GERMAN ATV-DVWK RULES AND STANDARDS
Advisory Leaflet ATV-DVWK-M 374E Production specific wastewater and waste from the glass and mineral fibre industry August 2004 ISBN 3-937758-76-3
Publisher/Distribution: ATV-DVWK Deutsche Vereinigung für Wasserwirtschaft, Abwasser und Abfall e. V. Theodor-Heuss-Allee 17 y D-53773 Hennef Tel. 0 22 42 / 8 72-120 y Fax: 0 22 42 / 8 72-100 E-Mail:
[email protected] y Internet: www.atv-dvwk.de
ATV-DVWK-M 374E
The German Association for Water, Wastewater and Waste, ATV-DVWK, is the spokesman in Germany for all universal questions on water and is involved intensively in the development of secure and sustainable water management. As politically and economically independent organisation it operates specifically in the areas of water management, wastewater, waste and soil protection. In Europe the ATV-DVWK is the association in this field with the greatest number of members and, due to its specialist competence, it holds a special position with regard to standardisation, professional training and information of the public. The ca. 15,000 members represent the experts and executive personnel from municipalities, universities, engineer offices, authorities and business. The emphasis of its activities is on the elaboration and updating of a common set of technical rules and standards and with collaboration with the creation of technical standard specifications at the national and international levels. To this belong not only the technical-scientific subjects but also economical and legal demands of environmental protection of bodies of waters.
Imprint Publisher/marketing:
Setting and printing (German original):
ATV-DVWK German Association for Water, Wastewater and Waste Theodor-Heuss-Allee 17 D-53773 Hennef Tel.: +49 (0) 22 42 / 8 72-120 Fax: +49 (0) 22 42 / 8 72-100 E-Mail:
[email protected] Internet: www.atv-dvwk.de
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ISBN: 3-937758-76-3 Printed on 100 % recycling paper
© ATV-DVWK Deutsche Vereinigung für Wasserwirtschaft, Abwasser und Abfall e. V., Hennef 2004 All rights in particular the translation into other languages are reserved. No part of this Standard may be reproduced in any form – by photocopy, microfilm or any other process – or transferred into a language usable in a machine, in particular data processing machines, without the written approval of the publisher. The scientific correctness of the texts, diagrams and tables does not fall under the responsibility of the publisher.
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August 2004
ATV-DVWK-M 374E
Foreword Virtually, regarding the topic of production specific waste from the glass industry, there is only the "Musterverwaltungsvorschrift" (=administrative model regulation) of the "Länder" study group on emission protection (LAI) of 1995, which at that time could not have taken into account the current keys of the "Abfallverzeichnisverordnung (AVV)" (=regulation regarding waste inventory). Now this gap is closed by the present Advisory leaflet which also covers the recent research results as well as the current state of the industrial development. It replaces the advisory leaflet ATV-M 763 „Wastewater occurring in the glass industry“ of 1995. As the range of production as well as the facility's size play a substantial role regarding the occurrence and avoidance of wastewater and waste, also these factors are taken into consideration. The advisory leaflet has been elaborated based on progressive procedures, equipment and operational activities, as they could be taken into account for new constructions and re-equipment of existing facilities at the time of the leaflet's publication. The requirements to be met are stated in European Guidelines, e. g. the Guideline regarding the integrated avoidance and reduction of pollution (IVU) and other regulations, in Germany in the "Bundesimmissionsschutzgesetz (BImSchG)" (=law on emission protection) , "Wasserhaushaltsgesetz (WHG)" (=law on water management), "Kreislaufwirtschafts- und Abfallgesetz (KrW-/AbfG)" (=law on recycling management and waste) as well as all associated law-subordinated sets of rules. Regarding the effects on costs and environment please refer to the reference document on the best available techniques in the glass industry (BREF document).
Authors For the elaboration of the advisory leaflet a mutual working group (AG AK-4.1) was formed by the ATVDVWK expert committee IG-1 „Industry wastewater with inorganic contents“ and the ATV-DVWK expert committee AK-4 „Production specific industry waste“, consisting of members of FA AK-4 and the working group IG-1.14 „Glass industry“, in which die following members and guests participated: Dr. rer. nat. Rainer Werthmann, Kassel (Chairman FA AK-4) Dr.-Ing. Walter Schaefer-Rolffs, Essen (Spokesman AG IG-1.14 and AG AK-4.1) Dipl.-Ing. Gerhard Borcherding, Emden Dipl.-Ing. Johannes Martin Düngelhoff, Herne Dipl.-Ing. Matthias Fraaß, Gelsenkirchen Dipl.-Ing. Günter Höller, Gelsenkirchen Dr.-Ing. Thomas Hünlich, Mainz Dr.-Ing. Heinz-Eckhard Lennertz, Düsseldorf (until November 2002) Dipl.-Ing. Rüdiger Lilie, Wedel Dr. rer nat. Michael Kühnapfel, Herzogenrath Dipl.-Ing. Klaus Neukirch, Herne Dr. rer. nat. Johann Overath, Düsseldorf (from Januar 2003) Dipl.-Ing. Franz Puder, Berlin Dipl.-Ing. Johann Georg Schönberger, Riedlhütte Dipl.-Ing. Jürgen Westrup, Ludwigshafen For the main business site: Dipl.-Ing. Anett Baum, Hennef Dipl.-Biol. Almuth Spitzer, Hennef
August 2004
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ATV-DVWK-M 374E
Contents Foreword ............................................................................................................................................................3 Authors
............................................................................................................................................................3
User Notes ..........................................................................................................................................................7 1
Area of application...........................................................................................................................7
1.1
Objective................................................................................................................................... 7
1.2
Branch presentation ................................................................................................................. 7
2
Production and treatment procedures.........................................................................................8
2.1
Raw and additional materials ................................................................................................... 8
2.2
Melting ...................................................................................................................................... 13
2.3
Forming .................................................................................................................................... 13
2.3.1
Hollow glass (container glass, tableware, special glass) ......................................................... 13
2.3.2
Flat glass .................................................................................................................................. 13
2.3.3
Tubes........................................................................................................................................ 13
2.3.4
Glass and mineral fibres........................................................................................................... 14
2.4
Work and finish......................................................................................................................... 14
2.4.1
Mechanical work....................................................................................................................... 14
2.4.2
Chemical work.......................................................................................................................... 16
2.4.3
Coating ..................................................................................................................................... 16
2.4.4
PICVD process......................................................................................................................... 16
2.4.5
Chemical tempering of flat glass .............................................................................................. 16
2.4.6
Further treatment of glass and mineral fibres .......................................................................... 17
3
Wastewater .......................................................................................................................................17
3.1
Cooling water ........................................................................................................................... 17
3.2
Process water........................................................................................................................... 17
3.2.1
Shear cooling ........................................................................................................................... 18
3.2.2
Water in the forming process ................................................................................................... 18
3.2.3
Water in the further treatment .................................................................................................. 18
3.2.3.1
Washing and rinsing................................................................................................................. 18
3.2.3.2
Mechanical treatment ............................................................................................................... 18
3.2.3.3
Chemical work.......................................................................................................................... 18
3.2.3.4
Coating ..................................................................................................................................... 18
3.2.3.5
PICVD process......................................................................................................................... 19
3.2.3.6
Further treatment of mineral fibres........................................................................................... 19
3.3
Wastewater from side installations and exhaust gas washers................................................. 19
3.3.1
Side installations ...................................................................................................................... 19
3.3.2
Exhaust gas wash .................................................................................................................... 19
3.4
Measures for avoidance, reduction and recovery .................................................................... 20
4
August 2004
ATV-DVWK-M 374E 4
Wastewater treatment......................................................................................................................22
4.1
Dissolved solids ........................................................................................................................22
4.1.1
Chemical precipitation and neutralisation .................................................................................22
4.1.2
Subsequent treatment...............................................................................................................23
4.2
Non-dissolved solids .................................................................................................................23
4.2.1
Sedimentation ...........................................................................................................................23
4.2.2
Separation by centrifugal force .................................................................................................24
4.2.3
Flotation ....................................................................................................................................24
4.2.4
Filtration ....................................................................................................................................24
4.2.5
Separation devices for light liquids ...........................................................................................24
4.2.6
Process integrated burning of wastewater................................................................................24
4.3
Heat load...................................................................................................................................25
4.4
External disposal.......................................................................................................................25
5
Waste .................................................................................................................................................25
5.1
Type of wastes ..........................................................................................................................25
5.2
Waste amounts .........................................................................................................................25
5.3
Characterisation, avoidance, re-use and disposal of waste .....................................................25
5.3.1
Batch residues ..........................................................................................................................25
5.3.2
Filter dust ..................................................................................................................................28
5.3.3
Glass cullet................................................................................................................................28
5.3.4
Furnace material .......................................................................................................................29
5.3.5
Mud from the wastewater treatment (wastewater treatment mud) ...........................................31
5.3.5.1
Mechanical surface treatment...................................................................................................32
5.3.5.2
Chemical surface treatment ......................................................................................................32
5.3.5.2.1 Etching slime.............................................................................................................................32 5.3.5.2.2 Neutralisation gypsum...............................................................................................................33 5.3.5.2.3 Neutralisation mud ....................................................................................................................33 5.3.5.3
Waste from the PICVD procecs ................................................................................................33
5.3.6
Salt melt from the chemical tempering of flat glass ..................................................................33
5.3.7
Glass fibre and mineral fibre waste...........................................................................................33
5.3.8
Mud from the treatment of production water with organic load.................................................34
5.4
Rules on dangerous goods regarding the transport of waste ...................................................34
Bibliography .......................................................................................................................................................35 Reference Sources....................................................................................................................................37
Liste of figures Fig. 1: Fig. 2: Fig. 3: Fig. 4: Fig. 5:
Substance streams in the glass production (Bundesverband Glas).......................................12 Substance streams in the glass production: production of special glass, for example production of TV cones .......................................................................................12 Substance streams in the mechanical surface treatment.......................................................15 Substance streams of acid in the special glass production ....................................................15 Wastewater treatment in the special glass industry................................................................21
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5
ATV-DVWK-M 374E List of tables Table 1: Table 2: Table 3: Table 4: Table 5: Table 6: Table 7: Table 8: Table 9:
6
Production values of the glass industry in 2002 .................................................................... 8 Chemical composition of important glasses as mass content in % ....................................... 9 Maximum use of refining agent, referring to a glass mass of 100 kg .................................... 10 Cullet ratios (mass content in %) ........................................................................................... 10 Selection of the most important colouring agent and the according glass colour.................. 11 Selection of the most import decolourising agents ................................................................ 11 Measures for wastewater treatment in the single production processes ............................... 21 Types of waste in the glass industry, including mineral fibre industry ................................... 26 Characteristic components of filter dust (mass content in %) ................................................ 27
August 2004
ATV-DVWK-M 374E
User Notes This Advisory Leaflet is the result of honorary, technical-scientific/economic collaboration which has been achieved in accordance with the principles applicable therefore (statutes, rules of procedure of the ATV-DVWK and the Standard ATV-DVWK-A 400). For this, according to precedents, there exists an actual presumption that it is textually and technically correct and also generally recognised. The application of this Advisory Leaflet is open to everyone. However, an obligation for application can arise from legal or administrative regulations, a contract or other legal reason. This Advisory Leaflet is an important, however, not the sole source of information for correct solutions. With its application no one avoids responsibility for his own action or for the correct application in specific cases; this applies in particular to the correct handling of the margins described in the Advisory Leaflet.
1
Area of application
1.1
Objective
It is the aim of this leaflet to give processengineering instructions to industry and authorities for measures regarding the area of wastewater and waste which are both environment-appropriate and economically efficient. This includes the description of the progressive state of the technical development in the glass and mineral fibre industry as well as the presentation of measures for the treatment and avoidance of wastewater and for the avoidance or re-use of waste and, if need be, its disposal. It also addresses establishments which are occupied with the planning and operation of such facilities as well as institutions offering education and training in the field of industrial wastewater techniques and the avoidance and disposal of waste. Production specific wastewater within the meaning of this Advisory leaflet contains mainly inorganic components. The scope of application covers the feeding into waters (direct injection) as well as the feeding into public wastewater systems (indirect injection).
1.2
Branch presentation
According to the standard DIN 1259-1 „Glass: terms for glass types and glass groups“, glass is „an inorganic non-metallic substance that is achieved by complete meting of a mixture of raw materials at high temperature, in the course of which a homogenous liquid develops that is then cooled down to its solid status, usually without crystallisation“. Depending on the composition it is differentiated between soda-lime-silica glass (e.g. flat glass, container glass), potash glasses (e.g. crystal glass), lead silicate glasses (e.g. lead crystal glass) and borosilicate glass (e.g. laboratory glass, E-glass1). Beside glass wool and stone wool there is also a multitude of special glasses, the amount of which however does not achieve the meaning of the glass types stated above. In 2002, the glass and mineral fibre industry in Germany employed approx. 64,000 people and generated a production value of 7.7 billion €. Table 1 shows the production values, divided in main product groups.
Production specific waste is that what arises during production and processing (including treatment) of products. 1
Definition according to LOEWENSTEIN (1997)
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7
ATV-DVWK-M 374E Table 1:
Production values of the glass industry in 2002 (Bundesverband Glas)
Main product groups
Production value in Mio. €
Share in %
1.430
18,4
759
9,8
1.468
18,9
Crystal glass and tableware
456
5,9
Glass and mineral fibre
961
12,4
Flat glass refinement
2.680
34,6
Total
7.754
100,0
Container glass Flat glass Utility and special glass, incl. hollow glass processing
2
Production and treatment procedures
For the classification of the arising wastewater and waste, below a short sketch of the raw and additional materials as well as of the production procedures.
2.1
Raw and additional materials
Table 2 shows the chemical composition of important glasses. The raw materials used for the production of theses glasses are divided in natural and synthetic products: The natural raw materials are: quartz sand, partly also quartz flour, lime, dolomite, feldspar, nepheline syenite, phonolithe, anhydrite, chromic oxides, barytes, sassoline (boric acid), tetraborax and others. For the production of stone wool also basalt and diabas are used. Synthetic raw materials are: soda, potash, hydrated alumina, bor(III)-oxide, lead oxides, sodium sulphate, sodium nitrate, barium carbonate, barium nitrate and others. Also the used refining agents are classified as synthetic raw materials (also refer to table 3).
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August 2004
The demands for raw materials are very high. Mainly a homogenous chemical composition over long supply periods and a very low contents of iron are requested. By iron and chrome the glass is discoloured and reduced in its transmission. Furthermore, raw materials are not allowed to contain minerals difficult to melt (corundum, disthene and others), because depending on the melting conditions, these, as larger minerals corns, cannot be melted and lead to disturbing residues. Substances that are used as refining agents split off gases at the glass melting temperature (compare table 3). For the production of some special glasses – especially opal and pot-opal glasses – fluorine containing raw materials are necessary. For lead crystal glass, crystal glasses and optical glasses oxide compounds of lead, barium and others are used to increase their refractive index. Textile glasses and glass wool contain boric oxide due to product specific reasons. The same applies for special glasses (borosilicate glasses) which are characterised by their high chemical resistance. The role of recycling glass cullet (cullet recycling) as a raw material for the melting of glass becomes increasingly important. Own as well as foreign cullet is used; usually, the one arising at the production site or in the associated further processing comply with the respective batch composition and after separation according to given criteria and being free of foreign substances, can be used without any problems (VDI 2578). Table 4 shows approx. values for cullet ratios.
Chemical composition of important glasses2,3 as mass content in % [VDI 2578, Nov. 1999, p. 4; amended]
Table 2: Substance
3 4
Container glass
Crystal glass (tableware)
Lead crystalglass
Lighting glass (fluorescent tubes)
Picture tube glass screen
Chem. tech. Opt. glass apparatus glass (boron crown)
Glass ceramics
cone
Glass and mineral fibres E-glass
Glass wool
Endless glass fibres
Steam blowing procedure
Water glass
Stone wool
SiO2
72,6
73,0
69 – 74
58 – 62
67,5
60 – 63
53,5 – 55,3
80,4
61,7
60,0 – 63,5
52 – 56
Steam centrifugal blowing procedure 56 – 67
Cascade centrifugal procedure
50 – 61,5
34,5 – 43
68 – 77
Al2O3
0,7
1,4
0,2 – 1,2
0–1
5
2 – 3,4
1 – 5,2
2,27
03,3 – 3
10 – 20
12 – 16
0 – 2,5
0 – 4,5
17,5 – 22,5
0,1 –
Fe2O3
0,1
0,1
0,015 – 0,02
0,01 – 0,015
0,15
–
–
0,03
–
0,1 – 0,3
0–1
0–7
2 – 8,5
0,03
CaO
8,6
10,5
4–7
0–4
9,4
0 – 3,2
0,9 – 3,8
–
up to 3
0,5 – 7,0
16 – 25
5,5 – 9,5
17 – 32
14 – 22
0,008
PbO
–
–
0–5
24 – 32
–
–
21,6 – 23,5
–
–
–
–
–
–
<0,0002
MgO Na2O
4,1 13,3
1,6 12,8
– 4 – 10
– 3–5
– 13,6
0 – 1,2 6,6 – 9,4
0,6 – 2,2 5,8 – 6,7
– 3,8
– up to 5
0,5 – 1,0 0,5 – 10,0
0,1 – 1,0 0,1 – 1,04
1–6 14,5 – 20,5
7 – 11,5 2 – 6,5
7 – 14 0–3
0,008 22,5 – 24 (Soda water glass)
K2O
0,31
0,4
8 – 12
9 – 11
1,8
6,6 – 8,4
7,8 – 8,1
0,6
12 – 18
–
0,1 – 1,0[4]
0 – 1,5
0–2
0 – 2,5
27 – 32 (potash water glass)
SO3 F
0,2 –
0,2 –
– –
– –
0,2 4,0
– –
– –
– –
– –
– –
0,01 – 0,10 0,005 – 0,050
– –
– –
– –
0,015 –
B2O3
–
–
0–2
0–2
–
–
–
12,9
6 – 20
–
5 – 10
4,5 – 13
–
–
–
BaO
–
–
0–7
–
–
8,3 – 13
0 – 2,5
–
up to 10
1–2
–
–
–
–
–
ZnO
–
–
–
0–2
–
–
–
–
–
0,5 – 6,0
–
–
–
–
–
SrO
–
–
–
–
–
2,2 – 8,8
0 – 0,5
–
–
0,05 – 0,20
–
–
–
–
ZrO2 P2O5
– –
– –
– –
– –
– –
0 – 2,3 –
0 – 0,2 –
– –
– –
1 – 2,0 –
0,01 – 0,10 –
– 0–1
– –
1 – 2,0 0 – 1,5
– –
TiO2
–
–
–
–
–
–
–
–
–
–
–
–
0–1
0–3
–
Cr2O3
–
–
–
–
–
–
–
–
–
–
0,001 – 0,020
–
–
–
–
The glasses' composition is very manifold, so the data stated do only serve as an example. Especially broad is the variety of optical glasses. Therefore only the scope can be stated. This table does not contain batch material related pollution (e.g. PbO from recycling cullet). The sum of Na2O and K2O has to be smaller or equal to 1% !
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ATV-DVWK-M 374E
August 2004
2
Flat glass (float glass)
Maximum use of refining agent, referring to a glass mass of 100 kg [VDI 2578, p. 8]
ATV-DVWK-M 374E
10
Table 3:
5
Mass of refining agent in kg/100 kg glass mass 6 made of batch
August 2004
Kind of refining agent
Use e. g. for
CaSO4 or Na2SO4 from filter dust
1,2
soda-lime glasses
Sulphates e.g. Na2SO4) and sulphides
1,2
soda-lime glasses
Chlorides (e.g. NaCl)
1,5
borate glasses
Nitrates (e.g. NaNO3)
1,7
Oxides (e.g. As2O3, Sb2O3, NaSbO3 or CeO2)
0,3
Oxides (e.g. Mn2O3)
1,0
Table 4: Cullet
Cullet ratios (mass content in %)7 Flat glass (float glass)
flint
amber
green
own share furnace melt pot melt
5 – 15
5 – 15
5 – 15
foreign share
10 – 25
35 – 70
35 – 70
total cullet ratio Cullet
own share foreign share total cullet ratio
tableware and special glasses in different combinations
15 – 30
Container glass
40 – 85
Chem.-tech. apparatus glass
40 – 85
Opt. glass (boron crown)
Crystal glass (tableware)
Lead crystal glass
5 – 15
65 – 85 25 – 35
45 – 75
0
50 – 90
25 – 85
Lighting glass (fluorescent tubes)
screen
cone
65 – 85 25 – 35
25 – 45
30 – 50
20 – 50
0
2–5
25 – 85
Glass ceramics
Picture tube glass
8
25 – 50
0 – 30
0 – 50
30 – 70
20 – 80
Glass and mineral fibres E-glass
glass wool
endless glass fibres
steam centrifugal blowing procedure
Water glass stone wool
steam blowing procedure
cascade centrifugal procedure
0 – 15
0 – 20
10 – 40
0
9 9
50 – 80
0 – 15
30 – 70
0 – 18
0
0
0
0
> 50 – 75
ca. 30
0 – 20
0
50 – 80
0 – 15
30 – 70
0 – 18
> 50 – 80
30 – 45
10 – 60
0
Several compounds, mainly metal oxides, serve as colouring or decolourising agent. A small selection of possible compounds is shown in tables 5 and 6.
5 6 7 8 9
The numbers stated are only rough values. Typ and amount of the refining agent, solely or in combination with other, is depending on the glass type, the melting device, its size, the capacity, the furnace atmosphere, the temperature, the furnace material etc. Also other reference and code sizes are used, e. g.: „kg refining agent/t glass made of batch“ or „kg SO3/t glass“ (e. g. when using filter dust). The cullet ratios can be very different. The stated ranges are for orientation purposes only. The total cullet ratio does not necessarily have to be the addition of own and foreign share. Limited by the mercury content of the recycling cullet, which can contain depending on the pre-treatment (shredded only) 30 – 40 mg mercury per kg, with post-cleaning in a cullet cleaning device with water up to 5 mg mercury per kg. Water glass is produced in so-called „glass pieces“ with a size of approx. a palm of a hand, with waste cullet; no foreign cullet material.
ATV-DVWK-M 374E Table 5:
Selection of the most important colouring agents and the according glass colour [VDI 2578, p. 8]
Colouring agent chromic oxides ferric oxides cobalt oxide copper oxide, oxidising manganese oxide nickel oxide selenium sulphides with Fe cadmium sulphide + ZnO gold copper oxide, reducing silver
Table 6:
Glass colour green to yellow-green blue-green to yellow-green blue greenish blue violet grey-red to blue-red pink yellow to amber-red yellow ruby red deep red
Colouring type Ion colouring Ion colouring Ion colouring Ion colouring Ion colouring Ion colouring Ion colouring Ion colouring colloid colouring colloid colouring colloid colouring
yellow
colloid colouring
Selection of the most import decolourising agents [VDI 2578, p. 9]
Type nickel oxide manganese oxide cobalt oxide selenium, e.g. zinc selenite neodym oxide erbium oxide
Mass of decolourising agent in g/100 kg glass mass made of batch 0,5 – 1,0 5,0 – 25,0 0,04 – 0,1 3,0 – 20,0 5,0 – 15,0 10,0 – 20,0
August 2004
11
ATV-DVWK-M 374E Raw and additional materials
Sand Soda Lime Dolomite Cullet Others
Glass production facility
Waste / wastewater
Batch dust Batch composition Faulty batch
Waste glass Furnace demolition material Ca(OH)2 Na2CO3 NaHCO3
Clean gas
Exhaust gas Glass melt
cleaning
Filter dust
Energy Water
Glazed melting mass Wastewater Wastewater preparation Filter cake
Compressor oils Hot treatment Forming
Lubrication oils
Waste glass, waste glass wool
Hager process
Waste oil
Water
Oil water mixes
Products
*depending on production process
Fig. 1: Substance streams in the glass production Raw and additional materials
Lead oxide Quartz sand Soda Potash Cullet Other additives
Oxygen Natural gas
Special glass production facility
Waste / wastewater
Batch dust
Batch composition
Faulty batch
Waste glass Furnace demolition material
Glass melt Exhaust gas cleaning
Ammonia
Clean gas Filter dust
Hot Forming
Natural gas
Water Cooling lubricant
Neck Sealing
Waste glass
Grinding Wastewater treatment
Precipitation and flaking agents
Product cone
Fig 2: Substance streams in the glass production: production of special glass, for example production of TV cones
12
August 2004
Wastewater Slime
ATV-DVWK-M 374E 2.2
Melting
The glass melting occurs at temperatures up to 1700 °C in continuously operated furnaces or noncontinuous pots and daily furnaces. The continuos furnaces are continuously charged with batch and melted and refined glass is continuously taken out for the forming process. Fig. 1 shows the substance streams in the glass production10 and Fig. 2 the substance streams in the production of special glass, as an example the production of TV cones. For the production of stone wool diabas and basalt are also melting in water cooled shaft furnaces, in which the raw materials are stacked in layers alternately with coke.
the gob funnel's cooling normally cooling lubricants are added to the water. The further forming is carried out either by quickly operating multiple-section machines or manually by pressing, blowing, centrifugation or combination of theses procedures. Faulty gobs or posts are often granulated in a water tank. Usually, the mould material is made of metal, coal or wood. For the mould cooling air and/or water is used. Literature: SCHAEFFER (1990), PFÄNDER (1997)
2.3.2 Different types of fuel oil, natural gas, liquid gas and electricity are used as energy source. Coke is used in shaft furnaces. Regenerators or recuperators are used for the recovery of a part of the waste gas heat. The melting ovens as well as their additional facilities and equipment are cooled by air or water. The melting ovens' waste gases are treated with filters, sorption or other procedures according to the rules of the TA Luft. The waste arising from these procedures is discussed in 5.3.2.
2.3
Forming
2.3.1
Hollow glass (container glass, tableware, special glass)
Flat glass
Mainly, flat glass is produced according to the socalled float process. From the furnace the glass is flowing through a spout channel to a following tin bath (float bath). The arriving glass mass stretches on the liquid tin (800 °C) which is under bath atmosphere in the float bath. Carried by the density difference between tin and glass, the glass swims (floats) – guided as an endless ribbon – to the special rollers outside the float bath. These rollers lift the glass ribbon and guide to into a following cooling channel, in which the glass is slowly cooled down from 600 °C to 60 °C under controlled circumstances. Furthermore, sporadically flat glass is produced according to some older drawing processes (Fourcault, Libby-Owens and others) and according to the machine flow process (rolled glass).
The forming of the glass is carried out both in automatic and manual procedures.
Literature: SCHAEFFER (1990)
Substantial areas of container glass, tableware and special glasses are produced according to the gob feeding process, working in single gob as well as in multiple gob procedures. With these procedures, the hot glass gob is cut by shears from the remaining glass mass. For the shear blades' and
2.3.3
10
For parts of the mineral fibre industry, Fig. 1 differs in respect to the use of other raw materials as well as their preparation and charging.
Tubes
The main part of glass tubes is produced automatically. The most common process is the one according to DANNER. From the furnace the melted glass flows in a continuous string on a sloping, conical, and rotating tube („Danner blowpipe“) and is separated by drawing at its lower end. By feeding air into the hollow space the forming hollow glass body is maintained until its setting. The
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ATV-DVWK-M 374E desired pipe sizes are defined among other things by the drawing machine's speed. Also the VELLO process is important, in which the hot glass exits from a debiteuse and is separated by drawing in a similar way. Literature: PFÄNDER (1997), GIEGERICH, W. And TRIER, W. (1964) , SCHUMANN, D. et al. (1979)
2.3.4
Glass and mineral fibres
The following processes are used for the production of endless glass fibres (also refer to VDI 3457): Drawing from a bushing: the glass is fed to the bushing either directly from the glass melting furnace (direct melting procedure) or as re-melted balls or pellets (ball melting procedure). In the bushings' bottom there are spinning holes from which the liquid glass gets out and is drawn to fibres. Drawing process for optical purposes: Premanufactured canes and/or tubes are melted at one end, from which then fibres are drawn, which is especially used for optical fibres. For the production of mineral fibres (glass wool and stone wool) the following processes are used (also refer to VDI 3457): Centrifugal drawing: by centrifugal force and the assistance of an air-stream the vertically fed melt is split into mineral fibres, which are collected as uncured mat in forming hoods, forming sections or similar. The most common process is the steam centrifugal blowing procedure (TEL process). Steam blowing procedure: The melt flowing from a bushing is split by a parallel directed air-stream. Like in the centrifugal drawing process, the mineral fibre is either sucked or blown and collected.
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Cascade centrifugal process: The melt is falling freely on the circumference of a horizontal rotor which distributes it on the surface of two or three additional rotors; by that the melt is drawn to fibres under assistance of the air friction. The mineral fibres are sucked or blown and collected (ULLMANN, 1988).
2.4
Work and finish
2.4.1
Mechanical work
In many cases, the formed rough glass has to be worked mechanically to achieve the requested geometrical, decorative and optical characteristics. For that purpose it is made use of techniques referring to cutting, grinding, drilling, milling and polishing. This leads to abrasions from grinding agent and glass which either can be re-used in the process or have to be disposed. Usually the rough work (cutting, drilling, milling) is carry out with diamond tools. For the fine work, beside diamond tools there are also several auxiliary inorganic substances like oxides (e. g. corundum, ferric oxide, ceria), carbides (e. g. silicon carbide, boric carbide), quartz sand, garnet, pumice flour and others, for which usually water is used as vehicle medium. The work is mainly carried out automatically. After the work the glasses are mostly washed. Usually the cooling agent during the mechanical work and the washing water is completely salt-free water, with or without additives (cooling and lubrication agents). They are guided in circles (see Fig. 3). Exceptions are only possible for certain cases (refer to annex 41 of the Abwasserverordnung (AbwV) part D, part 1 item 1).
ATV-DVWK-M 374E Raw and additional materials
Work process
Fresh water Cooling agent Flaking agent Carbon dioxide
Waste / wastewater
Grinding watertreatment
dirty grinding water
Glass grinding slime
cleaned grinding water
mechanical surface treatment
Rough glass
Splash water Cleaning water
Glass grinding slime (Wastewater slime)
Slaked lime Wastewater treatment
Flaking agent Ferric-IIIchloride
Wastewater
finished product finished or semi-finished
Fig. 3: Substance streams in the mechanical surface treatment Raw and additional materials
Fresh water Fluorine hydrogen acid
Acid polishing process
Exhaust air
Absorption
Hexa fluoronic silicic acid
Vapors Rough glass Fluorine hydrogen acid Sulphuric acid Fresh water
Wastel / wastewater
Acid polishing
Vapors Used acid
Vaporiser Etching slime Concentrate Distillate
Glass rinsing
Acetous rinsing water Used acid
Slaked lime
Neutralisation
Neutralisation gypsum
Neutralised water Slaked lime Precipitation agent Flaking agent
Neutralisation mud (Wastewater mud)
Final wastewater treatment
Wastewater
Ferric-IIIchloride
Product
Fig. 4: Substance streams of acid in the special glass production
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ATV-DVWK-M 374E 2.4.2
Chemical work
The acid polishing of lead crystal glass, crystal glass and special glass is carried out with different procedures, using a mixture of fluorine hydrogen acid (1 % to 5 %), sulphuric acid (50 % to 70 %) and water at a temperature of 50 °C to 70 °C. The glass to be worked is placed in baskets or drums and gets polished in a dipping procedure. Depending on the number of acid baths, it is differentiated between the single-bath procedure (polishing bath) and the multiple-bath procedures (polishing bath and washing bath). Before the polishing bath a cleaning bath takes place, which can be either acetous or basic. Following the polishing baths, there are always one or more rinsing baths. Fig. 4 shows the substance streams of acid in the special glass production. Similar to the acid polishing, the frosting with aqueous fluorine hydrogen acid and sulphuric acid with additional alkali and ammonium compounds is carried out. Afterwards the glasses are rinsed with water. In another finishing procedure the glass achieves different mechanical and optical characteristics (pressure, breakage strength, refractive index) by ion exchanges in the surface. Usually this process is carried out in hydrochloric melts at temperatures between 200 °C and max. 800 °C.
chloride (TiCl4, SnCl4) or metal organic compounds (e. g. mono butyl tin triple chloride), and, if need be, be sprayed with lubricant after annealing. These latter substances stick only on glass and do not occur in any wastewater or waste stream. For special purposes, glass can be coated with plastics or other substances in a liquid procedure.
2.4.4
PICVD process
The PICVD (Plasma Impulse Chemical Vapour Deposition) process which was developed by Schott is especially suited for the coating of threedimensioned subjects. In this process the two single components – titanium tetra chloride and HMDSO (hexa methyl disiloxan) – are brought to a reaction with oxygen in a vacuum by plasma creation via a magnetron, so that finest and highly pure particles of titanium and silicon dioxide from the gas phase can deposit on a surface. Initially developed for the finish of glass fibres for optical purposes, this method now is used for the coating of spectacle glasses (de-mirroring and improvement of scratch resistance of glass and plastic spectacle glasses), as well as for the coating of energy saving halogen lamps and high end lamp reflectors. Here up to 100 high temperature resistant layers with thickness between 20 nm and 300 nm care for the required lamp reflectors' characteristics. They are the layers of titanium oxide and silicon dioxide mentioned above. Literature: GLÄSER (1994), KRAUSE (2003).
2.4.3
Coating
Usually the decoration of glass (screen printing, painting, golden rims) is made in an application procedure with suitable colours. Depending on type and glass composition these colours are fired on at 400 °C to 600 °C. The silvering is achieved by application of thin metal layers (e. g. silver, copper) after a preliminary cleaning of the glass surface. The desired metal deposit arises either from the liquid phase by chemical reduction or dry by vacuum evaporation. The metal cover is protected against damages by one or two varnish layers. For surface coating container glass in hot status can be subject to a vapour deposition with metal
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2.4.5
Chemical tempering of flat glass
This procedure is characterised by the fact that a pressure tempering of the glass surface is achieved by creating a difference compared to the glass inside by changing the surface's composition. The method of chemical tempering is based on ion exchange. The ions of the single chemical elements have different radiuses and are arranged with different distances related to each other. If for instance a sodium containing glass is heated slowly in a potassium hydrochloric melt close to the transformation temperature, the sodium ions migrate form the glass into the hydrochloric melt and the potash ions from the hydrochloric melt into the glass surface. As the potash ions entering the glass surface have an ion radius which is approx.
ATV-DVWK-M 374E 30 % larger, a kind of "shortage of space" is created in the glass surface, which causes the compression. The exchange zone has to have a minimum thickness of 0.1 mm to achieve a strength improvement of factor 5 to 8. Glasses tempered by ion exchange are required for special demands, e. g. in the air plane industry, for centrifuge glasses and in the lighting branch as well as for the tempering of spectacle glasses.
2.4.6
Further treatment of glass and mineral fibres
With glass fibres for textile applications as well as for plastics reinforcement the endless fibres have to be coated due to the sensibility of the untreated surface. For that purpose organic substances (size; see 3.2.2) are applied on the fibres. By that the friction effect of glass-on-glass and the risk of mechanical damage during the further treatment is reduced to a minimum. With fibres for plastics reinforcement the coating serves to achieve the compatibility with the plastic of the respective use. The filaments are bundled and wound up on packages. The wound up fibres can be further treated to become e. g. thread, mats, rovings (cylindrical packages with precision winding) or short fibres. In the production of mats the fibres are cut, split and treated with a binding agent. With glass fibres for optical application the fibres wound up on drums after the drawing process are equipped with a protective coat, either as single fibre or as fibre bundle. Usually, this consists of plastic (e. g. polyethylene) or, to a lesser extent, a flexible metal hose. The end of the fibre has to be cut plain and polished for a defined front area. For that purpose the fibres, either as single fibre or as bundles, are fixed in a metal shell and glued in advance. Usually mineral fibres are worked by coating, impregnation or soaking with binding agent and/or lubricants and, if need be, with the assistance of subsequent hardening procedures, to become different finished products. The work comprises besides others: cutting, pressing, stamping, sawing, milling, grinding, and facing (compare VDI 3457).
3
Wastewater
This section deals with the water consumption in the glass and mineral fibre industry, irrespective of the question, if in the single case wastewater occurs or not.
3.1
Cooling water
It is differentiated between direct and indirect cooling circuits with and without product contact. Cooling water with product contact arises if due to standstills, job changes, trouble or other operational reasons hot glass is chilled with water. Usually the generated granule is taken out with a scraper conveyor and in general is re-entered in the production process again. The generated wastewater (so-called scraper water) is warm and possibly slightly polluted with glass components (depositable substances, alkalis, earth alkalis) and oils. Cooling water without product contact comprises: boiler water systems, cooling circuits for compressors, cooling circuits for other cooling purposes like e. g. cooling of certain parts of the furnace or the inside cooling of the forming tools. Cooling water circuit are either closed or work as open systems with de-mudding. In these cases wastewater occurs, which is slightly charged with common conditioning agents. The rules stated in annex 31 AbwV and possible requirements of the local drainage/wastewater statutes are valid for the injection of wastewater from open and closed cooling circuits. Especially a possible charge of the cooling water with biocides has to be checked. Further literature: ATV-DVWK-M 706 „Kraftwerke und Energieversorgungsbetriebe“, Parts 1 to 3.
3.2
Process water
According to annex 41 AbwV part B „the wastewater is not allowed to contain any halogen hydrocarbons originating from additional substances like cooling lubricants. The proof that there are no
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ATV-DVWK-M 374E halogen hydrocarbons in the wastewater can be achieved by a manufacturers' statement that the used additional substances do not contain halogen hydrocarbons.“ Also annex 41 AbwV part E has to be paid attention to, according to which the requirements for wastewater are defined at the place of occurrence.
3.2.1
Shear cooling
Like described in 2.3.1, in the gob feeder process the hot glass gob is cut by a shear from the remaining glass mass. For improvement of the shear blades' lubrication and cooling effect, water mixable cooling lubricants can be used, which have been developed for this purpose. Usually they are biologically decomposable and contain e. g. alcanol amines, polyoles, tensides. Referring to the "Technische Regeln für Gefahrstoffe (TRGS 611)" the cooling lubricants are not allowed to contain neither nitrosating agents or their preliminary stages (like nitrites) nor secondary amines.
3.2.2
3.2.3
Water in the further treatment
3.2.3.1 Washing and rinsing Washing procedures are used for a preliminary cleaning of glass for a subsequent finishing process. Usually, common detergents (surface active substances) are added to the wash water manually or automatically. In special cases acids and lye are used. After the rinsing process the wastewater may contain substances from preceding treatment steps.
3.2.3.2 Mechanical treatment According to 2.4.1 usually during the treatment of glass water is used as cooling or transport medium for substances mentioned in that section. Furthermore biologically decomposable cooling lubricants are used. Besides others they contain e. g. alcanol amines, polyoles, tensides. During the mechanical treatment the cooling water gets charged with glass friction, possible also contents of the glass matrix can dissolve to a small extent.
Water in the forming process
In the production of hollow glass water is used in the forming process for cooling and lubrication, when a glass article's turn or movement in the mould takes places. This can lead to a slight wastewater charge with mineral oil carbohydrates. Endless glass fibres are coated with a size during drawing. In that context losses of the used sizes occur. Depending on the purpose of the produced fibres either "textile sizes“ or „plastic sizes“ are used. Textile sizes are substances like potato or corn starch as glue and film shaper as well as vegetable fat as lubricant. The plastics sizes contain besides others: polyester resins, epoxid resins (few), polyvinyl alcohol (few), polyurethane, film shaper, sticking agents like silanes, rinsing agents and emulsifier. These lead to increased CSB values in the wastewater (see 5.3.8).
3.2.3.3 Chemical work All work and finishing processes being carried out in a liquid, mainly aqueous phase may generate wastewater in the subsequent rinsing which is charged with components of the glass matrix. Usually acid polishing and frosting happen in acetous solution. Besides the acids (e. g.: sulphuric acid, fluorine hydrogen acid, hydrochloric acid) also ions from the glass can occur in the wastewater. In other cases, e. g. at the ion exchange both basic and acetous wastewater shares can arise.
3.2.3.4 Coating Usually the decoration and surface coating are carried out without wastewater (also refer to 2.4.3 and 3.3.2).
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ATV-DVWK-M 374E During the mirror production after preliminary treatment with tin (II) chloride a silver solution consisting of silver nitrate, ammonia and sodium or potash oxide in completely salt-free water as well as a reducing solution containing mainly glucose is splashed on the glass surface for silvering. Afterwards a copper layer is applied in a similar way. After respective cleaning, the surplus solution is guided into the wastewater. Literature: Gläser (1994), Kempf (1959).
3.2.3.5 PICVD process The exhaust air components from the coating process have to be washed out of the exhaust gas stream with a moist washer (in principle also dry sorption is possible, however not yet tested) on alkaline basis (soda lye respectively sodium bisulphite solution). After de-mudding the wash water of the exhaust gas washer can be injected into the sewers, if it complies with the state of the art according to annex 41 AbwV and the injection conditions of the rules for direct injections issued by the Länder respectively with the requirements of the local drainage/wastewater statutes.
3.2.3.6 Further treatment of mineral fibres Usually binding agents and lubricants are added during the production of the different glass and mineral wool products. This is carried out by spraying an aqueous solution, emulsion or suspension. For this purpose are mainly used: duromere synthetic resins (based on phenol, urea or melamine formaldehyde), mineral oil, vegetable fat, silanes and silicon oils. Usually water is consumed in the production of mineral fibres. Substantial amounts of steam evaporate from the area of splitting, lesser amounts from the area of the curing ovens in the surrounding air. Apart from that no more water is drained. The process water is guided in a closed circuit. Fresh water is added to the system as cooling or washing water. Usually washer water is injected in the process water circuit (VDI 3457).
3.3
Wastewater from side installations and exhaust gas washers
3.3.1
Side installations
Usually the cleaning of machines, machine parts, mould parts and tools complies with the standard procedures for cleaning and de-greasing commonly used in engineering works. The detergents in normal commercial use can contain sodium hydroxide, soda, tri sodium phosphate, polyphosphate, alkali silicates, alkali borates and tensides. They enrich with oils, fats, tinder and dirty substances and have to be transferred to an appropriate external disposal or a waste water treatment.
3.3.2
Exhaust gas wash
Exhaust gas wash can be used in different areas: • Glass melt: for deposit of acetous gaseous exhaust gas components like sulphur oxides, fluorine and chloride carbohydrates usually dry or nearly-dry sorption procedures are used. These procedures are free of wastewater. In some cases also exhaust gas washers are used (whirl washers, Venturi washers and others). • Chemical work: during the glasses' treatment with sulphuric and fluorine hydrogen acid (acid polishing, frosting) gaseous silicon tetra fluoride is generated. In multiple-step washers equipped with filling bodies this gas is washed out and concentrated as hexa fluoronic silicic acid. This can be transferred to recycling. According to annex 41 AbwV part E no wastewater is allowed to be generated from the exhaust gas wash. • Surface coating: like described in 2.4.3 container glass in hot status is subject to vapour deposition with metal chlorides, e. g. titanium or tin tetra chloride. Usually the sucked exhaust gases are cleaned together with the furnace exhaust gases. • In single cases the suction devices are equipped with moist washers instead. This can lead to slight loads of the wastewater with the respective metal oxides and hydrochloric acid, which has to be disposed appropriately. Metal organic coating agents are usually sucked, collected and used again after re-working by the manufacturer.
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ATV-DVWK-M 374E • With the online coating occur exhaust gases; they consist of gases of an inorganic chloride compound (e. g. tin chloride) that have already reacted completely and gases, which have not completed their reaction yet. For to complete the reaction, the coating gases can react in total in a reactor, that means, they change into the oxide form. The hot gases are guided over an exhaust gas cooler, which decreases the exhaust gas temperature by sprayed-in water, and then they are transferred to the electric filter. in the electric filter the metal oxides e. g. of the tin are deposited and collected. These metal oxides are recycled. The exhaust gases leaving the filter are neutralised in a soda lye washer. The cleaned air is released over a stacker. The arising salt-containing water is collected in tanks for a later transfer to the wastewater cleaning, where they are injected in a spray dryer. The spray dryer evaporates the water and the dry salt is taken out over a cell wheel sluice. The spray dryer's hot air can consist of the waste heat of the roller annealing lehr which is guided over an after-heater. Usually the salts are used in mine filling.
3.4
• Further treatment of mineral fibres: during impregnation, hardening and final work exhaust gas streams occur which are cleaned. This is carried out with moist or dry working devices for exhaust gas treatment, like e. g. moist washer, moist electric filter, hose filter, thermal after-burn (combined with heat re-transfer systems). Wash water from these exhaust gas treatment devices contains as main components residues of mineral fibres as well as organic parts (phenol formaldehyde resin in different condensation stages). After mechanical separation of the mineral fibre residues the washer water is retransferred to the process water circuit.
In contrast to the multiple use without intermediate treatment, in the rinsing water circuit with ion exchanger a nearly permanent use of the same water is aimed. The regenerates arising after treatment of the exchanger resins represent a wastewater charged with pollutant which has to be treated according to section 4. In this context lot treatment units have proven good.
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Measures for avoidance, reduction and recovery
Multiple water use depending on its further use, slightly charged process water can be used for further purposes in the plant, either with or without treatment. This saves water and the amount of wastewater is substantially reduced. Attention has to be paid to a possible enrichment of contents. The multiple use can be different: • in the first phase of use taking up heat, in the second taking up dissolved solids or vice versa. • in two or more steps taking up of different or same substances (cascade rinsing system). Examples of application: • use as consumption water in vaporisation systems, • use as consumption water for moistening raw materials, • multiple use as cooling water, • cascade rinsing in washing procedures.
Completely closed water circuits do not exist. Substances that enrich, either solid or dissolved, have to be extracted, continuously or non-continuously. For the treatment of such wastewater the procedures described in section 4 have proven good.
ATV-DVWK-M 374E Table 7:
Measures for wastewater treatment in the single production processes
Ref. section 3.2.1 Shear cooling 3.2.2 Forming process 3.2.3.1 Washing and rinsing 3.2.3.2 Mechan. treatment 3.2.3.3 Chemical work 3.2.3.4 Coating 3.3.1 Side installations 3.3.2 Exhaust gas wash
Sedimen- Centrifugal tation force deFlaking posit – –
Floating
Filtering
–
–
Deposit of Precipilight subtation stances (X) –
Ion exchange
Neutralisation
Burning
–
–
(X)
–
–
(X)
–
(X)
(X)
–
(X)
(X)
X
–
(X)
X
–
–
–
X
–
X
(X)
(X)
(X)
(X)
–
–
–
–
X
(X)
(X)
X
–
X
–
X
–
X
–
–
X
–
X
X
X
–
–
–
–
X
X
X
–
X
(X)
(X)
X
(X)
X
–
X
–
X
–
X ... usual; (X) ... done sometimes
K polymere
FeCl3
A polymere
FeCl3
H2SO4
Wastewater
PUMP SUMP
CHLORINE DIOXIDE DEVICE
FLAKING CONTAINER
SEDIMENTATION COURSE
BUFFERCONTAINER
Sand filter
MUD
THICKENER
CHAMBER FILTER PRESS
BUFFER CONTAINER
MUD Filtrate
PLANT NET
WASTEWATER SEWER
Fig. 5: Wastewater treatment in the special glass industry
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ATV-DVWK-M 374E
4
Wastewater treatment
The measures' type and scope are based on procedures which have been tested for the respective cleaning problems (see table 7). Fig. 5 shows the possible steps in wastewater treatment at the example of the special glass industry. Direct and indirect injectors have to pay attention to the rules stated in annex 41 of the Abwasserverordnung. In due case, indirect injectors have to carry out preliminary treatment measures, especially for the reduction of concentration and/or load of heavy metals, for being allowed to inject the wastewater in the public sewer system. The rules of the municipality statutes have to be respected, which regarding the limitation values for heavy metals mostly refer to e. g. annex 41 AbwV or ATV-DVWK-M 115-2 „Indirekteinleitungen nicht häuslichen Abwassers, Teil 2 Anforderungen“. The main tasks of wastewater treatment are • the elimination of sedimentable substances, • the separation of organic light liquids, • the neutralisation of acetous and basic wastewater, • the precipitation and retention of dissolved heavy metals. The lot procedures is recommend due to the water saving by the multiple use of rinsing water (see 3.4) and for to be able to keep after-reactions under control. Lot treatment devices should be used in such cases where the arising wastewater amounts can be stored and treated in containers with efficient size. Therefore it is important to minimise the wastewater arising from the production. This can be achieved e. g. by cascade rinsing, rinsing water circuits or multiple use of the wastewater. In general, the lot procedure is the most safe method of wastewater treatment because every step is controllable and in due case it can be started manually at important points. Further advantages of lot treatment devices are:
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• Lot treatment devices do not have lingering time characteristics and so do present the disadvantages connected with it. • The single process steps can be tested and defined in the laboratory and afterwards transferred to the lot treatment device. • Use of treatment methods with long-term reactions. • Realisation of several necessary reactions one after the other in one container. • Treatment of concentrated solutions. Mostly wastewater treatment is a series of single steps (e. g. filling – reaction – deposit – filtering). The slowest process sets the frame for the capacity. With larger amounts of wastewater it is efficient to use several smaller reactors which are filled alternately instead of one big reactor. By that the capacity can be increased in a nearly continuous operation. Usually the reactor sizes are limited to max. 20 m³ – 30 m³ due to the occurrence of reaction technical trouble, especially the quick and efficient mixture of the reactors content with the treatment chemicals (HARTINGER, 1991). However, it should be decided individually for every wastewater problem which type of wastewater treatment – lot by lot or continuously – is efficient and by that appropriate.
4.1
Dissolved solids
With the treatment of glass in aqueous media, especially by chemical procedures, dissolve actions take place. For the treatment of the arising wastewater the same treatment processes like in other industrial branches are applied.
4.1.1
Chemical precipitation and neutralisation
One of the widest spread treatment methods is the transformation from the dissolved to the hard to dissolve detachable status by precipitation with suitable reagents. The most important precipitation reaction in this context is the formation of hard to dissolve calcium
ATV-DVWK-M 374E fluoride (CaF2) and anhydrous gypsum (CaSO4) with slaked lime in the treatment of wastewater of the chemical surface treatment (see 3.2.2.3) containing fluorine hydrogen and sulphuric acid. During monitoring fluoride is often determined as fluoride in total. However, if it is present in wastewater in complex-bound type, e. g. as tetra fluorine borate (e. g. from acetous metal electrolytes), its precipitation is not possible. The same conditions like for fluoride are valid for the precipitation of anhydrous gypsum by neutralisation with slaked lime. Some metals can be precipitated not only as hydroxides with lye but also as carbonates or sulphites, e. g. lead as lead carbonate and arsenic and antimony as according sulphites. These procedures can be applied for treatments according to 3.2.3.2 (Mechan. treatment), 3.2.3.3 (Chem. work), 3.2.3.4 (Coating), 3.3.2 (Exhaust gas wash). The precipitation of free fluoride is carried out with calcium compounds, usually with slaked lime in combination with the neutralisation. Here it has to be considered that the fluoride precipitation can only be successful if per equivalent fluoride also an equivalent calcium is present. Otherwise additional calcium ions have to be added in form of dissolvable calcium compounds. According to DIN 4030-1 sulphate in concentrations between 200 mg/l and 600 mg/l has slightly concrete aggressive characteristics. Therefore it is usually limited in the indirect injection. In most favourite case, concentrations around 1400 mg/l SO4 (equilibrium concentration) can be achieved, depending on the concentration of neutral salt and temperature. However, with higher neutral salt concentrations this can be exceeded by far. Because of that reason annex 41 of the Abwasserverordnung states a limitation value for sulphate of 3000 mg/l. The value of 1000 mg/l mentioned in the BREF document for the glass industry can not be achieved with slaked lime precipitation. Another possibility could be to precipitate the sulphate as ettringite (calcium sulphate aluminate), which enables sulphate concentrations of less than 400 mg/l (HARTINGER, 1991). However, this procedure causes a substantially big amount of wastewater mud and is hard to control. The forming of ettringite happens spontaneously and can lead to
the blocking of piping. So from both economical and also ecological point of view this procedure can not be recommed. The requirements regarding the admissible sulphate concentration at the transfer point for the injection into public sewer systems are defined on the basis of the municipality statutes. Usually the drainage statutes of cities and towns contain a generally applicable monitoring value for sulphate. In most cities and towns however, under certain circumstances (sewer system material, dilution conditions) a higher sulphate concentration may be allowed after checking each single case. Usually acetous or basic and metal containing wastewater, especially from the finishing sector, has to be transferred into a pH value scope between 6,5 and 9,5 (up to 10). This occurs in reactors, either continuously or in lot procedures, using acetous or basic reagents (e. g. hydrochloric acid, slaked lime, soda lye and others). Arising mud is separated (see 4.2.1.), more to mud see section 5.
4.1.2
Subsequent treatment
The most frequent reasons for a possible excess of the requirements of annex 41 AbwV respectively the local drainage/wastewater statutes for rest concentrations of metals are very small amounts of solid particles which despite of sedimentation or flotation (see 4.2.1 and 4.2.3) remain in the wastewater. In this case a final filtration is necessary. Usually it is carried out with sand or flint filters. It is also possible to use candle or membrane filters. If after the treatment the waster water still contains small amounts of cat-ioncally dissolved metals or if the requirements can not be kept under guarantee at all times, a selectively working cat-ion exchanger can be installed after the final filter.
4.2
Non-dissolved solids
4.2.1
Sedimentation
The treatment residues in the glass industry are substances that can be fairly easy separated by sedimentation, possibly under preliminary use of a
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ATV-DVWK-M 374E sieve for the bigger fraction. For to accelerate the phase separation solid - liquid and for the separation of colloids often auxiliary substances (flaking agents e. g. aluminium or ferric sulphate or chlorides and flaking auxiliary substances, e. g. polyacrylic amides) are added in small amounts to increase the sinking speed of small parts. The separation process is carried out in suitable devices in which the cleared wastewater can overflow and the sediment can be extracted as mud. Subsequently the mud has to be partly drained (see section 5).
der pressure dissolved in the wastewater (release flotation) or by electrolytic water disintegration (electric flotation).
4.2.4
Filtering devices in form of belt filters and chamber filter presses are used where due to processrelated reasons larger amounts of solid substances to be separated have to be taken out and drained e. g. thin mud from the sedimentation.
4.2.5 4.2.2
Separation by centrifugal force
With the separation by centrifugal force the sinking speed of the parts to be separated can be substantially increased in comparison with the separation by force of gravity. Therefore, depending on the device's construction, also such particles which in separators using force of gravity would not deposit, can be separated. The procedures depend on size and density of the parts. As separators working with centrifugal force are used: Hydrocyclones, that means devices without moving parts in which the centrifugal force is created by tangential feeding of the suspension. This is separated into one liquid stream which is richer of solid substances and one that is poorer. Centrifuges, in which the centrifugal force is created by quickly rotating machine parts. Sedimentation, decanter and filter centrifuges as well as separators are used.
4.2.3
Flotation
Flotation means the separation of non-colloid disperse particles from liquids by provoking the swimming up using fine gas bubbles and subsequent taking out of the generated foam. Emulsion containing wastewater can be cleaned by flotation by way of preliminary breaking of the emulsion and coagulation of the organic substances with flaking agents. In the waster water technique, the gas bubbles' docking necessary for the swimming up usually is realised by release of air previously un-
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Filtration
Separation devices for light liquids
Substances that can not or only to a small extent be mixed with water and which are not emulsified in a stable way, separate from water by creation of an own phase. So due to the density difference they can be extensively separated from the water with suitable devices. Separators for light liquids according to DIN 1999-2 are especially used for the separation of oils. In the glass industry a wastewater pollution with oils occurs mainly in the machine area. In cases where the separation capacity of oil separators is insufficient (according to annex 49 AbwV „Mineralölhaltiges Abwasser“ the monitoring value for carbohydrates is 20 mg/l), coalescence separators according to DIN 1999-6 can be used.
4.2.6
Process integrated burning of wastewater
Cleaning water from the under-floor heating or cleaning and washing water from the cleaning of machines or machine parts as well as collected leaking and splashing water. e. g. from the trough cooling or other cooling systems for machines for the production of hollow glass are collected in a central reception container. From here, depending on the amount, the water is fed to the single burners in a controlled manner and injected into the burner area of the furnace parallel to the fuel-airmix. It has to be paid attention that no quality impairment occurs.
ATV-DVWK-M 374E 4.3
Heat load
Usually high specific heat loads at devices for glass production require water as cooling agent for heat discharge. In normal operation the cooling water heats up to 30 °C to 40 °C. Mainly the cooling down is carried out in open systems (evaporation cooler) in which depending on the surrounding's conditions the cooling water is cooled down in an amount of up to 10 Kelvin.
4.4
External disposal
In case certain highly charged plant wastewater can not be treated with cost-efficient method within the plant, this wastewater has to be collected and disposed externally.
5
Waste
5.1
Type of wastes
Table 8 shows the type of waste in the glass industry, including mineral fibre industry, according to the Abfallverzeichnisverordnung (AVV). Dangerous waste is marked with asterisks and has to be monitored in a special way in Germany according to § 41 par. 1 sentence 1 and par. 3 No. 1 KrW-/AbfG. In due case, it is subject to bringing duties according to § 13 par. 4 sentece 1 KrW/AbfG in case these have been stated by local law (e. g. in Berlin, Brandenburg, Baden-Württemberg, Niedersachsen, Rheinland-Pfalz, Sachsen-Anhalt and Thüringen).
5.2
Waste amounts
With the production of the different glass types and products waste arises in every production step. However, it has to be taken into consideration that glass raw materials, glass compositions, recycling ratios, melting methods, procedures for further treatment, environmental rules and quality requirements are subjects to permanent changes. Therefore the waste amounts of a production unit as well as comparable productions of different manufacturers and plants can differ considerably over the time. So it is not possible to state common waste amounts.
5.3
Characterisation, avoidance, reuse and disposal of waste
5.3.1
Batch residues
Usually batch residues occur with faulty weighing during batch preparation. Faulty weighing happens due to trouble in the steering procedures or by malfunction of the dosing devices in the batch preparation. This happens only very rarely. Another form of batch residues is the dust that deposits in the batch house or within the transport devices and the batch charger. Place of occurrence: batch house, transport devices, batch charging area Composition: general batch composition with one component in excess or mixture with sweepings.
Dangerous waste is supposed to have one or more dangerous characteristics mentioned in annex II of the European Guideline regarding dangerous waste (EU, 91/689/EWG).
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ATV-DVWK-M 374E Table 8:
Types of waste in the glass industry, including mineral fibre industry
Waste code 01 04 07* 01 04 10 01 04 13 06 01 06 06 04 04* 06 04 05* 10 01 21 10 02 02 10 11 03 10 11 05 10 11 09* 10 11 10 10 11 11* 10 11 12 10 11 13* 10 11 14 10 11 15* 10 11 16 10 11 17* 10 11 18 10 11 19* 10 11 20 10 11 99 16 11 05* 16 11 06 17 04 05 17 06 03* 17 06 04 19 02 05* * a b c d
26
Waste description Waste arising from the physical and chemical treatment of non-metallic mineral resources, containing dangerous substance Dusty and powdery waste without such being subject to 01 04 07 Waste arising from stone-mason and stone sawing work without such being subject to 01 04 07 Other acidsa Waste containing mercury Waste containing other heavy metalsb Mud from the plant-owned wastewater treatment without such being subject to 10 01 20 Non-processed slag Glass fibre waste Parts and dust Batch waste before melting with dangerous substances Batch waste before melting without such being subject to 10 11 09 Glass waste in small parts and glass dust containing heavy metals (e. g. from electron probe tubes) Glass waste without such being subject to 10 11 11 Glass polishing and glass grinding slimes containing dangerous substances Glass polishing and glass grinding slimes without such being subject to 10 11 13 solid waste from the exhaust gas treatment containing dangerous substances solid waste from the exhaust gas treatment without such being subject to 10 11 15 Mud and filter cakes from the exhaust gas treatment containing dangerous substances Mud and filter cakes from the exhaust gas treatment without such being subject to 10 11 17 solid waste from the plant-owned wastewater treatment containing dangerous substances solid waste from the plant-owned wastewater treatment without such being subject to 10 11 19* Waste a. n. g.c Linings and refractory materials from non-metallurgic processes containing dangerous substances Linings and refractory materials from non-metallurgic processes without such being subject to 16 11 05 Iron and steel Other isolation material consisting of dangerous substances or containing such substances Isolation material without such being subject to 17 06 01 and 17 06 03 Mud from physical - chemical treatment containing dangerous substancesd
dangerous type of waste according to the Abfallverzeichnisverordnung in the glass industry e. g. hexa fluoronic silicic acid Etching mud from the acid polishing a. n. g. = not mentioned anywhere else Neutralisation gypsum form the acid polishing
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Table 9: Substance
11
27
12
Flat glass (float glass)
Container glass
– 0,01 – – 35 – 37 – – 0,03 – – 0,12 – 0,47 2,2 0,01 – – – – 0,15 0,05 52 – 54 0,01 0,41 – – –
0,07 0,02 – – 34,9 2,3 – 0,04 – 0,44 0,10 0,40 0,31 12,8 – 0,05 0,33 – 0,23 0,36 0,10 30,9 0,01 0,64 0,03 0,02 –
Crystal glass (tableware)
0,02 – 0,11 0,05 – 5,0 0,5 – 2,0 < 0,01 – 2,0 0,50 – 1,2 – 0,003 0,001 – 0,003 – 0,1 – 0,7 0,02 – 0,8 10,0 – 20,0 0,01 – 0,02 2,0 – 20,0 0,003 – 0,2 – 30,012 3,0 – 10,0 – 2,0 – 8,0 – 0,5 – 7,0 – 0,01 – 0,07 – 0,01 – 1,5 0,01 – 0,03
Lead crystal glass
0,05 – 0,11 0,1 – 3,0 0,5 – 4,0 0,01 0,01 – 0,15 – 0,003 0,003 – 0,04 0,04 – 05 5,0 – 18,0 < 0,01 3,0 – 10,0 0,003 – 25,0 – 40,0 0,1 – 0,5 – 25,0 – 50,0 – 0,05 – 2,0 – 0,03 – < 0,01 – 1,0 0,01 – 0,09
Picture tube glass
Glass and mineral fibres E-glass
Glass wool
screen
cone
endless glass fibres
0,25 – 0,35 – – 0,20 – 0,25 30 – 40 0,8 – 1,5 – 0,01 – 0,03 – 8 – 10 0,05 10 – 13 0,2 – 0,3 0,01 4–5 – 0,2 – 0,3 2,0 – 3,0 – 2,0 – 3,0 – 9,0 – 12,0 0,3 – 0,6 0,02 – 0,8 – 1,0 0,01
0,05 – 0,15 – – 0,1 – 0,2 0,05 – 0,15 0,5 – 1,0 – < 0,005 – 0,5 – 1,5 0,005 2–4 0,01 0,01 0,8 – 1,2 – 80 – 90 0,5 – 1,0 – 0,5 – 1,0 – 1,0 – 1,5 0,05 0,01 – 0,04 0,01
0,5 – 10 0 – 0,1 17 – 65 – 2 – 33 0 – 0,5 – 0 – 0,3 0 – 0,1 2–3 0 – 0,2 8 – 22 0,2 – 1 3–8 – 0 – 0,6 0,5 – 0,7 – – 2 – 30 – 2 – 28 0 – 0,2 0 – 0,1 – – –
Steam centrifugal blowing procedure 0–3 – 5 – 45 < 0,5 < 1 – 50 – – < 0,5 – 0 – 10 0–1 0–5 < 30 5 – 35 – < 0,5 – – – < 0,5 – 25 – 1 – 30 – < 0,5 – < 0,5 –
Stone wool Steam blowing procedure
Cascade centrifugal procedure
0–2 – – – 15 – 25 – – – – – 0–5 0–3 0 – 10 0–5 – – – – – 20 – 45 – 0–2 – – – – –
1 – 27 – – < 0,5 1 – 18 – – – – – 2–7 6 – 14 1–6 5 – 20 – <1 – – – 10 – 40 – – < 0,5 <1 – – –
The filter dust's composition is very manifold. The data stated here do only serve for orientation purposes. The composition largely varies with exhaust gas cleaning process' steering and type. Lead free crystal glass usually has got only lead emissions close to zero in the exhaust gas due to raw material pollution. However, with common lead contents of 5 % to 8 % in the batch the filter dust can enrich with lead oxide up to 30 %.
ATV-DVWK-M 374E
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Al2O3 As2O3 B2O3 BaO CaO Cl CoO Cr2O3 CuO F Fe2O3 K2O MgO Na2O NiO P2O5 PbO Sb2O3 Se SiO2 SnO SO3 SrO TiO2 V2O5 ZnO ZrO2
Characteristic components of filter dust (mass content in %)11
ATV-DVWK-M 374E Avoidance: Faulty batch can only be reduced if the device's general reliability can be further increased. At the moment these devices' capacity is already at 98 % to nearly 100 %. The occurrence of dust can be minimised or avoided by closed systems. Closed systems are mostly installed at the places of occurrence. Re-use and disposal: Batch residues are re-used in the container glass industry, in the flat and special glass industry usually rejected due to quality reasons. Mixtures with sweepings also have to be rejected. Given suitable composition or suitable preliminary treatment, rejected batch residues can be re-used e. g. in mine filling (also refer to 5.3.2 and 5.3.4). Due to the small and non-continuously arising amount as well as individual quality requirements regarding raw material and product a use in other glass plants can not be realised. If re-use is not possible, the disposal is carried out on a dump licensed for such substances.
5.3.2
Filter dust
Glass plants in Germany are equipped with exhaust gas cleaning and filtering devices for generated dust. With the exhaust gas cleaning and the suction of glass and batch dust different filter dust arises depending on glass type, production conditions and exhaust gas cleaning procedure. Depending on the exhaust gas composition and exhaust gas temperatures electric filters or filtering separators, in due case with preliminary dry or nearly dry sorption procedure for separation of acetous waste gas components are used. The filters are automatically cleaned in regular intervals. The filter dust is collected in bunkers or transport containers.
The complete re-transfer of filter dust e. g. in facilities for the production of flat glass, container glass and glass fibres is explicitly appreciated according to the TA Luft. Taking into consideration other conditions, the TA Luft enables the assertion of a higher emission values regarding sulphur dioxide in comparison to other plants in which the filter dust is not completely re-entered in the production. Re-use and disposal: In the container glass, flat glass and mineral fibre industry filter dust is mainly re-used again. With special glasses, pollution e. g. by colourdonating metal oxides can limit a re-use, Dust which can not be re-entered in the process, can be used externally (e. g. non-ferric metal plant, mine filling) or disposed (surface dump, underground dump).
5.3.3
Glass cullet
Usually non-soiled glass cullet is immediately reentered in the melting process and so does not represent waste. Glass cullet with dirt from the melting process is cullet that is miss-coloured or interspersed with metallic, mineral oder glassy inconsistencies or glass cullet that after the forming process, especially during further treatment has become dirty due to e. g. lubricants, foil residues (flat glass laminated screens), grinding agents and/or sweepings. Usually the separation of the cullet from it's pollution is carried out at a place different from the place of glass production.
Place of occurrence: exhaust gas cleaning devices, batch houses, hot end, cold end
Place of occurrence: glass melt, glass forming, glass treatment, sorting, packing, warehouse
Composition: See following table 9.
Composition: the glass cullet composition is equal to the product composition. In general, the pollution (as stated above) is insignificant in regard to weight and volume.
Avoidance: By an appropriate selection of raw and additional materials as well as an optimised way of operation the amount of filter dust can be reduced, as far as this it technically and economically tenable. This minimises the expenses for secondary measures (e. g. filter dimension).
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Avoidance: avoidance is achieved by a reduction of defects in the production process, a reduction of inconsistencies in glass by optimisation of batch
ATV-DVWK-M 374E production and melting process (e. g. by keeping the minimum times for homogenisation and refining), use of more resistant refractory materials. The amounts of miss-coloured glass arising during colour changes can be reduced by an optimised management of job and melting changes. Under certain circumstances also the cullet with pollution can be melted in the production of glass products of different quality. A respective melting unit has to be on hand. The products have to be saleable on the market. Re-use: The transfer to other glass plants for melting is limited due to the pollution and/or different chemical compositions. Suitable cullet, e. g. lead-containing, can also be reused in non-ferric metal plants. The re-use of lighting glass in the melt has to be limited due to the sticking mercury parts. Usually shredded fluorescent tubes have got mercury shares of 30 mg/kg to 40 mg/kg. By an subsequent cleaning in a cullet cleaning device with water, the mercury share can be reduced to 5 mg/kg. A further reduction is technically impossible. Therefore the cullet ratio in the existing technical production facilities is limited 2 to 5 mass % for to keep the respective exhaust gas values of the TA-Luft. Before being used as construction material or additive an aptitude test has to be carried out. The reuse has to be carried out properly and without causing any damage. For underground mining reuse the "Verordnung über den Versatz von Abfällen unter Tage (VersatzV)" has to be respected.
5.3.4
Furnace material
Furnace material arises with repairs and reconstruction (approx. all 4 to 14 years) of the furnaces. It mainly consists of refractory materials and dust products of glass melt, chamber and exhaust gas channel deposits. Shaft furnaces for the production of stone wool are constructed approx. weekly, during which small amounts of fire-light bricks arise which are internally re-used as melting raw material. By targeted measures during the demolition and subsequent careful sorting, the part of furnace material that hat to be disposed can be substantially reduced. Place of occurrence: furnace, feeder (glass channel), recuperator, regenerator and exhaust gas channels. Composition: Refractory materials are nonmetallic materials with a pyrometric cone equivalent (PCE)13 of minimum 1500 °C. Refractory materials consist of high melting oxides (Al2O3, MgO, Cr2O3, ZrO2), fire-proof silicates and other materials (see table 10). A priori, refractory materials do only contain small amounts of water-soluble contents. However, glass melting furnaces are subject to a strong mechanical, thermal, and chemical permanent stress. Besides the components of the refractory materials, the composition of the processed batch (raw materials and additives) and the type of heating are important for the furnace material's chemical composition.
Disposal: In case neither avoidance nor re-use of the polluted cullet is possible, it has to be disposed according to its composition and its leaching characteristics on an appropriate dump. Usually for container and flat glass settlement waste dumps can be considered. For other glass it has to be decided from case to case depending on the glass composition's type and condition. Literature: GREULICH und HÜNLICH (1996), LARMS et. al. (1999)
13
The PCE is an auxiliary tool for monitoring and control of the burning operation. Not only the temperature is determined with the PCE, but also the influence of temperature and time which both are conditions for the achieved burning degree. Details are stated in DIN EN 993-12 and -13.
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ATV-DVWK-M 374E Table 10:
Main components of refractory materials (ISO 1109)
Products
Limit content of main components
High alumina containing products group 1
Al2O3 > 56 %
High alumina containing products group 2
45 % < Al2O3 < 56 %
Fire-clays
30 % < Al2O3 < 45 %
Fire-clays low in alumina
10 % < Al2O3 < 30 %; SiO2 < 85 %
Half silica products
85 % < SiO2 < 93 %
Silica products
SiO2 > 93 %
Basic products: Magnesite
MgO > 80 % (main component magnesite)
Magnesiumchromite
55 % < MgO < 80 % (main component magnesite and chromite)
Chromitemagnesite
25 % < MgO < 55 % (main components chromite and magnesite)
Chromite
Cr2O3 > 25 %; MgO < 25 % (main component chromite)
Forsterite
main component forsterite = Mg2SiO4
Dolomite
main component colomite = CaMg(CO3)2
Special products
On the basis of: carbon graphite, zirconium, zirconia (ZrO2), silicon carbide, carbide (others than SiC), nitride borides, spinels (other than chromite), products of different oxides (others than basic products) products of pure oxides including aluminium, silicon, magnesium, zirconium
Avoidance: Waste avoidance is possible by optimisation of the furnace campaign. Furthermore in some application cases new technologies (e. g. fuel-oxygen heating instead of fuel-air-heating) which make regenerators obsolete, offer the possibility to avoid refractory material waste. Re-use: Re-use possibilities depend on material composition, pollutant content and material status. Primary recycling: primary recycling is possible if after selective demolition undamaged refractory bricks can be directly re-used. With handing back lesser stressed material to the refractory material's manufacturer, maybe a direct re-use (with or without preparative treatment) is possible.
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Secondary recycling: material's use after transformation into a new product in other production branches and conditions of use (secondary construction material, depending on the classification values of the LAGA rules e. g. for the installation in free areas and for use in road construction as well as intermediate or filling layer in dumps). The harmlessness has to be checked in every single case as long as no federal unitary standard values are available. Mining technological re-use: Here in particularly the mechanical and the construction material characteristics of waste are used to achieve a mining technological target. The set of rules to be applied for this purpose is the VersatzV. Apart from the limitation values for heavy metals between 1 % (Cu)
ATV-DVWK-M 374E and 50 % (Fe), above which the metal recovery is emphasised, and the classification values in the TOC (Total Organic Carbon) and glow loss, further limitation values depend on the specific geological situation of the mine. These could be e. g. obsolete if „in plants in salt stone“ „a long-term safety proof was given to the authorities in charge“. For details refer also to Advisory leaflet ATV-DVWK-M 358 (2003).
class 0 dumps according to the "Deponieverordnung (DepV)".
Re-use as additive to the batch: under certain circumstances the deposit from the chambers and channel, which have arisen in the container glass industry in connection with a furnace material, can be used after preliminary treatment as batch component.
Place of occurrence: mud from the wastewater treatment arise in context with:
Disposal: Is neither avoidance nor re-use of the furnace materials and the deposits possible, only disposal remains. According to the material's analytical characteristics it has to be disposed at underground dumps, special waste dumps, settlement waste dumps or
Table 11:
Parameter SiO2 PbO As2O3 Sb2O3 K2O Na2O Al2O3 CaO BaO B2O3 Fe2O3 MgO CuO CoO Glow loss
5.3.5
Mud from the wastewater treatment (wastewater treatment mud)
1. the mechanical surface treatment of glass, 2. the chemical surface treatment of glass, 3. aqueous exhaust gas cleaning systems (e. g. PICVD process), 4. special procedures (e. g. chemical tempering of glass). Composition: The wastewater treatment mud's composition depends on the places of occurrence which are described below.
Examples for the composition of dried glass grinding slimes (mass content in %) Lead crystal 55,7 24,8 0,16 0,41 7,4 3,6 2,7 0,86 – 0,82 0,40 0,32 0,19 0,08 2,56
Crystal glass 62,0 <0,01 <0,01 <0,01 1,1 11,7 7,2 11,5 0,2 <5 0,7 0,1 0,5 0,01 8,4
Flat glass 72,9 <0,01 – – 0,07 11,9 0,3 8,9 – – 0,08 4,4 – – –
Picture tube glass 48,0 0,24 < 0,01 0,21 4,1 4,1 20,6 1,1 5,9 – 3,75 0,22 – – 2,51
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ATV-DVWK-M 374E 5.3.5.1 Mechanical surface treatment The main source for wastewater treatment mud is the mechanical surface treatment of glass. Usually the grinding process is carried out automatically, however partly still manually. The composition of mud arising during the preparation of the grinding water (table 11) mainly reflects the composition of the glass being treated, enriched with the natural friction of the grinding tools (iron), the grinding agents (pumice flour, corundum, diamond) as well as usually biologically decomposable cooling lubricants (common cooling lubricant share 3 % to 5 % in the grinding water). For to improve the separation also of dissolved heavy metals, in due case possibly acid treatment steps (barium sulphate precipitation) have to be foreseen, and further precipitation and flaking agents (e. g. aluminium sulphate, ferric-(III)chloride, cat-ionic and an-ionic polymeres) have to be added. Another feature of this mud is it's fine grain size (99 % < 30 µm). Despite of the fine grain size and so the quite big material's surface the leaching values mentioned below are quite low due to the surface's passive state (re-carbonisation). Avoidance: In most cases the occurrence of glass grinding slime is directly proportionate to the amount of glass to be disengaged during grinding. By the growing improvement of melting technology with subsequent forming procedures which are close to the product's final shape, the necessity for a following grinding process is reduced more and more, so that the amount of glass grinding slime decreases automatically. Re-use: Only after having checked every single case, glass grinding slime can be re-used internally. Even if the main composition of the glass grinding slime reflects the initial glass matrix, the small mass parts of: • flaking agents,
quality. Because of this reason in most cases the glass grinding slime is re-used externally. After according aptitude tests, there are ways of re-use e. g. in the earthenware industry (additive to brick-clay for back wall bricks), in the construction material industry (additive to concrete stones for paving stones and bottom plates), covering materials for dumps or for mine filling in suitable mines. Disposal: The ways of disposal depend on the glass grinding slime's composition and not on its place of occurrence. The mud's leaching characteristic is the main criterion as well as the dry substance contents of the heavy metals and organic components in question.
5.3.5.2
Chemical surface treatment
With the chemical surface treatment, several kinds of wastewater treatment mud arise:
5.3.5.2.1 Etching slime Etching slime occurs during the chemical polishing (finishing) of lead crystal and crystal glass with fluorine hydrogen and sulphuric acid. In the preparation of the polishing acid, the etching slime is separated by chamber filter presses. Besides lead sulphate as „main product” also small amounts of lead fluoride, alkali silicon fluoride and alkali sulphate are generated. Avoidance: In most cases the amount of etching slime is directly proportionate to the amount of glass to be disengaged during the chemical polishing. By the growing improvement of melting technology with subsequent forming procedures which are close the product's final shape, the necessity for a following grinding process that requires a subsequent acid polishing is reduced more and more. So the amount of etching slime decreases automatically.
• organic components from the cooling lubricants
Re-use: The high fluorine content makes the pyrometallurgic re-work in a lead plant practically impossible. Other re-use procedures are yet unknown.
mentioned above can make a re-use impossible due to the high requirements regarding product
Disposal: Due to its high fluorine content and the incorporated acid residues, the etching slime is
• grinding tools' friction and grinding agents,
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ATV-DVWK-M 374E disposed at special waste dumps, possibly after preliminary treatment.
Re-use: The neutralisation mud can be externally re-used in the same way like neutralisation gypsum or glass grinding slime.
5.3.5.2.2 Neutralisation gypsum
Disposal: In case a re-use is not possible the neutralisation mud has to be disposed on a dump of appropriate classification depending on its composition and its leaching characteristics.
The second waste arising in the acid polishing area is neutralisation gypsum. It occurs during the neutralisation of the sulphate containing wastewater with slaked lime. In small amounts also calcium fluoride is generated. Lead, arsenic and antimony are present as trace elements. The neutralised suspension is drained e. g. with a chamber filter press. Avoidance: By re-transfer of rinsing water concentrates and used acids, the occurrence of neutralisation gypsum can be avoided. For that purpose the mixtures of used acids are concentrated up by an evaporator, so that they can be completely reentered in the polishing process again. This can decrease the amount of neutralisation gypsum substantially. Re-use: There are external re-use possibilities for neutralisation gypsum in mine filling and as additive in the dump construction. Disposal: In case a re-use is not possible, the neutralisation gypsum has to be disposed on special waste dumps or settlement waste dumps, depending on its composition and its leaching characteristics.
5.3.5.3 Waste from the PICVD procecs At the moment, the solid residues (titanium dioxide with components of silicon dioxide) which occur in the exhaust gas washers of the PICVD process, are disposed as waste to be monitored. Research work is necessary to enable titanium preparation for re-use in the future.
5.3.6
The procedure is operated free of wastewater. The potash containing salt melt can be re-used in mine filling. In general, a use as fertiliser in farming is possible, however necessitates an approval according to the law on fertilisers.
5.3.7 5.3.5.2.3 Neutralisation mud This wastewater treatment mud occurs during the final treatment of neutralised acid water. Lead, arsenic and antimony are separated by adding flaking agent, slaked lime, ferric-(III)-chloride. The complex-bound heavy metals and antimony are precipitated with a specific precipitation agent. The neutralisation mud is drained by either a belt filter or a chamber filter press. Avoidance: By re-transfer of the neutralised acid wastewater, e. g. into the rinsing circuits, the wastewater to be treated and the arising wastewater treatment mud can be minimised.
Salt melt from the chemical tempering of flat glass
Glass fibre and mineral fibre waste
Glass fibre and mineral fibre waste occurs during product changes, production interruptions, faulty product lots and when edge cuts arise. Moreover, mineral fibre waste occurs in the area of process water filtration, and in the stone wool production, waste from stone wool filter material can arise. Place of occurrence: drawing device, splitting and further treatment, process water preparation, filtering devices. Composition: Usually the composition of glass fibre and mineral fibre waste corresponds to the one of the products.
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ATV-DVWK-M 374E Avoidance: Waste avoidance can be achieved by improvement of the material's efficiency. Re-use: Primary recycling: primary recycling is possible in the mineral fibre production (glass wool and stone wool) if the mineral fibre waste can be re-entered into the production process after mechanical preparation. Mineral fibre waste from the process water filtration and stone wool waste from the filtering devices is usually re-used over the melting process. In general waste from endless glass fibres is not re-used again because it disturbs the production process substantially. Secondary recycling: In single cases it is possible to use mineral fibre waste as additive in the brick industry after mechanical preparation of the material. Glass fibre waste arising from E-glass can be used as additive to construction materials. Before the use as construction material or additive a preliminary aptitude test is necessary. The re-use has to be carried out properly and without causing any damage. Drawn fibres can be worked to simples products made of glass fibres, e. g. quilted mats. Disposal: In case neither avoidance nor re-use of the glass fibre and mineral fibre waste is possible, only disposal remains. According to the material's analytical characteristics, a disposal on appropriate dumps of class 0 or on settlement waste dumps has to be foreseen.
5.3.8
Mud from the treatment of production water with organic load
Place of occurrence: For the production of endless fibres made of E-glass it is necessary to coat the drawn fibres with a so-called size (see 3.2.2).
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A part of the size does not stick to the fibres and washes away with the water used for the drawing process. In the wastewater treatment device, the organic components are separated with the addition of flaking agents, slaked lime, ferric chlorides and a precipitation agent. The organic mud is drained e. g. by a chamber filter press. Avoidance: At the moment it is not possible to avoid these solid residues in the production wastewater. A reduction should be aimed to decrease the use of size in the production. Re-use: A re-use as additive in re-cultivation measures or in dump construction could be possible, as far as the organic pollution does not bar it. The rules of the KrW-/AbfG (§ 8) and the BBodSchV (§ 12) have to be respected. Disposal: Usually a disposal is not necessary.
5.4
Rules on dangerous goods regarding the transport of waste
Most waste arising during the production of glass and mineral fibres is not subject to marking duties according to the rules of the European Guideline regarding dangerous goods (ADR). However, in single cases, especially with waste form the special glass or lead crystal glass production, dangerous goods can be present, for which the rules on dangerous goods have to be respected. Dangerous goods are defined in chapter 3.2 of ADR in the list of dangerous goods. They are classified with UN numbers (substance numbers). The according national rules can be found besides others in the "Gefahrgutverordnung Straße und Eisenbahn (GGVSE)". The GGVSE regulates the classification of substances as dangerous transport goods = dangerous goods, their packaging for the transport, the requirements regarding the vehicle, the driver's training and further aspects and is generally valid above certain volume thresholds. For the transport of different dangerous goods in the same transport unit part 1 of annex A to the GGVSE has to be respected.
ATV-DVWK-M 374E There are simplified rules for smaller and minor amounts. The application of the rules regarding dangerous goods has to be monitored by an appropriately trained representative with valid training certificate, who has been appointed in writing. Exceptions are regulated by the "Gefahrgutbeauftragtenverordnung (GbV)".
Bibliography AbwV: Verordnung über Anforderungen an das Einleiten von Abwasser in Gewässer (Abwasserverordnung) i. d. Neufassung durch Bek. v. 15. 10. 2002 BGBl. I 4047, S. 4550 Anhang 31: Wasseraufbereitung, Kühlsysteme, Dampferzeugung (BGBl. I 2002, S. 4085-4088) Anhang 39: Nichteisenmetallherstellung (BGBl. I 2002, S. 4095-4097) Anhang 41: Herstellung und Verarbeitung von Glas und künstlichen Mineralfasern (BGBl. I 2002, S. 4100-4102) Anhang 49: Mineralölhaltiges Abwassr (BGBl. I 2002, S. 4111-4112) ADR: Anlagen A und B des Europäischen Übereinkommens über die internationale Beförderung gefährlicher Güter auf der Straße. Neufassung des ADR 2003, BGBl. II S. 1743 ATV-DVWK (1985): Lehr- und Handbuch der Abwassertechnik Band VII „Industrieabwässer mit anorganischen Hilfsstoffen“. Berlin: Verlag Ernst & Sohn, 1985 ATV-DVWK-A 400: Grundsätze für die Erarbeitung des ATV-DVWK-Regelwerks. Hennef: Gesellschaft zur Förderung der Abwassertechnik. Juli 2000 ATV-DVWK-M 115-2: Indirekteinleitungen nicht häuslichen Abwassers – Teil 2: Anforderungen. Entwurf August 2003 ATV-DVWK-M 358: Behandlung, Verwertung und Beseitigung produktionsspezifischer Abfälle: Schlämme aus Zink- und Eisenphosphatieranlagen. Dezember 2003
ATV-DVWK-M 706: Kraftwerke und Entsorgungsbetriebe: Teil 1 – Abwasser, das bei der Wasseraufbereitung entsteht. Juni 2000 Teil 2 – Abwasser, das beim Betrieb von Kühlsystemen entsteht. April 1997 Teil 3 – Abwasser, das bei der Dampf- und Heißwassererzeugung entsteht. Juli 2003 AVV: Verordnung über das Europäische Abfallverzeichnis (Abfallverzeichnisverordnung) i. d. F. vom 10. 12. 2001, BGBl. I S. 3379, gültig seit 01. 01. 2002; Stand: zuletzt geändert durch Artikel 2 Verordnung v. 24. 07. 2002, BGBl. I S. 2833 BBodSchV: Bundes-Bodenschutz- und Altlastenverordnung i. d. F. vom 12. 07. 1999, BGBl. I 1999, S. 1554, gültig ab 17. 07. 1999 BImSchG: Gesetz zum Schutz vor schädlichen Umwelteinwirkungen durch Luftverunreinigungen, Geräusche, Erschütterungen und ähnliche Vorgänge (Bundes-Immissionsschutzgesetz) in der Neufassung durch Bekanntmachung v. 26. 09. 2002, BGBl. I S. 3830; Stand: zuletzt geändert: zuletzt geändert durch Artikel 7 Gesetz v. 6. 1. 2004 BGBl. I S. 2 BREF-Dokument: Referenzdokument über die besten verfügbaren Techniken in der Glasindustrie (Reference Document on Best Available Technique –, kurz BREF). Oktober 2000 http://eippcb.jrc.es/pages/FActivities.htm ChemVerbotsV: Verordnung über Verbote und Beschränkungen des Inverkehrbringens gefährlicher Stoffe, Zubereitungen und Erzeugnisse nach dem Chemikaliengesetz (Chemikalien-Verbotsverordnung) in der Neufassung durch Bekanntmachung v. 13. 6. 2003, BGBl. I S. 867; Stand: zuletzt geändert durch Artikel 1 Verordnung v. 25. 2. 2004, BGBl. I S. 328 DepV: Verordnung über Deponien und Langzeitlager (Deponieverordnung) i. d. F. vom 24. 07. 2002, BGBl. I S. 2807; Stand: geändert durch Artikel 1 Verordnung v. 26. 11. 2002, BGBl. I S. 4417 DIN 1259-1: Glas – Teil 1: Begriffe für Glasarten und Glasgruppen. September 2001 DIN 1999-100: Abscheideranlagen für Leichtflüssigkeiten – Teil 100: Anforderungen für die Anwendung von Abscheideranlagen nach DIN EN 858-1 und DIN EN 858-2. Oktober 2003 DIN 4030-1: Beurteilung betonangreifender Wässer, Böden und Gase; Grundlagen und Grenzwerte. Juni 1991
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ATV-DVWK-M 374E DIN 4030-2: Beurteilung betonangreifender Wässer, Böden und Gase; Entnahme und Analyse von Water- und Bodenproben. Juni 1991 DIN 32640: Chemische Elemente und einfach anorganische Verbindungen; Namen und Symbole. Dezember 1986 DIN EN 858-1: Abscheideranlagen für Leichtflüssigkeiten (z. B. Öl und Benzin) – Teil 1: Bau-, Funktions- und Prüfgrundsätze, Kennzeichnung und Güteüberwachung. Mai 2002 DIN EN 858-2: Abscheideranlagen für Leichtflüssigkeiten (z. B. Öl und Benzin) – Teil 2: Wahl der Nenngröße, Einbau, Betrieb und Wartung. Oktober 2003
Giegerich W. und Trier, W.: Glasmaschinen. Berlin, Göttingen, Heidelberg: Springer-Verlag, 1964 Gläser, H. J.: Beschichtungen auf Flachglas. Vorlesung der TU Clausthal, Dozent: Dr. Hans Joachim Gläser, Bundesverband Flachglas, 1994 Graf, J. et al.: Entwicklung von Verfahren zur Herstellung von verkaufsfähigen Produkten vor allem aus Reststoffen der Bleikristallerzeugung. Abschlussbericht der F. X. Nachtmann Bleikristallwerke GmbH zum Fördervorhaben des Bundesministeriums für Bildung, Wissenschaft, Forschung und Technologie (BMBF) vom 31. Dezember 1997, Förderkennzeichen 1480934
DIN EN 993-12: Prüfverfahren für dichte geformte feuerfeste Erzeugnisse – Teil 12: Bestimmung des Kegelfallpunktes (Feuerfestigkeit). Juni 1997
Greulich, N., Hünlich, Th.: Elution von Bildröhrenglas zur Charakterisierung seines Deponieverhaltens. In: Glastechn. Ber. Glass Sci. Technol. 69 (1996) Nr. 8, S. 77-81
DIN EN 993-13: Prüfverfahren für dichte geformte feuerfeste Erzeugnisse – Teil 13: Festlegungen für Referenz-Brennkegel für den Laboratoriumsgebrauch. April 1995
Hartinger, L.: Handbuch der Abwater- und Recyclingtechnik – für die metallverarbeitende Industrie. 2. Aufl. München, Wien: Carl Hanser Verlag, 1991
EU, 91/689/EWG: Richtlinie des Rates über gefährliche Abfälle, (Richtlinie 91/689/EWG) vom 12. 12. 1991, ABl. EG Nr. L 37 S. 20; Stand: zuletzt geändert durch Richtlinie 94/31/EG des Rates vom 27. 06. 1994, ABl. EG Nr. L 168 S. 28
ISO 1109: Feuerfeste Erzeugnisse, Klassifikationvon dichten, feuerfesten Erzeugnissen. Dezember 1975
GbV: Verordnung über die Bestellung von Gefahrgutbeauftragten und die Schulung der beauftragten Personen in Unternehmen und Betrieben (Gefahrgutbeauftragenverordnung) i. d. F. vom 26. 03. 1998, BGBl. I S. 648, Stand: zuletzt geändert am 11. 12. 2001, BGBl. I S. 3529
ISO 10081-1: Klassifizierung von dichten geformten feuerfesten Erzeugnisses – Teil 1: AluminaSilika. Dezember 2003 ISO 10081-2: Klassifizierung von dichten geformten feuerfesten Erzeugnissen – Teil 2: Basische Erzeugnisse mit einem Massenanteil an Restkohlenstoff kleiner 7 %. Dezember 2003
GefÄndV: Verordnungen zur Änderung gefahrgutrechtlicher Verordnungen i. d. F. vom 11. 12. 2001, BGBl. I S. 3529. Stand: zuletzt geändert 28. 04. 2003, BGBl. I S. 595
ISO 10081-3: Klassifizierung von dichten geformten feuerfesten Erzeugnissen – Teil 3: Basische Erzeugnisse mit einem Massenanteil an Restkohlenstoff von 7 % bis 50 %. Dezember 2003
GefStoffV: Verordnung zum Schutz vor gefährlichen Stoffen (Gefahrstoff-Verordnung) in der Neufassung durch Bekanntmachung v. 15. 11. 1999, BGBl. I S. 2233; Stand: zuletzt geändert durch Artikel 2 Verordnung v. 25. 2. 2004, BGBl. I S. 328
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GGVSE: Verordnung über die innerstaatliche und grenzüberschreitende Beförderung gefährlicher Güter auf der Straße und mit Eisenbahnen (Gefahrgutverordnung Straße und Eisenbahn) in der Neufassung durch Bekanntmachung. v. 10. 9. 2003, BGBl. I S. 1913, (2139); Stand: zuletzt geändert durch Verordnung v. 24. 3. 2004, BGBl. I S. 485
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Krause, D.: Plasma Impulse Chemical Vapour Deposition (PICVD). In : Thin Films on Glass. 2. korrigierte Auflage, Berlin, Göttingen, Heidelberg: Springer-Verlag, 2003, p. 243 ff
ATV-DVWK-M 374E KrW-/AbfG: Gesetz zur Förderung der Kreislaufwirtschaft und Sicherung der umweltverträglichen Beseitigung von Abfällen ((Kreislaufwirtschafts- und Abfallgesetz) i. d. F. vom 06. 10. 1994, BGBl. I S. 2705; Stand: zuletzt geändert durch Artikel 2 Gesetz v. 25. 1.2004, BGBl. I S. 82 LAGA M 20: Mitteilungen der Länderarbeitsgemeinschaft Abfall: Anforderungen an die stoffliche Verwertung von mineralischen Reststoffen / Abfällen – Technische Regeln – 4. Auflage, Berlin: Erich Schmidt Verlag, 1998 LAI (1995): Musterverwaltungsvorschrift der Länderarbeitsgemeinschaft Immissionsschutz (LAI) zur Vermeidung und Verwertung von Reststoffen nach § 5 Abs. 1 Nr. 3 BImSchG bei Anlagen nach Nr. 2.8 des Anhangs zur 4. BImSchV (Anlagen zur Herstellung von Glas). Berlin: Erich Schmidt Verlag, Loseblatt-Ausgabe, Grundwerk 1995 Larms, A. et al.: Mobilisierbarkeit von Schwermetallen und Arsen aus Schlacken, Gläsern und Gesteinen, Anwendung des pHstat-Verfahrens für Sonderfragestellungen bei Verwertungsvorhaben. Hrsg.: Niedersächsisches Landsamt für Ökologie, 1999 Loewenstein, K. L.: The Manufacturing Technology of Continous Glass Fibres. Glass science and technology 6; Elsevier 1993 Mansmann, M.: Ullmanns Enzyklopädie der technischen Chemie. Glasige Mineralfasern. Band 11, S. 361-374. Weinheim, New York: Verlag Chemie, 1976 Martinek, K.-P.: Stoffkreislaufschließung bei abtragenden Verfahren in Prozesslösungen. Teilvorhaben 12: Säurepolieren von Bleikristall-Kristallglas, Abschlussbericht der F. X. Nachtmann Bleikristallwerke GmbH zum Fördervorhaben des Bundesministeriums für Bildung, Wissenschaft, Forschung und Technologie (BMBF) vom 31. Dezember 1997, Förderkennzeichen 01 ZH9406, 2001 Müller, G.: Glas und Glaskeramik. Band 12, S. 317366. Weinheim, New York: Verlag Chemie, 1976 Pfänder, H. G.: Schott-Glaslexikon. Überarbeitet und ergänzt, 5. Auflage, Landsberg am Lech: mvg-Verlag, 1997
Schaeffer, H. A.: Allgemeine Technologie des Glases. Erlangen: Institut für Werkstoffwissenschaften, Lehrstuhl III (Glas und Keramik), 1990 Schumann, D., et al.: Maschinen der Glastechnik. Leipzig: VEB Deutsch, Verlag für Grundstoffindustrie, 1979 TA Luft: Technische Anleitung zur Reinhaltung der Luft, Erste Allgemeine Verwaltungsvorschrift zum BimSchG i. d. F. vom 24. 07. 2002, GMBl. 2002, Heft 25-29, S. 511 TRGS 611: Verwendungsbeschränkungen für wassermischbare bzw. wassergemischte Kühlschmierstoffe, bei deren Einsatz N-Nitrosamine auftreten können. BArbBl. 10/2002 S. 67 http://www.baua.de/prax/ags/trgs.htm Ullmann: Ullmanns Encyclopedia of Industrial Chemistry. Vol. A 11, Fibers, 5. Synthetic Inorganic. 5. Auflage, Weinheim: VCH Verlagsgesellschaft mbH, 1988 VDI 2578: Emissionsminderung – Glashütten. November 1999 VDI 3457: Emissionsminderung – Anlagen zur Herstellung von Mineralfaserprodukten. September 1994 VersatzV: Verordnung über den Versatz von Abfällen unter Tage (Versatzverordnung) i. d. F. vom 24. 07. 2002, BGBl. I S. 283; in Kraft getreten: 30. 10. 2002 WHG: Gesetz zur Ordnung des Wasserhaushalts (Wasserhaushaltsgesetz) in der Neufassung der Bekanntmachung v. 19. 08. 2002, BGBl. I S. 3245; Stand: geändert durch Artikel 6 Gesetz v. 6. 1. 2004, BGBI. S. 2
Reference Sources ATV-DVWK-Publikationen: Deutsche Vereinigung für Wasserwirtschaft, Abwasser und Abfall e.V., Hennef DIN-Normen: Beuth Verlag GmbH, Berlin VDI-Richtlinien: Beuth Verlag GmbH, Berlin
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