Papers by Keyword: Sedimentation

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Authors: G. Kapelski, A. Varloteaux
Authors: Li Hua Cheng, Ai Hua He, Xue Jun Bi, Qi Wang
Abstract: Due to increasing water scarcity, reclamation and reuse of the secondary effluent of wastewater treatment plant are widely concerned in many countries. Before reuse, the residual contaminant in the secondary effluent should be further removed to guarantee safe reuse. Coagulation/sedimentation and subsequent chlorine dioxide(ClO2) disinfection was adopted for tertiary treatment of secondary effluent. Selection of coagulant and optimization of tertiary treatment parameters were performed in this study. The results showed that coagulation could remove turbidity and total phosphours(TP) effectively. Polyaluminium chloride(PAC) was the most suitable coagulant. The optimal coagulation condition was as follows: PAC dosage of 10mg/L(measured as Al3+), reaction time of 20 min, settling time of 40 min, in this case, the average removal rate of turbidity, color, UV254, TP and TOC could reach to 58.2%, 22.8%, 18.2%, 60.6% and 22.2%, respectively. ClO2 could inactive bacteria and E. coli effectively. ClO2 could further remove UV254, color and TOC. In case of ClO2 dosage of 5mg/L, the sterilization efficiency could reach 100%, and the removal rate of UV254, color and TOC was higher than 25%, 70% and 25%, respectively. In the optimal condition, the removal efficiency of residual contaminant by the combination process was as follows: UV254 of 45.9%, color of 76.5%, TOC of 66.7%, turbidity of 61.9% and TP of 96.3%.
Authors: Bruno Arantes Moreira, Fábio de Oliveira Arouca, João Jorge Ribeiro Damasceno
Abstract: The study of the sedimentation of particulate materials is of interest in several industrial processes, such as in the design and optimization of operating conditions of thickeners and during the operational stages of drilling oil wells. In this context, this work aims to study the sedimentation of particles in viscous Newtonian fluids. For the tests, aqueous solutions of glycerol were used in the volumetric concentration of 80% and 92%. The suspensions were prepared using sand with the size range of 150-212 μm. The settling of particles was studied by using a nondestructive technique based upon the measurement of gamma-ray attenuation for achieving the local concentration of solids. The results showed that the sedimentation velocity of particles was changed significantly with increasing fluid viscosity. Moreover, the dynamic behavior of the particles settling in both glycerol solutions showed similar, with two regions of varying concentration of solids very defined: one in which the solids concentration remained constant until the transition from descending clarified interface; and the other in which the concentration remained constant until the formation of sediment.
Authors: Shamala Ramasamy, Hanafi Ismail, Yamuna Munusamy
Abstract: Rice husk powder (RHP) which is a fibrous agricultural waste is widely used as potential filler, novel adsorbent or coating for dry polymers. However, the compatibility of RHP with natural rubber latex (NRL) is yet to be studied. The main goal of this reported work was to create a method to incorporate RHP with NRL and achieve a compatible dispersion. However the amorphous silica content (acidic nature) in RHP makes it difficult to directly incorporate RHP to NRL compound. In this research, RHP was modified by adding ammonia, distilled water and dispersing agents to make an aqueous compatible alkaline dispersion for NRL. Also the particle size of RHP is reduced up to - 300micron to make it more compatible with the NRL. The compatibility of modified RHP is analyzed by sedimentation with time, particle size analyzer, pH and morphology study. The test results supports that modified RHP is more compatible with the NRL compound to obtain a stable foam in NRLF preparation.
Authors: Fumio Watari, Atsuro Yokoyama, Hironobu Matsuno, F. Saso, Motohiro Uo, Takao Kawasaki
Authors: Il Han Chang, Gye Chun Cho, Joo Gong Lee, Lee Hyung Kim
Abstract: Sedimentation is one of the most basic processes in the formation of a soil structure in nature. Many studies have been performed to describe the characteristics of clay sedimentation, based on settlement and water content measurement. In addition, there have been some attempts in numerical modeling to describe soil structure formation as a whole. However, these effects still fall short in explaining the overall process of soil structure formation because some relevant properties are measured after a self-weight consolidation is completed. Furthermore some measurement techniques significantly alter soil structure. Thus, a non-destructive evaluation is necessary for the effective description of soil characteristics during the sedimentation process. In this study, a testing device is designed that continuously monitors the self-weight consolidation process of sedimentation with shear waves. Piezoelectric bender elements are installed into a testing cell to generate and receive shear waves in a small strain regime. Slurries are prepared with kaolinite-type clay and placed in the cell. Shear wave velocities are continuously measured as a function of time during the whole process of the self weight consolidation. The experimental results suggest that as clay sediment is subjected to a certain loading, the shear wave velocity increases as time increases, showing an abrupt change in log time. This abrupt change is relevant to the formation of a stable soil skeleton. It is concluded that the time-dependent variations in shear wave velocity reflect sedimentation and self weight consolidation behavior and the evolution of the effective stress increment.
Authors: Liga Grase, Gundars Mezinskis, Inta Vitina
Abstract: A variety of industrial minerals, such as kaolinite, feldspars, and etc., have been used as solid raw materials in the geopolymerization technology. The illite-containing raw material in this study was obtained by the use of sedimentation method. Clay and dust fractions was subjected to the treatment with NaOH alkaline solution and afterwards treated at different temperatures. Results obtained by X-ray diffraction, Scanning electron microscopy, nitrogen adsorption method confirmed the usability of Liepas deposit homogenized gray and red clays for possible realization of geopolymer method.
Authors: Jing Zou, Jun Tao Zhu, Chao Pan, Jun Ma
Abstract: In this research, the dissolved air flotation (DAF) were tried to treat drinking water to replace traditional sedimentation technology. Experimental study of sedimentation process and DAF was carried out in a jet tester and a glass bubble column respectively. The experimental results demonstrated that the indicators of water quality such as turbidity, chromaticity and CODMn after two processes decreased firstly and then increased with the PAC-dose increasing, and 7.41 mg Al L-1 was the optimum PAC dosage. Moreover, with the optimum PAC dosage, water quality after DAF proved much better than that after sedimentation process. As a result, DAF is a more effective technology to treat the reservoir water with low temperature, low turbidity and high NOM.
Authors: Qi Zhou, Yan Yi Yin
Abstract: Discovered in recent years, Chang 4+5 reservoir group of Yanchang Formation in Jiyuan area is ultra-low permeability reservoir. The evaluation and prediction of the reservoir is the most critical technology in reservoir development. Comprehensive analysis with multiple research approaches shows that the storage potential of the ultra-low permeability reservoir is jointly controlled by sedimentation and diagenesis. Sedimentary factor includes lithology and sedimentary facies, two basic factors affecting the storage potential. The reservoir lithology is of fine-grained debris-arkose and miliary arkose. Pore types are mainly intergranular pores and dissolved pores. The sandstone microfacies in the delta front underwater distributary channel has the best storage potential. Diagenetic factors, including diagenesis types, evolution, intensity, combination etc., have direct influence on the reservoir storage potential. Compaction and calcite cementation are the main factors that weaken the storage potential, whereas carbonate dissolution, especially the dissolution of feldspar plays an important role in the improvement of the storage potential.
Authors: Naohiro Nishikawa, Yoshinori Sato, Fumika Andou, Takekazu Sawa, Yoshihiro Hagihara, Hiromasa Kato, Nobuhito Yoshihara, Hiroaki Okawai, Takatoshi Murase, Toshiro Iyama, Masahiro Mizuno, Shinya Tsukamoto
Abstract: The machining (cutting, grinding etc.) is conducted in manufacturing. Machining fluid (cutting oil, grinding fluid) that consists of oil, surface active agent, and extreme pressure agent, anti rust agent etc. is used. It improves machining performance, but it needs waste fluid disposal that is incineration or coagulative precipitation and so on. It causes huge cost and environmental load. Furthermore, it is afraid of workers health hazard for several chemicals while machining. Therefore, the electric rust preventive machining method system (water machining) is proposed and developed. This method uses only harmless water (tap water etc.) as machining fluid. In this paper, improvement of electric rust preventive chip sedimentation system that is part of water recycle system which is used for machining water purification and re-use. On long time (3 days) preservation of iron chip in water, decreasing of rust and turbidity is examined. Improved electric rust preventive chip sedimentation system is equipped simple circulation filter unit newly and its effectiveness is clarified. When many quantity of iron powder (3kg) likened to actual sludge is sunken in sedimentation water tank, if electric rust prevention and simple circulation filter activated, turbidity and colour would be decreased greatly. Therefore, it is expected that purification load of next part of filters is decreased and life-time of filter and system will be prolonged.
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