Volvo Cars Gent
Water reuse and waste water minimization
Reverse osmosis process on rinsing waters
after the phosphating process
for water and raw material recuperation
Michel Schauwvliege (senior engineer pretreatment VCG)
Jan Gruwez (senior environmentalist TREVI)
Issue 1 - M. Schauwvliege & J. Gruwez - Page 1 - Date : 2004-11-09
Production area of the RO project
WELDING
SHOP
PRETREATMENT
PHOSPHATE LINE
1
2
FINAL
ASSEMBLY
PAINT SHOP
3
NON COLOUR
COLOUR
FINISHING
ELECTROCOAT
4
5
Degreasing area
Issue 1 - M. Schauwvliege & J. Gruwez - Page 2 - Date : 2004-11-09
6
7
8
Phosphate area
9
10
11
Passivation area
Original phosphating process VCG
Production flow car bodies
(max. 45 bodies/hour)
Deionised water
supply : 0,5 m³/h
DRAG-IN
(0,5 m³/h)
Evaporation : 0,5 m³/h
PHOSPHATE BATH
Deionised water
supply : 5 m³/h
DRAG-OUT
(0,5 m³/h)
SPRAY
RINSING
Industrial waste water flow : 5 m³/h
(approximately 27.000 m³/year)
Issue 1 - M. Schauwvliege & J. Gruwez - Page 3 - Date : 2004-11-09
DIP
RINSING
Principle closed loop phosphating
Production flow car bodies
(max. 45 bodies/hour)
DRAG-IN
(0,5 m³/h)
Evaporation : 0,5 m³/h
Deionised water
supply : 0,5 m³/h
DRAG-OUT
(0,5 m³/h)
SPRAY
RINSING
PHOSPHATE BATH
DIP
RINSING
5 m³/h
Concentrate flow :
0,5 m³/h
Issue 1 - M. Schauwvliege & J. Gruwez - Page 4 - Date : 2004-11-09
MEMBRANE
FILTRATION
UNIT
Permeate flow : 4,5 m³/h
Project motivation (1)
³ Introduction aluminium
Addition of free fluoride in phosphate bath
´ increased sludge production
´ higher fluor concentration
Significant increase of the fluor load to the waste
water which makes fluor removal in the physicochemical waste water treatment plant necessary !
Issue 1 - M. Schauwvliege & J. Gruwez - Page 5 - Date : 2004-11-09
Project motivation (2)
³ No aluminium
5 m³/h
10 mg F/l
No PAC dosage
Fluor concentration (mg F/l)
100
80
³ Alu without RO
60
5 m³/h
20 mg F/l
PAC dosage 2 g/l
(= 240 kg/d)
40
20
³ Alu with RO
0
0
1
2
3
4
PAC dosage (g/l)
Issue 1 - M. Schauwvliege & J. Gruwez - Page 6 - Date : 2004-11-09
5
6
1 m³/h
100 mg F/l
PAC dosage 3 g/l
(= 72 kg/d)
Advantages of closed loop phosphating
³
³
³
Reduction of the water consumption
Reduction of the amount of industrial waste water
Lower running cost in the waste water treatment
less waste water to treat
higher fluor concentration, resulting in a higher efficiëncy of
the PAC dosage for fluor removal
³ Reduction of the emission of heavy metals (Zn, Ni,
Mn,…) and nutrients (N, P) to the environment
³ More capacity free in the waste water treatment for
future projects (e.g. increased production capacity)
Issue 1 - M. Schauwvliege & J. Gruwez - Page 7 - Date : 2004-11-09
The Filtration Spectrum
Angstrom Units
1
101
Sugar
Aqueous
Salts
102
103
Virus
Colloids
(e.g. F-, Na+, K+,
NO3-, Cl-, Fe3+,…)
104
105
Pollen
Bacteria
106
Beach
Sand
Particle Filtration
Microfiltration
Ultrafiltration
Nanofiltration
Reverse Osmosis (hyperfiltration)
Issue 1 - M. Schauwvliege & J. Gruwez - Page 8 - Date : 2004-11-09
107
Principle of osmosis
Start situation
Equilibrium
membrane
concentrated
solution
membrane
concentrated
solution
water
osmotic
pressure
water
Water is passing through the membrane from the water
compartment to the concentrated solution compartment
Issue 1 - M. Schauwvliege & J. Gruwez - Page 9 - Date : 2004-11-09
Principle of reverse osmosis
Start situation
P > osmotic
pressure
concentrated
solution
Equilibrium
membrane
membrane
concentrated
solution
water
water
Water is passing through the membrane from the concentrated
solution compartment to the water compartment
Issue 1 - M. Schauwvliege & J. Gruwez - Page 10 - Date : 2004-11-09
Principle flow diagram test-unit (1 stage)
deionized water supply
level
sensor
DRAG-OVER
agitator
Temp.
agitator pH
NaOH
RINSING
BATH
PHOSPHATE
BATH
PERMEATE
HEATING
Qp= 300 l/h
R Technical information :
membrane surface : 7.7 m²
REVERSE OSMOSIS
pressure : 20 bar
SAND
and
MICROFILTERS
drag over : 5.4 l/h
permeate flow : 300 l/h
CONCENTRATE
Qc= 100 l/h
concentrate flow : 100 l/h
recovery ratio : 75%
Issue 1 - M. Schauwvliege & J. Gruwez - Page 11 - Date : 2004-11-09
PURGE TO WASTE
WATER TREATMENT
Qf = 400 l/h
Recovery (symbol S)
³ Definition
The recovery ratio is the relation between the permeate flow rate
and the feed flow rate (sum of permeate and concentrate flow).
³ Formula
³ Recovery during tests
Qp
S=
x 100 %
Qf
Issue 1 - M. Schauwvliege & J. Gruwez - Page 12 - Date : 2004-11-09
adjusted to obtain an
average recovery of 75%
(80% at start, 70% at end)
Rejection (symbol R)
³ Definition
The reductions of components were calculated by comparing
the content in the permeate with the content in the feed.
³ Theoretical values
³ Formula
Cp
R= 1-
x 100 %
Cf
Issue 1 - M. Schauwvliege & J. Gruwez - Page 13 - Date : 2004-11-09
NaF
98%
NaNO3
93%
NiSO4
99%
SiO2
98%
Flux (symbol J)
³ Definition
The flux is the unit membrane throughput, usually expressed in
volume per unit time per area, such as liters per hour per m².
³ Formula
³ Theoretical values
Qp
Nominal active surface of the
FilmTec membrane : 41 m²
A
Product water flow rate : 44 m³/d
J=
¸ Flux : 45 l/m².h
Issue 1 - M. Schauwvliege & J. Gruwez - Page 14 - Date : 2004-11-09
Technical data FilmTec RO membrane
³ Membrane characteristics
Supplier : FilmTec Corporation (Dow Chemical Company)
Type : spiral wound thin-film composite polyamide
³ Operating limits
Maximum operating pressure : 69 bar
Maximum operating temperature : 45 °C
Free chlorine tolerance : < 0.1 mg/l
pH range during operation : 2-11
pH range during cleaning (short-term 30 min.) : 1-12
Issue 1 - M. Schauwvliege & J. Gruwez - Page 15 - Date : 2004-11-09
Spiral Wound RO Membrane
Concentrate Channel Spacer
Permeate
Water Flow
Membranes
Permeate
Channel Spacer
Issue 1 - M. Schauwvliege & J. Gruwez - Page 16 - Date : 2004-11-09
Photos FilmTec RO elements
Issue 1 - M. Schauwvliege & J. Gruwez - Page 17 - Date : 2004-11-09
Fluor rejection versus
membrane fouling (%)
Influence of the pH on the RO process
100
90
80
70
60
50
40
30
20
10
0
fluor rejection
cycle time
(membrane fouling)
compromise
testvalue pH
2,0
2,5
3,0
3,5
4,0
4,5
5,0
5,5
6,0
6,5
pH-value
¯ Fluor rejection and membrane fouling are strongly pH dependant !
Issue 1 - M. Schauwvliege & J. Gruwez - Page 18 - Date : 2004-11-09
Evolution flux RO test in 1 stage
60
Flux (l/m².h)
50
pH 4.0
40
30
pH 5.5
20
Chemical cleaning
of RO membrane
10
0
0
1000
2000
3000
4000
Operating time (minutes)
Issue 1 - M. Schauwvliege & J. Gruwez - Page 19 - Date : 2004-11-09
5000
Principle flow diagram test-unit (2 stages)
RECIRCULATION OF
PERMEATE RO2
INTO RINSING BATH
NaOH
deionized water supply
REVERSE OSMOSIS
STAGE 2
CONCENTRATE
RO2
DRAG-OVER
agitator
agitator
Temp.
RINSING
BATH
PHOSPHATE
BATH
pH 6.0
level
sensor
HEATING
pH 3.4
agitator
REVERSE OSMOSIS
STAGE 1
BUFFER
PERMEATE
RO1
CONCENTRATE
RO1
PURGE TO WASTE
WATER TREATMENT
Issue 1 - M. Schauwvliege & J. Gruwez - Page 20 - Date : 2004-11-09
SAND
and
MICROFILTERS
Evolution flux RO test in 2 stages
80
™
Flu x (l/m ² .h )
70
60
50
™
pH 6.0
RO stage 2
š
40
pH 3.4
30
20
10
RO stage 1
0
0
2500
5000
7500
10000 12500 15000 17500 20000
Operating time (minutes)
™
š
Issue 1 - M. Schauwvliege & J. Gruwez - Page 21 - Date : 2004-11-09
Lower temperature after weekend
Chemical cleaning of RO membranes
Test results analysis RO - stage 1
Dipphosphatation
area
Parameter
Unit
Flow
pH
Conductivity
Zinc
Nickel
Manganese
Phosphate
Nitrate
Nitrite
Ammonium
Fluoride
Sodium
l/h
µS/cm
mg Zn/l
mg Ni/l
mg Mn/l
mg P/l
mg N/l
mg N/l
mg N/l
mg F/l
mg Na/l
Phosphate
bath
5.4
3.4
18220
1580
628
660
5680
1690
1.8
250
1700
4970
Issue 1 - M. Schauwvliege & J. Gruwez - Page 22 - Date : 2004-11-09
Rinsing
bath
325
3.6
402
17
7.5
7.4
63
18
0.03
2.6
21
59
Reverse osmosis
– stage 1 Permeate
RO1
225
3.3
192
0.21
< 0.1
< 0.2
0.13
3.7
< 0.015
0.44
9.5
0.6
Concentrate
RO1
100
3.8
771
49
18
18
169
44
0.06
6.4
48
138
Rejection
RO1
52 %
99 %
> 99 %
> 97 %
> 99 %
80 %
> 56 %
98 %
55 %
99 %
Test results analysis RO - stage 2
Dipphosphatation
area
Parameter
Unit
Flow
pH
Conductivity
Zinc
Nickel
Manganese
Phosphate
Nitrate
Nitrite
Ammonium
Fluoride
Sodium
l/h
µS/cm
mg Zn/l
mg Ni/l
mg Mn/l
mg P/l
mg N/l
mg N/l
mg N/l
mg F/l
mg Na/l
Phosphate
bath
5.4
3.4
18220
1580
628
660
5680
1690
1.8
250
1700
4970
Buffer
tank
540
6.3 *
79
< 0.2
< 0.1
< 0.2
0.09
3.8
0.02
0.04
9.5
18
Reverse osmosis
– stage 2 Permeate
RO2
495
6.6
25
< 0.2
< 0.1
< 0.2
< 0.05
0.90
< 0.015
0.02
2.9
4.9
Concentrate
RO2
45
59
440
0.76
0.23
0.23
0.38
24
0.10
0.16
55
95
Rejection
RO2
68 %
76 %
69 %
73 %
* Neutralization to pH 6.0 by dosing NaOH
Issue 1 - M. Schauwvliege & J. Gruwez - Page 23 - Date : 2004-11-09
Test results analysis RO - stage 1 & 2
Dipphosphatation
area
Parameter
Unit
Flow
pH
Conductivity
Zinc
Nickel
Manganese
Phosphate
Nitrate
Nitrite
Ammonium
Fluoride
Sodium
l/h
µS/cm
mg Zn/l
mg Ni/l
mg Mn/l
mg P/l
mg N/l
mg N/l
mg N/l
mg F/l
mg Na/l
Phosphate
bath
5.4
3.4
18220
1580
628
660
5680
1690
1.8
250
1700
4970
Rinsing
bath
325
3.6
402
17
7.5
7.4
63
18
0.03
2.6
21
59
Reverse osmosis
– stage 1 & 2 Buffer
tank
540
6.3 *
79
< 0.2
< 0.1
< 0.2
0.09
3.8
0.02
0.04
9.5
18
Permeate
RO2
495
6.6
25
< 0.2
< 0.1
< 0.2
< 0.05
0.90
< 0.015
0.02
2.9
4.9
Rejection
RO1 & RO2
94 %
> 99 %
> 99 %
> 97 %
> 99 %
95 %
> 95 %
> 99 %
86 %
92 %
* Neutralization to pH 6.0 by dosing NaOH
Issue 1 - M. Schauwvliege & J. Gruwez - Page 24 - Date : 2004-11-09
Chemical cleaning of RO membranes
³ Acid cleaning
product name : P3-ultrasil 75 (Henkel Ecolab)
composition : based on nitric acid (max. 30% HNO3)
dosage : 0.6% (6 ml/l or 8.4 g/l in deionized water)
temperature during cleaning : operating temperature + 5°C
duration : 30’ cleaning with product; 3 x 10’ rinsing with deionized water
³ Alkaline cleaning
product name : P3-ultrasil 11 (Henkel Ecolab)
composition : based on sodium hydroxide (max. 30% NaOH)
dosage : 0.5% (5 g/l in deionized water)
temperature during cleaning : operating temperature + 5°C
duration : 30’ cleaning with product; 3 x 10’ rinsing with deionized water
Issue 1 - M. Schauwvliege & J. Gruwez - Page 25 - Date : 2004-11-09
Final reverse osmosis installation VCG
3200 l/h
DRAG-OVER
300 l/h
1800 l/h
1800 l/h
PHOSPHATATION
BATH
Deionised water
5000 l/h
RINSING
BATH
centrifuge
STORAGE TANK
CONCENTRATE
1500 l/h
waste water
treatment
NaOH
dosage
pH 5,5
buffer
tank
sand
filter
Activated
carbon filters
H3PO4
dosage
pH 2,6
microfilters
REVERSE OSMOSIS
STAGE 2
(3 membranes)
800 l/h
BUFFER
REVERSE OSMOSIS
STAGE 1
(6 membranes)
4000 l/h
Issue 1 - M. Schauwvliege & J. Gruwez - Page 26 - Date : 2004-11-09
1000 l/h
1
10
µm
µm
5000 l/h
BUFFER
Reverse osmosis installation VCG
Membrane modules
Cleaning unit
Issue 1 - M. Schauwvliege & J. Gruwez - Page 27 - Date : 2004-11-09
Savings reverse osmosis VCG
³ Water consumption
Consumption of deionised water decreased from 5,0 to 1,8 m³/h
per phosphate line
´ 32.400 m³/year or 0,12 m³/car
´ 64.800 EUR/year or 0,24 EUR/car
³ Running cost waste water treatment
Industrial waste water flow decreased from 5,0 to 1,5 m³/h
per phosphate line
´ 35.100 m³/year or 0,13 m³/car
´ 175.500 EUR/year or 0,65 EUR/car
TOTAL SAVINGS WATER & WASTE WATER
240.300 EUR/year or 0,89 EUR/car
Issue 1 - M. Schauwvliege & J. Gruwez - Page 28 - Date : 2004-11-09
Pay-back period reverse osmosis VCG
³ Estimation operating cost per year
power consumption
cleaning membranes and chemicals
replacing membranes
manpower
8.000 EUR
10.000 EUR
30.000 EUR
6.000 EUR
TOTAL OPERATING COST RO
54.000 EUR/year or 0,20 EUR/car
³ Estimation pay-back period
netto saving
total investment cost
186.300 EUR
750.000 EUR
ESTIMATED PAY-BACK PERIOD RO
4 YEARS
Issue 1 - M. Schauwvliege & J. Gruwez - Page 29 - Date : 2004-11-09
Extra information RO results VCG
³ Significant decrease of water consumption and amount
of industrial waste water to “World Class” level
³ Fluor concentrations in effluent far below discharge
standard
³ Project nominated for the European
Environmental Press (EEP) Award
2003 (Pollutec, Paris)
Issue 1 - M. Schauwvliege & J. Gruwez - Page 30 - Date : 2004-11-09
Evolution waste water production VCG
2,0
1,5
1,0
0,5
0,0
1,44
1,65
1,83
1,37
1,13
0,85
0,94
0,76
0,64
0,62
1994 1995 1996 1997 1998 1999 2000 2001 2002 2003
industrial waste water (in m³/body)
Issue 1 - M. Schauwvliege & J. Gruwez - Page 31 - Date : 2004-11-09
Project realization by
TREVI NV
Environmental Engineering
Dulle-Grietlaan 17/1
B-9050 Gentbrugge (Gent)
Tel. +32 9 220 05 77
Contact: Jan Gruwez
VOLVO CARS GENT NV
Purchaser
J.F. Kennedylaan 25
B-9000 Gent
Tel. +32 9 250 23 85
Contact: Michel Schauwvliege
FABRICOM GTI NV
General Contractor
Gatti de Gamondstraat 254
B-1180 Brussel
Tel. +32 2 370 31 11
Contact: Marc Debou
Issue 1 - M. Schauwvliege & J. Gruwez - Page 32 - Date : 2004-11-09
CHEMETALL NV
Chemical Supplier
Satenrozen 1A - Bus 1
B-2550 Kontich
Tel. +32 3 450 37 10
Contact: Johan De Boiserie
EUROWATER BELGIUM NV
Supplier Reverse Osmosis
Scheldestraat 104-106
B-9040 Sint-Amandsberg (Gent)
Tel. +32 9 228 18 61
Contact: Eddy Van Assche