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Among all the technologies of water treatment, membrane technology appears to be the most promising. The major advantage of this technology is its ability to produce water with a constant and well adjusted quality. Moreover, membranes remove a wide range of substances, ranging from particles to ions, including bacteria and viruses, and they can operate without any chemical addition to raw water. The paper presents the results of investigations concerning the application of capillary microfiltration (polypropylene) and ultrafiltration (polysulfone) membranes for the purpose of treatment of natural water. The effectiveness of ultra- and microfiltration was assessed by volumetric measurements of the permeate flux as well as by microbiological and physico-chemical analyses.
This work presents the verification of the model of the membrane filtration process of natural waters for non-stationary filtration flux J=f(t), as well as the results of tests involving the filtration process of the said model in constant pressure conditions. Also, the characteristic time of permeate flux decay was determined, and the mechanisms reducing the efficiency of filtration process were analyzed.
Clarification and stabilization of beer as well as recovery of beer from surplus yeast are subjects of great interest. Microfiltration through ceramic membranes could address both these applications if the economy of this process is improved. The aim of the present work was an experimental study of the flux decline in cross flow microfiltration of the filtered beer and aqueous solutions of model foulants. Ceramic membranes with two mean pore sizes of 200 and 500 nm were used. The used microfiltration stand enabled the cleaning of the membrane by backflushing with the permeate. For better understanding of the fouling process and for identifying of the fouling capacity of individual foulants, the runs were conducted with aqueous solutions of selected model foulants as a- and β-amylase, catechin, commercial α-bitter acids, mixture of maltose and sucrose and washed beer yeast suspension. The concentration of the model foulants was similar as in beer. The suspension of the purified beer yeast (four times washed yeast with a physiological solution) was studied as well. A rapid flux decline was observed during the first two-three minutes. The membrane with larger pores, of 500 nm, exhibited lower steady flux than the more dense membrane with 200 nm pores. Repeated rinsing of the fouled membrane with water after microfiltration recovers only a small part of the initial flux. The order of model foulants with increasing flux decline capacity is: mixture of maltose and sucrose < amylase
This EPA treatment technology project was designed to collect data on the performance of existing water treatment processes in order to remove arsenic on pilot-scale. Our paper contains verification testing of the reverse osmosis membrane module conducted over a 30-day period at the Spiro Tunnel Bulkhead water (Park City, Utah, USA), which is considered to be a ground water. The total arsenic concentration in the feedwater averaged 60 ppb during the test period and was reduced to an average of 1 ppb in the treated (permeate) water. The work reported here focused on obtaining accurate readings for arsenic valence states (III) and (V), using an anion exchange resin column. The dominant arsenic species in the abandoned silver mine tunnel feedwater was As(V). Results of analysis showed that 70% of the arsenic present in the feed- water was in dissolved form. Arsenic speciation for valence states (III) and (V) showed that arsenic (V) represented 76% of the dissolved arsenic in the source water. The method detection limit (MDL) for arsenic using ICP-MS was determined to be 0.1 ppb. Our matrix spiked recovery, spiked blank samples and refer­ence materials deviated only a few percentage points from the listed true values.
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