Wastewater treatment fouling

Juang LC, Tseng DH, Lin HY (2007) Membrane processes for water reuse from the effluent of industrial wastewater treatment plant a study on flux and fouling of membrane. Desalination 202 302-309... 

Belfort, G., and Marx, B., "Wastewater Treatment by Membranes What Can be Done About Fouling " in Proc. 33rd Industrial Waste Conference, May 9-11, 1978, Purdue University. 

The discharge from both domestic and industrial wastewater treatment plants (for example, from activated sludge processes) has been a low-cost source of makeup for cooling systems for many years. Efforts to reuse water continue to gain momentum for environmental conservancy and economic reasons, but the fact that secondary use waters are, by definition, of a lower grade than other supply sources inevitably means an increased risk of deposition or fouling problems in the cooling system. 

In addition to the monopolar membrane described above a large number of special property membranes are used in various applications such as low-fouling anion-exchange membranes used in certain wastewater treatment applications or composite membranes with a thin layer of weakly dissociated carboxylic acid groups on the surface used in the chlorine-alkaline production, and bipolar membranes composed of a laminate of an anion- and a cation-exchange layer used in the production of protons and hydroxide ions to convert a salt in the corresponding acids and bases. The preparation techniques are described in detail in numerous publications [13-15]. 

Another interesting possibility is the use of pressure-driven membrane processes, in particular MF and UF are becoming standard and very efficient pretreatment options for sea- and brackish-water desalination. Also, for wastewater treatment, MF/UF pretreatment technology can efficiently reduce the highly fouling nature of the feed. 

Tardieu, E., Grasmick, A., Geaugey, V. and Manem, J. (1999) Influence of hydrodynamics on fouling velocity in a recirculated MBR for wastewater treatment. Journal of Membrane Science, 156, 131-140. 

Another example of using ultrafiltration for wastewater treatment and resource recovery is the separation of oil-water emulsions generated from metal machining, oil field wastes, and enhanced oil recovery effluents. Hydrophilic membranes such as cellulose acetate are preferred because they are effective barriers to oil droplets and are less prone to fouling. The UF permeate readily meets direct discharge standards. The oil-rich stream can be processed to reclaim the oil, or disposed at reduced transportation cost because of its reduced volume. 

Hi) Improved Wastewater Treatment Plant Operation. Solids in the drainage system tend to collect and foul some wastewater treatment plant equipment. Reducing solids by removing soil would reduce fouling and maintenance needs. 

The future for electrodialysis-based wastewater treatment processes appears bright. The dilute concentrations of metals in the waste streams do not degrade or foul the cation or anion exchange membranes. The concentrate streams are recirculated to build up their metal content to a level that is useful for further recovery or direct return to the process stream. Ongoing research in the development of cheaper cation exchange membranes, and stable anion exchange and bipolar membranes will allow electrodialysis-based applications to become more competitive with other treatments. 

Ridgway H.F., Kelly A., Justice C., and Olson B.H., Microbial fouling of reverse osmosis membranes used in advanced wastewater treatment technology Chemical bacteriological and ultrastiuctural analyses. Applied and Environmental Microbiology 46 1983 1066-1084. 

Rimpelainen, S. and Tremblay, A.Y., Verification of Species Responsible for the Fouling of RO Membranes during Mixed Wastewater Treatment, ULTRAPURE WATER, Knowledgebase, UP170136, 1, 2000. 

Choi H, Zhang K, Dionysiou DD, Oerther DB, and Sorial GA. Effect of permeate flux and tangential flow on membrane fouling for wastewater treatment. Sep. Pur. Techn. 2005 45(1) 68-78. 

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