Aerobic granulation process applied to landfill leachate treatment

Abstract

The performance of aerobic granular sludge (AGS) process was evaluated for real leachate treatment, assessing the system capacity to form granules, biomass characteristics, and other engineering and microbiological aspects. Two sequencing batch reactors were operated with a leachate concentration of 25% (R1) and 50% (R2), with an 8-h cycle. The time required for granulation was greater than 80 days in both reactors, and solids loss was significant. The sedimentation rate was also outside the typical values for AGS reactors, with a sludge volumetric index in 30 min (SVI30) greater than 70 mL/g. Although the granules produced in R2 were more compact (200 μm), they were more resistant. Proteobacteria and Rhodobacteraceae were the phyla and the most abundant family in R2. The phylum Planctomycetota and the family Pirellulaceae were the most abundant in R1. Settling time reduction, feeding phase increase, and increased dissolved oxygen (DO) levels were fundamental strategies to improve reactors’ performance and stability.