Helsinki Airport is located in a watershed area – meaning that much of the rain that falls on the airport’s 300 hectares of covered land runs to local watercourses.
To minimise the adverse effects of the airport’s urban runoff on local water systems, Finavia carefully manages its runoff water according to its environmental permit.
“We need to temporarily hold the water so that is does not run into the watercourses all at once, which could cause erosion. We also treat the water to mitigate the impacts of aircraft and runway anti- and de-icing fluids on the local waters,” explains Finavia’s Environmental Specialist Tuija Hänninen.
Innovative water treatment under ground
Typically, floodwater is managed by keeping it in detainment basins. Helsinki Airport's basins need to be regularly emptied as permanent water structures could attract nesting water birds and increase the risk of birds colliding with departing and arriving aircraft.
Specialists from Sitowise and Finavia have together designed a novel solution for Helsinki Airport's water management, in which the runoff water could be treated underground. Above ground, the structure would look like an ordinary meadow, but below the surface it would hold a water cleansing system.
“The water is distributed to the area through piping. As it sinks through the ground structure, built from gravel and other soil material, the microbes in the ground clean the water. Afterwards, the clean water is led to the local watercourses through underground drains,” Hänninen says.
The planned underground water treatment areas would improve the condition of the nearby Kirkonkylänoja and Veromiehenkylänpuro streams.
“This treatment system is more effective than flood basins, as the soil has more biological activity hat decomposes the organic compounds used in anti- and de-icing fluids.”
A new solution under development
Currently, the right structure for Helsinki Airport’s new underground water treatment system is being developed in a study by Aalto University, as part of the New Smart & Clean solutions for urban runoff management project. According to Hänninen, this would be the first time such a solution is tested for airport urban runoff management in the Nordics.
A similar system is already in use at Heathrow, London, but there are no experiences of underground water treatment in Northern weather conditions.
“First, we have to test how this solution works in Finnish winter temperatures and for Helsinki Airport’s waters,” Hänninen says.
If everything goes to plan, the first pilot of the new solution would be built during 2019.
“Water management is a crucial part of Finavia’s environmental responsibility and we do our best to make sure the local waters are in the best possible condition. New solutions can help us improve our water management from its already good level,” sums up Hänninen.
