DISPOSAL OF DE-ICING EFFLUENTS BY IRRIGATION
ZURICH AIRPORT

At Zurich Airport alcohols, as well as formates, are utilized for de-icing in order to maintain the air traffic during winter.

To purify the accumulated de-icing effluents, JUNGO ENGINEERING LTD. has developed a new and groundbreaking method which has been successfully applied since winter 2000/2001. The de-icing effluents are irrigated onto the surrounding green areas and decomposed by microorganisms in the soil in a natural way.

The de-icing effluents are collected in storage reservoirs where pumps feed them into the irrigation system. A total of 20 ha (50 acres) are equipped with heated pop-up sprinklers.

The largely automated procedure is computer-controlled (local and/or remote), monitoring the degradation performance and supplying us with data for an optimum operation.

Experience verifies that the irrigation technique is effective even on snow (pict. 1). The carbon degradation performance (DOC) of the previous six years lies between excellent 98.3 and 99.8% (fig. 1) and is comparable at very low temperatures. It has never been lower than 97.8% (fig. 2).

The main advantages of this technique are:

-  Cost-efficiency (investment and maintenance)
-  Only small size reservoirs are required
-  Proven on snow and at low temperatures
-  Environmentally friendly and innovative, so enhancing the airport's public image

We watch nature closely at Zurich Airport, learn and copy. A major part of the de-icing effluents are unintentionally being blown over the surrounding fields by the air traffic but nevertheless no increased impact was detected in the ground water. It is therefore reasonable to distribute the rest of the effluents onto the surrounding green areas where they are decomposed by microorganisms in a controlled, sustainable and economic way.

We were awarded the contract following a competition.