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close this bookEnvironmental Handbook Volume II: Agriculture, Mining/Energy, Trade/Industry (GTZ, 1995, 736 p.)
close this folderTrade and industry
close this folder48. Glass
View the document1. Scope
View the document2. Environmental impacts and protective measures
View the document3. Notes on the analysis and evaluation of environmental impacts
View the document4. Interaction with other sectors
View the document5. Summary assessment of environmental relevance
View the document6. References

3. Notes on the analysis and evaluation of environmental impacts

The limits - based on TA-Luft (Technical Instructions on Air Quality Control) and TA-L (Technical Instructions on Noise Abatement) and other regulations - summarised in Table 4 for waste gas, dust and noise are now applicable in Germany and are being adopted in similar form by most European countries. The minimum requirements in Germany regarding treated wastewater discharged into receiving bodies of water are also indicated.

Table 4 - Limitation of hazardous substances under TA-Luft (Technical Instructions on Air Quality Control) and the 17th Administrative Regulation (VwV) according to § 7a of the Federal Water Act (WHG)



Glass industry


Direct discharger g/m3

Sample type

Indirect discharger3) g/m3

Dust Sulphur dioxide as SO2 Glass melting furnaces Pot furnaces and day tanks NOx nitrous oxide as NO2 Fluorides Chlorine Filterable solids Total suspended solids Chemical oxygen demand Antimony Arsenic Lead Cadmium Chromium Cobalt CyanideS2) Copper Manganese Nickel Palladium Platinum Mercury Rhodium Selenium Tellurium Thallium Vanadium Zinc Tin

SO2 NOx F CI TSS COD Sb As Pb Cd Cr Co -CN Cu Mn Ni Pd Pt Hg Rh Se Te TI V Zn Sn

50 1800 1100 400-3500 5 30 5 1 5 0.20 5 1 5 5 5 1 5 5 5 0.20 1 1 5 0.20 5

100 0.50 80 0.50 0.07 0.10 0.10 0.10 0.10 2.00

1) 2) 2) 2) 2) 2) 2) 2) 2)

50 1 1 2 0.50 2 0.20 2 3 0.05


May be formed in reduced burning


Chemical Oxygen Demand


Law applicable in the German state of Baden-Wberg


Total Suspended Solids Technical Instructions on Air Quality Control


Two hour mixed sample


Administrative Regulation


Random sample


Federal Water Act

Glass works, which are generally large-scale plants, produce considerable emissions. In principle a maximum of 1800 mg SO2Nm3 should be established as the mean guideline value for avoiding serious environmental pollution. The NOx emissions must not exceed the currently applicable values, and nitrate refining should be dispensed with because of the high NOx levels generated.

No separate wet or dry sorption plants are required to comply with these relatively high mean values. Accurate control of the tank heating is vital in order to attain the required values.

Fluorine and chlorine emissions which may give rise to direct damage must be kept as low as possible. The values indicated above can be achieved by suitable selection of raw materials and fuels and systematic monitoring of burner operation. A further benefit is that energy consumption can be further reduced by conforming to these guideline values, resulting in greater economy.

The dust emission from glass furnaces should not exceed 50 mg/Nm3. A dedusting plant should always be installed in order to comply with this limit.

It is vital to adhere to the emission limits for toxic dusts (heavy metals) such as cadmium, lead, fluorine, selenium and arsenic; the maximum values specified in TA-Luft must not be exceeded.

For individual substances, the Compendium of Environmental Standards contains notes on evaluating environmental relevance.

It is absolutely essential to comply with the regulations on permissible noise levels, since failure to prevent or protect against noise can result in permanent injury of employees.

To avoid environmental pollution, the limits laid down for direct water dischargers must be observed, particularly regarding heavy metal concentrations in the effluent.

If no national regulations exist, values in line with German or European standards should be established for the erection of new glass works, particularly in areas already suffering from serious environmental pollution. Special regulations must be introduced for plants already in operation. The parameters defined for the principal hazardous substances must in future be regularly monitored and disclosed by the glass works, so that appropriate steps can be taken immediately in the event of nonconformance (see 3.1).

For all practical purposes it may be assumed that in order to comply with the limits indicated all alkali borosilicate, borate, lead and most special glass furnaces must be equipped with dedusting systems. Allowance must be made for these dedusting and sorption systems as early as the planning phase.

In countries with low-cost electricity it is possible to construct glass furnaces of special design which produce far lower emissions and do not require expensive environmental protection equipment. The energy requirement per kg of glass can also be reduced by introducing such melting methods.

3.1 Inspection and maintenance of environmental protection installations

A control centre independent of the production process must be established to comply with existing environmental protection regulations. The responsible personnel must be enabled to perform and monitor all inspection functions including measurements relating to environmental protection in the works. They should be available for consultation on investments and take charge of negotiations with environmental protection authorities. Moreover, this department is responsible for ensuring that all environmental protection installations are regularly maintained and upgraded. This internal environmental department is also responsible for staff training.