Enhancement of sludge dewaterability by repeated inoculation of acidified sludge: Extracellular polymeric substances molecular structure and microbial community succession

Yunbei Li; Chunyan Fu; Xinyu Cao; Xin Wang; Ninghao Wang; Mengyu Zheng; Lijun Quan; Jinghua Lv; Zhensheng Guo

doi:10.1016/j.chemosphere.2023.139714

Enhancement of sludge dewaterability by repeated inoculation of acidified sludge: Extracellular polymeric substances molecular structure and microbial community succession

Chemosphere. 2023 Oct:339:139714. doi: 10.1016/j.chemosphere.2023.139714. Epub 2023 Aug 3.

Authors

Yunbei Li¹, Chunyan Fu², Xinyu Cao², Xin Wang², Ninghao Wang², Mengyu Zheng², Lijun Quan², Jinghua Lv², Zhensheng Guo²

Affiliations

¹ School of Environment, Key Laboratory of Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Normal University, Xinxiang, 453007, China. Electronic address: liyunbei@163.com.
² School of Environment, Key Laboratory of Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Normal University, Xinxiang, 453007, China.

PMID: 37543234
DOI: 10.1016/j.chemosphere.2023.139714

Abstract

Improving the dewatering performance of sewage sludge is of great scientific and engineering significance in the context of accelerated urbanization and increasingly strict environmental regulations. Acidified sludge (AS) can improve sludge dewatering performance, but the dewatering effect of repeated inoculation is unclear. The effects of long-term repeated inoculation of AS on the sludge dewaterability were investigated. The molecular structure and microbial community succession of extracellular polymeric substances (EPS) are emphasized. The results revealed that increasing the inoculation ratio of AS reduced the pH, absolute value of sludge zeta potential, and sludge particle size, and the decreasing trend was more evident with prolonging treatment time. Under the conditions of 30% and 50% AS inoculation, the dewatering performance of the sludge was significantly improved (p < 0.05). Compared with the raw sludge, the specific resistance of filtration (SRF) and capillary suction time of 30% inoculation were reduced by 64.3% and 50.1% after 30 cycles, respectively. Excluding loosely bound (LB)-EPS, soluble (S)-EPS and tightly bound (TB)-EPS exhibited a visible decrease, the protein in TB-EPS was significantly related to sludge dewaterability (p < 0.05). The fluorescent components of aromatic protein and fulvic acid-like substances in TB-EPS were significantly associated with SRF, with a correlation coefficient 0.99 (p < 0.05). Both the increase in the percentages of random coil and decrease in α-helix in TB-EPS contributed to improving dewaterability. Increasing Firmicutes and decreasing Chloroflexi levels improved the sludge dewatering capacity. Repeated inoculation did not disrupt the dewatering effect of AS rather increased the feasibility of the engineering application of AS. Considering the dewatering performance and cost synthetically, 30% AS inoculated ratio is feasible for practical applications.

Keywords: Acidified sludge; Extracellular polymeric substances; Microbial community; Sewage sludge; Sludge dewaterability.

MeSH terms

Extracellular Polymeric Substance Matrix*
Molecular Structure
Proteins / chemistry
Sewage* / chemistry
Waste Disposal, Fluid / methods
Water / chemistry

Substances

Sewage
Water
Proteins