The WasteWater Treatment Plant (WWTP) of the Municipal Enterprise “Apă-Canal” Măgdăcești, of type Moving Bed Biofilm Reactor (MBBR) was conceived, designed and built for the treatment of domestic wastewater, coming from the households of the inhabitants of the Măgdăcești commune. For a good efficiency, under normal operating conditions in the technical project documentation of the station was established a flow of wastewater for treatment (influential) of 15.5 m3 /h, with a chemical oxygen demand (CODCr) of no more than 650 mgO/L. However, under real operating conditions, there are often a number of factors that seriously affect the technological process, resulting in the discharge into natural reservoirs of effluent with a low degree of purification, including: reduction of the effective surface of biofilms due to uncontrolled filling losses, wear and clogging, reduction of aeration intensity, decrease of aerated layer height, increase of water velocity through interlamellar spaces, oscillations of base index values, change in the composition of organic pollutants, etc. All these factors, but also other complementary lead to a decreased efficiency of the process. Currently, WWTP Măgdăcești faces also deficiencies such as those mentioned above, as a result of which the pollution of the Ichel River occurs through discharges of insufficiently treated waters. At the same time, toxic gases with an unbearable pestilential odor are spreading in the environment. Apart from the Măgdăcești commune, in the Republic of Moldova there are several localities where there are operating treatment plants of the same type (MBBR), all facing problems of the same nature and are looking for solutions to remedy the situation. One of the solutions can be the discharge of non-compliant effluent into biological lakes, which, forming a waterfall of two or even three units, act as a buffer to reduce the concentration of pollutants, running concomitantly a natural process of tertiary treatment: sedimentation, anaerobic decomposition and natural oxidation of the remaining organic pollutants, most of them water-soluble. In order to elucidate the causes of low efficiency and to elaborate some technical recommendations, meant to ensure the good functioning of the WWTP Măgdăcești, based on the Agreement of scientificpractical collaboration of the Măgdăcești City Hall with the Institute of Chemistry of the Republic of Moldova, a series of field investigations were performed.