5 4 Wastewater produced by the European production units At present 18 of the 42 European production units (breweries, malting plants and soft drinks factories) have an on-site wastewater treatment plant. Five production facili ties make use of an on-site anaerobic pre-treatment system (4 anaerobic plants and 1 aerobic plant), followed by an external post-treatment. At 13 locations the waste water is discharged to surface water after treatment. In 10 cases this involves aerobic plants; in 3 cases the water is treated by anaerobic and aerobic plants. At the remain ing production units (24) wastewater treatment is carried out by a third party. 5.4.1 COD and suspended matter in the breweries' wastewater We inspect the quality of the wastewater by carefully monitoring the quality and com paring the results of our measurements with pre-set indicators. The COD parameter is used as the measure for the organic pollution of our wastewater. The quantity of was tewater and the pollution load are largely determined by the individual breweries. The total COD of the 42 production units before treatment amounts to 63.4 thousand tonnes, of which 39 thousand tonnes are treated in our own treatment plants. The pre-treatment COD efficiency is 60-80%. The aerobic and combined anaerobic and aerobic systems have a COD efficiency of around 97%. The final amount of COD discharged by the latter systems was 680 tonnes. The treated wastewater also contains small amounts of suspended matter. A total of 385 tonnes was discharged into the surface water. The specific COD (KgCOD/hl) of the wastewater prior to treatment is an indica tion of good housekeeping within our breweries. Since 1997 the specific COD has remained more or less stable. Total COD before treatment all production units kg COD/year 0 20,000,000 40,000,000 60,000,000 80,000,000 1999 63,442,130 1998 1997 HEINEKEN ENVIRONMENT REPORT 1998-1999

Jaarverslagen en Personeelsbladen Heineken

Heineken - Milieuverslag | 1998 | | pagina 52