Nutrient retention in tile-fed and non-tile reconstructed oxbows in north central Iowa

Nutrient export from the agricultural Midwest threatens the Gulf of Mexico and new conservation practices are needed to reduce the loss of nutrient from subsurface tile drainage systems. Oxbows are natural waterbodies formed when a river cuts off a meander loop and water quality benefits of reconstructed oxbows are being increasingly recognized. In this study, we monitored four reconstructed oxbow sites (two tile-fed, two non-tile) over a 2-year period in north-central Iowa and assessed their capacity for NO₃-N and dissolved reactive phosphorus (DRP) reductions. Water flow and quality monitoring of tiles, shallow groundwater, oxbow and receiving streams documented that the oxbows were dominated by tile drainage inputs. NO₃-N concentrations were highest in the drainage tiles flowing into the tile-fed oxbows (mean 8–10 mg/L) and much lower in floodplain groundwater (<1–2 mg/L). Annual NO₃-N loads into the tile-fed oxbows were substantially larger than input loads into the non-tiled oxbows. For the two tile-fed oxbows, the 2-year NO₃-N retention efficiencies were very similar (0.76–0.77) and on a monthly basis, greater retention efficiencies were measured in summer and fall. DRP concentrations and loads into the tile-fed oxbows were too low to allow for meaningful estimates of retention. Reconstructing oxbows to receive tile drainage water should be considered a sustainable conservation practice for tile drainage treatment in agricultural areas.     

丰水期乌江上游干流水库-河流体系硫同位素组成

2007年7月对乌江上游河流、乌江干流上的3座不同库龄的梯级水库（洪家渡水库、东风水库、乌江渡水库）表层及垂直剖面水体的可溶性硫酸盐的硫同位素组成进行了研究。在垂直剖面上，洪家渡水库硫同位素值（δ34S）介于+03‰~+31‰，下泄水为-07‰；东风水库δ34S值介于-75‰~-55‰，下泄水为-68‰；乌江渡水库δ34S值介于-43‰~-06‰，下泄水为-29‰。上述结论表明，硫同位素组成变化反映了水库硫的不同来源及生物地球化学过程。不同水库表层和垂直剖面水体的硫同位素平均值有差别，水库表层的硫同位素比值主要受输入水体的控制，垂直剖面由表层向下硫同位素比值偏负，主要是由于生物作用以及有机硫的氧化造成的。     

牡丹江市水源地水栉霉污染事件成因分析及对策研究

通过现场调查和实验室测试,对牡丹江水源地污染事件进行了全面的研究,分析水栉霉的形成的原因.得出海林雪原酒业公司向海浪河大量排放酒糟是产生该事件的主要因素这一结论,并提出预防因这种水生生物而引起的水污染的建议和措施.     

山西煤矿矿井水处理与利用

分析了山西煤矿矿井水的水质特性及用途,并依据原水水质的不同和用水对象的不同,提出相适应的处理工艺。     

植物群落蒸散耗水量研究进展

本文主要介绍了植物群落蒸散量的研究方法及影响因素，并根据作者所处地区的特点，对内蒙古典型草原的蒸散研究进展进行了综述。     

Characterization of aliphatic hydrocarbons in deep subsurface soils near the outskirts of Beijing, China

Thirty-nine deep subsurface soils( 150—180 cm depth) near the outskirts of Beijing were investagated. The concentrations including n-alkanes from C13 to C36, pristane and phytane were in the range of 0.60 to 170.10μg/g, with a median value of 4.26. Carbon preference index values for n-alkanes ranged from 1.08 to 2.98, with a median value of 1.48. The percentage contribution of “wax” nalkanes was in the range of 6.03%--46.22%. A predominance of odd/even carbon n-alkanes and unresolved complex mixtures with different shapes and ranges were frequently observed. Factor analysis reduced the data set into three principal components and confirming contributions from low ( 19.58% ), medium ( 20.49% ) molecular weight species and long-chain n-alkanes (43.41% ), respectively.Molecular biomarkers such as pristane, phytane, hopanes and steranes were detected. Based on the principal component analysis, the concentration profiles and molecular markers, it was found that the aliphatic hydrocarbons were from both biogenic and anthropogenic sources.     

姚桥煤矿矿井水净化处理计算机控制系统设计

姚桥煤矿采用水力循环澄清池和重力式无阀滤池相结合的方法处理矿井水，是一种经济可靠的矿井水净化处理工艺。工程设计了一种实现该处理工艺的计算机控制系统，具有较好的灵活性、较高的可靠性和可维护性。     

稻麦轮作田氮素径流流失特征初步研究

针对近年来氮素化肥施用量大而利用率较低现状，在江苏太湖地区设计田间试验，研究稻麦轮作田全年氮素流失特征。结果表明，在本试验条件下稻季和麦季径流中氮损失量相近，麦季略高，约占施氮量的2％左右。麦稻轮作田径流氮损失中氨态氮较少，以硝态氮和其他形态氮为主，其中氨态氮损失以稻季为主，硝态氮损失稻季和麦季相近，其他形态氮损失麦季较多。不同作物田径流氮组成存在差异，麦季径流氮以硝态氮和其他形态氮为主，氨态氮极少，而稻季在施肥后短时间内径流氮中氨态氮、硝态氮和其他形态氮大致相当，其他时间以硝态氮和其他形态氮为主。     

火电厂灰场排水除氟与降pH的试验研究

本文根据湖北荆门热电厂灰场排水水质情况采用硫酸铝－助凝剂的方法进行了除氟与降ｐＨ的试验研究．分别通过静态试验、实验室配水动态试验和现场动态试验,使灰场排水中的氟离子含量由１８ｍｇ／Ｌ左右降至１０ｍｇ／Ｌ以下,ｐＨ值由９左右降至８以下。灰场排水处理量为每小时５ｔ的现场试验结果表明,降低水中氟离子含量并同时降低其ｐＨ值的药品成本费为每吨灰火０．０５元左右,只降低ｐＨ的药成本费为每吨灰水０．０３元以下．     

高效集约式净化设备处理矿井水

高效集约式净化设备适用于净矿井水净化处理后作为矿区生产或生活用水，其特征在于在进水管中投加适当的混凝剂和絮凝剂后，采用水力循环泥渣回流反应、斜管沉淀、无烟煤和石英砂双层滤料过滤，能够有效去除矿井水中悬浮物和油类物质。