Most of the wastewater generated at the airport is of a communal nature, coming from the hygiene facilities of airport buildings and aircraft, and requires no special pre-treatment prior to entering the sewage system. Facilities which generate technological waste water (kitchens and catering technology) are equipped with local pre-treatment systems, such as oil-fat separators. Wastewater generated in workshops, during the washing of aircraft or in the course of other technological processes is also pre-treated, until its quality enables discharge into the communal sewage system.
Separate sanitary sewer systems have been built at the airport. Rainwater from the vicinity of Terminal 1 flows, via a gravity drainage system, into the mine lake located at the airport, and is then pumped, via a pressurized sewer, into the gravity water drainage system operating at Terminal 2. From there, rainwater is channeled via a gravity conduit into canal number 171 and 17. Canal 17 flows into the Maglódi canal, which in turn is a tributary of the Gyáli creek.
Some of the liquids produced during aircraft de-icing within the area of Budapest Airport become mixed with precipitation, and thus end up in the rainwater drainage system. During winter weather conditions aircraft de-icing is indispensable, since ice forming on the various accessories of aircraft endanger aviation safety. Liquids originating from aircraft de-icing may greatly reduce the concentration of solute oxygen in water, since their biochemical and chemical oxygen demands are high. This means that during the biological or chemical decomposition of de-icing substances in water, oxygen reacts with organic compounds, and is discharged from water together with them. Consequently, the addition of the de-icing substances to water could result in the death of organisms living there.
In order to protect nearby natural waters, notably the Gyáli creek and other hydrological basins, Budapest Airport operates a total organic carbon (TOC) monitoring station, which channels rainwater in accordance with organic content. If the concentration of organic matter exceeds the relevant threshold, the facility directs rainwater into the sewage system of the airport, thus protecting natural waters.
Self-control, i.e. tests of the components of discharged wastewater, is performed on a quarterly basis. Based on the results we can conclude that the quality of discharged wastewater complies with the thresholds prescribed by applicable legal provisions.