Characteristics of a Ceramic Carrier after Wastewater Treatment Process in the Model Column Cascade with Ethanol Addition

Abstract

Nitrogen and phosphorus removal from wastewater remains one of the serious environmental problems worldwide. The present study was aimed at combining the both nitrification and phosphorus accumulation processes in the laboratory-scale model system. Synthetic wastewaters (28 mg N-NH L) were treated consequently in the cascade of three columns, which were designed for nitrification and phosphorus accumulation processes, respectively, and were packed with porous ceramic beads. Six treatment cycles of seven days in each column were performed. Addition of 3% ethanol to wastewater increased the efficiency of ammonium removal in the first column of the cascade during the 7 day period to 81.9 %, which was accompanied by a decrease of pH from 7.3 to 6.2. An increase of soluble phosphates was shown in Columns II and III of the cascade. Microbial enzyme activity, number of CFU and diversity of the microbial community differed among the three columns tested. The most active biofilm formation was detected in Column I. The thermal analysis of beads has revealed mass losses of 0.23% and 0.08%, due to decomposition of light volatile organic substances at 173 °C and 481 °C, respectively. In turn, the beads in Column II and III were not covered by thick biofilm, while blue crystals were found on the surface. Accumulation of nitrogen and phosphorus on the beads was detected. Vegetation experiments have revealed some stimulation effect of the beads applied as an amendment to loamy sand soil, to the growth of rye and cress.

Keywords: Columns cascade, nitrification, phosphorus accumulation, porous ceramics, synthetic wastewater.