expoquimia20

8/4/2019 Expoquimia20

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SOLIDIFICATION/STABILIZATION OF PAINT BOOTHS SLUDGES

Arce, R.; Andrs A.; Irabien J.A.; Viguri J.

Dpto. Ingeniera Qumica y Qumica Inorgnica, Universidad de Cantabria . ETSIIyT .

Avda. de los Castros s/n 39005 Santander, Spain

E-mail: [email protected]

Subject : Enviromental and sustainable development

Introduction

Wastewater from the paint of metallic pieces (Figure 1) may be treated by overspray coagulation and continuosly extracting the paint slurry as floating

or settling sludge . These sludges represent an important environmental problem due to their hazardous characteristiques being necessary a previous

treatment before final management . In this work a solidificaton/stabilization (S/S) process has been developed in order to obtain a non hazardous and

workable material

Figure 1.- Paint Spray Booth Flowsheet

Boothwater

WATER-WASHED

PAINT SPRAYBOOTH

Toluene PaintWater

VOCs

Metallic Pieces Painted Metallic Pieces

Solid Wastes

Energy

Material and Methods

The basis of the S/S process is the mixture of the waste with micronized lime as a binder, and sepiolite as additiv e in controlled atmosphere of N2 or

CO2 . The stabilization process is carried out in two phases :

1) Organic compounds in the mixture waste-sepiolite are absorbed by the micronized lime , the sludge-water in this phase does not take part in the

mixture.

2) The VOCs are removed and adsorbed using activated carbon . A dry-solid product is formed due to the heat of hydratation of lime .

Mixer

Adsorption tower

Scrubber

Additive and binder

Water

Waste

N2 CO2

S/S

Clean air

CONCLUSIONS

1.- Sludges generated in water-washed paint spray booth from an automotive components industry has been characterized . These sludges are hazardous wastes, because its high VOCs content (14%) and its flash point .

2.- The S/S process developped of paint booths sludges using different percentages of micronized lime ( 0%-72%) as binder, and different percentages of sepiolite as additive (6%-50%) allowing to reduce the organic content and to obtaindry-solid product. The direct characterization of %VOCs and leachate characterization of the S/S products show a non flammable and non ecotoxic product .

3.- The best results has been obtained with the formulation Sepiol 4 (100 g. of waste , 20% of water, 36% of sepiolite and 40% of micronized lime).

4.- The S/S products obtained are adequate to disposal take into account the catalan regulation in relation to the organic content , < 3% VOCs .

Adknowledgements

This work has been carried out thanks to the financing of the Project I + D of the Department of Education and Spanish Culture. It programs FEDER N: 1FD97-2013-C02-02.

Figure 2. % VOCs versus at % sepiolite

OCa- VOC'sy = -0,0037x

2+ 0,4464x - 11,254

R2

= 0,9828

0

0,5

1

1,5

2

2,5

40 50 60 70

% OCa

%V

OC's

Figure 3 . % VOCs versus at % CaO

24

12

6

36

4

66

2

72

0

5

10

15

20

25

30

35

40

0 0,5 1 1,5 2 2,5

% VOCs

%S

EPIOLITE

0

10

20

30

40

50

60

70

80

%O

Ca

Figura 4 . % VOCs versus at % of sepiolite

and % CaO

Paint waste characterization

Direct characterization% Toluene ...................... 5,95

% Ethylbenzene ............. 2,40 VOCs total ..................... 14 %

% Xylenes ..................... 5,65

Flash Point ...................... < 21 C

Lecheate characterization

TCLP lecheate : EC50 4.132 mg/l

DIN 38414-S4 lecheate :COD 8.400 mg/l

DIN 38414-S4 lecheate : TOC 4.850 mg/l

S/S Product characterization

Direct characterization Limits

% Toluene

% Ethylbenzene % VOCs > 3% (Non stabilised)

S/S Product % Xylenes

Flash Point < 55 C ( flammable)

Lecheates characterization

TCLP lecheate : EC50 < 3.000 mg/l (ecotoxic)

DIN S-4 lecheate : TOC

COD

Gas stream

Product

SEPIOLITE - VOCs

1,96,16 2,24

1,02

2,06

1

10

100

0 5 10 15 20 25 30 35 40 45 50 55

% SEPIOLITE

%V

OCs

y = -0,1755Ln(x) + 2,4128

OCa-VOCs

1,022, 24 , 16

1,961

10

100

30 50 70 90

% OCa

%VOCs

y = 1,7638Ln(x) - 5,295 4

12

6

36

54

66

42

72

0

5

10

15

20

25

30

35

40

1 10

% VOCs

%C

AL

0

10

20

30

40

50

60

70

80

%SEPIOLITA

Paint waste characterization

Direct characterization

% Toluene ...................... 5,95

% Ethylbenzene ............. 2,40 VOCs total ..................... 14 %

% Xylenes ..................... 5,65

Flash Point ...................... < 21 C

Leachate characterization

TCLP leachate : EC50 4.132 mg/l

DIN 38414-S4 leachate :COD1 8.400 mg/l

DIN 38414-S4 leachate : TOC2 4.850 mg/l

1) COD= Chemical Oxygen Demand 2)TOC = Total Organic Carbon

Mixer

Adsorption tower

Scrubber

Additive and binder

Water

Waste

N2 CO2

S/S

Clean air

Experimental Flowsheet S/S Product characterization

Direct characterization Limits

% Toluene

% Ethylbenzene % VOCs > 3% (Non stabilised)

S/S Product % Xylenes

Flash Point < 55 C ( flammable)

Leachates characterization

TCLP leachate : EC50 < 3.000 mg/l (ecotoxic)

DIN S-4 leachate : TOC , COD

Figure 1.- Paint Spray Booth Flowsheet

Boothwater

WATER-WASHED

PAINT SPRAYBOOTH

Toluene PaintWater

VOCs

Metallic Pieces Painted Metallic Pieces

Solid Wastes

Energy

RESULTS

SAMPLE

S/SH2O

%CaO

%

SEPIOLITE

%TOLUENE

%ETHYLBENZENE

%XYLENES

%COVs

%FLASH POINT

CEC50

LEACHATE

TCLP (mg/l)

TOC

LEACHATE

DIN S-4 (mg/l)

COD

LEACHATE

DIN S-4 (mg/l)

SEPIOL 1 20 0 50 0,72 0,27 2,06 3,05 Non stabilized < 55C Flammable 7.515 Non ecotoxic 1.189 2.700

SEPIOL 2 20 72 6 0,56 0,14 1,25 1,95 Stabilized > 55C Non flammable 6.125 Non ecotoxic 1.969 4.300

SEPIOL 3 20 66 12 0,55 0,16 1,44 2,15 Stabilized > 55 C Non flammable 6.550 Non ecotoxic 2.453 5.950



24

1 2

6

36

4

66

2

72

0

5

1 0

1 5

20

25

30

35

40

0 0,5 1 1 ,5 2 2, 5

% VOCs

%SEPIOLITE

0

1 0

20

30

40

50

60

70

80

%CaO

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