Water technology powered by nature

AnoxKaldnes is a world-leading supplier of biological water purification solutions for industries and municipalities. Our technology is found in more than 1,200 treatment plants worldwide.
Water technology powered by nature

Creating a better future is about finding workable solutions to concrete problems. It’s the starting point for everything we do at AnoxKaldnes.

The story behind our company began in a research laboratory at Lund University in Lund, Sweden, in the mid 1980s. Thomas Welander, a doctoral student, developed a new approach to wastewater treatment focusing on understanding nature's microorganisms and the formation of biofilms to optimize treatment.

Biological purification is nothing new. But what was pioneering with Thomas Welander's research is that he created environments for microorganisms to do the right things at the right time, and under controlled conditions. These new findings created commercial opportunities which is why Anox was founded. There was strong interest from various process industries with large water consumption where new, stringent environmental directives need to be followed, such as pulp and paper and pharmaceuticals where it was now possible to achieve effective purification of wastewater. 

At the same time, Professor Hallvard Ødegaard at the University of Trondheim invented a new method to increase the efficiency of biofilm processes in municipal wastewater treatment plants - MBBR (Moving Bed Biofilm Reactor). MBBR is based on small carriers made of plastic where microorganisms attach while the carriers are in constant motion. The plastic pieces are engineered to create spaces for the bacteria to grow. MBBR works so that the plastic pieces become a "mini-house". Professor Hallvard Ødegaard's invention led to the founding of Kaldnes.

Thomas Welander realized that the MBBR technology would fit Anox's water purification technology and the two collaborated. This led to Anox acquiring Kaldnes in 2002 and the new company was given its current name - AnoxKaldnes.



AnoxKaldnes is a knowledge-based company characterized by research and development. We are world leaders in our field, and constantly work on new innovations. We are also developing new technologies to remove drug residues found in wastewater through biological treatment.

A large part of our research is focused on the role that water treatment plays in the circular economy. The goal is to minimize energy consumption in treatment plants to generate an energy surplus that can be reused or sold.


Ak Lab

AnoxKaldnes Lab