Biological Treatment of Pulp and Paper Wastewater: Effect of Aeration Mode on Airlift Bioreactor with Petrophilic Bacteria

The pulp and paper industry, a major consumer of freshwater, generates wastewater rich in contaminants, including ammonia, chemical oxygen demand (COD), total suspended solids (TSS), and organic materials. Effective treatment of this liquid pulp waste is crucial to prevent environmental pollution. This study investigated the microbiological treatment of primary pulp industry liquid waste using the petrophilic bacterium Brevundimonas diminuta. The research assessed the bacterium's capacity to degrade ammonia, COD, and TSS under varying aeration rates (0 L/min, 2.25 L/min, and 4.5 L/min) and observation durations (4, 6, and 8 hours). Results revealed that the optimal reduction in ammonia levels, reaching 64%, occurred within 6-8 hours with 4.5 L/min aeration. Likewise, COD reduction peaked at 90% under 4.5 L/min aeration over 8 hours, while TSS degradation reached 76% under 4.5 L/min aeration within 6 hours. These findings demonstrate the ability of petrophilic bacteria to effectively mitigate liquid pulp and paper waste under specific processing conditions, emphasizing the significance of aeration rate and duration in this biodegradation process