From waste to wealth: Exploring the effect of particle size on biopolymer harvesting from aerobic granular sludge

Bioresour Technol. 2024 Dec 12:418:131977. doi: 10.1016/j.biortech.2024.131977. Online ahead of print.

Abstract

This study aimed to examine the impact of aerobic granular sludge (AGS) sizes on its properties and alginate-like exopolymers (ALE) recovery potential. The AGS was cultivated in a lab-scale bioreactor and categorized into six size classes with 200 μm intervals. There appeared a critical size (400-800 μm) for developing stable AGS structure and excellent ALE recovery. A higher hydrophobicity (74.36 %) and density (1,037 g/L) was observed in AGS400-600μm than other sizes. Moreover, the highest ALE yield was obtained in ALE600-800μm (388 mg/g VSS) for its higher abundance of EPS-producers (35.1 %), while the PN content of ALE400-600μm was higher than other samples. Meanwhile, the concentrations of metal elements within the ALE and AGS identified that there was no bio-accumulation of metal elements in the ALE. This study offers an in-depth understanding of biopolymer recovery from AGS, paving the way for a novel resource recovery strategy through the regulation of AGS sizes.

Keywords: Alginate-like exopolymers; Critical AGS size; Metal elements; Microbial community; Wastewater reclamation.