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How NOAH processes the inorganic hazardous waste

NOAH’s process neutralises acid waste with alkaline fly ash and other alkaline waste. A neutralization process is used to turn this into gypsum residue, which does not pose any risk on the surrounding environment.

The neutralization treatment process is planned to continue to take place at Langøya off the coast of Holmestrand. If the authorities grant permission, gas-free and stable gypsum residue will then be stored in the Dalen mines in Brevik.

The treatment process on Langøya is based on a neutralization process between the acid waste, the alkaline fly ash and other alkaline waste. The end product is a stable gypsum residue in which the hazardous substances are bound in a new chemical composition. The processing of the hazardous substances results in permanent chemical changes. This means that water ingress into the waste disposal site over time will not cause the environmentally hazardous substances to dissolve again.

Preventing gas

During the neutralization process, hydrogen gas is formed. This is not an issue, since the gypsum residue is stored in the open air. Since NOAH started using this process, it has been developed and improved regarding the off-gas. This has been thoroughly tested and verified through full-scale tests. A gas-free end product is a prerequisite for final disposal in Brevik.