Short-time aerobic digestion treatment of waste activated sludge to enhance EPS production and sludge dewatering performance by changing microbial communities: The impact of temperature

Abstract

Short-time aerobic digestion (STAD) of sludge requires low investment and has the advantages of short sludge retention time and rapid degradation of organic matter in waste activated sludge (WAS). This research conducted STAD at three temperature gradients (15 °C, 25 °C, and 35 °C). Characteristics of EPS and microbial community structure of raw and fermented sludge were analyzed, and environmental application potential of STAD at different temperatures was explored. STAD treatment improved both polysaccharide (PS) and protein (PN) contents in EPS, with increases of 5.7–18.35 % and 20.98–28.57 %, respectively. Aromatic protein-like substances (Peak E) and tryptophan protein substances (Peak F) were main components of PN in EPS. The microbial species richness decreased as the STAD temperature increased. At the class level, STAD temperature significantly affected Alphaproteobacteria, Gemm-1, Chloracidobacteria, Acidimicrobiia, Ellin6529, Betaproteobacteria, and SJA-28. From an application perspective, the specific resistance to filtration (SRF) value of WAS after STAD treatment at 35 °C was decreased to 7.01 × 107 m/kg with a 17.34 % reduction, indicating improvement in the dewaterability of the sludge. The Pb2+ adsorption efficiency per unit volume of EPS increased by 10.0–16.2 % after STAD treatment of WAS at different temperatures for 4 h. This research elucidated the impact of temperature on WAS in STAD systems, finding that microbial abundance correlated with EPS characteristics. The research results provide a basis for optimizing the system temperatures in STAD systems and a deeper understanding of the benefits of STAD in practical applications for sludge resource utilization.