Baker's yeast wastewater advanced treatment using ozonation and membrane process for irrigation reuse

This study focused on the advanced treatment of biologically treated baker's yeast wastewater for the purpose of irrigation reuse. The effects of pH (3, 7.5, 9, 11) and temperature (25 °C, 35 °C, 45 °C) on the removal efficiencies were investigated for ozonation process. Ozone utilization rates were determined at different pH and temperature levels. There were not significant changes in pollutant removal efficiencies at the temperature of 25 °C-45 °C for ozonation process. 96-98% color, 56% COD, 67% UV254, 10% conductivity, 33% chloride, and 29% total hardness removals were obtained with ozonation process at pH 7.5 and 25 °C. NF 90 and BW 30 membranes were used to improve the quality of treated wastewater. Relatively lower flux decline caused from membrane fouling (18%) was occurred for BW 30 membrane. Although higher permeate qualities were achieved with both membranes, the chloride and conductivity values as 35 mg/L and 530 μs/cm were relatively lower for BW 30 permeate. As a result, the treated wastewater using ozonation and membrane process met the quality of class B regarding pH, biological oxygen demand (BOD5), suspended solids (SS) and fecal coliform parameters. Also, II. class irrigation water was obtained considering SAR parameter for degree of restriction on irrigation use.