New Biofilm Process for Biological Sewage Treatment

The MOFIX process is based on biofilm technology and has been developed and tested in a joint research project of GEA 2H Water Technologies (Germany) and the Martin-Luther University Halle-Wittenberg. A pilot plant was operated and tested in Halle (Saale), before being transferred and built up in Tunisia. Since 2008 a village of 200 inhabitants has used the plant for full biological treatment. The concept has meanwhile been implemented in several plants in Germany including a large well-known oil processing site in Germany.

MOFIX (MOving bed + FIXed bed) is a process combining both biofilm technologies. A special feature of this application is the denitrification in a moving bed as a first process step. Here random media is used a biofilm carrier. In the second step the final BIOD reduction is carried out in a submerged fixed bed, followed by an intermediate clarifier which eliminates excess sludge. Now the nitrification reactor follows, consisting of a 2-3-stage cascade equipped with a BIOdek fixed beds. A final clarifier removed solids before the water exits.

The denitrification reactor is equipped with Random Media BCN. A special agitator mixes water and the random media. Although moving slowly, the agitator develops a high stirring power with only low shearing forces, thus conserving the biofilm on carriers.

In the aerated zones only fixed bed consisting of BIOdek® structured packing is installed, because of the advantages of fixed beds. For the carbonaceous oxidation step BIOdek vertical flow fills type 2H KVP provide optimum features for discharge of the excess sludge.

For nitrification after intermediate clarification high specific surfaces of the BIOdek® fills provide high efficiency.

Intermediate and final clarification are equipped with TUBEdek® tube settlers. An efficient sludge removal is achieved by the chevron shaped TUBEdek® channels giving a multiplication of sedimentation areas in a small volume even with high recirculation rates.