Clean water is a scarce resource, and since 1989 RGS Nordic has purified more than 5,000,000 tonnes of water to be included in the circle of nature again. We purify water which is too contaminated for public wastewater treatment plants, and we have the skills and the plants to ensure that the water can be discharged without harming nature.

As the environmental requirements are increasing in society, the documentation requirements from the authorities are increasing as well. At the same time, more of our customers need to document that their wastewater is actually purified from harmful substances and not just diluted with clean water so that it formally complies with the discharge limits.

We have dedicated ourselves to meet this need of documentation. Not because we previously needed or still need to change our purification methods. Our wastewater treatment plants have always purified water by removing harmful substances, no by diluting them and they also will in the future. Full transparency is the best policy – both for our customers, for society and for us.

We believe that the best competitive parameter for environmental companies is to solve the problems in the best possible way – not to cut corners to beat the competitors on pricing.

In Stigsnæs, Scandinavia’s largest commercial biological purification plant for industrial wastewater, we have specifically established a monitoring facility with a measuring method called mass balance.

In brief, this means that we measure the weight of the harmful substances in the water we receive where it then undergoes our treatment process. After the biological treatment, we measure the weight of substances - both in the sludge released and the water which is taken to the next purification step in the carbon filters. When the water is purified in the carbon filters, we will measure the weight of substances in the water once again.

Thus we are able to document how large amounts of harmful substances that are removed during the two purification steps. Moreover we can document how efficiently we remove the substances and the content of the water we discharge after the purification process. In that way we make sure that the water has been purified efficiently, and that it will not have a negative impact on the environment or nature.

So far this measuring method has been conducted on a project basis, and further investments are required for a full-scale implementation at all plants. We expect that this will be achieved within the coming years.

Documented water purification removes contamination


The water is purified in a process consisting of two main steps. A biological step with an active sludge plant a physical and chemical step with an active carbon filter. The first step conducts the primary purification. For some substances, however, a secondary treatment may be required in the active carbon filter.

The figure below is based on an example of when we receive wastewater contaminated with PFOS. Thanks to mass balance, we can document the amount of removed substances before the water is discharged. This example corresponds to our actual purification activity for the total content of organic matter (COD) and for the substance PFOS.