，可以确定：温度越高越有利于二氧化氯的膜分离，但温度高于20℃时二氧化氯会发生分解，故最佳分离温度应为20℃。