The particle characterization from the influent and effluent of a chemical-biological flocculation （CBF） process was studied with a laser diffraction device. Water samples from a chemically enhanced primary treatme...The particle characterization from the influent and effluent of a chemical-biological flocculation （CBF） process was studied with a laser diffraction device. Water samples from a chemically enhanced primary treatment （CEPT） process and a primary sediment tank process were also analyzed for comparison. The results showed that CBF process was not only effective for both the big size particles and small size particles removal, but also the best particle removal process in the three processes. The results also indicated that CBF process was superior to CEPT process in the heavy metals removal. The high and non-selective removal for heavy metals might be closely related to its strong ability to eliminate small particles. Samples from different locations in CBF reactors showed that small particles were easier to aggregate into big ones and those disrupted flocs could properly flocculate again along CBF reactor because of the biological flocculation.展开更多
This study selected polyaluminum chloride（PAC） coagulant to remove suspended particles in Kaolin suspension solution and used a turbidimeter and particle counter to monitor the flocculation process online and collec...This study selected polyaluminum chloride（PAC） coagulant to remove suspended particles in Kaolin suspension solution and used a turbidimeter and particle counter to monitor the flocculation process online and collected the experiment data. The experiments were conducted to study the dynamic distribution characteristics of suspended particles under different hydrodynamic conditions. The results show the self-similarity and scale invariance of particle size distribution. The study further proposed the concept of fractal dimension of particle size distribution and found out that fractal dimension changed in a similar way as residual turbidity did and could excellently indicate the variation of coagulation effect. Therefore, fractal dimension could be adopted to optimize the addition of coagulants and the quality of outflow could be further improved to reduce production costs.展开更多
Settling characteristics of floes, including relative settling velocity, relative flocculation coefficient and flocculation exponent, are obtained by the suspended load equations for different size fractions. Data of ...Settling characteristics of floes, including relative settling velocity, relative flocculation coefficient and flocculation exponent, are obtained by the suspended load equations for different size fractions. Data of the Changjiang Estuary suggest that level of flocculation changes from river section, river mouth (turbidity maximum) to offshore area in sequence of low, very high and high. The settling characteristics of floes reflected by in situ estimation performs a similar feature as that obtained from still water experiment.展开更多
为了研究絮团的形态对絮团与气泡碰撞及吸附的影响,设计了图像分析系统,拍摄了絮团与气泡接触过程中的视频文件并从中提取含有絮团位置及形态特征的静态帧。使用Image Pro Plus 6.0根据絮团的粒径对絮团进行了粒度级的划分,使用统计学...为了研究絮团的形态对絮团与气泡碰撞及吸附的影响,设计了图像分析系统,拍摄了絮团与气泡接触过程中的视频文件并从中提取含有絮团位置及形态特征的静态帧。使用Image Pro Plus 6.0根据絮团的粒径对絮团进行了粒度级的划分,使用统计学的方法,对每个粒度级的絮团与气泡的碰撞及吸附效率进行了分析及计算,发现碰撞效率随絮团粒径的增加而增长,吸附效率先随着粒径的增加而增长但是在絮团粒径为200μm左右时出现转折,开始下降。利用Matlab位置提取程序对絮团运动过程中位置信息进行获取,根据Stokes沉降原理,计算絮团密度,发现絮团的密度随着粒径的规律性变化,在粒径为170μm时密度最大。认为絮团粒径对碰撞效率起主导作用,絮团密度对吸附效率起主导作用。此外,通过观测絮团与气泡接触过程发现,结构密实的絮团自与气泡发生接触后接触点恒定,而结构疏松的絮团与气泡接触后普遍存在旋转的现象,接触点的变化,导致结构疏松的絮团极易从气泡上脱落,吸附效率低。展开更多
基金Project supported by the Hi-Tech Research and Development Program (863) of China (No. 2002AA601320) the Shandong Environment Protection Bureau Program (No. 2006032, 2006043)the Ph.D Fund of Shandong Jianzhu University (No. 624006, 2006043).
文摘The particle characterization from the influent and effluent of a chemical-biological flocculation （CBF） process was studied with a laser diffraction device. Water samples from a chemically enhanced primary treatment （CEPT） process and a primary sediment tank process were also analyzed for comparison. The results showed that CBF process was not only effective for both the big size particles and small size particles removal, but also the best particle removal process in the three processes. The results also indicated that CBF process was superior to CEPT process in the heavy metals removal. The high and non-selective removal for heavy metals might be closely related to its strong ability to eliminate small particles. Samples from different locations in CBF reactors showed that small particles were easier to aggregate into big ones and those disrupted flocs could properly flocculate again along CBF reactor because of the biological flocculation.
基金The National High Technology Research and Development Program of China(863 Program) (2006AA06Z305)the National Science and Technology Project of Eleventh Five Years(2006BAJ08B05-2)Supported by the National Natural Science Foundation of China(50678047)
文摘This study selected polyaluminum chloride（PAC） coagulant to remove suspended particles in Kaolin suspension solution and used a turbidimeter and particle counter to monitor the flocculation process online and collected the experiment data. The experiments were conducted to study the dynamic distribution characteristics of suspended particles under different hydrodynamic conditions. The results show the self-similarity and scale invariance of particle size distribution. The study further proposed the concept of fractal dimension of particle size distribution and found out that fractal dimension changed in a similar way as residual turbidity did and could excellently indicate the variation of coagulation effect. Therefore, fractal dimension could be adopted to optimize the addition of coagulants and the quality of outflow could be further improved to reduce production costs.
文摘Settling characteristics of floes, including relative settling velocity, relative flocculation coefficient and flocculation exponent, are obtained by the suspended load equations for different size fractions. Data of the Changjiang Estuary suggest that level of flocculation changes from river section, river mouth (turbidity maximum) to offshore area in sequence of low, very high and high. The settling characteristics of floes reflected by in situ estimation performs a similar feature as that obtained from still water experiment.
文摘为了研究絮团的形态对絮团与气泡碰撞及吸附的影响,设计了图像分析系统,拍摄了絮团与气泡接触过程中的视频文件并从中提取含有絮团位置及形态特征的静态帧。使用Image Pro Plus 6.0根据絮团的粒径对絮团进行了粒度级的划分,使用统计学的方法,对每个粒度级的絮团与气泡的碰撞及吸附效率进行了分析及计算,发现碰撞效率随絮团粒径的增加而增长,吸附效率先随着粒径的增加而增长但是在絮团粒径为200μm左右时出现转折,开始下降。利用Matlab位置提取程序对絮团运动过程中位置信息进行获取,根据Stokes沉降原理,计算絮团密度,发现絮团的密度随着粒径的规律性变化,在粒径为170μm时密度最大。认为絮团粒径对碰撞效率起主导作用,絮团密度对吸附效率起主导作用。此外,通过观测絮团与气泡接触过程发现,结构密实的絮团自与气泡发生接触后接触点恒定,而结构疏松的絮团与气泡接触后普遍存在旋转的现象,接触点的变化,导致结构疏松的絮团极易从气泡上脱落,吸附效率低。
