NOAH receives and treats different kinds of hazardous waste and contaminated soil. All waste material is stabilized before being deposited below sea level in a former limestone quarry.

Besides being a modern industrial plant, NOAH is also responsible for the rehabilitation of the old limestone quarries and for rebuilding the island of Langøya to a safe and useful place.

Local and national authorities have expressed the intention to rebuild and recycle the island for future recreational purposes. The local population consider Langøya to be a valuable recreation area, now and in the future.
At Langøya NOAH is annually treating 300 000 – 400.000 tonnes of inorganic hazardous waste. In 2001 this included 90 000 tonnes waste containing mercury. According to NOAH’s in-house developed treatment method, inorganic hazardous waste is mixed with lime and gypsum and transformed into a chemically stable matrix.

The stabilized gypsum is deposited below sea level in old limestone craters and thus the wounds after 100 years of mining are being healed.
The industrial plant at Langøya is complying strictly with ISO 9001 and is also certified according to the EU EMAS-system. The organization consists of highly qualified personnel with a background in chemistry and other fields.

 

Stabilizing hazardous waste containing mercury

NOAH receives and treats different kinds of hazardous waste and contaminated soil. All waste material is stabilized before being deposited below sea level in a former limestone quarry.

Recycling waste sulphuric acid from the pigment industry mixed with limestone (extracted) from Langøya produces a special type of gypsum. This material absorbs heavy metals and mercury well.

The absorbing effects of this gypsum may be compared to amalgamation and reduces the solubility of mercury by 20-30 times.

Analyses of processwater from this treatment show low values for dissolved mercury – between less than 0,1 µg/L and 1 µg/L. This verifies the suitability of the method. In addition, the plant has its own water purificationsystem with total control of all water discharged to sea.
Many years with high pressure within the gypsum deposit has resulted in the mineralization of heavy metals and a reduction of permeability (Report from Norges Geotekniske Institutt, NGI). Several years of monitoring the stabilized gypsum has verified these positive effects.

This method also reduces the risk of methylmercury formation due to the strong absorbtion of mercury and the high content of alkali in the gypsum. (Report from NGI, Jan. 2001).

Waste from demolition and contaminated soil may also be shipped to Langøya, either by boat or truck (lorry). All waste received at NOAH is thoroughly analysed and tested for compability with the NOAH gypsum.
Analysis and monitoring processwater and surplus? surface water is made by NOAHs own laboratory.