Protecting Areas of Water and soil

Stretches of water and the soil are almost inextricably linked to each other as parts of the natural ecosystem and have a mutual effect on each other. Protecting them when operating the airports is an important matter for us, because they form the basis for people’s lives and act as a habitat for animals and plants.

Stretches of water in the sense of water law include all the sources of water above ground as well as groundwater.

Soil in the sense of the Soil Protection Act is the uppermost layer of the earth’s crust.  

Our goal is to safeguard the functions of these connected parts of the environment in the long term and avert any damaging changes, among other things, by tracking the “soil-groundwater” impact route. As a result, protecting stretches of water also creates opportunities for protecting the soil.

The water and waste water cycle

At first sight, an airport appears to be subject to the same water and waste water cycle as any other manufacturing company or service provider. This may well be largely true in terms of the drinking water and waste water cycle. However, there are some special operating circumstances for waste water. Managing rainwater is also very important, given the enormous operating space that the two airports use.

Both the airports are connected to the waste water network of the relevant cities (Dresden and Leipzig) via a separation system.

  • Waste water from kitchens, workshop areas and vehicle washing facilities is pretreated before being fed into the waste water sewer system, e.g. with the help of grease or light liquid separators.
  • Waste water from the terminal and office buildings is handled in a similar way to domestic waste water.
  • The waste water from aircraft largely involves waste water from the toilets. The solid materials are removed at a toilet waste collection point in DRS and the liquid is then fed into the waste water network. The toilet waste water is stored temporarily at a collection point in LEJ. It is regularly emptied by a vacuum tanker, which then transports the waste water to a treatment centre.  

The waste water is finally treated at the municipal sewage treatment facility at Dresden-Kaditz and at Leipzig’s largest waste water treatment centre at the Rosental purification plant. 

The following description about draining surface water is in part very specific to the local airport site because of different legal requirements, different procedures at the facilities caused by the infrastructure and the regional differences at the two airports. 

The rainwater at Dresden Airport is collected in drainage systems and either fed to the stretches of water above ground or to the municipal rainwater network – or it just seeps away naturally. The rainwater retention basins, which exist in all the drainage areas, reduce the peak discharge from the paved surfaces into the stretches of water. 

Regenrückhaltebecken Dornbuschgraben, Flughafen Dresden (Quelle: Gewässerschutzbeauftragte DRS)

It is not possible for the water to seep away at Leipzig/Halle Airport because of the nature of the soil there. A sophisticated system is used to drain the surface water from the paved areas on the two runways. This includes slotted channel collectors, channels, hollows and drainage trenches along the airport operating areas. All the rainwater is collected in the drainage systems, subjected to quality checks and is fed into sedimentation tanks, if necessary. It is then fed into the surrounding streams in small doses via the rainwater retention basins further downstream.

In general terms, the quality of the rainwater that is collected depends greatly on the way that the individual surfaces are used (roof areas, car parks, roads, handling areas for aircraft, taxiways, runways). Light liquid separators for all the relevant areas at both the airports ensure that any residual amounts of operating materials, which are still present in the rainwater, are removed.

The airport is able to control and manage the drainage systems using the latest computer technology. As a result, it is possible to create a reliable system for the soil and the surrounding stretches of water in many different ways:

  • protection from flooding through storing and releasing water in a regulated manner if the rainfall is persistent
  • protection from feeding hazardous substances into the surrounding streams by isolating the retention basins

Special requirements for feeding rainwater into stretches of water exist to protect against disasters. The following measures have been adopted:  

  • The area where the tank storage facility is located is connected to the drainage system using a protection system consisting of light liquid separators, retention areas and gate valves.
  • All the storage facilities for substances that pose a threat to water supplies, e.g. diesel fuel, de-icing fluid and extinguishing agents, fulfil the strict technical requirements and those contained in environmental law.
  • Rainwater from apron areas, where aircraft are fuelled and prepared for departure, is purified before being fed into rainwater sedimentation tanks.
  • The entire drainage system for the airport operating areas can be blocked off by gate valves, if a disaster occurs. Any contaminated water is retained in overflow channels or retention basins, if this is the case. It is therefore possible to dispose of it properly after appropriate separate tests have been performed.

The rainwater from about five hectares of roof surfaces is collected in water tanks at Dresden Airport and is fed to the consumer facilities that are spread over the entire airport site via a circular pipeline. This water is then used in toilets, air conditioning units, as fire-fighting water, to clean drains and to water green spaces instead of drinking water.

Precautions to protect stretches of water and the soil

In addition to its primary task of fighting fires and handling disasters, the airport fire brigade is responsible for protecting the soil and stretches of water (particularly during any disasters). This means that the airport fire brigade is always present with an environmental heavy rescue vehicle, for example, if any fuel reaches the concrete surfaces despite operators using the standard drip-free fuelling operations. If this occurs, the fluid that has leaked is treated using binding agents or the airport fire brigade soaks it up using a special machine prior to its professional disposal. If required, we use road sweepers provided with oil spill removal equipment at both the airports in these kinds of situations.

The airport fire brigade, surrounding local fire brigades, the Federal Agency for Technical Relief and the oil emergency teams work all cooperate if an emergency occurs in line with an emergency plan.

Environmentally-friendly winter services

The winter services at both the airports also ensure a clean environment, thanks to the modern equipment in use. The aim is to primarily guarantee flight safety without using any chemicals. If required, that is to say, if the weather conditions are unfavourable, biologically degradable de-icing agents based on formate are used to de-ice air traffic areas.

The aircraft are de-iced with a mixture of glycol and water on parking stands, some of which are separate. It is then possible to deliberately collect any excess de-icing agent, feed it into underground containers and then dispose of it professionally or feed it into the waste water network.

Snow desposition, Dresden Airport

Using de-icing agents economically as well as using environmentally-friendly materials are operating measures that are designed to reduce the pollution levels in stretches of water. A black ice early warning system constantly monitors the state of the runways. Thanks to being able to use surface de-icing agents as a precautionary measure because of this, it is possible to significantly reduce the quantities used. 

The de-icing systems have been improved at LEJ by placing the de-icing areas right next to the taxiways leading to the runways. It is then possible to de-ice the aircraft directly before they take off, so that fewer de-icing chemicals are required.

Technical measures supplement the operational ones. A process management system technically measures the quality of the run-off water and the filling levels in the rain retention basins. If the qualitative thresholds for feeding in surface water into stretches of water without causing any damage are exceeded, the rainwater, which contains some de-icing agent, is fed into the municipal waste water network. This waste water is then treated at the sewage works in Dresden-Kaditz and at the Rosental water treatment centre in Leipzig.

Any snow, which is contaminated by de-icing agents, is collected on separate paved areas at Dresden and Leipzig/Halle Airports and the melted water is fed into the waste water network.

Measures to improve the protection of stretches of water

The airports have adopted various measures to minimise the contamination of stretches of water resulting from airport operations and so improve the protection of sources of water. They include the following measures:

  • Minimising the rainwater drainage from the airport operational areas by constructing new rainwater retention facilities and having seepage troughs along the runway (DRS)
  • Delaying and pre-treating the run-off water by constructing new rainwater retention basins with a retention base filter (LEJ)
  • Using de-icing agents for aircraft and air traffic areas economically and draining rainwater, which contains any de-icing agents, into the waste water network of the cities of Dresden and Leipzig to prevent any contamination of the flood protection areas (LEJ and DRS)
  • Reducing the consumption of drinking water, among other things, by building and operating a rainwater usage system (DRS)