Application of Floating Carriers in Two-Step Technology of Wastewater Treatment

This study finalizes a series of research previously conducted by the authors that aimed to apply polymer floating carriers for municipal wastewater treatment. A two-step technological scheme was applied, with a trickling filter reactor in the first step and an activated sludge reactor in the second step. Three types of floating carriers were applied in the activated sludge reactor. The study took three stages to pursue the goal of organic pollutant and nitrogen removal. During the first stage, only one of the three floating carriers demonstrated results that can be considered positive. Throughout the second and third stages, the technological parameters (modified treatment sequence and extended hydraulic retention time) were gradually altered to meet current regulatory requirements applied to discharged wastewater. The following pollutant values in the effluent were obtained after the third stage: BOD5 (2.3 mg/L), NH4 (0.4 mg/L), NO2 (0.1 mg/L), and NO3 (19 mg/L), with the filling ratio of the round-shaped polymer floating carrier being 20%.