Characterization and mitigation of the fouling of flat-sheet ceramic membranes for direct filtration of the coagulated domestic wastewater

Yan-Xia Zhao; Pu Li; Ruo-Hong Li; Xiao-Yan Li

doi:10.1016/j.jhazmat.2019.121557

Characterization and mitigation of the fouling of flat-sheet ceramic membranes for direct filtration of the coagulated domestic wastewater

J Hazard Mater. 2020 Mar 5:385:121557. doi: 10.1016/j.jhazmat.2019.121557. Epub 2019 Nov 2.

Authors

Yan-Xia Zhao¹, Pu Li², Ruo-Hong Li³, Xiao-Yan Li⁴

Affiliations

¹ School of Water Conservancy and Environment, University of Jinan, 250022, Shandong, China; Environmental Engineering Research Centre, Department of Civil Engineering, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region; Key Laboratory for Special Functional Aggregated Materials of Education Ministry, School of Chemistry and Chemical Engineering, Shandong University, Jinan, 250100, Shandong, China.
² Environmental Engineering Research Centre, Department of Civil Engineering, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region.
³ Environmental Engineering Research Centre, Department of Civil Engineering, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region; Shenzhen Engineering Research Laboratory for Sludge and Food Waste Treatment and Resource Recovery, Graduate School at Shenzhen, Tsinghua University, Shenzhen, China.
⁴ Environmental Engineering Research Centre, Department of Civil Engineering, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region; Shenzhen Engineering Research Laboratory for Sludge and Food Waste Treatment and Resource Recovery, Graduate School at Shenzhen, Tsinghua University, Shenzhen, China; Tsinghua-Berkeley Shenzhen Institute, Tsinghua University, Shenzhen, China. Electronic address: xlia@hku.hk.

PMID: 31735469
DOI: 10.1016/j.jhazmat.2019.121557

Abstract

Ceramic membranes allow a high filtration flux with a low fouling propensity. Direct filtration of municipal wastewater using flat-sheet ceramic membranes (FSCM) is an attractive and promising technology for wastewater treatment and resource recovery. Urgent need is to determine the fouling behavior of FSCM and its optimal cleaning strategy in direct filtration applications. This study was conducted on pre-coagulation of sewage with FeCl₃ (20 mg Fe/L) or polyaluminum chloride (15 mg Al/L), followed by FSCM filtration at around 1.0 m/d (as high as 41.7 L/m²-h in flux). The results showed that the coagulation-FSCM filtration removed chemical oxygen demand and total phosphorus by up to 90.0% and 99.9%, respectively. The pollutants (organics and nutrients) in the sewage influent were concentrated into the sludge for potential resource recovery. Without pre-coagulation, foulants easily entered the membrane pores, causing rapid membrane fouling. Chemically enhanced coagulation greatly decreased the membrane fouling rate by aggregating various foulants into flocs. Fouled membranes were effectively renewed by physical means, such as water flushing and sonication, or a short period of chemical backwashing with NaOH, HCl or oxidizing agents. The study revealed the fouling mechanisms of FSCM in sewage filtration and developed effective cleaning strategies for its long-term operation.

Keywords: Direct membrane filtration; Flat-sheet ceramic membranes; Membrane cleaning; Membrane fouling; Municipal wastewater.

Publication types

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