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Charged UF membrane for fermentation separation
News and Views Analysis of quinone c o m p o n e n t s of the sludge suggested a decrease of strict aerobic bacteria percentages during t e m p e r a t u r e decrease. Increasing percentages were observed during recovery of nitrification at low temperature. The a u t h o r s concluded that the oxygen transfer condition was the most important factor governing the nitrification, a n d hence nitrogen removal.
Further information from: C. Chiemchatsri, Department of Urban Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113, Japan.
N e w l i n e o f UF membranes Ionics Inc h a s a n n o u n c e d the introduction of its new llne of ultraflltration m e m b r a n e s to be used for the purification of water a n d other liquids. The m e m b r a n e s are being produced in the form of spiral w o u n d modules in i n d u s t r y s t a n d a r d (4 b y 40 inch a n d 8 b y 40 inch) sizes on a new state-of-the-art casting a n d rolling line at Ionlcs in Watertown, Massachusetts. The modules have been field-tested for the past year, a n d will also be u s e d in water purification systems sold or leased b y Ionics.
Further Information from: lonlcs Inc, 65 Grove Street, Watertown, MA 021 72, USA. Tel: +1 617 926 2500.
C h a r g e d UF m e m b r a n e for fermentation separation A newly developed thin-film composite (TFC) ultrafiltration m e m b r a n e m a d e of sulfonated poly~phenylene oxide) (SPPO) was u s e d in studies to establish the feaslbflity of separating L-phenylalanine from fermentation broth (Sep. Scl. Technol., 29, pp 171-192, 1994). Charged UF m e m b r a n e s are more versatile from the industrial point of view in c o m p a r i s o n to neutral NF m e m b r a n e s . They can be used as conventional UF m e m b r a n e s as well as being capable of rejecting macromolecules bearing charges of the same sign as that of the m e m b r a n e . Therefore, it m a y be possible to separate charged solutes from neutral solutes even t h o u g h both types of solutes are of similar molecular size. For these studies two m e m b r a n e samples of the SPPO m e m b r a n e which h a d MWCO ratings of I 0 000 a n d 20 000 were investigated with regard to their rejection capabilities for various c o m p o n e n t s which are usually present in fermentation broth, using a
Membrane Technology No. 48
single solute system. The fermentation b r o t h contained a n u m b e r of dissolved inorganic a n d organic solutes as a n alternative a p p r o a c h to ion-exchange schemes. The researchers found that the rejection of various salts was strongly dependent on the concentration of the salts in the feed solution. The pH of the feed solution was found to have a strong effect on the rejection of L-phenylalanine, changing it from - I 0 to 90%. This rejection behaviour was identical for both m e m b r a n e samples, although the permeate flux of the 20 000 MWCO sample was almost twice that of the I 0 000 MWCO sample. The a u t h o r s concluded that rejection is very strongly governed b y the electrostatic forces c a u s e d by the fixed negative charges due to sulfonic groups on the m e m b r a n e for the two m e m b r a n e samples tested.
Further Informatlon from: R.Y.M. Huang, Department of Chemical Engineering, University of Waterloo, Waterloo, Ontario N2L 3GI, Canada.
Distillery wastes treated with ceramic membrane Studies into the p r e t r e a t m e n t of alcohol-distillery wastes with ceramic m e m b r a n e s prior to anaerobic digestion have been carried out in Korea (J. Membrane Scl., 90, pp 131-139, 1994). Anaerobic digestion is u s e d to stabilize domestically derived organic sludges, a n d h a s been u s e d in treating alcohol-dlsttllery wastes, b u t w h e n n a k e d barley is u s e d in the process, COD removal efficiency and m e t h a n e gas p r o d u c t i o n are reduced. This seems to be due to the presence of toxins a n d Inhibltors in these particular stillages, a n d pretreatment of the waste by ceramic m e m b r a n e s to remove these s u b s t a n c e s was performed. Ceramic m e m b r a n e s were c h o s e n a s the temperature of the stillages is over 70°C, and a pore size of 0.05 ~m was u s e d b a s e d on the particle size distribution in raw wastes. In these experiments, m e m b r a n e separation characteristics were studied with different types of stlllages a n d inorganic m e m b r a n e s . The efficiency of physicochemical cleaning m e t h o d s was studied, together with the cleaning mechanism. The performance of digesters with and without m e m b r a n e p r e t r e a t m e n t was also compared. It was found that COD was r e d u c e d from 36 000 to 18 000 m g / L a n d s u s p e n d e d solids were almost completely removed. The permeates from the ceramic m e m b r a n e s were further separated by ultraflltration, b u t further COD reduction by u s i n g the PM30 a n d PM10 m e m b r a n e s was not achieved. Permeation flux during concentration of mixed stillages was prone to decrease more rapidly due to higher fouling t e n d e n c y t h a n that of n a k e d barley b a s e d stfllage. Several cleaning m e t h o d s were attempted to recover water flux. A cleaning sequence of hydrogen
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Further information from: C. Chiemchatsri, Department of Urban Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113, Japan.
N e w l i n e o f UF membranes Ionics Inc h a s a n n o u n c e d the introduction of its new llne of ultraflltration m e m b r a n e s to be used for the purification of water a n d other liquids. The m e m b r a n e s are being produced in the form of spiral w o u n d modules in i n d u s t r y s t a n d a r d (4 b y 40 inch a n d 8 b y 40 inch) sizes on a new state-of-the-art casting a n d rolling line at Ionlcs in Watertown, Massachusetts. The modules have been field-tested for the past year, a n d will also be u s e d in water purification systems sold or leased b y Ionics.
Further Information from: lonlcs Inc, 65 Grove Street, Watertown, MA 021 72, USA. Tel: +1 617 926 2500.
C h a r g e d UF m e m b r a n e for fermentation separation A newly developed thin-film composite (TFC) ultrafiltration m e m b r a n e m a d e of sulfonated poly~phenylene oxide) (SPPO) was u s e d in studies to establish the feaslbflity of separating L-phenylalanine from fermentation broth (Sep. Scl. Technol., 29, pp 171-192, 1994). Charged UF m e m b r a n e s are more versatile from the industrial point of view in c o m p a r i s o n to neutral NF m e m b r a n e s . They can be used as conventional UF m e m b r a n e s as well as being capable of rejecting macromolecules bearing charges of the same sign as that of the m e m b r a n e . Therefore, it m a y be possible to separate charged solutes from neutral solutes even t h o u g h both types of solutes are of similar molecular size. For these studies two m e m b r a n e samples of the SPPO m e m b r a n e which h a d MWCO ratings of I 0 000 a n d 20 000 were investigated with regard to their rejection capabilities for various c o m p o n e n t s which are usually present in fermentation broth, using a
Membrane Technology No. 48
single solute system. The fermentation b r o t h contained a n u m b e r of dissolved inorganic a n d organic solutes as a n alternative a p p r o a c h to ion-exchange schemes. The researchers found that the rejection of various salts was strongly dependent on the concentration of the salts in the feed solution. The pH of the feed solution was found to have a strong effect on the rejection of L-phenylalanine, changing it from - I 0 to 90%. This rejection behaviour was identical for both m e m b r a n e samples, although the permeate flux of the 20 000 MWCO sample was almost twice that of the I 0 000 MWCO sample. The a u t h o r s concluded that rejection is very strongly governed b y the electrostatic forces c a u s e d by the fixed negative charges due to sulfonic groups on the m e m b r a n e for the two m e m b r a n e samples tested.
Further Informatlon from: R.Y.M. Huang, Department of Chemical Engineering, University of Waterloo, Waterloo, Ontario N2L 3GI, Canada.
Distillery wastes treated with ceramic membrane Studies into the p r e t r e a t m e n t of alcohol-distillery wastes with ceramic m e m b r a n e s prior to anaerobic digestion have been carried out in Korea (J. Membrane Scl., 90, pp 131-139, 1994). Anaerobic digestion is u s e d to stabilize domestically derived organic sludges, a n d h a s been u s e d in treating alcohol-dlsttllery wastes, b u t w h e n n a k e d barley is u s e d in the process, COD removal efficiency and m e t h a n e gas p r o d u c t i o n are reduced. This seems to be due to the presence of toxins a n d Inhibltors in these particular stillages, a n d pretreatment of the waste by ceramic m e m b r a n e s to remove these s u b s t a n c e s was performed. Ceramic m e m b r a n e s were c h o s e n a s the temperature of the stillages is over 70°C, and a pore size of 0.05 ~m was u s e d b a s e d on the particle size distribution in raw wastes. In these experiments, m e m b r a n e separation characteristics were studied with different types of stlllages a n d inorganic m e m b r a n e s . The efficiency of physicochemical cleaning m e t h o d s was studied, together with the cleaning mechanism. The performance of digesters with and without m e m b r a n e p r e t r e a t m e n t was also compared. It was found that COD was r e d u c e d from 36 000 to 18 000 m g / L a n d s u s p e n d e d solids were almost completely removed. The permeates from the ceramic m e m b r a n e s were further separated by ultraflltration, b u t further COD reduction by u s i n g the PM30 a n d PM10 m e m b r a n e s was not achieved. Permeation flux during concentration of mixed stillages was prone to decrease more rapidly due to higher fouling t e n d e n c y t h a n that of n a k e d barley b a s e d stfllage. Several cleaning m e t h o d s were attempted to recover water flux. A cleaning sequence of hydrogen
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