Pretreatment of ceramic membrane microfiltration in wastewater reuse: A comparison between ozonation and coagulation. (1st December 2019)

• Record Type: Journal Article
• Authors: Im, Dongbum; Nakada, Norihide; Kato, Yasuhiro; Aoki, Michiko; Tanaka, Hiroaki
• Is Part Of: Journal of environmental management. Volume 251(2019)
• Publication Date: 2019-12-01
• Subjects: Coagulation -- Ceramic membrane -- Ozonation -- Membrane fouling -- Virus removal -- Water reclamation; Environmental policy -- Periodicals; Environmental management -- Periodicals; Environment -- Periodicals; Ecology -- Periodicals; 363.705
• DOI: 10.1016/j.jenvman.2019.109555
• Languages: English
• ISSNs: 0301-4797

Abstract

Abstract: To determine the most efficient pretreatment for ceramic membrane filtration (CMF) of primary clarifier effluent (PE), the effectiveness of ozonation and coagulation was investigated from the viewpoint of both virus removal and mitigation of membrane fouling. Our results showed virus removal by coagulation to be more efficient as a CMF pretreatment, whereas ozonation showed better efficiency when used as a CMF posttreatment. The effect of ozonation and coagulation on ceramic membrane fouling was investigated during short-term operation. With the use of coagulation before CMF (PACl + CMF), irreversible fouling resistance was 0.5 × 10 11 m −1 at a dosage of 150 mg/L of polyaluminum chloride (PACl), which was 10 times lower than when ozonation was used as a pretreatment to CMF (O3 +CMF) (0.7 × 10 12 m −1 at 50 mg-O3 /L). This result indicates coagulation to be more efficient than ozonation for mitigating ceramic membrane fouling. Based on these results, the process sustainability of PACl + CMF was then investigated during longer-term operation. At a dosage of 150 mg/L of PACl, the PACl + CMF process could be sustainably operated for 120 h without any need for chemically enhanced backwashing, which was twice as long as for PACl dosages of 50 and 100 mg/L. Coagulation is thus a more efficient pretreatment for CMF of PE from the viewpoint of both virus removal and mitigation of ceramic membrane fouling. The hygienic safety of reclaimed water can be further improved if ozonation is used as a CMF posttreatment. Highlights: Coagulation was more efficient pretreatment for virus removal than ozonation. Ozonation more efficiently removed virus as posttreatment for CMF than pretreatment. Coagulation could effectively mitigate ceramic membrane fouling than ozonation. At 150 mg/L of PACl dosage, CMF could be sustainably operated for 120 h without CEB.