Combined freezing-thawing pretreatment and microbial electrolysis cell for enhancement of highly concentrated organics degradation from dewatered sludge

ABSTRACT

The influence of freezing-thawing (F/T) pretreatment on the degradation of highly concentrated organic matters from dewatered sludge (DS) in microbial electrolysis cell (MEC) was investigated in this study. Extended freezing disintegrated the DS matrix and resulted in accelerated hydrolysis rate. The biogas production and stabilization were increased due to the pretreatment by 25–70% of H₂ production rate and 17.8–33.8% of COD reduction rate, respectively. Fourier transform infrared spectroscopy analysis indicated that the pretreatment was unable to alter the bioelectrochemical reactions except for accelerating degradation rate. Excitation and emission matrix (EEM) spectra showed that aromatic protein and soluble microbial products (SMPs)-like materials in DS were increasingly solubilized by the pretreatment and significantly removed during electrogenesis. The F/T-pretreated DS favored the enrichment of exoelectrogens in MEC.

Graphical Abstract

KEYWORDS:

• Microbial electrolysis cell
• dewatered sludge
• freezing-thawing pretreatment
• organic matter

Highlight

1. A novel integrated process was proposed for DS disintegration and degradation.

2. F/T effectively disrupted DS.

3. The MEC performance was enhanced by the pretreatment.

4. Aromatic proteins and SMPs in DS were significantly removed in the combined process.

Acknowledgements

The authors gratefully acknowledge funding from Major Science and Technology Program for Water Pollution Control and Treatment (Grant No. 2017ZX07201002), Fundamental Research Funds for the Central Universities (Grant No.2019B14114), National Science and Technology Major Project (Grant No. 2016YFC0400800-04), and Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD).

Disclosure Statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Major Science and Technology Program for Water Pollution Control and Treatment [2017ZX07201002]; Fundamental Research Funds for the Central Universities [2019B14114]; National Science and Technology Major Project [2016YFC0400800-04];Priority Academic Program Development of Jiangsu Higher Education Institutions [PAPD].