7 NEW CONTRACT SIGNED Methane Quite a lot of water is needed to brew beer. For one litre of beer an average of seven to ten litres of water is requi red. Modern breweries use least water, the older ones use slightly more.The pollution of waste water is caused by what is referred to as "extract loss" .These are residues which are released during beer production, for instance when the brewery is being cleaned. What does Heineken do with that waste water? Achat with Mr. Klijnhout of the Water and Environment Department (the effluent specialist at HTB's Central Research). Buffer tank technologically) and, with it being a decomposition process, there is a risk of foul smells. Besides, anaerobic purification works best at 30 to 35 degrees Celsius. If the waste water has first to be heated to that temperature, a lot of energy will be needed. Anaerobic purification works best when there is a uniform supply of an (almost) constant quality of waste water. At a brewery the supply usually varies. "To solve that problem you need a buffer tank to equalise the flow of waste water from the brewery, and building such a buffer tank is a costly business", says Mr. Klijnhout. Naturally, both systems also have their advantages. "An aerobic system almost always works. You don't, as it were, have to keep an eye on the aerobic process itself. The advantage of an anaerobic installation is the limited space it occupies compared to an aerobic process. Besides, less excess sludge is produced. However, in return, you also get a limited degree of purification. The choice between aerobic and anaerobic will mainly be determined by the local circumstances in the brewery", concludes Mr. Klijnhout. Just one example: the aerobic purification plant installed at the El Aguila brewery near Madrid in Spain proved to be too small. An anaerobic plant, which is currently being started up, has been constructed upstream of it.The experience being gained in Madrid and in other locations will certainly be of great value to the Heineken group of companies as a whole. Since 1987 Heineken has been doing business with the Soviet Union. Every year Heineken negotiates a new contract for the following year with the central purchasing organisation Vneshposyltorg for the quantities of beer, soft drinks and distilled products to be delivered and the price. Also for 1988 a new contract was concluded. Mr. Kondratjev of Vneshposyltorg visited Holland late last year in order to have the contract signed. A rather significant part of the deliveries for this year will consist of soft drinks. These soft drinks are produced by Vrumona, Heine ken's soft drink factory. Heineken has built a number of bars in several cities in the Soviet Union. In these bars Heineken beer and the other contracted products are being sold. Part of the deliveries goes to these bars. Another part is destined for the big international hotels and tourist shops. From left to right (sitting): Export Director J. van der Zee, V.P Kondratjev, Vice President Vneshpolytorg, A.S. Peshkov, member of the Trade Representation of the USSR in the Netherlands(standing) J.M. Holthuizen, Managing Director Peja Export B. V (our agent in the Soviet Union), K. Brandt, Regional Export Manager and E.N. Bakker, Area Export Manager. Anaerobic purification is in fact a sort of controlled rotting. So it does not require any air (oxygen). During the process a gas is formed which consists mostly (but not entirely) of methane. Methane is a combustible gas which means a source of energy. Isn't it possible to make use of that energy? "It's a very appealing idea of course, but the quality of the gas emitted is not yet suitable for that; it is too wet and still contains some unwanted pollutants", says Mr. Klijnhout. Both forms of water purification have a substantial number of drawbacks. "For aerobic purification you need a big installation which requires a lot of energy (for the aeration) and produces a lot of excess sludge. In fact, most of the pollution is converted into bacteria (excess sludge). Quite large amounts are produced and these have to be properly disposed of: after all, we have the Heineken name to live up to!" An added drawback is that aerobic purification may lead to secondary environmental problems, such as noise, smells and flies. The five (anaerobic) reactor vessels in the pre-treatment plant near the El Aguila brewery inAlgete. Buffer tanks, services building and aerobic purification are not visible on the picture. Part of the (aerobic) water purification plant in Zoeterwoude. Activated sludge carries out its useful work in these tanks. Purifying waste water with or without oxygen? At Heineken care for the waste water only when it can no longer environment is of have any adverse effects on the paramount importance. environment. "At the moment we are More and more operating companies basically faced with a choice between are taking steps to discharge their aerobic and anaerobic purification. Both systems have great benefits but they also have their drawbacks", explains Mr. Klijnhout. In aerobic waste water purification the effluent in the water is broken down by bacteria which breathe oxygen and live in what is known as activated sludge.This activated sludge "digests" the effluent in the waste water, leaving clean water behind. Aerobic means that air (oxygen) has to be introduced into the process and this costs money. Activated sludge grows in volume during the purification process; the excess sludge has to be removed. That's an expensive operation! Aerobic purification takes up a lot of space and is a costly process in all respects, but it is one that produces a very good quality of purified waste water without problems: water that is even drinkable! Anaerobic purification, too, has its disadvantages. Although the process is fast-acting, it only gives a limited degree of purification. It is a highly complex process (both technically and

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Heineken International Magazine | 1988 | | pagina 7