Contamination of the transformer oil of power transformers and shunting reactors by metal-containing colloidal particles

The results of a measurement of the contamination of the oil in 66 transformers by metal-containing colloidal particles, formed as a result of the interaction of the oil with the structural materials (the copper of the windings, the iron of the tank and core etc.), and also the results of measurements of the optical turbidity of the oil in 136 transformers when they were examined at the Power Engineering Research and Development Center Company are presented. Methods of determining the concentration of copper and iron in transformer oil are considered. The limiting values of the optical turbidity factors, the copper and iron content are determined. These can serve as a basis for taking decisions on whether to replace the silica gel of the filters for continuously purifying the oil of power transformers and the shunting reactors in addition to the standardized oil contamination factors, namely, the dielectric loss tangent and the acidity number of the oil.     

利用溶气气浮工艺强化处理低浊高色富含有机物地表水

低浊高色富含有机物地表水难于混凝,试验采用“混凝-溶气气浮”(“混凝-DAF”)工艺处理此类水,并与常规“混凝-沉淀”工艺进行了比较。结果表明,“混凝-DAF”工艺在较低投药量时能取得更好的处理效果;对于“混凝-DAF”工艺,增大混凝剂投量后出水浊度基本不变,但出水色度及CODMn可进一步降低;“混凝-DAF”工艺去除水中有机物的能力优于“混凝-沉淀”工艺。最后,对“混凝-DAF”工艺去除水中有机污染物的机理进行了探讨。     

Remote turbidity measurement with a laser reflectometer

A simple, laser-based reflectometer is described for the measurement of water turbidity via 180° optical scattering. Applications exist both in clean source waters (0–1000NTU) with a minimum detectable turbidity better than 1NTU, and in dense wastewater primary-clarifier sludges. The non-contact measurement is performed from a distance at least up to 10m, substantially avoiding the usual window fouling problems of optical instruments. By measuring directly in the process, through a free water surface or on the side of a flowing water stream, the difficulties of transporting sample to the instrument are also avoided. Extensions to be described allow measurement also of water colour.     

Predicting suspended sediment concentration from nephelometric turbidity in organic‐rich waters

Nephelometric turbidity is an optical index for the side scattering of light caused by fine particles suspended in water. When a mixed composition of suspended inorganic and organic materials, including dissolved organic material, is present, turbidity measurements can be affected by the different optical properties of the organic and inorganic materials present, and different turbidimeters are more or less sensitive to these influences. Two different methods of nephelometric turbidity measurement were assessed (using instruments confirming to two different turbidity standard methods: EPA 180.1 and ISO 7027). We investigated the influence of particulate organic matter and coloured dissolved organic matter on relationships between turbidity and suspended sediment concentration for rivers in diverse Otago catchments, in the South Island of New Zealand. The presence of organic matter and dissolved colour affected turbidity measurement owing to light absorption; however, turbidity measurement following the ISO 7027 standard, which specifies near infrared radiation at wavelengths where organic absorption is very weak, was less affected by organics. As a result, rating equations between suspended sediment and turbidity may be significantly different with ISO 7027 compared with EPA 180.1 methods.     

高锰酸钾复合药剂强化过滤效能研究

在对高锰酸钾复合药剂预处理工艺强化过滤去除微污染水中色度、浊度和有机物效果的生产性试验研究中发现 :高锰酸钾复合药剂预处理工艺对水中色度、浊度和有机物的去除效果理想 ,强化过滤去除效果要优于预氯化和聚合硫酸铁混凝工艺的去除效果。     

复合絮凝剂去除册田水库污染物实验

以"PAC+PDADMAC"复合、"PAC+PAM"复合、PDADMAC为絮凝剂,用于册田水库污染物强化混凝处理.通过混凝烧杯实验,以TOC、色度、浊度、Zeta电位为考察指标,研究"PAC+PDADMAC"复合投加对册田水库水中污染物的去除,并对其絮凝作用机理进行了探讨.结果表明,"PAC+PDADMAC"复合投加对...     

Effect of Timber Harvest on Physical Water Quality Characteristics

The effect of 11% thinning on selected stream water properties in an oak-beech forest ecosystem in the Belgrad Forest of Istanbul, Turkey was studied with a paired catchment experiment. Regression equations for some physical properties of the stream water were developed between control (W-I) and treatment (W-II) watersheds for calibration (with their 95% confidence limits) and treatment periods. The study discovered significant linear regressions between control and treatment watersheds for color, turbidity, air and water temperatures, suspended sediment concentration, pH and electrical conductivity in the calibration period but not turbidity and suspended sediment concentration in the treatment period. The impact of the timber removal was calculated as the difference between measured and predicted values derived from calibration equations. Results showed that timber harvest caused significant decreases in the color, turbidity, temperature, pH, and electrical conductivity values of the stream water and air temperature under the canopy but did not affect the suspended sediment concentration in the stream water.     

MF与次氯酸钠协同处理微污染水试验研究

通过在一体式膜反应器(MF)中投加强氧化剂次氯酸钠,考察MF与次氯酸钠协同处理微污染饮用水的处理效果。通过从浊度、色度、CODMn和UV410这4个指标,研究不同剂量的次氯酸钠对MF与次氯酸钠协同处理微污染饮用水的处理效果。结果表明,从处理效果和经济两个角度,确定在原水浊度在3-8 NTU、色度30°-50°、CODMn5~8mg/L、UV2542.0-4.5cm-1时,反应器中强氧化剂次氯酸钠最佳投量为10mg/L。     

高浓度纺丝废水的超滤试验研究

高浓度乳化纺丝油剂性质极其稳定,采用芬顿氧化——膜分离技术联合工艺处理该油剂废水,通过正交实验找出最佳氧化破乳条件。经过芬顿氧化——高效纤维束过滤——活性炭吸附后,COD和浊度的去除率分别达到97％和95％,超滤后COD和浊度的去除率分别达到98％和99％。     

You can’t just use gold: Elevated turbidity alters successful lure color for recreational Walleye fishing

Increasing anthropogenic turbidity alters underwater visual environments, leading to disrupted perception of visual cues with a variety of consequences, such as diet shifts and reduced prey consumption. In this study, we used novel techniques, including a citizen science mobile phone application (app), to investigate the effects of altered water clarity on recreational fisheries. Our objectives were to determine if elevated turbidity (suspended sediments or algae) alters lure success in the recreational Walleye (Sander vitreus) fishery and if the behavior of recreational anglers shifts with algal blooms. We developed a mobile phone app to gather real time data on lure success across water clarity conditions in collaboration with Lake Erie charter captains. Citizen science data collected with the app showed that lure color success shifted with water color and clarity: white lures were most successful in clear water, yellow in sedimentary turbidity, and black in algal conditions. A survey of charter captains suggested that fishing practices and lure usage may change over the long term if algal blooms persist.     

水解/MBR工艺处理低浓度煤化工废水的研究

应用水解/MBR工艺对低浓度煤化工废水的处理进行了研究,实验结果表明,在合适的条件下膜出水水质:COD为70.23～96.65 mg/L,浊度为0.10～0.32NTU,色度为23～38度,氨氮为1.3～4.8 mg/L,满足国家二级排放标准.通过扫描电镜清晰的观察到:膜外表面的污泥层及宽度不等的裂缝和泥孔,膜内表面没有受到污染.推测膜外表面呈凝胶状的污染物质是胞外聚合物.     

Use of submerged anaerobic membrane bioreactor (SAMBR) containing powdered activated carbon (PAC) for the treatment of textile effluents

This work investigated the use of submerged anaerobic membrane bioreactors (SAMBRs) in the presence and absence of powdered activated carbon (PAC) for the treatment of genuine textile wastewater. The reactors were operated at 35 °C with an HRT of 24 h and the textile effluent was diluted (1:10) with nutrient solution containing yeast extract as the source of the redox mediation riboflavin. The results showed that although both SAMBRs exhibited an excellent performance, the presence of PAC inside SAMBR-1 enhanced reactor stability and removal efficiency of chemical oxygen demand (COD), volatile fatty acids (VFA), turbidity and color. The median removal efficiencies of COD and color in SAMBR-1 were, 90 and 94% respectively; whereas for SAMBR-2 (without PAC) these values were 79 and 86%, In addition, the median values of turbidity and VFA were 8 NTU and 8 mg/L for SAMBR-1 and 14 NTU and 26 mg/L for SAMBR-2, indicating that the presence of PAC inside SAMBR-1 led to the production of an anaerobic effluent of high quality regarding such parameters.     

The effect of polymeric flocculants on floc strength and filter performance.

Polymeric flocculants are widely used throughout the water industry as flocculant aids, they are known to increase floc density and aid settlement in the clarification stage of the water treatment process. In this research, polymeric flocculants were used to improve floc strength prior to filtration on a dissolved air flotation (DAF) plant in an attempt to prevent filter breakthrough. A modified jar test procedure using a PDA (photometric dispersion analyser) optical flocculation monitor was developed in order to evaluate the system floc strength. Filtration trials were carried out on a pilot filter rig situated on a surface water treatment works in Yorkshire. The filter feed originated from the main plant filter channel. Filter performance was assessed by continuous online monitoring of effluent particle counts, turbidity and headloss over the period of the filter run. Results indicated that low doses of polymeric flocculants had a beneficial effect on filtered water quality, as measured by particle counts, turbidity, UV254 absorption and dissolved organic carbon (DOC). Polymeric flocculants also had the effect of extending filter run length. The modified jar test results indicated that the flocculants used improved the floc strength and enhanced reflocculation of the micro flocs present after the flotation process.     

Comparison of satellite reflectance algorithms for estimating turbidity and cyanobacterial concentrations in productive freshwaters using hyperspectral aircraft imagery and dense coincident surface observations

We analyzed 37 satellite reflectance algorithms and 321 variants for five satellites for estimating turbidity in a freshwater inland lake in Ohio using coincident real hyperspectral aircraft imagery converted to relative reflectance and dense coincident surface observations. This study is part of an effort to develop simple proxies for turbidity and algal blooms and to evaluate their performance and portability between satellite imagers for regional operational turbidity and algal bloom monitoring. Turbidity algorithms were then applied to synthetic satellite images and compared to in situ measurements of turbidity, chlorophyll-a (Chl-a), total suspended solids (TSS) and phycocyanin as an indicator of cyanobacterial/blue green algal (BGA) abundance. Several turbidity algorithms worked well with real Compact Airborne Spectrographic Imager (CASI) and synthetic WorldView-2, Sentinel-2 and Sentinel-3/MERIS/OLCI imagery. A simple red band algorithm for MODIS imagery and a new fluorescence line height algorithm for Landsat-8 imagery had limited performance with regard to turbidity estimation. Blue-Green Algae/Phycocyanin (BGA/PC) and Chl-a algorithms were the most widely applicable algorithms for turbidity estimation because strong co-variance of turbidity, TSS, Chl-a, and BGA made them mutual proxies in this experiment.     

表面张力对单空泡运动特性的影响

本文利用高速摄影技术，在摄像电子计算机的辅助下，了在５种不同表面张力（液体－空气）液体中由电火花放电所造成的空泡膨胀及收缩运动过程，记录，分析，计算了空泡的半径Ｒ，泡壁速度Ｒ及加速度Ｒ随时间的变化，结果表明：表面张力加速了空泡的收缩过程，对其膨胀过程则起了延缓作用，通过实验给出了空泡膨胀时间与收缩时间的比值，一般来说，在空泡溃灭以前，表面张力愈小的液体中，空泡泡速度最大值愈大，泡壁的加速度通常具有     

表面张力对铝材料空蚀的影响

在磁致伸缩仪上，研究了５种不同表面张力系数的液体中铝试件的空蚀过程。结果发现在试验范围内，虽然液体的表面张力系数有所不同，但铝试件的空蚀过程仍包括４个阶段；得出前人文献中均未得到过的、铝试件的失质率及总失质量与液体表面张力系数呈线性增长的试验结果。并用空泡生命周期随液体表面张力系数增长呈线性减小的试验研究结果对上述现象从理论上加以说明。     

辐流沉淀池在处理高浊度水中的应用研究

本文结合阜新闹德海引水工程运行实际资料，阐述高浊度水的沉降机理，提出浑液面沉速的概念，并说明了辐流沉淀池是处理高浊度水合理的构筑物，及其相应改进措施。     

Numerical and experimental study of continuous and discontinuous turbidity currents on a flat slope

When the sediment and the dissolved matter laden in the river meet a clear water in reservoirs, the turbid water will plunge and spread into the clear water, forming the turbidity current and influencing the water quality and the life of the reservoir. Due to the unsteady nature of the flood, the turbidity current is unsteady. In the present study, we use the MIKE 3 computational fluid dynamics code to simulate continuous and discontinuous turbidity currents on a flat slope. With the model used by us, the turbulence is divided into two parts: the horizontal turbulence and the vertical turbulence, which are separately modeled by the Smagorinsky model and our model to capture the anisotropic turbulence. In this model, the sediment settling and deposition are considered. The simulation results concerning the flume water surface level, the front velocity and sediment concentration profiles are found consistent with the experimental data, particularly, for the sediment concentration profiles with an absolute mean error of 0.026 kg/m~3 and the root mean square error of 0.046 kg/m~3. This finding suggests that this model can be used to well predict the turbidity current on the flat slope.     

A case study of dissolved air flotation for seasonal high turbidity water in Korea.

A DAF (Dissolved-Air-Flotation) process has been designed considering raw water quality characteristics in Korea. Although direct filtration is usually operated, DAF is operated when freshwater algae blooms occur or raw water turbidity becomes high. Pre-sedimentation is operated in case when the raw water turbidity is very high due to rainstorms. A main feature of this plant is that the operation mode can be changed (controlled) based on the characteristics of the raw water to optimize the effluent quality and the operation costs. Treatment capacity (surface loading rate) and efficiency of DAF was found to be better than the conventional sedimentation process. Moreover, low-density particles (algae and alum flocs) are easily separated while the removal of them by sedimentation is more difficult. One of the main concerns for DAF operation is a high raw water turbidity. DAF is not adequate for raw water, which is more turbid than 100 NTU. In order to avoid this problem, pre-sedimentation basins are installed in the DAF plant to decrease the turbidity of the DAF inflow. For simulation of the actual operation, bench and full-scale tests were performed for highly turbid water conditions. Consequently, it is suggested that pre-sedimentation with optimum coagulation prior to DAF is the appropriate treatment scheme.     

非黏性沙级配对浊度法测量含沙量的影响

利用浊度仪测量水流含沙量时,泥沙颗粒级配和矿物成分是影响浊度仪标定结果的主要泥沙因素。采用黄河原型非黏性沙配制不同粒径、不同含沙量浑水水体,开展固定粒径、粗细沙、混合沙等多组次试验研究,对黄河天然沙粒径及级配对浊度仪输出浊度的影响进行定量分析和机制探讨。结果表明:固定含沙量条件下,非黏性泥沙粒径对水体浊度的影响特征符合Mie散射定律;含沙量变化对浊度仪输出浊度的影响数量级为10～10²,泥沙颗粒粒径变化对浊度仪输出浊度的影响数量级为10^-1～1;相同含沙量条件下,悬沙比表面积与浊度仪输出浊度符合线性分布。建立了考虑非黏性沙级配影响的含沙量与浊度关系模型,能够较准确地反映非黏性沙粒径及泥沙浓度对水体浊度的影响,可为浊度与含沙量关系的准确率定及测量结果的校准提供可靠依据。