Sustainable Mining and Metallurgy

To explore the effect of particulate organic matter (POM) on the characteristics of aerobic granular sludge（AGS）, two sequencing batch reactors（Rs and Rp）with soluble organic matter and POM influent were established. AGS variations in its treatment performance, physicochemical characteristics, and microbial community were investigated. The results showed that the effluent concentrations of COD and NO-3-N in the Rp reactor were higher than those in Rs reactor. which were 35.5 and 32.9mg/L, respectively. Typical AGS did not form in Rp, and its sludge exhibited inferior settling ability and mechanical strength, with a sludge volume index (SVI) of 36.5mL/g and an integrity coefficient of 95.4%. In contrast, well-structured AGS was successfully developed in Rs. The presence of POM stimulated the secretion of extracellular polymeric substances (EPS). The contents of polysaccharide (PS) and protein (PN) in EPS were 3.2 times and 2.1 times higher in Rp than those in Rs, respectively. Moreover, the PN/PS ratio decreased from 2.1 in Rs to 1.4 in Rp, which adversely affected AGS formation. Microbial community analysis revealed that the dominant genera in Rp were Pseudofulvimonas, Rhodobacter, and Nannocystis, whereas Micropruina and Flavobacterium were predominant in Rs.. The specific bacterial genera in Rp failed to aggregate effectively into granular structures. These findings offer theoretical insights for the cultivation and stable maintenance of AGS.