Wastewater microfiltration

Whereas many of these technologies are not really new, they have never had the regulatory and economic justification for their use in metallizing. Each of these general methods has many variants. Some may be directed to waste treatment, some to recycle, and some to reclaim. An example is filtration, used to prevent release to air of zinc particles from flame spraying, microfiltration of cleaners to extend hfe, in combination with chemical precipitation to remove metal particles from wastewater, and many other uses. 

There have been only a few studies have evaluated membrane microfiltration of secondary wastewater effluent. Microfiltration membranes might be used to achieve very low turbidy effluents with very little variance in treated water quality. Because bacteria and many other microorganisms are also removed, such membrane disinfection might avoid the need for chlorine and subsequent dechlorination. Metal... 

Other membrane processes such as microfiltration, ultrafiltration, reverse osmosis, and colloid-enhanced ultrafiltration have been applied to the separation of beta-cypermethrin from wastewater samples [27]. In this study, a separation of above 92% was performed by reverse osmosis by the use of composite membranes and above 80% by colloid-enhanced ultrafiltration by the use of nonionic surfactants. 

Filtration, 11 321-397 75 824—825. See also Filter cycles Filter performance Filters Microfiltration Nanofiltration membranes Ultrafiltration as advanced wastewater treatment, 25 908-909... 

In the recent years, many researchers have devoted attention to the development of membrane science and technology. Different important types of membranes, such as these for nanofiltration, ultrafiltration, microfiltration, separation of gases and inorganic membranes, facilitated or liquid membranes, catalytic and conducting membranes, and their applications and processes, such as wastewater purification and bio-processing have been developed [303], In fact, almost 40 % of the sales from membrane production market are for purifying wastewaters. 

The El Segundo, CA, Chevron refinery takes a further step in water reuse [76]. It receives 16,300 m /day of reclaimed water to feed its boilers. Microfiltration (ME) and RO are used to treat secondary effluent from the Hyperion Wastewater Treatment Plant to provide low-pressure boiler feedwater while a second pass RO is used to produce high-pressure boiler feedwater. 

T0192 CURE International, Inc., CURE Electrocoagulation Wastewater Treatment System T0214 DuPont/Oberlin, Microfiltration Technology T0230 EET Corporation, Microwaste Waste Solidification T0232 Eichrom Industries, Inc., Diphonix... 

Environmental Research and Development, Inc., offers the neutral process, which reduces hex-avalent chromium using sulfide catalyzed by ferrous iron, while precipitating heavy metals at pH ranges from 7.4 to 8.4. The vendor has combined this technology with cross-flow microfiltration to remove heavy metals from contaminated groundwater and wastewater without the need for large clarifiers. The technology has been used at U.S. Department of Defense (DOD) sites and is commercially available. 

The EPOC microfiltration process is based on the ability of a proprietary woven polyester filter to retain particles and allow water to permeate through the filter. The technology uses a three-step process in which (1) reagents are added to the wastewater to precipitate metals and/or sorb other contaminants (2) the microfiltration unit (known as EXXFLOW) removes and concentrates the precipitates, while allowing water (permeate) to pass and (3) the concentrated precipitate is dewatered (by a module called EXXPRESS) to produce a semidry filter cake containing the metal precipitates and other filtered solids. 

Microfiltration, ultrafiltration, and nanofiltration are becoming standard in feed pretreatment for water desalination, wastewater treatment and fruit-juice concentration. 

Bouhabila, E.H., Ben Aim, R. and Buisson, H. (1998) Microfiltration of activated sludge using submerged membrane with air bubbling (application to wastewater treatment). Conference on Membranes in Drinking and Industrial Water Production, Amsterdam. 

Xing, C.-H., Wena, X.-H. and Tardieub, E. (2001) Microfiltration-membrane-coupled bioreactor for urban wastewater reclamation. Desalination, 141, 63-73. 

Davies, W. J., M. S. Le, and C. R. Heath (1998). Intensified activated sludge process with submerged membrane microfiltration. Water Science and Technology Wastewater Industrial Wastewater Treatment, Proc. 199819th Biennial Conf. Int Assoc, on Water Quality. Part 4, June 21-26, Vancouver, Canada, 38, 4-5, 421 28. Elsevier Science Ltd., Exeter, England. 

Maccoimick A. B., The application of microfiltration in water and wastewater treatment . In Modem Tech, in Water and Wastewater Treatment, CSIRO Publishing, Australia, 1995, p. 45. 

Xu L, Li W, Lu S, Wang Z, Zhu Q, and Ling Y. Treating dyeing wastewater by ceramic membrane in cross-flow microfiltration. Desalination 2002 149(l-3) 199-203. 

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