Effect of aromatic repolymerization of humic acid-like fraction on digestate phytotoxicity reduction during high-solid anaerobic digestion for stabilization treatment of sewage sludge

Yanfei Tang; Xiaowei Li; Bin Dong; Junjie Huang; Yanhong Wei; Xiaohu Dai; Lingling Dai

doi:10.1016/j.watres.2018.07.003

Effect of aromatic repolymerization of humic acid-like fraction on digestate phytotoxicity reduction during high-solid anaerobic digestion for stabilization treatment of sewage sludge

Water Res. 2018 Oct 15:143:436-444. doi: 10.1016/j.watres.2018.07.003. Epub 2018 Jul 3.

Authors

Yanfei Tang¹, Xiaowei Li², Bin Dong¹, Junjie Huang¹, Yanhong Wei¹, Xiaohu Dai³, Lingling Dai⁴

Affiliations

¹ State Key Laboratory of Pollution Control and Resources Reuse, National Engineering Research Center for Urban Pollution Control, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China.
² State Key Laboratory of Pollution Control and Resources Reuse, National Engineering Research Center for Urban Pollution Control, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China; School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, PR China.
³ State Key Laboratory of Pollution Control and Resources Reuse, National Engineering Research Center for Urban Pollution Control, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, PR China. Electronic address: daixiaohu@tongji.edu.cn.
⁴ State Key Laboratory of Pollution Control and Resources Reuse, National Engineering Research Center for Urban Pollution Control, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China. Electronic address: linglingd@tongji.edu.cn.

PMID: 29986252
DOI: 10.1016/j.watres.2018.07.003

Abstract

Humification plays an important role in the sewage sludge stabilization treatment and probably influences the end-product ecotoxicity, which are not fully understood for high-solid anaerobic digestion (AD) process. This study monitored the aromaticity degree of humic acid-like fraction (HA) and detected digestate phytotoxicity during a 48-d high-solid AD. Significant repolymerization of aromatic structures in HA. Electrical conductivity (EC) of digestate changed negatively with the aromaticity degree in HA, and the digestate with high EC had low seed germination index (SGI). A positive correlation between SGI and the aromaticity degree of HA was found. Aromatic repolymerization of HA supplies more aromatic electron-rich sites to form neo-humic polymers and to determine the distribution of organic and/or inorganic phytotoxic compounds; thus, aromatic repolymerization of HA may control the digestate phytotoxicity by reducing excessive salinity. The results showed the effect of HA repolymerization on digestate stabilization and phytotoxicity reduction during the high-solid AD process. The inadequate phytotoxicity reduction efficiency (SGI ≤ 17%) may be ascribed to unaccomplished HA repolymerization, creating a demand for humification intensification studies.

Keywords: Aromatization; High-solid anaerobic digestion; Humic acid-like fraction; Phytotoxicity; Sewage sludge; Stabilization.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Anaerobiosis
Electric Conductivity
Germination / drug effects
Humic Substances* / analysis
Polymerization
Sewage / chemistry*
Spectrophotometry, Ultraviolet
Spectroscopy, Fourier Transform Infrared
Toxicity Tests / methods
Waste Disposal, Fluid / methods*
Wastewater / chemistry
Wastewater / toxicity*

Substances

Humic Substances
Sewage
Waste Water