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Air & Water Emissions
Glass manufacturing is a high-temperature, energy-intensive activity that can lead to some release of pollutants to air and water, emissions of greenhouse gases, and, like almost all economic activities, generation of solid waste. Although an increased use of recycled glass reduces the consumption of energy and raw materials, it still requires extensive sorting and cleaning prior to batch treatment to remove impurities. While the glass industry develops products that can make an important contribution to fighting climate change and attaining CO2 emission reduction goals, glass producers are also keenly aware of the need for applying very high environmental standards in the glass manufacturing process.
The glass manufacturing process typically generates two types of air emissions: those originating from the fuel combustion in the glass-melting furnaces of the float lines (mostly sulphur dioxide, carbon dioxide, and nitrogen oxides) on the one hand, and, on the other, emissions generated by the vaporisation and recrystallisation of materials in the melt (for example heavy metals such as arsenic and lead).
The proposed revision to air quality legislation would, in its current form, introduce binding limit values for particulate matter. It may also entail stricter rules on monitoring and controlling particulate levels by EU Member States.
Directive 2008/50/EC set out ambient air quality standards and introduced binding limit values for the substances sulphur dioxide, carbon dioxide, nitrogen oxides and dioxide, carbon monoxide, benzene, ozone and lead. This Directive has merged most of the previous legislation into a single Directive, except for the four 'daughter directives'. These other directives also aim to harmonise monitoring strategies and measuring methods in order to achieve comparable measurements at the European Union level.
The most significant water use during the glass manufacturing process occurs during the cooling phase of the float process (and, in the glass recycling process, cleaning of used glass that has been crushed and is ready for recycling).
However, liquid effluents discharged from glass manufacturing are marginal when compared to other industrial sectors. Waste water may include soluble glass-making materials such as sodium sulphate, organic compounds from lubricant oil used in the cutting process, or treatment chemicals from the cooling water systems.
The Water Framework Directive establishes limits for permissible concentrations in surface water of substances believed to be harmful to animal and plant life in the aquatic environment and to human health. The list of priority chemicals substances should be reviewed and adpated every four years.