Natural zeolite enhances anaerobic digestion of waste activated sludge: Insights into the performance and the role of biofilm

Cong-Cong Tang; Bao-Cai Zhang; Xing-Ye Yao; Thangavel Sangeetha; Ai-Juan Zhou; Wenzong Liu; Yong-Xiang Ren; Zhihua Li; Aijie Wang; Zhang-Wei He

doi:10.1016/j.jenvman.2023.118704

Natural zeolite enhances anaerobic digestion of waste activated sludge: Insights into the performance and the role of biofilm

J Environ Manage. 2023 Nov 1:345:118704. doi: 10.1016/j.jenvman.2023.118704. Epub 2023 Aug 2.

Authors

Affiliations

¹ Key Laboratory of Northwest Water Resource, Environment and Ecology, Ministry of Education, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China.
² Research Center of Energy Conservation for New Generation of Residential, Commercial, And Industrial Sectors, National Taipei University of Technology, Taipei, 10608, Taiwan, China; Department of Energy and Refrigerating Air-Conditioning Engineering, National Taipei University of Technology, Taipei, 10608, Taiwan, China.
³ College of Environmental Science and Engineering, Taiyuan University of Technology, Taiyuan, 030024, China.
⁴ State Key Laboratory of Urban Water Resource and Environment, School of Civil and Environmental Engineering, Harbin Institute of Technology Shenzhen, Shenzhen, 518055, China.
⁵ Key Laboratory of Northwest Water Resource, Environment and Ecology, Ministry of Education, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China. Electronic address: zwhe@xauat.edu.cn.

PMID: 37540982
DOI: 10.1016/j.jenvman.2023.118704

Abstract

Anaerobic digestion is widely employed for the treatment of waste activated sludge (WAS) due to its advantages like simultaneous energy recovery and sludge stabilization, promoting carbon-neutral operation of wastewater treatment plants. Natural zeolite, a low-cost and eco-friendly additive, has the potential to improve methane production from anaerobic digestion. This study investigated the effects of natural zeolite on anaerobic digestion when the substrate was WAS. It was found that methane production potential in response to natural zeolite was dosage-dependent. The optimal dosage was 0.1 g zeolite/g volatile suspended solids (VSS), with a methane yield of 181.89 ± 6.75 mL/g VSS, which increased by 20.1% compared to that of the control. Although the methane yields with other dosages of natural zeolite were higher than that of control, they were lesser than that with 0.1 g zeolite/g VSS. Natural zeolite affected transfer and conversion of proteins much more than polysaccharides in liquid phase and extracellular polymeric substances. In anaerobic digestion, natural zeolite had with little effects on WAS solubilization, while it improved hydrolysis, acidification, and methanogenesis. The dosages of natural zeolite did have significant effects on bacterial communities in biofilm rather than suspension, while the archaeal communities in biofilm and suspension were all greatly related to natural zeolite dosages. The developed biofilms promoted richness and functionality of microbial communities. The syntrophic metabolism relationships between methanogens and bacteria were improved, which was proved by selective enrichment of Methanosarcina, Syntrophomonas, and Petrimonas. The findings of this work provided some new solutions for promoting methane production from WAS, and the roles of natural zeolite in anaerobic digestion.

Keywords: Anaerobic digestion; Methane production; Microbial community; Natural zeolite; Waste activated sludge.

MeSH terms

Anaerobiosis
Bacteria / metabolism
Biofilms
Bioreactors
Methane
Sewage* / chemistry
Waste Disposal, Fluid
Zeolites*

Substances

Sewage
Zeolites
Methane