Municipal: Elverom, Norway


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Project Name:
Elverom RA

Nordre Land Kommune, Norway

Type of Plant:
Municipality - RBC Retrofit

Technology Used:
Biowater CMFF® Biofilm system

Biomedia Used:
Biowater BWT-X®

Operational Since:
July 2011


The Challenge

Nordre Land Kommune, Elverom, is a small municipality located in Norway approximately 14 miles North of Oslo. Elverom had two Rotating Biological Contactors (RBC’s) which did not work properly, were noisy and had odor issues. The required maintenance for the RBC’s had become overwhelming. Elverom wanted to change over to an biofilm technology because of it’s ease of operation and ability to retrofit into their existing tanks.


The Design

After researching various options the municipality decided on the Biowater CMFF® biological process. The Biowater CMFF® is based on the use of suspended biofilm carriers. The surface of the biofilm carriers provides a protective area for the biology to grow. Among the many benefits, the biofilms can handle extremely high loading conditions without any problems with clogging or shock.

The new plant design included two reactors in series, an aeration system, biomedia, blower, sieves, mixers for flocculation and all piping.

In the summertime when the temperature is higher (from 15oC to 20oC) and the bacterial activity is increased we have made it possible to bypass Reactor 2 so that there will not be risk of Nitrifcation that may lead to floating sludge in the sedimentation.

In addition, since the walls of an RBC are sloping inwards, Biowater has a custom aeration system specially designed for use in RBC retrofits. The aeration system has two levels so it maintains even air distribution throughout the tank.



By choosing the Biowater CMFF® Elverom removed an average of 87% COD and 97% BOD. After the biological treatment stage, chemical precipitation and Sedimentation was used and the effluent is discharged directly to the Livasselva, which is a fresh water lake. The odor is gone and the system is running smoothly with virtually no maintenance.

The BioWater CMFF® biological process - a concept where moving plastic carriers with fixed biofilm remove organic and inorganic substances in the water.