Man working with a geoprobe. Mads Tonnes Meldhedegaard (MMEL)

UV-light tells the tale of contamination on Søndre Harbour in Køge

A measuring probe drilled 11 meters into the ground gives a hitherto unseen precise image of contamination and residual chemicals in the ground. This is beneficial to Køge Kyst, as new attractive residences are scheduled to be built on that very ground.

30. Oct 2019

A drilling – called a geoprobe – is in the process of hammering a measuring probe through the soil layers at Køge Kyst. Here the ground is especially contaminated as a result of a previous chemical factory, which has left a significant amount of chemical residue in the ground.

A tattle tale in the form of a lightning source is placed on the probe, transmitting UV-light. The light causes contamination of hydrocarbon in the ground to illuminate, where after a camera detects the signals. The camera is connected to a computer, which generates charts showing what the probe encounters and how substantial the level of contamination is.

Project manager for Køge Kyst, Lene Jensen,  has high expectations for this inspection method, which ensures an immediate image of the contaminated areas. It is thereafter possible to execute a precise and thorough remediation of the ground, and obtain a paragraph-8 permission in accordance with the Soil Pollution Act. This permit allows Køge Kyst and Pensiondanmark, who have bought the beach side areas, to commence the construction of residences on the contaminated soil.

No residual contamination allowed.

“During the past year, we have used traditional measuring methods, but now we need to inspect the soil even more precisely to make sure we remove all contamination, without excavating or remediating more soil than necessary. This method has been very beneficial on this project, as it has identified the highly contaminated areas with great accuracy,” Lene Jensen says.

“We are examining how far reaching the contamination is, to know where and how deep we need to drill. It is all about collecting knowledge on the extent of the contamination and the way in which it has spread,” says Søren Helt Jessen, Market Director in NIRAS.

The examined ground is a part of the old industrial area in Køge Harbour, which is being turned into a new city district with green areas and ocean views.

“And for the residences to be great, healthy, and attractive for people to live in, we need to ensure that the soil is remediated thoroughly without any residual contamination. This is the work we are in the process of completing during the next year,” Lene Jensen says.

Faster, cheaper and more accurate.

A chart on the computer screen is showing what the probe encounters and how substantial the level of contamination is.

“It is quite amazing that we can track how the contamination has spread live” Søren Helt Jessen says, and continues:

“This means that we are able act in accordance with the results and thereby strategically place the next drilling, resulting in a decreasing need for traditional soil samples. Consequently, soil inspections become much more accurate, faster and cheaper when we receive the data immediately,” he explains.

Want to know more?

Søren Helt Jessen