Effluent treatment membrane technology

Fersi C, Gzara L, Dhahbi M (2005) Treatment of textile effluents by membrane technologies. Desalination 185 1825-1835... 

Chabot B, Krishnagopalan GA, and Abubakr S. Flexographic newspaper deinking Treatment of wash filtrate effluent by membrane technology. J. Pulp Pap. Sci 1999 25(10) 337-343. 

Figure Seven (7) depicts a general schematic for membrane processes. In these technologies the implication of increasing the dewatering process is described by the term "recovery", which is defined as the purified water volume divided by the incoming stream volume in other words, percentage of the feed flow which is pumped through the membrane. Typically, for effluent treatment applications, the recovery figure is at least 90%. As recovery is increased (to decrease concentrated solute volume), the concentration of solute and suspended solids in the concentrate stream increases.

Membrane technologies can also be used in other parts of this total treatment system microfiltration could be substituted for the clarifier (see Figure 9), and reverse osmosis could purify the clarified effluent for re-use. 

Combining UF or MF membrane technologies with biological reactors for the treatment of wastewater in a one-stage process has led to the generation of the MBR concept in which MF or UF membranes have replaced the traditional sedimentation tank. An efficient clarification of the treated wastewater is achieved, membranes can reduce the disinfection practices such as chlorination, and a pathogen-free, tertiary quality effluent is thus obtained [11]. 

Membrane technology may become essential if zero-discharge mills become a requirement or legislation on water use becomes very restrictive. The type of membrane fractionation required varies according to the use that is to be made of the treated water. This issue is addressed in Chapter 35, which describes the apphcation of membrane processes in the pulp and paper industry for treatment of the effluent generated. Chapter 36 focuses on the apphcation of membrane bioreactors in wastewater treatment. Chapter 37 describes the apphcations of hollow fiber contactors in membrane-assisted solvent extraction for the recovery of metallic pollutants. The apphcations of membrane contactors in the treatment of gaseous waste streams are presented in Chapter 38. Chapter 39 deals with an important development in the strip dispersion technique for actinide recovery/metal separation. Chapter 40 focuses on electrically enhanced membrane separation and catalysis. Chapter 41 contains important case studies on the treatment of effluent in the leather industry. The case studies cover the work carried out at pilot plant level with membrane bioreactors and reverse osmosis. Development in nanofiltration and a case study on the recovery of impurity-free sodium thiocyanate in the acrylic industry are described in Chapter 42. 

Afonso MD and De Pinho MN. Treatment of bleaching effluents by pressure-driven membrane processes—a review. In Membrane Technology Applications to Industrial Wastewater Treatment, Cuetano et al., Eds., Kluwer Academic, The Netherlands, 1995. 

Nanofiltration is a rapidly advancing membrane separation technique for concentration/separation of important fine chemicals as well as treatment of effluents in pharmaceutical industry due to its unique charge-based repulsion property [5]. Nanofiltration, also termed as loose reverse osmosis, is capable of solving a wide variety of separation problems associated with bulk drug industry. It is a pressure-driven membrane process and indicates a specific domain of membrane technology that hes between ultrafiltration and reverse osmosis [6]. The process uses a membrane that selectively restricts flow of solutes while permitting flow of the solvent. It is closely related to reverse osmosis and is called loose RO as the pores in NF are more open than those in RO and compounds with molecular weight 150-300 Da are rejected. NF is a kinetic process and not equilibrium driven [7]. 

L. T. Rozelle, C. V. Kopp and K. E. Cobian, New membranes for reverse osmosis treatment of metal finishing effluents. Environmental Protection Technology Series, EPA-660/2-73-033, December 1973. 

Oily water wastes constitute a major environmental problem in many industries. Stable oil/water emulsions, which cannot be broken by mechanical or chemical means, require more sophisticated treatment to meet the effluent standards. Various physical methods including microfiltration, ultrafiltration, nanofiltration, centrifugation, air flotation, and fiber or packed bed coalescence have been applied in oil-surfactant-water separation [131]. Among these physical methods, membrane technology is by far the most widely used. 

As stated at the beginning of this section, various membrane technologies have been used successfiilly for water and wastewater treatment applications. FakhruT-Razi (1994) used UF membranes of 10,000 nominal molecular weight limit in conjunction with an anaerobic reactor to treat wastewater from a brewery. The percentages of COD removal achieved were above 96%. The results indicated that the UF membranes are capable of efficient biomass-effluent separation, thus preventing any biomass loss from the reactor, and have potential for treating industrial wastewaters. In an attempt to treat brewery wastewater for recycling. Bracken et al. (2004) used... 

In order to overcome the disadvantages associated with the conventional process, the development of new technologies is a very active research field in the area of effluent treatment. Ion exchange and membrane processes have been intensively investigated nowadays however, these processes only concentrate the... 

Idris, A., I. Ahmed, and W.J. Ho, Performance of cellulose acetate-polyethersulfone blend membrane prepared using microwave heating for pahn oil mill effluent treatment. Water Science and Technology, 2007. 56(8) 169-177. 

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