Efficacy and Adaptation Mechanisms of Algal-Bacterial Granular Sludge Treatment for Phenolic Wastewater

The ubiquitous presence of phenolic compounds in effluents poses a risk to aquatic organisms and human health. This study investigates the responses of the emerging algal-bacterial granular sludge process in treating phenolic wastewater. The results showed that phenol at 1, 10, and 100 mg/L had little effect on ammonia-N, chemical oxygen demand (COD), and phosphate-P removal. At the highest phenol concentration of 100 mg/L, the average removal rates of ammonia-N, COD, and phosphate-P were 94.8%, 72.9%, and 83.7%, respectively. The presence of phenol led to a decline in chlorophyll content of the algal-bacterial granular sludge, concurrently resulting in an increase in the abundance of microbial diversity. Algal-bacterial granular sludge exhibited mechanisms such as elevated extracellular polymeric substances (EPSs), superoxide dismutase (SOD), and catalase (CAT) production, which may aid in coping with oxidative stress from phenols. This research underscores the algal-bacterial granular sludge's potential for treating phenolic wastewater, thereby advancing knowledge in the field of phenol degradation with this innovative technology.