冬季黄河水源水库中藻类变化特征研究

对冬季以黄河水为水源的水库水在不同深度取样分析,得到了水库中藻类的分布情况,并分析了藻类繁殖原因、藻类种属及藻类数量的变化特征,为水厂有效了解藻类及去除异嗅味提供了参考.试验结果表明,水中溶解氧充足、氮磷等营养物质浓度过高、合适的温度以及缓慢流动的水体等为藻类提供了适宜生长的条件;水中藻类数量较大,最高值为4.5×107个/L,其中绿藻门、隐藻门和硅藻门三大类的藻类占藻类总数的90%以上.     

Measurement of sediment oxygen demand for modelling dissolved oxygen distribution in tidal Keelung River

The Keelung River is one of the major branches of the Danshuei River estuarine system, which runs the metropolitan capital city of Taipei, Taiwan, and receives a large of amount of wastewater. The dissolved oxygen (DO) concentration is generally low in the tidal portion of the Keelung River. Hypoxia/anoxia occurs often, particularly during a low-flow period. The sediment oxygen demand (SOD) amounts to a significant value, hence increasing the total oxygen demand load of the river. The present work reports on laboratory SOD made on grab sediment core samples in situ that are undisturbed. The results reveal that SOD values fluctuate with variations in seasons and are higher in summer due to a high-temperature effect. It was found in the laboratory tests that the average SOD (at 20 °C) value is 0.76 g/m²/day and the maximum SOD (at 20 °C) value reaches 1.58 g/m²/day. The mean values of measured SOD at each station were adopted in the vertical two-dimensional water quality model to simulate the DO distribution along the tidal Keelung River. The simulated results are in reasonable agreement with the measured DO distribution in the river. Model sensitivity analyses were also conducted with increasing and decreasing SOD. It reveals that SOD is an important parameter that affects the DO distribution in the tidal estuary.     

Impact of a desalination plant on the physical and chemical properties of seawater, Bahrain

The impact of effluent from the Sitra power and desalination plant (SPDP), Bahrain, on the physical and chemical properties of the receiving water was investigated. Two distinguished zones of the receiving water were recognized. These zones resulted from the presence of the jetty. The length of the first zone is about the same length as the jetty, 70 m. The length of the second zone extends to about 150 m. Seventy five case stations were selected on the receiving water. On the intake side, fifteen stations were considered as control stations. The SPDP effluent significantly changed the temperature and salinity of the receiving water of the first zone. The dissolved oxygen levels vary slightly from the control stations. The jetty was found to restrict the water circulation of the first zone. This restriction caused a delay in the temperature, salinity and dissolved oxygen dispersion. Beyond the first zone, this restriction is removed and the dispersion processes affected the control stations.     

The Use of Sediment Modelling Techniques to Address the Differing Needs of Management on the River Eden, Cumbria, UK

Sediment modelling techniques are applied to the River Eden at Great Musgrave (in Cumbria) utilising (for the first time) the software ISIS-Sediment for UK gravel-bed rivers. This work was undertaken in an attempt to determine any potential adverse geomorphological impacts which may result from the development of a weir for flood-warning purposes. The modelling exercise found that the development of the weir was unlikely to significantly affect sediment transport, and therefore would not impact upon the morphological characteristics of the river bed in the vicinity of the weir. Site investigation, subsequent to the construction of the weir, confirmed that the findings of the modelling exercise were fundamentally correct.     

Declines in phosphorus concentration in the upper River Thames (UK): Links to sewage effluent cleanup and extended end-member mixing analysis

Phosphorus concentrations in the upper River Thames Basin (southeastern England) are described and linked to sewage effluent sources. Weekly surveys between 1997 and 2007 of the Thames and two of its major tributaries, the Thame and the Kennet indicated that phosphorus was mainly in soluble reactive (SRP) form. Baseflow concentrations in the Thames reduced from 1584 μg/l in 1998 to 376 μg/l in 2006 and from 2655 to 715 μg/l for the Thame. Flow response, flux and endmember mixing analysis indicated that these declines resulted from SRP reductions in sewage treatment works (STW) effluent following phosphorus stripping for the major STWs in the region. This was confirmed by comparing our analysis with direct measurements of SRP in the effluents based on Environment Agency data. A within-river loss under baseflow of ~ 64% (range 56-78%) of the SRP-effluent input was estimated for the Thames, with a near balance for the Thame. SRP concentrations in the Kennet were an order of magnitude lower than the Thames/Thame: non-point sources dominated and were important for all the rivers at high flows. It was concluded that removal of SRP from effluents would be insufficient SRP in the Thames and Thame to meet annual average environmental targets of 50 to 120 μg/l.The paper flags the value of combining hydrological/chemical tracing and concentration/flux approaches to data interrogation and the bonus of having actual measurements of the effluent. It highlights the need for fuller assessment of water storage/sediment/biota interactions for phosphorus and for caution in using boron as a long-term tracer for effluent inputs, its concentrations having declined markedly in response to reduced usage in washing powders: the value of using sodium as a tracer for examining SRP changes is shown.     

Estuarine capacity in removal of trace metals from contaminated river water, Southern Caspian Sea

In the present investigation, the flocculation of dissolved Cd, Cu, Ni, Pb, Mn and Zn with initial concentrations of 1, 2.5 and 5 mg/L in Tadjan River water during mixing with the Caspian Sea water has been studied in order to determine estuarine capacity to remove dissolved metals in the accidental contamination of the river. The flocculation process was investigated on a series of mixtures with salinities ranging from 0.1 to 11 p.p.t. The flocculation rates were indicative of the nonconservative behaviour of Cd, Cu, Ni, Pb, Mn and Zn during estuarine mixing. The order of the final flocculation rate of dissolved metals at 1, 2.5 and 5 mg/L of initial metal concentrations in the river water is as follows:Cu (99%)>Cd (95%)>Zn (88%)>Mn (85%)>Pb (83%)>Ni (73%), Cu(95.6%)>Pb(92.4%)>Cd (90%)>Zn(88.4%)>Mn (81.6%)>Ni(78.8%) and Cd (100%)>Cu(88%)>Ni (85.2%)>Pb (84%)>Zn (83.2%)>Mn (81.2%), respectively. The results also revealed that removal of dissolved metals is not influenced by pH changes and precipitation processes. The flocculation rates revealed that the overall dissolved metal pollution loads may be reduced to about 70% up to about more than 90% during estuarine mixing of Tadjan River with the Caspian Sea water.     

Concentrations and loads of suspended sediment-associated pesticides in the San Joaquin River, California and tributaries during storm events

Current-use pesticides associated with suspended sediments were measured in the San Joaquin River, California and its tributaries during two storm events in 2008. Nineteen pesticides were detected: eight herbicides, nine insecticides, one fungicide and one insecticide synergist. Concentrations for the herbicides (0.1 to 3000 ng/g; median of 6.1 ng/g) were generally greater than those for the insecticides (0.2 to 51 ng/g; median of 1.5 ng/g). Concentrations in the tributaries were usually greater than in the mainstem San Joaquin River and the west side tributaries were higher than the east side tributaries. Estimated instantaneous loads ranged from 1.3 to 320 g/day for herbicides and 0.03 to 53 g/day for insecticides. The greatest instantaneous loads came from the Merced River on the east side. Instantaneous loads were greater for the first storm of 2008 than the second storm in the tributaries while the instantaneous loads within the San Joaquin River were greater during the second storm. Pesticide detections generally reflected pesticide application, but other factors such as physical-chemical properties and timing of application were also important to pesticide loads.     

Concentrations, enantiomeric compositions, and sources of HCH, DDT and chlordane in soils from the Pearl River Delta, South China

Concentrations, and enantiomeric compositions of HCH, DDT and chlordane in 74 soils of the Pearl River Delta, South China were investigated. The mean concentrations of HCHs and DDTs descended in the order: crop soils>paddy soils>natural soils. The concentrations (ng/g dw) of p,p'-DDE, p,p'-DDT, p,p'-DDD and o,p'-DDT in crop soils were 0.14-231, 0.07-315, 0.5. An EF value >0.5 generally suggested a preferential degradation of the (-) enantiomers of both TC and CC. The racemic alpha-HCH observed in the soils with higher HCH concentrations indicated that the transformation from gamma-HCH (e.g. lindane) to alpha-HCH may be an important process in the soils. The isomer ratios of p,p'-DDT/(DDE+DDD), o,p'-DDT/p,p'-DDT and enantiomeric compositions of o,p'-DDT suggested that both illegal use of technical DDT and the DDT impurity in dicofol may be responsible for the freshly DDT input in the region. The sources of DDTs were drawn by principal component analysis-multiple linear regression (PCA-MLR). The relative contributions of dicofol-type DDT, residues, and fresh technical DDT were estimated to be 55%, 21% and 17%, respectively. In addition, CC was found to degraded faster than TC in soils from the Pearl River Delta. The study demonstrated that the combination of isomer ratios and enantiomeric composition analysis may provide critical information on the potential sources and fate of organochlorine pesticides in soil.     

有机碳源及溶解氧对污水脱氮除磷的影响

介绍了有机碳源、溶解氧对常用污水生物脱氮处理工艺（A2O,Carrousel氧化沟,SBR）的影响,指出反硝化除磷、间歇曝气、低氧脱氮除磷技术在处理低碳、高氮磷城市污水方面具有良好的发展前景。     

黄河三角洲地区多水源联合调度及其环境效应研究

黄河三角洲地区南部广饶县处于淄河冲洪积平原与三角洲海积冲积平原交接部位,因形成以花园和稻庄为中心的地下水降落漏斗而造成北部咸水以3.0km~2/a的速度向南入侵。建立该区地下水、地表水和引黄河水多水源联合调度优化模型,其目标函数是使各时段研究区地下水位降深之和最小,其约束条件包括供水量、开采井取水量、引黄河水量、节水量、水位等。预测结果表明,每个区采取包括节水、减少地下水开采量、拦蓄地表水或引黄河水补给地下水、井灌区改为渠灌等不同措施,到2010年,花园和稻庄漏斗中心水位将分别由过去的低于-20.00m上升为-14.00m和-12.66m; 2003年后,能够在稻庄北部形成反漏斗(淡水帷幕),阻止北部咸水入侵。环境效应显著。     

水泥搅拌桩在厦门市建筑工程地基中的应用研究

从桩体本身和桩与土相互作用原理出发分析了水泥搅拌桩的加固机理,论述针对工程地质较为复杂的某多层建筑,通过采用深层搅拌水泥桩复合地基加固处理,对深层搅拌桩复合地基的承载力、沉降量等作了计算或判定。并从桩基检测和变形观测结果证明水泥搅拌桩可有效地应用于多层建筑的地基加固中,不但保证了安全,且成本低和工期短。     

Concentrations of copper, zinc and lead in the Sydney rock oyster, Saccostrea commercialis (Iredale and Roughley) from the Georges River, New South Wales.

Copper, zinc and lead were analysed from samples of non-commercially grown Sydney rock oysters collected from the Georges River estuary in spring 1987. The results, when compared with previous data from 1975, indicated a marked increase in the concentration of copper (up to 40%) and zinc (up to 300%). For several sites, the recommended (National Health and Medical Research Council) levels for copper and zinc (70 micrograms g-1 and 1000 micrograms g-1 respectively) were exceeded. There appears to be a decrease in the concentration of lead since 1975. The gradient of increasing copper and zinc concentrations with increasing distance upstream from the mouth of the estuary reported in 1975 could not be statistically validated. A significant correlation was found between copper and zinc loadings in the oysters. It was noted that data collected in 1975 were based on commercially grown oysters. The use of commercially grown oysters, rather than indigenous oysters, to examine interaction of contaminant load and distance upstream, is complicated as commercial oysters are moved within the estuary and between estuaries to maximise growth potential.     

The Role of Coal Recovery in the Reclamation of the Merthyr Vale Colliery Site, South Wales, UK

This paper describes the reclamation of the Merthyr Vale colliery site and shows that the incorporation of coal recovery produced economic, as well as environmental, benefits. The optimum plant throughput for a 2.1 m dia. barrel washer was 120 t/h at an operating density of 1200 kg/m³. Coal and discard qualities were acceptable, and the final landform was suitable for development with few restrictions.     

Impacts of River-Engineering Practices on the Conservation Interest and Water Quality in the Land Yeo, England

The environmental quality of many rivers on the Somerset Levels and Moors has been reduced because of past river-engineering practices and changes in land use. A new holistic and restorative approach to river management is now helping to improve the quality of aquatic ecosystems. This paper presents the results of a study which assessed the impact of past river and floodplain management on the Land Yeo, Somerset, with the objective of recommending measures for future management. The main findings are that (a) the ecological interest of the river has been reduced due to channel re-sectioning and flow diversion, and (b) the flow diversion is also causing water-quality problems such as dissolved-oxygen reduction. Most of this degradation could be reversed by the adoption of a number of channel and riparian-enhancement measures and by revising the annual maintenance programme.     

A2/O工艺的溶解氧控制及其对处理效果的影响

A2/O工艺是一种广泛使用的生物脱氮工艺,但在城市污水有机物浓度偏低的情况下,其存在反硝化碳源不足、全程硝化反硝化能耗高以及脱氮效果不稳定的问题,而控制溶解氧是解决上述问题的关键措施.为了研究溶解氧控制措施对A2/O工艺处理效果的影响,优化工艺运行,在成都航空港污水处理厂进行工程调试,并对溶解氧水平与风机能耗之间的关系进行定量分析.结果表明,A2/O工艺的好氧区采取低溶解氧策略(1.6 mg/L)能够改善脱氮效果,并能够保证其他主要污染物达标排放;同时,采用低溶解氧措施也有利于节能降耗,好氧区中点的DO为1.6mg/L较DO为2.0 mg/L时的风机能耗降低约8％.     

钉形水泥土双向搅拌桩软土地基加固中的控制和应用

钉形水泥土双向搅拌桩是处理地基的新型技术,通过改变同心双轴钻杆旋转方向,形成荷载传递规律的变径桩,并且可以根据不同工程的需求,控制钻杆下钻和提升速度、送浆量、进入持力层电流等途径,提高成桩的几率和质量。文章介绍而且探讨了钉形水泥土双向搅拌桩的施工技术的应用,并对质量控制注意事项进行了说明。     

水泥搅拌桩在高速公路涵式桥基础处理中的应用

水泥搅拌桩进行基础处理是高速公路涵式桥基础处理所采用的一种方法。由于涵式桥基础建造的特殊性,其对工后沉降要求严格。实践证明如果处理不好将产生“跳车”,严重影响通行安全,对路面结构造成破坏。     

深基坑水泥搅拌桩止水帷幕失效分析与修复

拟通过具体的案例,分析水泥搅拌桩失效的原因,提出有效的修复方案,确保周边建筑、构筑物以及基坑安全。     

Effects of a diesel spill on freshwater macroinvertebrates in two urban watercourses,Wiltshire, UK

The impacts of a spill of approximately 9800 L of diesel on a small stream and the River Ray (near Swindon, Wiltshire, UK) were examined using kick-net sampling of freshwater macroinvertebrate families at impacted and reference sites. Initial impacts (10 days after the spill) 50 m downstream of the spill were severe, with only 9% survival of individuals (excluding oligochaete worms) and 56% survival of invertebrate families. The percentage survival of macroinvertebrates increased progressing downstream from the spill, with no detectable impacts beyond approximately 4 km downstream. The crustacean families Asellidae and Gammaridae were particularly sensitive to the diesel spill. The recovery of the macroinvertebrate community was assessed 13.5 months after the spill. At this time, recovery was almost complete, with only minor impacts at the sites closest to the spill. The use of live laboratory sorting of samples from impacted sites provided essential information on the impacts of the diesel spill.     

The occurrence of pharmaceuticals, personal care products, endocrine disruptors and illicit drugs in surface water in South Wales, UK

The presence and fate of 56 pharmaceuticals, personal care products, endocrine disruptors and illicit drugs (PPCPs) were investigated in the South Wales region of the UK. Two contrasting rivers: River Taff and River Ely were chosen for this investigation and were monitored for a period of 10 months. The impact of the factors affecting the levels of concentration of PPCPs and illicit drugs in surface water such as surrounding area, proximity to wastewater effluent and weather conditions, mainly rainfall was also investigated. Most PPCPs were frequently found in river water at concentrations reaching single microgL(-1) and their levels depended mainly on the extent of water dilution resulting from rainfall. Discharge of treated wastewater effluent into the river course was found to be the main cause of water contamination with PPCPs. The most frequently detected PPCPs represent the group of pharmaceuticals dispensed at the highest levels in the Welsh community. These were antibacterial drugs (trimethoprim, erythromycin-H(2)O and amoxicillin), anti-inflammatories/analgesics (paracetamol, tramadol, codeine, naproxen, ibuprofen and diclofenac) and antiepileptic drugs (carbamazepine and gabapentin). Only four PPCPs out of 56 (simvastatin, pravastatin, digoxin and digoxigenin) were not quantified over the course of the study. Several PPCPs were found to be both ubiquitous and persistent in the aqueous environment (e.g. erythromycin-H(2)O, codeine, carbamazepine, gabapentin and valsartan). The calculated average daily loads of PPCPs indicated that in total almost 6 kg of studied PPCPs are discharged daily into the studied rivers. The illicit drugs studied were found in rivers at low levels of ng L(-1). Average daily loads of amphetamine, cocaine and its main metabolite benzoylecgonine were as follows: 8, 1.2 and 39 gday(-1), respectively. Their frequent occurrence in surface water is primarily associated with their high illegal usage and is strongly associated with the discharge of insufficiently treated wastewater effluent.