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Liquid Separation (liquid + separation)

Distribution by Scientific Domains
Life Sciences60%

Selected Abstracts

Two-phase bifurcated dividing pipe flow

ASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 1 2009
A. Murphy
Abstract Data are reported on the pressure drop of co-current air,water two-phase flow through 0.0454 m i.d. bifurcations with included angles of 60°, 90°, 120° and 180°. The pressure changes on account of the angles at the junctions depended on the superficial phase velocities and the angle of bifurcation. For the 60° lowest angle of bifurcation the pressure drop was insensitive to flow rates if the superficial liquid velocity was in the lower range at and below 0.1 m s,1. For higher liquid flows the pressure loss increased dramatically, particularly in the annular-type regimes. When the angle at the junction was increased, negative values of pressure loss, i.e. an increase in pressure was recorded across the bifurcation in the gas velocity region under 10 m s,1 and liquid rates at and above 0.1 m s,1 in the slug and blow-through slug regimes. The effect coincided with liquid separation from the inner inlet pipe wall of the junction and its subsequent reformation on the downstream walls. A second less dramatic increase in junction pressure drop occurred at the lowest liquid flow rate of 0.05 m s,1 for the tee (180° bifurcation) that was due both to the smooth transition of liquid through the junction and the damping of surface waves in stratified-type flow. A flow regime map was presented for the tee junction. The inlet flow showed agreement with the map but the flow regimes found in the outlet arms of the junction tended to form earlier than expected being triggered by the pressure disturbances in the passage through the bifurcation. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source]

Impact of membrane solid,liquid separation on design of biological nutrient removal activated sludge systems

BIOTECHNOLOGY & BIOENGINEERING, Issue 6 2005
M. Ramphao
Abstract Installing membranes for solid,liquid separation into biological nutrient removal (BNR) activated sludge (AS) systems makes a profound difference not only in the design of the BNR system itself, but also in the design approach for the whole wastewater treatment plant (WWTP). In multizone BNR systems with membranes in the aerobic reactor and fixed volumes for the anaerobic, anoxic, and aerobic zones (i.e., fixed volume fractions), the mass fractions can be controlled (within a range) with the interreactor recycle ratios. This zone mass fraction flexibility is a significant advantage in membrane BNR systems over conventional BNR systems with SSTs, because it allows for changing of the mass fractions to optimize biological N and P removal in conformity with influent wastewater characteristics and the effluent N and P concentrations required. For PWWF/ADWF ratios in the upper range (fq , 2.0), aerobic mass fractions in the lower range (fmaer < 0.60), and high (usually raw) wastewater strengths, the indicated mode of operation of MBR BNR systems is as extended aeration WWTPs. Although the volume reduction compared with equivalent conventional BNR systems with secondary settling tanks is not as large (40% to 60%), the cost of the membranes can be offset against sludge thickening and stabilization costs. Moving from a flow-unbalanced raw wastewater system to a flow-balanced (fq = 1), low (usually settled) wastewater strength system can double the ADWF capacity of the biological reactor, but the design approach of the WWTP changes from extended aeration to include primary sludge stabilization. The cost of primary sludge treatment then has to be paid from the savings from the increased WWTP capacity. © 2005 Wiley Periodicals, Inc. [source]

Improved model of secondary clarifier in A2/O process

ASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 4 2009
Ma Longhua
Abstract The complex behavior of the secondary clarifier and its great importance in the successful operation of the activated sludge process (ASP) have made the settling process a major issue for researchers working in the field of mathematical modeling. So, a precise model of the secondary clarifier can describe the actual behavior of a sewage plant better. But in ASM2, the solid/liquid separation in a secondary clarifier, which is highly nonlinear, is not considered. The solid/liquid separation affects not only the biological reaction but also the quality of the effluent. In this paper an improved secondary clarifier model based on a one-dimensional settler model is established in terms of the solid flux concept and a mass balance. Through some given assumptions, a model of A2/O process including secondary clarifier is built, and then simulated. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source]

Applications of the Liquid Cyclone in Biological Separations

ENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 2 2004
E. Ortega-Rivas
Abstract Hydrocyclone technology has been suggested as a practical alternative in solid/liquid separations involving biological materials. This paper reviews applications of hydrocyclones in food processing, considering the non-Newtonian nature of most suspensions treated in the food industry. The hydrocyclone is easy to install and operate, and requires very limited space. It represents an unsophisticated piece of equipment, which runs in a continuous manner and it can be operated at lower costs than most solid/liquid separation techniques. Hydrocyclones have been used in the food industry for the refining of starch, to separate gossypol from cottonseed protein in cottonseed oil processing, and for some other applications, such as multi-stage mixer/separator extraction systems for soluble coffee. More recently, some other applications in biological systems, which will be discussed in this article, have also been tested. [source]