scholarly journals Modern trends in the mathematical simulation of pressure-driven membrane processes

2020 ◽  
Vol 7 (1) ◽  
pp. F1-F21
Author(s):  
S. V. Huliienko ◽  
Y. M. Korniienko ◽  
K. O. Gatilov

The presented article is an attempt to evaluate the progress in the development of the mathematical simulation of the pressure-driven membrane processes. It was considered more than 170 articles devoted to the simulation of reverse osmosis, nanofiltration, ultrafiltration, and microfiltration and the others published between 2000 and 2010 years. Besides the conventional approaches, which include the irreversible thermodynamics, diffusion and pore flow (and models which consider the membrane surface charge for nanofiltration process), the application of the methods the computational fluid dynamics, artificial neural networks, optimization, and economic analysis have been considered. The main trends in this field have been pointed out, and the areas of using approaches under consideration have been determined. The technological problems which have been solved using the mentioned approaches have also been considered. Although the question of the concentration polarization has not been considered separately, it was defined that, in many cases, the sufficiently accurate model cannot be designed without considering this phenomenon. The findings allow evaluating more thoroughly the development of the simulation of pressure-driven membrane processes. Moreover, the review allows choosing the strategy of the simulation of the considered processes. Keywords: membrane, simulation, model, reverse osmosis nanofiltration, ultrafiltration, microfiltration.

2021 ◽  
Vol 7 (4) ◽  
pp. 739-747
Author(s):  
Chungheon Shin ◽  
Aleksandra Szczuka ◽  
Renjing Jiang ◽  
William A. Mitch ◽  
Craig S. Criddle

RO enables the recovery of clean water and ammonium in anaerobic membrane bioreactor effluent. pH governs the ammonia speciation and membrane surface charge and is the key operational factor that affects the total ammonia rejection efficiency of RO.


Membranes ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 334
Author(s):  
Aldo Bottino ◽  
Gustavo Capannelli ◽  
Antonio Comite ◽  
Camilla Costa ◽  
Raffaella Firpo ◽  
...  

The disposal of wastewater resulting from olive oil production (olive mill wastewater, OMW) is a major issue for olive oil producers. This wastewater is among the most polluting due to the very high concentration of organic substances and the presence of hardly degradable phenolic compounds. The systems proposed for OMW treatment are essentially based either on conventional chemical-physical, biological and thermal processes, or on membrane processes. With respect to conventional methods, membrane processes allow to separate different species without the use of chemicals or heat. This work deals with the use of the integrated pressure-driven membrane processes for the treatment of OMW. They consist of a first stage (microfiltration, MF) in which a porous multichannel ceramic membrane retains suspended materials and produces a clarified permeate for a second stage (reverse osmosis, RO), in order to separate (and concentrate) dissolved substances from water. Laboratory scale experiments with different small flat sheet RO membranes were first carried out in order to select the most appropriate one for the successive bench scale tests with a spiral wound module having a large membrane surface. The aim of this test was to concentrate the dissolved substances and to produce water with low salinity, chemical oxygen demand (COD), and reduced phytotoxicity due to a low content of phenolic compounds. The trend of the permeate flux and membrane retention as a function of the volume concentration ratio was investigated. The influence of OMW origin and its aging on the membrane performance was also studied.


2011 ◽  
Vol 65 (3) ◽  
pp. 233-239 ◽  
Author(s):  
Svetlana Popovic ◽  
Dragica Jovicevic ◽  
Mirjana Djuric ◽  
Spasenija Milanovic ◽  
Miodrag Tekic

Membrane filtration has become one of the major technologies in the food industry. It is widely applied in the dairy industry, and it is mostly used for the concentration and fractionation of milk proteins and for the whey processing. Of all pressure driven membrane processes, ultrafiltration is the most widely used. The major disadvantage of pressure driven membrane processes is severe fouling of membrane during filtration particularly when the fluids containing proteins are processed. Fouling with proteins is complex phenomenon because it occurs at the membrane surface as well as in the pores of membrane, and depends on the operating conditions and on the interactions of proteins and membrane material. In order to reduce fouling of the membrane different techniques have been developed, and one of them relies on the changing of the hydrodynamic conditions in the membrane or module. In this study, influence of twisted tape turbulence promoters on the fouling reduction in cross-flow microfiltration of skim milk was investigated. Twisted tapes with tree characteristic ratios of helix element length to the tape diameter (aspect ratio) were studied. It was shown that twisted tapes with different aspect ratios reduce fouling of membrane by a factor of three or more. The presence of twisted tape induces changes in the flow patterns from straight to helicoidally thus producing turbulence flow at the lower cross-flow rates. Turbulence intensification prevents accumulation of proteins at membrane surface enabling reduction in reversible fouling what results in the reduction of overall membrane fouling. The best performance was achieved using a twisted tape with the lowest aspect ratio of 1.0. This promoter reduces fouling seven times at low transmembrane pressure and low cross-flow velocity. The twisted tape with aspect ratio 1.0 induces the most intensive turbulence, the longest helicoidal flow path, and appearance of vortices near the membrane surfaces, so the scouring of proteins from the membrane surface is the most intensive in that case.


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