Water technology for specific water usage

BACKGROUND: Water is the basis for life and culture. In addition to the availability of water its quality has become a major issue in industrialized areas and in developing countries as well. Water usage has to be seen as part of the hydrological cycle. As a consequence water management has to be sustainable. The aim of the contribution is to give water usage oriented quality criteria and to focus on the technical means to achieve them. MAIN FEATURES: Water is used for many purposes, ranging from drinking and irrigation to a broad variety of technical processes. Most applications need specific hygienic, chemical and/or physical properties. RESULTS: To meet these demands separation and reaction principles are applied. The reuse of water and the application of water treatment with little or no waste and by-product formation is the way to go. Membrane separation and advanced oxidation including catalytic reactions are promising methods that apply natural processes in sustainable technical performance. Thus elimination of specific water constituents (e.g. salts and metals, microorganisms) and waste water cleaning (e.g. pollutants, nutrients and organic water) can be done efficiently. OUTLOOK: Learning from nature and helping nature with appropriate technology is a convincing strategy for sustainable water management.     

中国富营养化湖泊的生物修复

描述了中国湖泊富营养化污染现状 ,论述了湖泊富营养化形成的机理、生物修复富营养化湖泊 (尤其是去除水体和底泥碳、氮、磷 )的理论依据 ;提出了修复湖泊富营养化的技术途径 ,阐明了笔者对机械清淤和生物修复各自具有的优势和缺陷的看法。     

高效植物炭化炉是构筑循环经济的技术装备之一

高效植物炭化炉是将现代生物质资源通过热解,使资源得到充分利用,做到了清洁生产,实现了物质的反复循环,通过对副产品的进一步深加工,高效植物炭化炉成为制炭工业的最佳实用技术,是构成乡镇循环经济的技术装备之一.     

基于SPEI的西南农业区气象干旱时空演变特征

干旱已成为西南农业区的具有一定破坏力的自然灾害,研究干旱的时空变化对该区干旱的评估、预测具有重要的现实意义。根据西南农业区1962~2012年月气象资料,利用Penman-Monteith公式计算蒸散发和标准化降水蒸散指数(SPEI)值;采用线性回归、Mann-Kendall方法、小波分析和旋转经验正交函数(REOF)等方法分析了西南农业区干旱时空变化。研究结果表明:(1)西南农业区整体呈干旱化趋势;2000年以来年、四季变干趋势更加明显;秋季变干趋势显著;年均SPEI指数不存在显著突变点;年和四季干湿变化均存在2~8 a左右的振荡周期。(2)根据REOF分解的前6个空间模态,将西南农业区划分成6个干湿特征区域:云南高原东部区、汉中盆地区、东部山地区、云南高原西部区、四川盆地区、贵州高原区;其中云南高原东部区变干趋势显著,汉中盆地区和东部山地区有变湿润趋势,但并不明显;6个分区干湿变化普遍存在2~6 a左右的振荡周期。研究结果可为西南农业区防旱、抗旱提供科学参考。     

Drought-induced sulphate release from a wetland in south-central Ontario

Increased sulphate (SO₄) export from wetlands following summer droughts in central Ontario, Canada has been associated with the delayed chemical recovery of downstream surface waters following decreased sulphur (S) emissions. Prolonged summer droughts result in a decrease or cessation of stream flow, declines in wetland water table level and oxidation of reduced S compounds to SO₄, which is subsequently flushed into drainage streams when stream flow resumes. Sulphate input-output budget calculations (1983–1995 and 1999–2001) at a conifer Sphagnum swamp in the Plastic Lake catchment, indicate that SO₄ is retained in most years but is exported on a net basis following particularly severe summer droughts that result in the cessation of stream flow for more than 54 days (95% CI: 41–72 days). Hindcast calculations using long-term (1916–2000) stream discharge records from a nearby station indicate that while droughts occurred frequently in south-central Ontario over the past 85 years, sufficiently dry conditions to cause net SO₄ export occurred in only18 of the past 85 years, and indicate a cumulative positive SO₄ balance for the swamp (i.e. net SO₄ retention). Furthermore, the S pool at the Plastic Lake swamp has been estimated to be ∼1500 kg S/ha in the upper 40 cm peat layer, which is large compared to the amount of net SO₄ export that occurs even in years with particularly dry summers (e.g. −43 kg S/ha in 1987/88). Together, these data suggest that the wetland S pool at Plastic Lake has not been depleted by previous droughts and will continue to sustain episodic drought-related SO₄ export for the foreseeable future.     

茉莉酸甲酯(MeJA)对水稻幼苗的抗旱生理效应

茉莉酸类物质(Jas)是植物体内广泛存在的生长调节物质,它作为内源信号分子参与植物在机械伤害、病虫害、干旱、盐胁迫、低温等条件下的抗逆反应。选用抗旱性存在明显差异的两个水稻(Oryza sativa L.)品种中二欧六和丰华占作为实验材料,通过设置对照、干旱、干旱 茉莉酸甲酯(MeJA)三种处理研究了茉莉酸甲酯对水稻幼苗的抗旱生理效应。研究结果表明,干旱胁迫后两个水稻品种幼苗叶片水势均显著降低,而干旱后喷施茉莉酸甲酯能明显增加叶片的水势,改善叶片的水分状况,抗旱性强的品种水势增加幅度较大。干旱胁迫后水稻叶片的抗氧化酶活性,包括超氧化物歧化酶(SOD)、过氧化物酶(POD)及过氧化氢酶(CAT)和有机渗透调节物质,包括可溶性糖、脯氨酸及游离氨基酸含量均大幅度上升,而干旱 茉莉酸甲酯处理则能降低了这些物质的含量,两个水稻品种的变化趋势表现一致。研究结果表明外施茉莉酸甲酯在一定程度上能减缓干旱胁迫对水稻幼苗造成的伤害,有效地提高抗旱性,但这这种增强效应在不同水稻品种间存在一定差异。     

The 2007‐2009 Drought in Athens,Georgia, United States: A Climatological Analysis and an Assessment of Future Water Availability1

Campana, Pete, John Knox, Andrew Grundstein, and John Dowd, 2012. The 2007‐2009 Drought in Athens, Georgia, United States: A Climatological Analysis and an Assessment of Future Water Availability. Journal of the American Water Resources Association (JAWRA) 48(2): 379‐390. DOI: 10.1111/j.1752‐1688.2011.00619.x Abstract: Population growth and development in many regions of the world increase the demand for water and vulnerability to water shortages. Our research provides a case study of how population growth can augment the severity of a drought. During 2007‐2009, a drought event that caused extreme societal impacts occurred in the Athens, Georgia region (defined as Clarke, Barrow, Oconee, and Jackson counties). An examination of drought indices and precipitation records indicates that conditions were severe, but not worse than during the 1925‐1927, 1954‐1956, and 1985‐1987 drought events. A drought of similar length to the 2007‐2009 drought would be expected to occur approximately every 25 years. Streamflow analysis shows that discharge levels in area streams were at a record low during 2007 before water restrictions were implemented, because of greater water usage caused by recent population increases. These population increases, combined with a lack of water conservation, led to severe water shortages in the Athens region during late 2007. Only after per capita usage decreased did water resources last despite continuing drought conditions through 2009. Retaining mitigation strategies and withdrawal levels such as seen during the height of the drought will be an essential strategy to prevent water shortages during future extreme drought events. The key mitigation strategy, independent local action to restrict water use in advance of state‐level restrictions, is now prohibited by Georgia State Law.     

Unusual Salinity Conditions in the Yangtze Estuary in 2006: Impacts of an Extreme Drought or of the Three Gorges Dam?

During the extreme dry year of 2006, abnormal salinity conditions in the Changjiang Estuary of the Yangtze River occurred in partial coincidence with the second impoundment phase of the TGD (Three Gorges Dam). Analysis of discharge observations in the upper reaches of the estuary and of salinity observations in the estuary as a whole reveals that in 2006 salinity was over 100 mg/l during 275 days, over 250 mg/l during 75 days and over 400 mg/l during 48 days. It is well known that this is due to extreme low discharges from the upper catchment area into the estuary. Moreover, large amounts of water consumed along the lower reaches of the Yangtze River can also aggravate the low discharges that lead to stronger saltwater intrusion in the estuary. Of the 75 days that salinity was over 250 mg/l, the low discharge was decreased further by 10 to 20% due to water consumption. The additional impact of the impoundment phase of the TGD (lasting 37 days in autumn) was noticeable only during 7 days in 2006. During that period, the relative contributions of the TGD and the water consumption in the lower reaches of the Yangtze River amounted to 70 and 30%, respectively. It may be concluded that the impact of the second impoundment phase of the TGD on salinity intrusion in the estuary was modest, while the extreme drought of 2006 was the dominant cause.     

5种喀斯特生境植物叶片解剖结构特征

对我国喀斯特地区几种不同生活型植物——常绿植物桂花(Osmanthus fragrans Lour.)、竹叶椒(Zanthoxylunarmatum DC),落叶植物红背山麻杆(Alchornea trewioides Muell.),草本植物石上莲(Oreocharis benthamii Clark var.reticulata Dunn),草本植物单枝竹(Monocladus saxatilis Chia,Fung et Y.L.Yang)的叶片形态解剖特征(叶片厚度、气孔密度、气孔结构等)进行了观察和测量,发现差异较大:竹叶椒角质层较厚,红背山麻杆的叶片较厚,单枝竹叶片上下表皮均有气孔,桂花气孔密度最高,石上莲的气孔纵径最长.结果表明:1)喀斯特生境植物存在着普遍的抗旱功能性解剖结构,用以适应喀斯特地区的特殊干旱气候;2)不同生活型植物对干旱选择的策略不同.表3参20     

我国中亚热带人工林水热通量对干旱差异响应的模拟研究

季节性干旱现象在我国中亚热带地区时有发生,为了研究该区域大气-生态系统之间的相互作用关系及其碳水收支状况,2002年起在江西省千烟洲（26.7°N,115.1°E）人工林生态系统建立了通量观测塔。2003年7月该人工林生态系统遭遇了历史上少有的高温少雨天气,本研究应用基于生理生态学过程的EALCO（Ecological Assimilation of Land and Climate Observation）模型及2003和2004年通量观测数据对该生态系统的水热通量进行了模拟,同时分析了干旱胁迫对它们产生的影响。结果显示,模型能够很好的模拟该生态系统的能量通量的日变化,净辐射、显热和潜热通量模拟值与实测值相关系数的平方（R2）及标准差分别为0.99和8.05 W.m-2;0.81和41.02 W.m-2;0.90和31.49 W.m-2,模型可以解释87%的日蒸散量的变化。从模拟结果看,2003年7月下旬（发生较严重干旱胁迫）较2004年同期（干旱程度轻）相比,冠层及土壤水势下降约2倍,植物蒸腾的日变化形式改变,根系吸水滞后冠层蒸腾的时间缩短约半小时,冠层导度下降40%～60%。模拟与观测结果均表明,2003年7月下旬每天正午的波文比大都介于1～2.2,而2004年同期正午的波文比则介于0.2～0.6。EALCO模型通过Ball模型将植物碳水过程耦合在一起,从而可以很好的模拟植物的气孔行为,进而准确的模拟植物水热过程对干旱的响应。土壤水分匮乏对冠层导度的限制是2003年干旱期间冠层潜热通量模拟值下降的根本原因。