Influence of wastewater sludge properties on the performance of electro-osmosis dewatering

ABSTRACT

Although the properties of municipal wastewater sludge play key roles in the electro-osmosis dewatering process, it is still controversial which properties have the greatest effect on the dewatering performance. In this study, multiple regression models with the Group Lasso method were used to investigate the relationship between the final moisture content and the sludge properties, including pH, electrical conductivity (EC), volatile solids content, zeta potential (ζ), initial moisture content, extracellular polymeric substances (EPS), proteins of EPS (EPSPr), polysaccharides of EPS (EPSPo) and the ratio of EPSPr and EPSPo (EPSR). Under the optimal conditions (pressure = 100 kPa, voltage = 50 V and cake thickness = 15 mm), EPS, EC and ζ were significantly related to sludge dewaterability and EPS was the most important factor. Furthermore, the coefficient estimate of EPSPo was greater than that of EPSPr and the coefficient of EPSR was negative, indicating that EPSPo plays more important roles in electro-osmosis dewatering than EPSPr. Thus, reducing the EPS content of sludge, especially the EPSPo content, is necessary to improve the performance of electro-osmosis dewatering.

GRAPHICAL ABSTRACT

KEYWORDS:

• Wastewater sludge
• electro-osmosis dewatering
• sludge properties
• extracellular polymeric substances
• Group Lasso method

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Yan Zhang http://orcid.org/0000-0002-4762-6639

Additional information

Funding

This work was financially supported by the National Key Technology Support Program [2014BAC08B07]; the National Natural Science Foundation of China [21407076, 21777068 and 51508263] and Jiangsu Science and Technology Support Program [BE2015622].