RESERVOIR SEDIMENTATION1

ABSTRACT: Reservoirs, as well as lakes and estuaries, are subject to sediment accumulation. The rate at which sedimentation occurs is accelerated or diminished by man's activities. Acceptable rates of sedimentation are considered on the basis of costs of sediment storage and removal and a review of reservoirs constructed with sediment removal capabilities is given. The rates of reservoir sedimentation in the United States are summarized based on reliable data obtained from all sizes of reservoirs. Problems confronting the engineer concerning reservoir construction and maintenance are discussed on the basis of these data.     

Bathymetric and core analysis of the Latrobe River delta to assist in catchment management

In this study, an analysis of bathymetric surveys of the Latrobe River delta conducted in 1879 and 1992 is combined with pollen analysis of cores from the delta sediments to assist in setting management priorities for the Latrobe River catchment, a 5000 km²catchment in the south-east of Australia. Reconstructed delta surfaces from 1879 (not long after European settlement of the area) and 1992 were compared to quantify areas of net erosion and deposition. These were compared to post-European deposition depths determined by the presence of exotic pollen species in the sediment. The results indicated that: (1) average sedimentation rates in the receiving lake for the Latrobe River are less than 1 mm yr⁻¹; (2) the deposited material is fine with no material considered as bedload; and (3) the fine nature of the deposited material makes it suitable for carrying a large load of nutrients. These results created a shift in management focus from concern over sedimentation and erosion in general to a greater emphasis on nutrients. While the integrated management of catchments is implicitly contemporary, it should always be performed within a historical context. Failure to do this can lead to management priorities that do not concur with the facts of catchment response and can therefore result in inefficient resource allocation. The use of studies which provide a historical perspective on the problem are therefore critical.     

A SUPERCRITICAL FLUME FOR MEASURING SEDIMENT-LADEN STREAMFLOW1

ABSTRACT: After 25 years of operation on ephemeral streams in the semiarid Southwest, this supercritical flume has provided more than 350 station-years of reliable streamflow data, even under freezethaw conditions experienced at elevations of 1,500 to 2,100 m, in Arizona. The flume has also provided streamflow data during flood periods produced by high intensity summer thunderstorm conditions, where considerable sediment and other debris was moved downstream.     

油田井场废水配制压裂液处理技术实验研究

针对油田井场废水高悬浮物、高色度、高金属离子浓度的特征,以处理后配制压裂液为目标,通过p H值调节及无机高分子絮凝法对井场废水进行了处理实验。结果表明,碳酸钠作为优选的p H值调节剂,可以在较低的p H值条件下有效去除废水中的高价金属离子;无机絮凝剂聚合硫酸铁在强碱性条件下对于悬浮物、色度的去除效果明显优于聚合氯化铝。聚合硫酸铁絮凝法可以使井场废水达到配制压裂液用水的要求。     

微波-混凝处理高炉煤气洗涤水的实验研究

本文探索了微波作为辅助手段处理高炉煤气洗涤水过程中,微波辐射功率、微波辐射时间、聚合氯化铝(PAC)加入量、磷酸加入量对高炉煤气洗涤废水处理效果的影响。结果表明,微波和PAC混凝联用处理高炉煤气洗涤废水具有作用时间短、聚沉能力强等特点,可以有效去除废水中悬浮物,降低硬度及浊度。     

The Aging of America's Reservoirs: In‐Reservoir and Downstream Physical Changes and Habitat Implications

Reservoirs are important for various purposes including flood control, water supply, power generation, and recreation. The aging of America's reservoirs and progressive loss of water storage capacity resulting from ongoing sedimentation, coupled with increasing societal needs, will cause the social, economic, environmental, and political importance of reservoirs to continually increase. The short‐ and medium‐term (<50 years) environmental consequences of reservoir construction and operation are well known and include an altered flow regime, lost connectivity (longitudinal, floodplain), an altered sediment regime, substrate compositional change, and downstream channel degradation. In general, reservoir‐related changes have had adverse consequences for the natural ecosystem. Longer term (>50 years) environmental changes as reservoirs enter “old” age are less understood. Additional research is needed to help guide the future management of aging reservoir systems and support the difficult decisions that will have to be made. Important research directions include assessment of climate change effects on aging and determination of ecosystem response to ongoing aging and various management actions that may be taken with the intent of minimizing or reversing the physical effects of aging.     

鄱阳湖悬浮颗粒物絮凝沉降典型藻类的动力学研究

为了探讨鄱阳湖水动力条件改变引起的悬浮颗粒物浓度变化可能导致的鄱阳湖浮游植物群落结构的变化,本文研究了鄱阳湖悬浮颗粒物絮凝沉降3种典型藻类的动力学过程.以铜绿微囊藻(蓝藻)、四尾栅藻(绿藻)和菱形藻(硅藻)为研究对象、鄱阳湖采集沉积物为悬浮颗粒物,使用混凝试验搅拌仪模拟动力学条件,在颗粒物投加量为20 mg·L-1时分别研究了静置沉降时间、扰动强度和扰动时间对颗粒物絮凝沉降藻细胞的影响.结果表明,絮凝沉降效率:蓝藻绿藻硅藻.在扰动强度为20 s-1、扰动时间为30 min时,0.5~4 h静置沉降时间均促进3种藻类的絮凝沉降.绿藻和硅藻的絮凝沉降效率随着静置沉降时间的延长而降低,前0.5 h的絮凝沉降效率最大;而蓝藻的絮凝沉降效率变化无明显规律.扰动时间和静置沉降时间均为30 min时,随着扰动强度在2~40 s-1增加时,3种藻的絮凝沉降效率逐渐增大.扰动强度为20 s-1、静置沉降时间为30 min时,5~60 min扰动时间均促进藻细胞的絮凝沉降,并且随着扰动时间的增加,絮凝沉降效率呈先增大后降低的趋势.30 min为蓝藻絮凝沉降的最佳扰动时间,絮凝沉降效率为12.56%;45 min为绿藻和硅藻絮凝沉降的最佳扰动时间,絮凝沉降效率分别为11.93%和7.54%.因此,水动力条件的改变可以引起悬浮颗粒物与藻类的絮凝沉降效率发生变化,从而对藻类的群落结构以及水华发生规律产生影响.     

水质安全的动态超声波强化混凝除藻水处理试验研究

超声波辐射能够破坏蓝藻气囊,在水处理工艺中达到强化蓝藻混凝沉淀的效果.然而不适当的超声处理会进一步破坏蓝藻细胞,导致胞内毒素大量释放,加重水质污染负荷.本研究为获得水质安全的超声波强化混凝沉淀蓝藻水处理方法,采用频率40~120 k Hz的超声波辐射蓝藻水,考察处理后蓝藻混凝沉淀去除效果及藻毒素释放情况.结果表明,频率68~120 k Hz、能量密度59.1~186.4 W·L-1的静态超声波作用10~15 s后进行混凝沉淀,藻类去除率达98%以上,且频率越高效果越好;然而各频率静态超声波作用5 s以上均会导致藻细胞内藻毒素释放.采用内衬吸声棉及动态超声方式,频率120 k Hz、能量密度38.5~196.6 W·L-1超声波作用7.5~30 s后,可避免胞内藻毒素释放,且能去除水中溶解性藻毒素18.7%~30.7%,混凝沉淀后藻类去除率97.0%以上,其它有机物也降低.     

生物强化/混凝沉淀工艺处理电镀园区物化出水的试验研究

试验采用生物强化/混凝沉淀工艺处理电镀工业园区的物化出水,重点考察了本工艺对进水COD、氨氮的去除效果.结果表明,生物强化工艺能有效降低废水中的COD、氨氮,混凝沉淀工艺能进一步去除废水中的污染物.当进水COD在200～ 350 mg/L、氨氮在20～35 mg/L时,出水水质能够达到《电镀污染物排放标准》(GB 21900-2008)中表2的标准,即COD≤80 mg/L、氨氮≤15 mg/L.     

吉林油田稠油热采污水处理絮凝剂实验研究＊

在含油污水水质分析的基础上,采用烧杯实验和分光光度法研究絮凝剂的絮凝效果。筛选出以无机絮凝剂硫酸铝与两性高分子聚合物CE-3090的复配体系,同时研究了影响絮凝效果的因素并探究了其影响机理。结果表明:在温度为40℃,pH为7.72,170 r/min时高速搅拌1 min,然后50 r/min低速搅拌5 min,硫酸铝的加量为90 mg/L、CE-3090的加量为0.5 mg/L,絮凝沉降30 min后其絮凝效果较好。实验证明:该复配处理剂处理含油污水后,含油量和杂质含量都达到了SY/T 5329-94《碎屑岩油藏注水水质推荐指标及分析方法》油田污水回注的要求。