1.1 Background of the study
The brewing sector holds a strategic economic position with annual world beer production exceeding 1.34 billion hL in 2002 (FAO Source, 2003). Beer is the fifth most consumed beverage in the world besides tea, carbonates, milk and coffee and it continues to be a popular drink with an average consumption of 9.6 L/capita by population aged above 15 (OECD Health Data, 2005). Waste in its solid, liquid or gaseous state could play a significant role in the deterioration of the environment if not properly managed. A large portion of the many environmental problems around the world can be narrowed down to inefficient waste management. Developed countries are steadily finding solutions to many of these problems.
The brewing process is energy intensive and uses large volumes of water. The production of beer involves the blending of the extracts of malt, hops and sugar with water, followed by its subsequent fermentation with yeast (Wainwright, 1998). The brewing industry employs a number of batch-type operations in processing raw materials to the final beer product. In the process, large quantities of water are used for the production of beer itself, as well as for washing, cleaning and sterilising of various units after each batch are completed. A large amount of this water is discharged to the drains. The main water use areas of a typical brewery are brew house, cellars, packaging and general water use. Water use attributed to these areas includes all water used in the product, vessel washing, general washing and cleaning in place (CIP); which are of considerable importance both in terms of water intake and effluent produced (van der Merwe and Friend, 2002).
Improper industrial and municipal waste management can lead to many forms of contamination, such as groundwater contamination, air quality deterioration, and greenhouse gas emissions (example, methane gas emissions from anaerobic decomposition). Industrial waste is the waste produced by industrial activity which includes conventional wastes and hazardous waste. Currently, industrial activities are the main sources of world’s hazardous waste production.