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U.S. Filter — record third quarter
News and Views
bq Bleed
~ckflush b
~
Hydr~en Peroxide Dosing
SDI
> Drain
Test Kit
Figure 1: Kalsep Hydro-X pilot rig schematic. Pre-treated water reaching the main purification s y s t e m m u s t h a v e a n SDI of l e s s t h a n 5 if t h e m e d i a a r e to b e p r o t e c t e d f r o m fouling. In s e p a r a t e t e s t s , t h e p e r f o r m a n c e a n d o p e r a t i n g c h a r a c t e r i s t i c s of m o d u l e s c o n t a i n i n g a K a l m e m low-fouling U F m e m b r a n e a n d a s t a n d a r d m e m b r a n e w e r e c o m p a r e d u s i n g t h e H y d r o - X t e s t rig s h o w n in F i g u r e 1. B o t h m e m b r a n e s were m a n u f a c t u r e d on a hollow fibre c o n f i g u r a t i o n w i t h p o r e sizes in t h e c o a r s e u l t r a f i l t r a t i o n r a n g e of a p p r o x i m a t e l y 2 0 0 0 0 0 N o m i n a l Weight C u t Off (NWCO), t h e m o d u l e s w e r e o p e r a t e d in a d e a d - e n d m o d e . A p r o p o r t i o n of t h e p e r m e a t e w a s r e t a i n e d u n d e r p r e s s u r e in a v e s s e l c o n t a i n i n g a d i a p h r a g m to p r o v i d e f e e d s t o c k for b a c k f l u s h i n g t h e m e m b r a n e s . For each membrane, the experimental runs were c a r r i e d o u t in t h r e e p h a s e s , w i t h t h e t r a n s m e m b r a n e p r e s s u r e d r o p - a n i n d i c a t i o n of m e m b r a n e fouling b e i n g m e a s u r e d a t r e g u l a r i n t e r v a l s (Figure 2). D u r i n g t h e f r s t p h a s e , t h e t e s t rig w a s o p e r a t e d w i t h a feed flux of 9 0 lmh, r e s u l t i n g in a p e r m e a t e flux of 85 lmh. In t h e e a r l y s t a g e s of t h e r u n , t h e p r e s s u r e d r o p a c r o s s e a c h m e m b r a n e i n c r e a s e d from a p p r o x i m a t e l y 2 p s i to 5 psi. W h e n t h e m e m b r a n e s w e r e c l e a n e d b y b a c k f l u s h i n g a f t e r 75 m i n u t e s of o p e r a t i o n , t h e p r e s s u r e d r o p for K a l m e m w a s r e s t o r e d to the initial v a l u e , w h i l s t t h e p r e s s u r e d r o p a c r o s s the standard membrane was increased. The s t a n d a r d m e m b r a n e w a s t h e n c l e a n e d a g a i n a f t e r a n o t h e r 60 m i n u t e s of o p e r a t i o n , after w h i c h t h e p r e s s u r e d r o p h a d a g a i n i n c r e a s e d to m o r e t h a n twice t h a t of t h e o r i g i n a l v a l u e , b y c o n t r a s t , t h e low-fouling
Z,D 30 25 20 15 10 5
00
Standard
o
• onset of accelerated fouling (phase II) -. \ \ "-
50
~.
100
L
150
Kalmem
/, (
200
250
300
350
Time (mins) Figure 2: Membrane pressure drop versus time.
2
K a l m e m m e m b r a n e w a s allowed to r u n for a f u r t h e r 140 m i n u t e s , after w h i c h t h e p r e s s u r e d r o p fell b a c k close to its initial value. D u r i n g t h e s e c o n d p h a s e of t h e field trials, e a c h m e m b r a n e w a s s u b j e c t e d to a n a c c e l e r a t e d fouling r e g i m e b y o p e r a t i n g t h e rig a t a flux of 2 4 0 l m h . T h i s t e s t w a s e q u i v a l e n t to r u n n i n g t h e s y s t e m for four h o u r s a t t h e t a r g e t p r o d u c t i v i t y of 85 l m h w i t h o u t baekfiushing the membranes. Both membranes became progressively plugged by p a r t i c u l a t e s d u r i n g t h e a c c e l e r a t e d fouling test, r e s u l t i n g in a p e a k p r e s s u r e d r o p of 30 psi. W h e n t h e p e r m e a t e flux w a s r e d u c e d to t h e s t a n d a r d 85 i m h , t h e p r e s s u r e d r o p fell to 13 psi in e a c h case. T h e difference b e t w e e n t h e two m e m b r a n e s w a s t h e n f u r t h e r d e m o n s t r a t e d i n t h e t h i r d p h a s e of t h e field t e s t s , d u r i n g w h i c h m o d u l e s w e r e r e p e a t e d l y backflushed with permeate. The Kalmem membrane b e c a m e c l e a n e d m o r e r e a d i l y r e t u r n i n g to r e d u c e d equilibrium pressure drop compared with the s t a n d a r d m e m b r a n e . F u r t h e r m o r e , a final b a c k f l u s h w i t h a 0.01% s o l u t i o n of h y d r o g e n p e r o x i d e r e s t o r e d t h e K a l m e m p r e s s u r e d r o p to its original v a l u e , w h i l s t t h e s t a n d a r d m e m b r a n e still e x h i b i t e d c o n s i d e r a b l e r e s i d u a l fouling. In t e r m s of p e r m e a t e quality, b o t h m e m b r a n e s r e d u c e d t h e t u r b i d i t y of t h e r a w w a t e r b y a n o m i n a l ten-fold a n d gave SDI's of well b e l o w 3.0 in all c a s e s . T h e field trials d e m o n s t r a t e t h a t t h e K a l m e m m e m b r a n e is m o r e h i g h l y r e s i s t a n t to fouling t h a n standard membranes, and can be cleaned more r a p i d l y a n d effectively b y b a c k f l u s h i n g a n d sanitisation. For further information, contact: Kalsep Ltd, Doman Road, Yorktown Industrial Estate, Camberley, Surrey, GU15 3DF, UK. Tel: +44 1276 675675; fcc~: +44 1276 676276.
U.S. F i l t e r record third quarter U n i t e d S t a t e s Filter C o r p o r a t i o n h a s r e p o r t e d r e c o r d r e v e n u e s of $ 1 2 6 , 9 0 7 , 0 0 0 for t h e q u a r t e r e n d e d D e c e m b e r 31, 1995, c o m p a r e d w i t h $ 7 2 , 1 8 9 , 0 0 0 for t h e s a m e q u a r t e r in 1994, r e p r e s e n t i n g a 76% i n c r e a s e . T h e c o m p a n y a l s o r e p o r t e d n e t i n c o m e of $ 5 , 8 8 0 , 0 0 0 for t h e q u a r t e r , v e r s u s $ 2 , 4 0 8 , 0 0 0 for t h e s a m e p e r i o d l a s t year, a 144% i n c r e a s e . G r o s s m a r g i n i m p r o v e d to 3 0 . 1 % from 2 8 . 8 % in t h e y e a r ago t h i r d quarter, a n d n e t i n c o m e a s a p e r c e n t a g e of r e v e n u e s i m p r o v e d to 4.6% from 3.3%. T h e c o m p a n y ' s p r o d u c t m i x w a s evenly divided b e t w e e n c a p i t a l e q u i p m e n t (49%) a n d service a n d p a r t s (51%). For further information, contact: USF Europe AEIE, Avenida de Burgos 12, 28036 Madrid, Spain. Tel : +34 1 383 1200;fax: +34 1 383 8263.
M e m b r a n e T e c h n o l o g y No. 70
bq Bleed
~ckflush b
~
Hydr~en Peroxide Dosing
SDI
> Drain
Test Kit
Figure 1: Kalsep Hydro-X pilot rig schematic. Pre-treated water reaching the main purification s y s t e m m u s t h a v e a n SDI of l e s s t h a n 5 if t h e m e d i a a r e to b e p r o t e c t e d f r o m fouling. In s e p a r a t e t e s t s , t h e p e r f o r m a n c e a n d o p e r a t i n g c h a r a c t e r i s t i c s of m o d u l e s c o n t a i n i n g a K a l m e m low-fouling U F m e m b r a n e a n d a s t a n d a r d m e m b r a n e w e r e c o m p a r e d u s i n g t h e H y d r o - X t e s t rig s h o w n in F i g u r e 1. B o t h m e m b r a n e s were m a n u f a c t u r e d on a hollow fibre c o n f i g u r a t i o n w i t h p o r e sizes in t h e c o a r s e u l t r a f i l t r a t i o n r a n g e of a p p r o x i m a t e l y 2 0 0 0 0 0 N o m i n a l Weight C u t Off (NWCO), t h e m o d u l e s w e r e o p e r a t e d in a d e a d - e n d m o d e . A p r o p o r t i o n of t h e p e r m e a t e w a s r e t a i n e d u n d e r p r e s s u r e in a v e s s e l c o n t a i n i n g a d i a p h r a g m to p r o v i d e f e e d s t o c k for b a c k f l u s h i n g t h e m e m b r a n e s . For each membrane, the experimental runs were c a r r i e d o u t in t h r e e p h a s e s , w i t h t h e t r a n s m e m b r a n e p r e s s u r e d r o p - a n i n d i c a t i o n of m e m b r a n e fouling b e i n g m e a s u r e d a t r e g u l a r i n t e r v a l s (Figure 2). D u r i n g t h e f r s t p h a s e , t h e t e s t rig w a s o p e r a t e d w i t h a feed flux of 9 0 lmh, r e s u l t i n g in a p e r m e a t e flux of 85 lmh. In t h e e a r l y s t a g e s of t h e r u n , t h e p r e s s u r e d r o p a c r o s s e a c h m e m b r a n e i n c r e a s e d from a p p r o x i m a t e l y 2 p s i to 5 psi. W h e n t h e m e m b r a n e s w e r e c l e a n e d b y b a c k f l u s h i n g a f t e r 75 m i n u t e s of o p e r a t i o n , t h e p r e s s u r e d r o p for K a l m e m w a s r e s t o r e d to the initial v a l u e , w h i l s t t h e p r e s s u r e d r o p a c r o s s the standard membrane was increased. The s t a n d a r d m e m b r a n e w a s t h e n c l e a n e d a g a i n a f t e r a n o t h e r 60 m i n u t e s of o p e r a t i o n , after w h i c h t h e p r e s s u r e d r o p h a d a g a i n i n c r e a s e d to m o r e t h a n twice t h a t of t h e o r i g i n a l v a l u e , b y c o n t r a s t , t h e low-fouling
Z,D 30 25 20 15 10 5
00
Standard
o
• onset of accelerated fouling (phase II) -. \ \ "-
50
~.
100
L
150
Kalmem
/, (
200
250
300
350
Time (mins) Figure 2: Membrane pressure drop versus time.
2
K a l m e m m e m b r a n e w a s allowed to r u n for a f u r t h e r 140 m i n u t e s , after w h i c h t h e p r e s s u r e d r o p fell b a c k close to its initial value. D u r i n g t h e s e c o n d p h a s e of t h e field trials, e a c h m e m b r a n e w a s s u b j e c t e d to a n a c c e l e r a t e d fouling r e g i m e b y o p e r a t i n g t h e rig a t a flux of 2 4 0 l m h . T h i s t e s t w a s e q u i v a l e n t to r u n n i n g t h e s y s t e m for four h o u r s a t t h e t a r g e t p r o d u c t i v i t y of 85 l m h w i t h o u t baekfiushing the membranes. Both membranes became progressively plugged by p a r t i c u l a t e s d u r i n g t h e a c c e l e r a t e d fouling test, r e s u l t i n g in a p e a k p r e s s u r e d r o p of 30 psi. W h e n t h e p e r m e a t e flux w a s r e d u c e d to t h e s t a n d a r d 85 i m h , t h e p r e s s u r e d r o p fell to 13 psi in e a c h case. T h e difference b e t w e e n t h e two m e m b r a n e s w a s t h e n f u r t h e r d e m o n s t r a t e d i n t h e t h i r d p h a s e of t h e field t e s t s , d u r i n g w h i c h m o d u l e s w e r e r e p e a t e d l y backflushed with permeate. The Kalmem membrane b e c a m e c l e a n e d m o r e r e a d i l y r e t u r n i n g to r e d u c e d equilibrium pressure drop compared with the s t a n d a r d m e m b r a n e . F u r t h e r m o r e , a final b a c k f l u s h w i t h a 0.01% s o l u t i o n of h y d r o g e n p e r o x i d e r e s t o r e d t h e K a l m e m p r e s s u r e d r o p to its original v a l u e , w h i l s t t h e s t a n d a r d m e m b r a n e still e x h i b i t e d c o n s i d e r a b l e r e s i d u a l fouling. In t e r m s of p e r m e a t e quality, b o t h m e m b r a n e s r e d u c e d t h e t u r b i d i t y of t h e r a w w a t e r b y a n o m i n a l ten-fold a n d gave SDI's of well b e l o w 3.0 in all c a s e s . T h e field trials d e m o n s t r a t e t h a t t h e K a l m e m m e m b r a n e is m o r e h i g h l y r e s i s t a n t to fouling t h a n standard membranes, and can be cleaned more r a p i d l y a n d effectively b y b a c k f l u s h i n g a n d sanitisation. For further information, contact: Kalsep Ltd, Doman Road, Yorktown Industrial Estate, Camberley, Surrey, GU15 3DF, UK. Tel: +44 1276 675675; fcc~: +44 1276 676276.
U.S. F i l t e r record third quarter U n i t e d S t a t e s Filter C o r p o r a t i o n h a s r e p o r t e d r e c o r d r e v e n u e s of $ 1 2 6 , 9 0 7 , 0 0 0 for t h e q u a r t e r e n d e d D e c e m b e r 31, 1995, c o m p a r e d w i t h $ 7 2 , 1 8 9 , 0 0 0 for t h e s a m e q u a r t e r in 1994, r e p r e s e n t i n g a 76% i n c r e a s e . T h e c o m p a n y a l s o r e p o r t e d n e t i n c o m e of $ 5 , 8 8 0 , 0 0 0 for t h e q u a r t e r , v e r s u s $ 2 , 4 0 8 , 0 0 0 for t h e s a m e p e r i o d l a s t year, a 144% i n c r e a s e . G r o s s m a r g i n i m p r o v e d to 3 0 . 1 % from 2 8 . 8 % in t h e y e a r ago t h i r d quarter, a n d n e t i n c o m e a s a p e r c e n t a g e of r e v e n u e s i m p r o v e d to 4.6% from 3.3%. T h e c o m p a n y ' s p r o d u c t m i x w a s evenly divided b e t w e e n c a p i t a l e q u i p m e n t (49%) a n d service a n d p a r t s (51%). For further information, contact: USF Europe AEIE, Avenida de Burgos 12, 28036 Madrid, Spain. Tel : +34 1 383 1200;fax: +34 1 383 8263.
M e m b r a n e T e c h n o l o g y No. 70