Full Description

Submerged systems are increasingly being used in water and wastewater treatmentapplications because of the relatively lowoperating costs associated with submerged membrane systems compared to theirexternal counterparts. However, the operating costs associated with submergedmembrane systems are still relatively high when compared to that associated withconventional treatment technologies such as sand filtration. The magnitude of thepermeate flux that can be maintained is the most significant factor affecting the capitaland operating costs associated with submerged membrane systems. The currentbench-scale approach used to assess the performance of submerged membrane systemsdoes not provide the information that is necessary to design full-scale systems. As aresult, the design of full-scale systems is based on a time and capital extensive trial anderror approach using relatively large pilot-scale systems.The objective of this study was to develop a method for generating the data necessary forfull-scale designs based on bench scale testing. This approach is based on a betterunderstanding of the mechanisms behind the mass transfer at the membrane surface.The primary factor that causes the increase in the trans-membrane pressure during theoperation of the membrane is the occurrence of reversible and irreversible fouling on themembrane surface. The determination of the reversible and the irreversible fouling coefficients wereconducted through bench scale experiments for a chosen source water, membraneconfiguration and hydrodynamic condition. (The approach described herein can be usedto determine the fouling coefficients for different source water, membrane configurationand hydrodynamic conditions.) The extent of irreversible fouling was found to be afunction of the inverse of the permeate flux through the membrane. For the raw water used, the irreversible fouling coefficient at differentpermeate fluxes (Jv) can be estimated from the slope of the regression line. Includes 3 references, figures.

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Edition: Vol. - No. Published: 03/01/2005 Number of Pages: 5 File Size: 1 file , 310 KB