In a recent R&D project, an innovative biofilm micro-carrier was invented by Inno-Water Inc., that has a much smaller size compared to the traditional carriers. In this article, we show the capacities and structure of a new wastewater treatment system, that contains this new type of biofilm carrier. The “MICROBI” technology has an average of 99,4% ammonium, 94,3% COD, and 75,0% total nitrogen removal rates in municipal wastewater. During the period of bacterial colonization, we measured chemical parameters (COD, NO3-N, NO2-N, PO4-P, NH4-N) of the inflow and effluent twice a week for seven weeks. After that, a 24-hour measuring campaign was carried out to determine the full capacity of the system. Simultaneously we measured dissolved oxygen, pH, temperature, and conductivity in the reactor, and monitored the development of biofilm on the carrier with the light microscope and TTC colouring method. The results show a significant nitrification ability and high COD and ammonium removal at an inflow of 27-28 m3/day. Future improvement plans include the optimization of denitrification and increasing the daily wastewater treatment capacity.