The aim of this research was to elucidate the role of physicochemical processes, such as adsorption, ion exchange, and others, conducted on natural substrates/minerals (soil, underwater deposits) and the potential utilization of these materials as a support for microorganisms responsible for self-purification effects in aerobic and anaerobic processes, both in laboratory conditions and in WWTP. The investigations encompassed the study of the sorptive properties of fractions obtained from underwater sediment as well as the adjacent soils of the Ghidighici Lake in the Republic of Moldova, from which a sediment sample was extracted. The hydrologic basin surrounding this lake primarily consists of “Chernozem” soil, from which this specific sample was collected. Following selective sedimentation separation, five mineral fractions (Coarse Calcareous, Heavy Sandy, Semi-Heavy Sandy, Argillo-Sandy, and Clay, also referred to as organo-mineral, and the Nano-Clay fraction, highly hydrated, also named as “peptizing”) and two organic fractions (Coarse Organic and Medium Organic) were obtained. To highlight the composition of the soil and underwater sediment, the samples underwent X-ray analysis using the Dron UM-1 refractometer with a FeKα detector. Each tested fraction was obtained in a dry form. The same amount of 50 mg was taken for each fraction, to which 40 mL of previously tested distilled water was added as a reference sample. Each of the fraction samples was subjected to multiple titrations, resulting in the generation of curves for the seven fractions. The clay fraction contains higher quantities of carbonate minerals and humified organic matter. The medium clay fraction exhibits remarkable buffering capacity compared to the other fractions. In terms of sorptive qualities, the soil and sediment samples are very close in values. In one of the major fractions, medium clay, the organo-mineral complex washed from the soil was accumulated. Different concentrations of dye were also used in the experiment, with the same volume, while fractions separated from underwater sediments from the Ghidighici Lake, obtained through consecutive sedimentation, served as adsorbents over time. After contact, the adsorption systems (dye solution + sediment fraction) were subjected to centrifugation, separating the solution from the solid adsorbent. Equilibrium concentrations of the dye in the solution were measured and then compared with the initial concentrations, prior to adsorption. This revealed a sequence in increasing order of adsorptive properties (Medium Clay, Argillo-Sandy, and then Semi-Heavy Sandy). The most hydrated, finest fraction was chosen from the obtained fractions and named “peptizing”. A solution of cetylpyridinium chloride (CPir) C21H38ClN at a level of 6 - 10 mol/L was used in the model. The experiment demonstrated a very efficient separation of this surface-active substance. Upon fixation of CPir on the hydrated fraction, significant sedimentation properties were acquired, leading to complete separation within five hours. The capture efficiency of this fraction exceeded 2.6 mmol/g of CPir. This process helps to understand the self-purification process in the water-particle (hydrated clay) suspension system. A similar fixation and purification effect is presumed to occur in WWTP.