Accelerated stabilization of high solid sludge by thermal hydrolysis pretreatment in autothermal thermophilic aerobic digestion (ATAD) process. (15th September 2022)

• Record Type: Journal Article
• Authors: Liu, Yangyang; Yuan, Haiping; Zhu, Nanwen
• Is Part Of: Journal of environmental management. Volume 318(2022)
• Publication Date: 2022-09-15
• Subjects: High solid sludge -- Autothermal thermophilic aerobic digestion -- Stabilization -- Thermal hydrolysis pretreatment -- Microbial community analysis; Environmental policy -- Periodicals; Environmental management -- Periodicals; Environment -- Periodicals; Ecology -- Periodicals; 363.705
• DOI: 10.1016/j.jenvman.2022.115615
• Languages: English
• ISSNs: 0301-4797

Abstract

Abstract: Autothermal thermophilic aerobic digestion (ATAD) is a rapid biological treatment technology for sludge stabilization. To improve digestion efficiency and shorten stabilization time, thermal hydrolysis pretreatment was employed before ATAD of high solid sludge. The results showed that accelerated stabilization of high solid sludge (total solid = 10.1%) was achieved by thermal hydrolysis pretreatment with volatile solid removal efficiency of 40.3% after 8 days of ATAD, 11 days earlier than unpretreated sludge. The enhanced release and hydrolysis of intracellular organics resulted in a solubilization degree of 45.3%. The reduced sludge viscosity and improved fluidity after thermal hydrolysis facilitated mixing, aeration and organics degradation during ATAD. Excitation emission matrix analysis indicated that the fluorescence intensity of soluble microbial byproduct and tyrosine-like protein increased markedly after thermal hydrolysis and decreased after ATAD. The proportion of high molecular weight (MW > 10 kDa) substances in the supernatant increased significantly after thermal hydrolysis, while the low MW (MW < 1 kDa) substances decreased after ATAD. The significant difference in microbial composition between the pretreatment and control groups elucidated the accelerated sludge stabilization under thermal hydrolysis. This work provides an efficient and practical strategy to achieve rapid stabilization of high solid sludge. Graphical abstract: Image 1 Highlights: Thermal hydrolysis accelerates the stabilization of high solid sludge during ATAD. Sludge stabilization after thermal hydrolysis is 11 days earlier than unpretreated. Reduced sludge viscosity and enhanced fluidity are achieved after pretreatment. Thermal hydrolysis improves solubilization and degradation efficiency during ATAD. Shifts in microbial communities are revealed during ATAD of pretreated sludge.