Comparison between ozone and ferrate in oxidising geosmin and 2-MIB in water.

Among the chemicals causing taste and odour (T&O) in drinking water, the most commonly identified and problematic ones are geosmin and 2-MIB (2-methylisoborneol). Since the reported odour thresholds of geosmin and 2-MIB are as low as 4 and 8.5 ng/L, respectively, they are not readily removed by conventional water treatment processes. In this study, ozone (O3) and ferrate (Fe(VI)) were applied to oxidise geosmin and 2-MIB. Their performances were compared in terms of removal efficiency of geosmin and 2-MIB. In the case of O3, removal efficiency of geosmin and 2-MIB ozonation at different initial O3 doses, H2O2/O3 ratios and water temperatures were evaluated. The oxidation rates of geosmin and 2-MIB by Fe(VI) were measured within pH 6-8. The effect of H2O2 addition was also evaluated. In summary, O3, especially with H2O2, could almost completely oxidise geosmin and 2-MIB, while Fe(VI) could not oxidise them more than 25% at any pH that was considered in this study. This was attributed to the structure of the organics and high reaction selectivity of Fe(VI). Further study should be conducted to find the reason of inhibition of oxidation by Fe(VI).     

The effect of oxidants on 2-MIB concentration with the presence of cyanobacteria.

In this study, the effect of three oxidants, sodium hypochlorite, potassium permanganate, and ozone, were tested for the removal of 2-MIB with presence of cyanobacteria. Algae in water samples from the source water of Feng-Shen waterworks (FSW), Taiwan were cultivated at 30 degrees C with continuous light at an intensity between 2,500 and 3,400 lux. During the cultivating process, water samples were analyzed for nutrients, light absorbance at 665 nm (A665), and 2-MIB concentration. The 2-MIB concentrations within the incubated samples increased to as high as 1,000 ng/L to 2,000 ng/L, although no extra nutrients were added to the raw water. After 2 to 3 days incubation, the intracellular 2-MIB concentration was as high as 70% of the total 2-MIB in the samples. The algae that developed were mainly cyanobateria, and more than 90% belonged to the Genus Oscillatorias. An almost 100% removal of both 2-MIB and geosmin in the raw water was observed after ozonation for 10 minutes at a dosing rate of 0.91 mg/l-min. Chlorine and permanganate were much less effective, both removing only about 11% of the 2-MIB within 60 minutes at oxidant concentration of 10 mg/l. Oxidation of the cultivated samples showed that chlorine and permanganate may damage algae cells causing them to release intracellular 2-MIB. During the 60 minutes of reaction time, the total 2-MIB concentrations (intracellular plus dissolved) varied by no more than 10%, however, the ratios between dissolved and total 2-MIB concentrations increased. Two effects of ozonation on the 2-MIB concentration in the cultivated samples were observed when the algae were young, namely 2-MIB release from damaged cells and 2-MIB oxidization. The rates of 2-MIB release and 2-MIB destruction were similar. However, old algae cells were more easily damaged. As a result, intracellular 2-MIB was released faster, and the soluble 2-MIB was destroyed more quickly by ozonation.     

Fish yields in Cuban reservoirs and relationships with some morphometric and edaphic parameters

Cuba is located between 19°49' and 23°18' north latitude and 74°08' and 84°57' west longitude. It is the largest island in the Caribbean Sea and the paucity of natural lakes and the prolonged dry season makes it necessary to construct reservoirs. During the past 36 years, Cuba has built 220 large reservoirs (> 100 ha) and 800 smaller ones (< 100 ha). Reservoirs are the most important standing waters in Cuba and their fish, although of low diversity, support productive fisheries, with tilapias contributing 92% of the total production by weight. The fisheries in reservoirs located in the eastern and central parts of the island were analysed during the period 1983–92. The mean depth (z) of reservoirs here is 5.9 m, ranging from 1.8 to 16.0 m. The best correlation coefficients and fit regression in 54 Cuban reservoirs were between FY (fish yield) and DE (diversity of exploitation); when data were analysed with a multiplicative statistical model, r = 0.70, FY = 4.795 DE^0.9292; and between TC (total catch) and A (area), but in this case data were analysed with a linear statistical model, r = 0.91, TC = 17209A–6635.56. Regression between FY versus z was relatively low and inverse, r = −0.20, FY = 249.145–11.04z, although all regressions were statistically significant ( P < 0.01).     

Fish yields in Cuban reservoirs and relationships with some morphometric and edaphic parameters

Cuba is located between 19°49' and 23°18' north latitude and 74°08' and 84°57' west longitude. It is the largest island in the Caribbean Sea and the paucity of natural lakes and the prolonged dry season makes it necessary to construct reservoirs. During the past 36 years, Cuba has built 220 large reservoirs (> 100 ha) and 800 smaller ones (< 100 ha). Reservoirs are the most important standing waters in Cuba and their fish, although of low diversity, support productive fisheries, with tilapias contributing 92% of the total production by weight. The fisheries in reservoirs located in the eastern and central parts of the island were analysed during the period 1983–92. The mean depth (z) of reservoirs here is 5.9 m, ranging from 1.8 to 16.0 m. The best correlation coefficients and fit regression in 54 Cuban reservoirs were between FY (fish yield) and DE (diversity of exploitation); when data were analysed with a multiplicative statistical model, r = 0.70, FY = 4.795 DE^0.9292; and between TC (total catch) and A (area), but in this case data were analysed with a linear statistical model, r = 0.91, TC = 17209A–6635.56. Regression between FY versus z was relatively low and inverse, r = −0.20, FY = 249.145–11.04z, although all regressions were statistically significant ( P < 0.01).     

Nutrient reference concentrations and trophic state boundaries in subtropical reservoirs

Nutrient criteria as reference concentrations and trophic state boundaries are necessary for water management worldwide because anthropogenic eutrophication is a threat to the water uses. We compiled data on total phosphorus (TP), nitrogen (TN) and chlorophyll a (Chl a) from 17 subtropical reservoirs monitored from 2005-2009 in the S?o Paulo State (Brazil) to calculate reference concentrations through the trisection method (United States Environmental Protection Agency). By dividing our dataset into thirds we presented trophic state boundaries and frequency curves for the nutrient levels in water bodies with different enrichment conditions. TP and TN baseline concentrations (0.010 mg/L and 0.350 mg/L, respectively) were bracketed by ranges for temperate reservoirs available in the literature. We propose trophic state boundaries (upper limits for the oligotrophic category: 0.010 mg TP/L, 0.460 mg TN/L and 1.7 μg Chl a/L; for the mesotrophic: 0.030 mg TP/L, 0.820 mg TN/L and 9.0 μg Chl a/L). Through an example with a different dataset (from the Itupararanga Reservoir, Brazil), we encouraged the use of frequency curves to compare data from individual monitoring efforts with the expected concentrations in oligotrophic, mesotrophic and eutrophic regional systems. Such analysis might help designing recovery programs to reach targeted concentrations and mitigate the undesirable eutrophication symptoms in subtropical freshwaters.     

库区环境建设中“廊”的借鉴与思考

通过探究中国古建筑中“廊”的形成和发展，体味中国古哲学和传统文化对建筑的影响，感悟廊的传统意境化空间处理，认知廊的理性化流动空间分析，探索库区环境建设的处理手段。     

Ability of humans to smell geosmin, 2-MIB and nonadienal in indoor air when using contaminated drinking water.

The most common compounds responsible for off flavours are geosmin, 2-MIB, and nonadienal which are poorly removed by conventional water treatment operations and hence result in customer complaints. Because these odourants are moderately volatile and have very low odour threshold values, it is necessary to determine their concentrations in air when water is used indoors. If the detectable aqueous concentrations for these odourants are known, the utilities may take action to treat their water at times when the concentration of the raw water exceeds the threshold concentration. To predict the concentration in the shower stall and bathroom air after showering, recently published Henry's law constants for the selected odourants and a model developed to determine the volatilization of the odourous compounds by applying two-resistance theory were used. Then the results were compared with the odour threshold concentration data to determine under which conditions the odourants become detectable. For parameters representing a typical bathroom and shower stall setting, the results showed that the odourants become detectable when the aqueous concentration of geosmin and nonadienal exceed 10 ng/L at 42 degrees C. As the aqueous concentration increases, geosmin and nonadienal become detectable at lower temperatures, however 2-MIB is only detectable above 20 ng/L and at 42 degrees C.     

Combined effects of organic pollution and eutrophication in the South para reservoirs,South Australia

Preliminary results of a comparative limnological study of three Mediterranean reservoirs in South Australia from August 1995 until March 1996 am presented. The reservoirs are characterised by meso- to eutrophic and dystrophic conditions. Dynamics and interactions between DOC, SRP and phytoplankton biomass were investigated regarding differences in mixing conditions, water levels and catchment links of the reservoirs. A scenario analysis was conducted to predict effects of artificial aeration and DOC removal in the Barossa reservoir. Results indicate positive and negative feedbacks between organic pollution and eutrophication such as nutrient limitation by organic complexation of phosphorus, light limitation of phytoplankton growth by water colour and DOC release after phytoplankton breakdowns. Orientation of further research and management options are discussed.     

SPME-GC/MS/MS法测定水中2-甲基异莰醇和土臭素

研究了固相微萃取-气相色谱/二级质谱联用法测定水中2-甲基异坎醇(2-MIB)和土臭素(GSM)的方法.确定了最佳固相微萃取条件,NaCl加入量3 g,萃取温度60 ℃,搅拌时间30 min,搅拌速度800 r/min.在优化的仪器条件对臭味物质的测定结果显示,此方法灵敏度高,具有良好的精密度和准确度.2-MIB和GSM的相关系数均大于0.999;检出限及RSD分别为0.2 ng/L、0.4 ng/L和5.86%、6.50%;加标回收率分别为100.6%和92.3%.该方法操作简单省时,可满足水中痕量异臭物质的测定.     

实施王快西大洋两库联通对保定市区经济环境社会发展的影响

通过保定市区水资源开发利用现状以及供需分析,论述了实施王快、西大洋两库联通对保定市区经济、环境、社会发展的影响。     

Managing rivers under changing environmental and societal boundary conditions,Part 2: Expected compared with experienced conditions at U.S. Army Corps of Engineers reservoirs

Reservoirs are critical infrastructure typically built to function as designed for 50 to 100 years. The majority of U.S. Army Corps of Engineers reservoirs are more than 50 years old. The environmental, societal, and regulatory conditions surrounding the reservoir, that is, the reservoir's expected conditions, shaped its design. Many of these expectations assumed a future similar to the past. However, recent decades have experienced warming climates, cyclical changes in precipitation, the introduction of new regulations, and populations concentrating in urban environments. The design documents for nine U.S. Army Corps of Engineers were obtained to compare the expected conditions when reservoirs were authorized with the conditions experienced since the reservoir began operating. In some instances, we found large differences between expectations and reality. Average precipitation at Philpott, North Carolina was 15% less than expected whereas the sedimentation rate at Redmond, Kansas was twice the expected rate. Reservoirs can adapt to changing conditions by updating water control plans, which has occurred at five of these reservoirs in the last decade. Reallocations are sometimes needed to address more significant changes. For example, Redmond has reallocated storage space due to higher than expected sedimentation, and Falls, North Carolina is seeking reallocation due to higher than expected population growth and water demand. As conditions change, controversies and litigation around Corps reservoir management will likely continue. This highlights the importance of clearly documenting changing conditions through consistent and ongoing data collection and analysis to facilitate adapting reservoir operations in a timely manner, thereby minimizing controversy.     

黄河下游典型水库浮游植物群落结构及其与环境因子的关系

为发现浮游植物群落结构在黄河下游地区典型水库中的时空变化及其与环境因子的关系,了解两种山区与引黄水库浮游植物群落结构的差异,于2012年9月至2013年8月对黄河下游地区山区(卧虎山、锦绣川)和引黄(鹊山、玉清)水库浮游植物群落结构进行了调查研究。采样期间,共检出浮游植物55种属,以蓝藻、绿藻和硅藻门类群为主;常见属种包括脆杆藻属(Fragilaria Lyngbye)、浮丝藻属(Planktonema)、小环藻属(Cyclotella)、小球藻属(Chlorella)等。4座水库浮游植物丰度为42×10~4~4566×10~4cells/L,季节差异较大,丰水期丰度明显高于其他两个时期,以卧虎山和鹊山水库丰度较高。统计分析显示,山区和引黄水库浮游植物丰度分别受TP、水温的限制,两种类型水库浮游植物群落结构的差异与水体来源及类型关系密切。将数据汇总进行主成分分析(PCA),结果表明:离子类型、营养状态、氮磷营养盐组成及水温是影响黄河下游地区山区与引黄水库浮游植物群落结构的主要因素。     

南水北调中线地区土地利用变化 及生态环境效应

根据河南境内南水北调中线沿线地区的土地利用数据,分析了土地利用变化的空间特征,并在县域尺度上分析了不同时期土地利用的生态环境效应。结果表明,近年来该区域耕地向建设用地的转移面积较多,但土地利用的整体格局并未发生显著变化,而整个区域内土地利用变化强度的空间分布极不均匀。中线工程施工以来,沿线地区生态环境状况总体上有所改善。     

水环境影响预测中计算参数的确定及敏感性分析

无论采用解析计算还是数学模拟对河流污染混合区开展分析,其计算参数的准确性比选择不同数学模型对预测结果的影响更大,应予以重视。基于宽阔河流污染混合区几何特征尺度的理论公式,分析并提出了采用多年平均枯水期流量确定环境设计流量的方法和考虑排污风险修正系数的排污强度确定方法,给出了河流污染混合区各计算参数正、负误差分别引起的最大长度、最大宽度和面积误差的敏感性排序。结果表明,水深、流速和横向扩散系数的正误差会减小污染混合区范围,而排污强度的正误差则会增大污染范围,而且,污染混合区几何特征尺度的误差变化幅度远超过其计算参数的误差变化幅度,揭示了计算误差的放大效应。     

南湖生态补水配置及水环境影响分析

南湖是开滦采煤沉降区复垦重建的生态工程之一,现已成为唐山市区的重要旅游、观光胜地。分析了人工渠引陡河水、雨洪资源利用、水环境的影响因素,改善区域水环境来满足南湖生态用水要求,提出了具体的改进措施。     

Managing rivers under changing environmental and societal boundary conditions,Part 1: National trends and U.S. Army Corps of Engineers reservoirs

Most major rivers in the United States are managed by a system of reservoirs; many of which were built more than a half century ago. These reservoirs were designed based on environmental, societal, and regulatory assumptions at the time of construction. Since then, we have learned that climate is not stationary, population growth is being decoupled from energy needs and water demand, and new regulations (such as the Clean Water Act and Endangered Species Act) affect how river systems are managed. This study explores changing environmental, societal, and regulatory conditions relevant to the design and operation of U.S. Army Corps of Engineers reservoirs across the conterminous United States. Results demonstrate large geographic variability in how these conditions have changed over time. In the south‐western United States, there is an amplified trend towards drier conditions and less reservoir flexibility with warmer temperatures, less precipitation, high sedimentation rates, and large population growth. In the north‐eastern United States, the impacts of increased temperature on reservoirs may be masked by greater precipitation and lower water demand. Environmental, societal, and regulatory changes can reduce the flexibility of reservoir operations and, in some instances, make it challenging for the reservoir to meet its intended purpose as designed decades ago. This study is the first step towards formalizing a process for monitoring broad trends relevant to water resources management for the purpose of moving towards adaptation of infrastructure. An interactive tool was developed for each condition: https://nicholasinstitute.duke.edu/reservoir‐national‐trends/ .     

基于立面二维水动力-水温耦合模型的水库水温分布

建立了考虑浮力影响的立面二维水动力-水温耦合数学模型,对温差异重流进行了研究,分析了浮力流的水流结构和温度分层的形成、发展过程,利用水库物理模型的试验数据对模型进行了验证,再将该模型应用于一拟建水库,模拟预测了该水库建成后夏季典型条件下库区的流场及温度场分布,研究了不同高程放流洞放水对库区流场、温度场及下泄水温的影响。     

Seasonal distribution,movements and habitat associations of northern squawfish in two lower Columbia River reservoirs

We tracked 335 northern squawfish implanted with radio transmitters in the Columbia River in May–December 1993 and May–September 1994. Most fish were released near The Dalles and John Day dams, with the remaining fish released into reservoir areas away from dams. We used boats with mounted Yagi antennas, fixed site receiver stations near the dams and aerial surveys to track movements of tagged northern squawfish. Northern squawfish were commonly associated with water <5 m deep, water velocities <1 m/s and were <45 m from shore. The average movement from the release site was 19.5 km; fish released near dams remained closer to their release sites than fish released into reservoirs. Short-term movements (successive observations within 24 h) comprised 75% of all detected movements, represented fish moving short distances (mean=0.96 km) between dams and down-river areas and corresponded to increased passage of juvenile salmonids. Long-term movements (successive observations exceeding 24 h) were mainly attributed to fish released into the reservoirs moving up-river to a dam, and fish moving between the two dam tailrace areas. A strong up-river movement trend terminating at John Day Dam tailrace in June suggested that spawning occurred nearby. Reduced numbers of observations of fish in the autumn suggested that northern squawfish moved away from dam areas and into deeper water for the winter. © 1997 John Wiley & Sons, Ltd.