Remediation

NOAH has special expertise and documented methods for the treatment of heavy metals in general and mercury pollution in particular.

Contaminated ground

NOAH processes and deposits all types of inorganic environmental toxins in condition class 2-5, as well as hazardous waste. We have a very robust reception solution for contaminated masses from all over Norway and the rest of Scandinavia. Langøya is advantageous for shipping large quantities of contaminated mass when the projects are large and require efficient logistics. NOAH has agreements with several shipping companies and we adapt individual reception solutions along the entire Norwegian coast. Our logistics solutions ensure our customers efficient implementation and progress, adapted to the clean-up project's plan. In the harbor of Oslo, we have established our own tipping ramp which contributes to a very efficient and safe loading of the boats. NOAH also has a mobile tipping ramp that can be used for large and demanding projects. Transport of contaminated masses by sea relieves traffic in the cities and contributes to a very environmentally friendly logistics solution.

NOAH also accepts smaller volumes of demanding contaminated mass via truck transport. We have our own ferry which ensures that the cars are delivered to the island at the agreed time.

Annually, NOAH receives over 300.000 tonnes of contaminated mass. We process contaminated mass from demanding clean-up projects in most Nordic countries.

Construction and demolition waste

Remediation of old industrial buildings often results in waste fractions with a high content of e.g. heavy metals and organic pollutants such as PCBs. NOAH's treatment facility for hazardous waste is unique in the Nordic context and ensures a predictable solution for the customer. Typical waste fractions that NOAH receives and processes are concrete, brick and lightweight concrete. There can also be waste in the form of asbestos, steel constructions and other plastic/rubber constructions that are not degradable. We are happy to consider waste beyond what is mentioned.

NOAH's treatment method on Langøya involves the stabilization and breakdown of environmental toxins. The methods are well documented for all types of pollution we receive.

Alum slate

The alum slate NOAH receives constitutes ordinary waste and is stored in its own cells. The cells are encapsulated with basic sealants in layers of half a meter on all sides, and finally covered on top. The alum shale landfill is closely monitored and poses no danger Langøya or surrounding areas.

What is alum slate?

Alum slate is an acid-forming type of slate and is the rock that makes up large parts of the inner Oslofjord. Alum slate is what many of our houses are built on. Alum shale contains a lot of iron sulphide. It is important that the slate does not come into contact with the oxygen in the air and water, as it will weather over time. This means that the iron sulphide oxidizes, which further leads to the formation of sulfuric acid. In other words, the shale is acid-forming.

The shale can also contain heavy metals, such as zinc and copper, as well as uranium. Uranium is a heavy naturally occurring metal found in the earth's crust, with a content of 2,3 - 2,7 mg/kg.

NOAH's measurement program consists of water analyzes that are collected quarterly and sent to IFE and NIVA for analysis. Measured amounts of radiation activity are reported annually to DSA (Directorate for Nuclear Safety and Radiation Protection).

Uranium has no stable isotopes, therefore it is called radioactive. It is common to measure radiation on the most stable forms of uranium 238, uranium 234 and uranium 235. When uranium breaks down, the gas radon is also formed. Radon is found everywhere around us, but mostly in small concentrations. Most people are familiar with this gas, which arises from alum shale in the ground, and you do not want this to occur in excessive concentrations in and around residential buildings.

The acid-forming process generates heat and the temperature can build up over time, and can self-ignite if the temperature reaches a few hundred degrees. NOAH therefore covers the alum slate with basic masses with a low ability to penetrate so that oxygen from air and water will not get in. We monitor and analyze our process water for uranium and other heavy metals.

What is dose rate?

Dosate says something about how much radiation is absorbed and which can cause damage, for example to the human body. The Institute of Energy Technology (IFE) has calculated the dose rate at a distance of 10 meters above deposited alum slate that is not covered on Langøya. The dose rate is found to be very low and with coverage the dose rate is almost equal to zero, or not measurable.

The radiation dose from a car with crushed alum shale is far below the dose limit for the public of 1 milliSievert per year (mSv/year). Based on emission quantities and limits, we have calculated the maximum radiation dose to the public at 0,91 microSievert per year.

In comparison, an X-ray at the dentist will give a dose of 2 mSv/year and a flight from Oslo to Trondheim will give a dose of around 10 mSv/year.

Table 2. Activity in waste deposited on Langøya in 2020 and accumulated from 2010 to 2020. 

Total deposited in 2020			Deposited at Langøya accumulated 2010-20
Nuclides		Unit		Unit
40K	106250	MBq	444 208	MBq
210Pb	116303	MBq	369 345	MBq
226Ra	116303	MBq	374 011	MBq
228Ra	5510	MBq	21 567	MBq
228Th	5510	MBq	20 905	MBq
230Th	116303	MBq	374 011	MBq
232Th	5510	MBq	32 311	MBq
234U	116303	MBq	374 011	MBq
235U	5361	MBq	17 018	MBq
238U	116303	MBq	460 315	MBq

Measurement and monitoring

NOAH carries out radionuclide analyzes on the received masses in accordance with the requirements of permit TU17-10. This means that the number of Bequerels found in the rock masses is measured. It is analyzed for certain radioactive nuclides of uranium, thorium, radium, potassium and lead.

NOAH also has a self-initiated action-oriented monitoring program for Langøya in both the South and North Quarries where alum shale has been deposited. In practice, this means that sediment measurements, temperature monitoring and chemical methods are used to control possible leaching of radioactive nuclides. As part of the monitoring program, NOAH measures radioactivity in the seawater, mussels that we put out around the island, in addition to the sediments (seabed) around Langøya. The areas we collect samples from are the same from year to year, measured with GPS and carried out by an external consultant. The samples are taken and sent to external, accredited laboratories at home and abroad for analysis.

Analyzes of radionuclides in 2020 show similar levels that have been observed in previous years in both sediment and seawater. Results from the 2020 monitoring do not indicate that emissions from Langøya affects life in the sea to some extent.