Membrane regeneration and filtration modeling in treating oily wastewaters

Abstract Traditional membrane cleaning methods generate waste cleaning waters; whose disposal costs are an increasing concern. The use of backflushed coalescing microfiltration for the pre-treatment of oily wastewaters prior to ultrafiltration is an interesting technique offering potential as a physical pre-treatment method. The concept of this technique is to pre-treat oily wastewaters with a large pore microfiltration membrane operated with backflushing where the oils are partly coalesced in the pores of the membrane. The permeate from this membrane can then be treated by ultrafiltration. The coalescing membrane must eventually be regenerated in order to maintain a desirable permeate flux. The present work investigates environmentally friendly physical membrane cleaning methods, such as backflushing with hot water or steam followed by pressurized air. The treatment of oily wastewater containing half seawater using a microfiltration (MF)/ultrafiltration (UF) hybrid system was studied in this work. The beneficial effects for steam cleaning were quite evident. The results were also modeled using four traditional fouling models and a combined filtration model. They indicate that fouling of microfiltration membranes is due to the presence of oil and grease and seawater colloids in membrane pores. Optimal cycle times between physical cleanings were found to be in the range of 1.6–2.2 h.

[1]  S. Ebrahim.  Cleaning and regeneration of membranes in desalination and wastewater applications: State-of-the-art , 1994 .

[2]  A. Zydney,et al.  A Combined Pore Blockage and Cake Filtration Model for Protein Fouling during Microfiltration. , 2000, Journal of colloid and interface science.

[3]  S. Takizawa,et al.  Membrane fouling decrease by microfiltration with ozone scrubbing , 1996 .

[4]  S. Nakatsuka,et al.  Drinking water treatment by using ultrafiltration hollow fiber membranes , 1996 .

[5]  M. Hoare,et al.  The effect of high frequency backflushing on the microfiltration of yeast homogenate suspensions for the recovery of soluble proteins , 1999 .

[6]  F. Riera,et al.  Enzymatic cleaning of inorganic ultrafiltration membranes used for whey protein fractionation , 2003 .

[7]  E. P. Jacobs,et al.  Enzymatic cleaning of ultrafiltration membranes fouled by abattoir effluent. , 2003 .

[8]  A. Tremblay,et al.  The use of backflushed coalescing microfiltration as a pretreatment for the ultrafiltration of bilge water , 2005 .

[9]  Mark C. Porter,et al.  Handbook of Industrial Membrane Technology , 2007 .

[10]  A. Fane,et al.  Enzymatic and detergent cleaning of a polysulfone ultrafiltration membrane fouled with BSA and whey , 1996 .

[11]  Nandakishore Rajagopalan,et al.  Membrane processing of oily streams. Wastewater treatment and waste reduction , 1998 .

[12]  Guojun Zhang,et al.  Membrane fouling and cleaning in ultrafiltration of wastewater from banknote printing works , 2003 .

[13]  J. J. Sadhwani,et al.  Cleaning tests for seawater reverse osmosis membranes , 2001 .

[14]  Yves Aurelle,et al.  Unstable secondary oil/water emulsion treatment using ultrafiltration: fouling control by backflushing , 1999 .

[15]  Andrew L. Zydney,et al.  Microfiltration and Ultrafiltration: Principles and Applications , 1996 .

[16]  E. P. Jacobs,et al.  UF of pulp and paper effluent: membrane fouling-prevention and cleaning , 2002 .

[17]  O. Wallberg,et al.  Membrane cleaning — a case study in a sulphite pulp mill bleach plant , 2001 .

[18]  Andreas Weis,et al.  The chemical cleaning of polymeric UF membranes fouled with spent sulphite liquor over multiple operational cycles , 2003 .

[19]  J. Hermia,et al.  Constant Pressure Blocking Filtration Laws - Application To Power-law Non-newtonian Fluids , 1982 .

[20]  Kenji Mori,et al.  Advanced reverse osmosis process with automatic sponge ball cleaning for the reclamation of municipal sewage , 1980 .