Wpływ stałego pola magnetycznego na przemiany związków azotu w biologicznym złożu tarczowym

The processes of nitrification and denitrification are the most common and well-known methods of biological nitrogen removal from wastewater. Nitrifying bacteria are characterized by a low growth rate, a tendency to wash out from the reactors, which means that nitrification is the limiting factor in the course of the nitrogen compounds removal process. Therefore, it is necessary to keep a large amount of nitrifying biomass in reactors in order to ensure the proper level of nitrification efficiency. Previously performed researches have shown that the magnetic field can affect the growth of microorganisms and their ability to biodegrade contaminants. Application of a magnetic field enhances microbial activity, accelerates degradation of organic compounds and increases nitrification rate. Otherwise the magnetic field is beneficial for biomass biodiversity and abundance. The aim of this study was to determine the effect of magnetic field on the efficiency of organic compounds removal and nitrogen compounds transformations taking place in the biomass of rotating biological contactor. Investigations were carried out in a rotating biological contactor (RBC) working in a bench scale. Each section containedpackets of disks with a diameter of 0.22 m submerged in a semi-circular tank with a capacity of 2 L. Submergence of the disks was 40%. Disks rotated with speed of 60 rpm. The study was carried out using four RBCs – the first one was called the control unit, next three were under the influence of the magnetic field of 60 mT, 120 mT and 180 mT induction. Studies have shown that the efficiency of nitrification increased with growth ofmagnetic field induction. The magnetic field of 180 mT intensity increased nitrification efficiency significantly different, when compared with other systems, and was equal to 92%. Denitrification efficiency was the highest in the system, where the biomass was exposed to the magnetic field of 60 mT induction. Process efficiency decreased with increasing magnetic induction. Exposure of wastewaters and biofilm biomass in the magnetic field did not affect the statistical efficiency of the organic compounds removal. The highest percentage of COD biodegradation, on average 89.51%, was observed in a rotating biological contactor exposed to magnetic field of the highest tested induction.