- Email: [email protected]
Membrane Technology in Wastewater Management
IIIIII
I
Features
Membrane Technology in W a s t e w a t e r
T h e p r a c t i c a l a p p U c a t i o n o f m e m b r a n e t e c h n o l o g y in w a s t e w a t e ~ m a n a g e m e n t a n d r e c y c l i n g w a s c o n s i d e r e d at a c o n f e r e n c e h e l d i n C a p e T o w n , S o u t h Africa, o n t h e 2 - 5 M a r c h 1 9 9 2 . T h e m e e t i n g m o r g a n i z e d b y t h e M e m b r a n e T e c h n o l o g y D i v i s i o n o f t h e Water I n s t i t u t e o f S o u t h Africa u n d e r t h e a u s p i c e s o f t h e I n t e r n a t i o n a l A s s o c i a t i o n o n Water P o l l u t i o n R e s e a r c h a n d C o n t r o l 0LAWPRC) ~ f e a t u r e d p r e s e n t a t i o n s o n t h e a p p l i c a t i o n s o f m i c r o f l l t r a t i o n , ultra_filtration, r e v e r s e o s m o s i s a n d e l e c t r o d i a l y s i s . M o r e t h a n f i f t y oral a n d p o s t e r p a p e r s w e r e g i v e n a n d a s e l e c t i o n o f t h e s e are d i s c u s s e d b e l o w .
The ADUF process was developed in S o u t h Africa a n d h a s b e e n successfully u s e d in the treatment of wine distillery, malting, brewery, egg-processing and, m o s t recently, maize processing effluent. The design comprises an anaerobic digester a n d a n external UF unit: anaerobic digestion b r e a k s down organics which would otherwise foul the filter m e m b r a n e s ; the filters retain all b i o m a s s bacteria, n u t r i e n t s a n d buffer c o m p o n e n t s - - which is rapidly recycled b a c k to the digester with minimal activity loss a n d t e m p e r a t u r e drop. Tubular polyethersulphone m e m b r a n e s (Membratek Pty Ltd, PO Box 7240, Noorder Paarl 7623, RSA) are 9 n u n in diameter a n d have a pore size typically ranglng from 0.005 to 0.5 ~mI. The unsupported tubular membranes, or MEMTUF units, have been described in detail in a recent paper (Strohwald N K H a n d M u r p h y T J. Status of Membrane
Technology:from Membranes to Systems. Water Sewage a n d Effluent, 11(I), 1991, pp 23-29). In the particular application discussed at the conference treatment of maize processing
Membrane Technology
effluent - - the ADUF plant features a n u n h e a t e d digester volume of 2610 m 3 a n d a m o d u l a r MEMTUF m e m b r a n e area of 668 m 2. Average COD reduction h a s been 97%, b a s e d on feed a n d permeate concentrations of 15 a n d 0.4 kg m "3 respectively. Further information from W R Ross, Ross Consultancy, PO Box 3483, Tygerpark 7536, RSA.
Anaerobic biofiltration v. aerobic membranes The possibilities of aerobic and anaerobic m e t h o d s of filtering sludge treatment liquor at a municipal wastewater plant were compared by P Sauvegrain. A m o n g the anaerobic m e t h o d s u s e d or proposed for the hlghly-loaded biodegradable r e t u r n flow are sludge blanket reactors, fluidized beds, a n d plastic carriers combined with s u s p e n d e d biomass. With all of these a n d the m e m b r a n e alternative the goal is high b i o m a s s concentration in a high-rate process. Three alternative flow schemes have been studied: •
a n upflow floating polystyrene anaerobic filter (bead size 2 to 3 mm)
•
a n aerobic reactor coupled
with mlcrofiltration (0.2
Management
Anaerobic digestion ultrafiltration (ADUF)
•
a downflow wood-based charcoal anaerobic filter (grain size 2 to 5 nun)
pore size) The anaerobic reactors were capable of treating highly c o n c e n t r a t e d effluents in a detention tlme of I 0 hours, b u t COD removal efficiency was limited to 60%. By contrast, results for the b l o m e m b r a n e showed total COD reduced from I 0 000 m g l "I to 1400 m g l ' l a n d all other c o m p o n e n t s removed to the same extent or better. The virtual elimination of solids a n d oxidation of biodegradable c o m p o n e n t s implies that residual pollution is m u c h lower t h a n with the aerobic treatments. Nevertheless, loading rates a n d b i o m a s s concentrations remained low a n d flux on the m e m b r a n e s was heavily restricted. The way a h e a d seems to be to couple anaerobic biofilters with m e m b r a n e s a n d to compromise between effluent quality a n d energy needs. F u r t h e r information from P Sauvegrain, Anjou Recherche, Research Centre Compagnie Gdndrale des E a u x - - OTV, Chemin de la Digue, F-78600 Maisons Laffltte, France.
Optimal design membranes compared As p a r t of a project to produce a s u p p l y of industrial process water from treated u r b a n wastewater the p e r f o r m a n c e of several commercial ultra filtration m e m b r a n e s h a s been studied a n d c o m p a r e d u s i n g field trials and optimal design methodology. Trials were u n d e r t a k e n using plate a n d frame m o d u l e s to replace the settling t a n k following aeration of effluent from u r b a n wastewater. T r a n s - m e m b r a n e p r e s s u r e a n d velocity were varied a n d in the analysis a Doehlert matrix was used to define each working condition. The methodology p r o d u c e d a model which related the permeate flux
5
I
[
[
I
Features a n d energy requirement of each module a n d allowed response surface diagrams to be plotted. Similarly the total r u n n i n g cost for each m e m b r a n e type u n d e r each set of working conditions could be determined. The m e m b r a n e s tested were p r o d u c e d by Dow-DDS Filtration a n d Rh6ne Poulenc. Although no notable differences were found in the quality of the water p r o d u c e d b y the two types of m e m b r a n e , t h e a u t h o r s claim to have identified differences in r u n n i n g costs to p r o d u c e industrial water. However, It would be unfair to n a m e the Xvlnner' or 'loser' here without publishing the full details of the trials. For more information contact D Vial, Lyonnaise des Eaux, Central Laboratory, 38 rue du Pdt Wilson, F-78230 Le Pecq, France.
Food wastewater processing a review Water Is used in food processing for a variety of tasks which include w a s h i n g of raw materials, rinsing process equipment, conveying p r o d u c t s a n d as a n addition to finished products. The wastewater portion will typically contain s u s p e n d e d solids, solids that settle, BOD, COD, dissolved organics, heavy metals, off a n d grease. Discharge regulations are similar to other industrial waste facflitles a n d are becoming increasingly stringent. In a paper by S u s a n Walker (Koch Membrane Systems, Wilmington, MA 01887, USA) the c u r r e n t uses a n d performance of m e m b r a n e systems in this application are reviewed. Ultraflltration m e m b r a n e s are particularly suited to: •
emulsified off a n d grease s t r e a m s m reduction to 75-100 p p m or lower, depending on the feed material
•
formulated oil p r o d u c t waste - - t u b u l a r UF p r o d u c t s have p r o d u c e d concentrates with
6
30-50% oil a n d grease - - use of spongeballs to clean the m e m b r a n e is essential! •
concentration of s t a r c h wastewaters - - with a wastewater stream containing 0.5-1.0% total solids, spiral UF modules can reduce volume by a factor of 20 a n d produce a permeate with a 50% reduction in COD a n d BOD
•
slaughterhouse waste grease waste streams containing 1-2% total solids reduced in volume b y a factor of 15 to 25 with BOD a n d COD reductions of 50% in the permeate; blood waste streams containing 1-1.5% total solids reduced in volume by a factor of 5 to I 0 with BOD a n d COD reductions of 60+% The permeate from the ultrafilter is treatable b y RO m e m b r a n e s if further reductions In BOD are required. Typically systems are capable of operating for up to 14 days without cleaning,
Metal r e c o v e r y from p l a t i n g wastes
(Paper 1) A research a n d applications p r o g r a m m e at the Centre for Membrane a n d Separation Technology of the University of New S o u t h Wales h a s been examining strategies for minimizing the wastes p r o d u c e d by the metal plating industry. Wastes are conventionally disposed of either as precipitated solids or concentrated solutions. The work h a s shown that m e m b r a n e nanoflltration is capable of separating monovalent a n d divalent Ions in mixed solutions a n d h a s p r o d u c e d clarification of the rules governing the separation. Supported liquid m e m b r a n e s (SLM) provide a n alternative strategy, b a s e d on selective extraction, b u t there are operational constraints which need to be considered.
Further information from A G Fane, Centre for Membrane a n d Separation Technology, School of Chemical Engineering a n d Industrial Chemistry, University of New S o u t h Wales, PO Box I, Kensington, NSW, Australia. Tel +61 2 697 4316.
(Paper 2) In S o u t h Africa the performance of locally-manufactured reverse osmosis a n d electrodialysis s y s t e m s for the treatment of Ni, Cd, Cr a n d mixed electroplating effluent h a s been studied b y the Water Research Commission. The a n n u a l c o n s u m p t i o n of water by the electroplatlng i n d u s t r y in S o u t h Africa is a b o u t 9 mlllion m 3, of which 80% is discharged as effluent. According to the WRC approximately 90% of the effluent c a n be recovered t h r o u g h use of RO or ED technology for re-use within the industry; expensive chemicals a n d metals are recovered for re-use a n d toxic materials removed from the effluent; sludge disposal problems are correspondingly reduced. Although problems c a n be e n c o u n t e r e d with m e m b r a n e fouling these c a n be easily overcome b y chemical cleaning of the m e m b r a n e s . The RO systems examined u s e d ceUulose acetate (Ni) or polyamide (Cd, Cr) membranes. F u r t h e r information from J J S c h o e m a n , CSIR Division of Water Technology, PO Box 395, Pretoria, RSA. Tel +27 12 841 4479. Fax +27 12 841 4785.
In brief: MPW nanofiltration membranes Nanoflltration m e m b r a n e s developed b y Membrane Products Kiryat Weizraan Ltd (MPW) have been u s e d for the concentration a n d desalination of organic solutes in a range of pH conditions. Typical applications include: •
concentration of dye b a t h waste streams
M e m b r a n e Technology
Features •
recovery of brine from ion exchange resin regeneration effluent in chemical a n d food industries
•
recovery of solvents a n d binders from overspray car paint effluents
•
treatment of cellulose digestion a n d bleaching wastes
•
whey desalting
of domestic wastewater is being developed a n d studied at the University of Tokyo. The system comprises a m a i n bioreactor (volume 62 I) a n d a separation unit (volume 10 I) which sits inside. Solid-liquid separation is achieved using two 0.3 m 2 hollow fibre microporous m e m b r a n e modules -- hlgh-density polyethylene with 0.03 tan pores (Mitsubishi Rayon Co Ltd). Permeate is extracted by a suction p u m p u n d e r intermittent operation. Paddles, driven by a motor, provide crossflow of mixed liquor across the m e m b r a n e surfaces. Turbulence from the paddles serves to detach some portion of sludge from the surfaces a n d a jet aerating device operates for 1 m i n u t e every 90 m i n u t e s to reduce sludge a c c u m u l a t i o n inside the m e m b r a n e module. Trials to date have involved a synthetic feed solution with addition of shredded toilet paper to simulate actual household application. Permeate flux was maintained above 0.4 m 3 / m 2 d for 50 days with a low
•
recovery a n d purification of antibiotics F u r t h e r information on the SeIRO m e m b r a n e separation systems a n d applications from K Treffry-Goafley, Explochem (Pty) Ltd, PO Box 167, Hillcrest 3650, RSA.
Wastewater treatment in the home A small-scale m e m b r a n e separation bioreactor for direct treatment at the h o u s e h o l d level
t r a n s - m e m b r a n e p r e s s u r e of between 20 a n d 40 kPa. COD in the effluent was in the range 10-25 m g / l . More t h a n 85% of influent COD from b o t h synthetic waste a n d toilet paper was degraded (see table below). F u r t h e r information on the system a n d the trials from K Yamamoto, D e p a r t m e n t of U r b a n Engineering, The University of Tokyo, 7-3-1 Hongo, B u n k y o - k u , Tokyo 113, J a p a n .
COD values measured Inflow of synthetic waste Inflow of toilet paper Accumulated i n reactor Outflow from the reactor Oxidation Percentage of oxidation
Forfurther information on the availability of the full conference proceedings contact the Conference Secretariat (Mrs E Esterhuyse), IAWPRC Conference, PO Box 36815, Menlo Park, 0102 Republic of South Africa. Tel~Fax +27 12 47 3398.
Motor
I
'
~.
II
Suction l:~.p
l
Level Sensor
0 0 0 o
llollow Fiber Membrmle
~
( 0 . 0 3 pm pore size)
,o
ol
e-w
o
Tempera t.ure Con trollet
Air Diffusor
"
..
O~-smt rlted
S y n t h e t i c Sul~tratq Tap Water
Air
I
Separation Tank I
N=
°
•
~
COD (g) 233.4 35.6 18.1 16.2 234.7 87.2%
I
220 Jet Aerating Device
4go
The experimental system for domestic wastewater treatment under development at the University of Tokyo (all dimensions in mm)
M e m b r a n e Technology
7
I
Features
Membrane Technology in W a s t e w a t e r
T h e p r a c t i c a l a p p U c a t i o n o f m e m b r a n e t e c h n o l o g y in w a s t e w a t e ~ m a n a g e m e n t a n d r e c y c l i n g w a s c o n s i d e r e d at a c o n f e r e n c e h e l d i n C a p e T o w n , S o u t h Africa, o n t h e 2 - 5 M a r c h 1 9 9 2 . T h e m e e t i n g m o r g a n i z e d b y t h e M e m b r a n e T e c h n o l o g y D i v i s i o n o f t h e Water I n s t i t u t e o f S o u t h Africa u n d e r t h e a u s p i c e s o f t h e I n t e r n a t i o n a l A s s o c i a t i o n o n Water P o l l u t i o n R e s e a r c h a n d C o n t r o l 0LAWPRC) ~ f e a t u r e d p r e s e n t a t i o n s o n t h e a p p l i c a t i o n s o f m i c r o f l l t r a t i o n , ultra_filtration, r e v e r s e o s m o s i s a n d e l e c t r o d i a l y s i s . M o r e t h a n f i f t y oral a n d p o s t e r p a p e r s w e r e g i v e n a n d a s e l e c t i o n o f t h e s e are d i s c u s s e d b e l o w .
The ADUF process was developed in S o u t h Africa a n d h a s b e e n successfully u s e d in the treatment of wine distillery, malting, brewery, egg-processing and, m o s t recently, maize processing effluent. The design comprises an anaerobic digester a n d a n external UF unit: anaerobic digestion b r e a k s down organics which would otherwise foul the filter m e m b r a n e s ; the filters retain all b i o m a s s bacteria, n u t r i e n t s a n d buffer c o m p o n e n t s - - which is rapidly recycled b a c k to the digester with minimal activity loss a n d t e m p e r a t u r e drop. Tubular polyethersulphone m e m b r a n e s (Membratek Pty Ltd, PO Box 7240, Noorder Paarl 7623, RSA) are 9 n u n in diameter a n d have a pore size typically ranglng from 0.005 to 0.5 ~mI. The unsupported tubular membranes, or MEMTUF units, have been described in detail in a recent paper (Strohwald N K H a n d M u r p h y T J. Status of Membrane
Technology:from Membranes to Systems. Water Sewage a n d Effluent, 11(I), 1991, pp 23-29). In the particular application discussed at the conference treatment of maize processing
Membrane Technology
effluent - - the ADUF plant features a n u n h e a t e d digester volume of 2610 m 3 a n d a m o d u l a r MEMTUF m e m b r a n e area of 668 m 2. Average COD reduction h a s been 97%, b a s e d on feed a n d permeate concentrations of 15 a n d 0.4 kg m "3 respectively. Further information from W R Ross, Ross Consultancy, PO Box 3483, Tygerpark 7536, RSA.
Anaerobic biofiltration v. aerobic membranes The possibilities of aerobic and anaerobic m e t h o d s of filtering sludge treatment liquor at a municipal wastewater plant were compared by P Sauvegrain. A m o n g the anaerobic m e t h o d s u s e d or proposed for the hlghly-loaded biodegradable r e t u r n flow are sludge blanket reactors, fluidized beds, a n d plastic carriers combined with s u s p e n d e d biomass. With all of these a n d the m e m b r a n e alternative the goal is high b i o m a s s concentration in a high-rate process. Three alternative flow schemes have been studied: •
a n upflow floating polystyrene anaerobic filter (bead size 2 to 3 mm)
•
a n aerobic reactor coupled
with mlcrofiltration (0.2
Management
Anaerobic digestion ultrafiltration (ADUF)
•
a downflow wood-based charcoal anaerobic filter (grain size 2 to 5 nun)
pore size) The anaerobic reactors were capable of treating highly c o n c e n t r a t e d effluents in a detention tlme of I 0 hours, b u t COD removal efficiency was limited to 60%. By contrast, results for the b l o m e m b r a n e showed total COD reduced from I 0 000 m g l "I to 1400 m g l ' l a n d all other c o m p o n e n t s removed to the same extent or better. The virtual elimination of solids a n d oxidation of biodegradable c o m p o n e n t s implies that residual pollution is m u c h lower t h a n with the aerobic treatments. Nevertheless, loading rates a n d b i o m a s s concentrations remained low a n d flux on the m e m b r a n e s was heavily restricted. The way a h e a d seems to be to couple anaerobic biofilters with m e m b r a n e s a n d to compromise between effluent quality a n d energy needs. F u r t h e r information from P Sauvegrain, Anjou Recherche, Research Centre Compagnie Gdndrale des E a u x - - OTV, Chemin de la Digue, F-78600 Maisons Laffltte, France.
Optimal design membranes compared As p a r t of a project to produce a s u p p l y of industrial process water from treated u r b a n wastewater the p e r f o r m a n c e of several commercial ultra filtration m e m b r a n e s h a s been studied a n d c o m p a r e d u s i n g field trials and optimal design methodology. Trials were u n d e r t a k e n using plate a n d frame m o d u l e s to replace the settling t a n k following aeration of effluent from u r b a n wastewater. T r a n s - m e m b r a n e p r e s s u r e a n d velocity were varied a n d in the analysis a Doehlert matrix was used to define each working condition. The methodology p r o d u c e d a model which related the permeate flux
5
I
[
[
I
Features a n d energy requirement of each module a n d allowed response surface diagrams to be plotted. Similarly the total r u n n i n g cost for each m e m b r a n e type u n d e r each set of working conditions could be determined. The m e m b r a n e s tested were p r o d u c e d by Dow-DDS Filtration a n d Rh6ne Poulenc. Although no notable differences were found in the quality of the water p r o d u c e d b y the two types of m e m b r a n e , t h e a u t h o r s claim to have identified differences in r u n n i n g costs to p r o d u c e industrial water. However, It would be unfair to n a m e the Xvlnner' or 'loser' here without publishing the full details of the trials. For more information contact D Vial, Lyonnaise des Eaux, Central Laboratory, 38 rue du Pdt Wilson, F-78230 Le Pecq, France.
Food wastewater processing a review Water Is used in food processing for a variety of tasks which include w a s h i n g of raw materials, rinsing process equipment, conveying p r o d u c t s a n d as a n addition to finished products. The wastewater portion will typically contain s u s p e n d e d solids, solids that settle, BOD, COD, dissolved organics, heavy metals, off a n d grease. Discharge regulations are similar to other industrial waste facflitles a n d are becoming increasingly stringent. In a paper by S u s a n Walker (Koch Membrane Systems, Wilmington, MA 01887, USA) the c u r r e n t uses a n d performance of m e m b r a n e systems in this application are reviewed. Ultraflltration m e m b r a n e s are particularly suited to: •
emulsified off a n d grease s t r e a m s m reduction to 75-100 p p m or lower, depending on the feed material
•
formulated oil p r o d u c t waste - - t u b u l a r UF p r o d u c t s have p r o d u c e d concentrates with
6
30-50% oil a n d grease - - use of spongeballs to clean the m e m b r a n e is essential! •
concentration of s t a r c h wastewaters - - with a wastewater stream containing 0.5-1.0% total solids, spiral UF modules can reduce volume by a factor of 20 a n d produce a permeate with a 50% reduction in COD a n d BOD
•
slaughterhouse waste grease waste streams containing 1-2% total solids reduced in volume b y a factor of 15 to 25 with BOD a n d COD reductions of 50% in the permeate; blood waste streams containing 1-1.5% total solids reduced in volume by a factor of 5 to I 0 with BOD a n d COD reductions of 60+% The permeate from the ultrafilter is treatable b y RO m e m b r a n e s if further reductions In BOD are required. Typically systems are capable of operating for up to 14 days without cleaning,
Metal r e c o v e r y from p l a t i n g wastes
(Paper 1) A research a n d applications p r o g r a m m e at the Centre for Membrane a n d Separation Technology of the University of New S o u t h Wales h a s been examining strategies for minimizing the wastes p r o d u c e d by the metal plating industry. Wastes are conventionally disposed of either as precipitated solids or concentrated solutions. The work h a s shown that m e m b r a n e nanoflltration is capable of separating monovalent a n d divalent Ions in mixed solutions a n d h a s p r o d u c e d clarification of the rules governing the separation. Supported liquid m e m b r a n e s (SLM) provide a n alternative strategy, b a s e d on selective extraction, b u t there are operational constraints which need to be considered.
Further information from A G Fane, Centre for Membrane a n d Separation Technology, School of Chemical Engineering a n d Industrial Chemistry, University of New S o u t h Wales, PO Box I, Kensington, NSW, Australia. Tel +61 2 697 4316.
(Paper 2) In S o u t h Africa the performance of locally-manufactured reverse osmosis a n d electrodialysis s y s t e m s for the treatment of Ni, Cd, Cr a n d mixed electroplating effluent h a s been studied b y the Water Research Commission. The a n n u a l c o n s u m p t i o n of water by the electroplatlng i n d u s t r y in S o u t h Africa is a b o u t 9 mlllion m 3, of which 80% is discharged as effluent. According to the WRC approximately 90% of the effluent c a n be recovered t h r o u g h use of RO or ED technology for re-use within the industry; expensive chemicals a n d metals are recovered for re-use a n d toxic materials removed from the effluent; sludge disposal problems are correspondingly reduced. Although problems c a n be e n c o u n t e r e d with m e m b r a n e fouling these c a n be easily overcome b y chemical cleaning of the m e m b r a n e s . The RO systems examined u s e d ceUulose acetate (Ni) or polyamide (Cd, Cr) membranes. F u r t h e r information from J J S c h o e m a n , CSIR Division of Water Technology, PO Box 395, Pretoria, RSA. Tel +27 12 841 4479. Fax +27 12 841 4785.
In brief: MPW nanofiltration membranes Nanoflltration m e m b r a n e s developed b y Membrane Products Kiryat Weizraan Ltd (MPW) have been u s e d for the concentration a n d desalination of organic solutes in a range of pH conditions. Typical applications include: •
concentration of dye b a t h waste streams
M e m b r a n e Technology
Features •
recovery of brine from ion exchange resin regeneration effluent in chemical a n d food industries
•
recovery of solvents a n d binders from overspray car paint effluents
•
treatment of cellulose digestion a n d bleaching wastes
•
whey desalting
of domestic wastewater is being developed a n d studied at the University of Tokyo. The system comprises a m a i n bioreactor (volume 62 I) a n d a separation unit (volume 10 I) which sits inside. Solid-liquid separation is achieved using two 0.3 m 2 hollow fibre microporous m e m b r a n e modules -- hlgh-density polyethylene with 0.03 tan pores (Mitsubishi Rayon Co Ltd). Permeate is extracted by a suction p u m p u n d e r intermittent operation. Paddles, driven by a motor, provide crossflow of mixed liquor across the m e m b r a n e surfaces. Turbulence from the paddles serves to detach some portion of sludge from the surfaces a n d a jet aerating device operates for 1 m i n u t e every 90 m i n u t e s to reduce sludge a c c u m u l a t i o n inside the m e m b r a n e module. Trials to date have involved a synthetic feed solution with addition of shredded toilet paper to simulate actual household application. Permeate flux was maintained above 0.4 m 3 / m 2 d for 50 days with a low
•
recovery a n d purification of antibiotics F u r t h e r information on the SeIRO m e m b r a n e separation systems a n d applications from K Treffry-Goafley, Explochem (Pty) Ltd, PO Box 167, Hillcrest 3650, RSA.
Wastewater treatment in the home A small-scale m e m b r a n e separation bioreactor for direct treatment at the h o u s e h o l d level
t r a n s - m e m b r a n e p r e s s u r e of between 20 a n d 40 kPa. COD in the effluent was in the range 10-25 m g / l . More t h a n 85% of influent COD from b o t h synthetic waste a n d toilet paper was degraded (see table below). F u r t h e r information on the system a n d the trials from K Yamamoto, D e p a r t m e n t of U r b a n Engineering, The University of Tokyo, 7-3-1 Hongo, B u n k y o - k u , Tokyo 113, J a p a n .
COD values measured Inflow of synthetic waste Inflow of toilet paper Accumulated i n reactor Outflow from the reactor Oxidation Percentage of oxidation
Forfurther information on the availability of the full conference proceedings contact the Conference Secretariat (Mrs E Esterhuyse), IAWPRC Conference, PO Box 36815, Menlo Park, 0102 Republic of South Africa. Tel~Fax +27 12 47 3398.
Motor
I
'
~.
II
Suction l:~.p
l
Level Sensor
0 0 0 o
llollow Fiber Membrmle
~
( 0 . 0 3 pm pore size)
,o
ol
e-w
o
Tempera t.ure Con trollet
Air Diffusor
"
..
O~-smt rlted
S y n t h e t i c Sul~tratq Tap Water
Air
I
Separation Tank I
N=
°
•
~
COD (g) 233.4 35.6 18.1 16.2 234.7 87.2%
I
220 Jet Aerating Device
4go
The experimental system for domestic wastewater treatment under development at the University of Tokyo (all dimensions in mm)
M e m b r a n e Technology
7