Promoting dewatering efficiency of sludge by bioleaching coupling chemical flocculation

• Published in: Environmental research Vol. 237; p. 117014
• Main Authors: Li, Ting, Yang, Jiawei, Zhou, Yujun, Liu, Xuan, Luo, Yixin, Fang, Di, Liang, Jianru, Li, Jiansheng, Zhou, Lixiang
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 15.11.2023
• Subjects: Bio-acidification; Bio-substitution; Bioleaching; Flocculation; Sludge dewaterability; Bio-substitution; Bioleaching; Bio-acidification; Flocculation; Sludge dewaterability
• ISSN: 0013-9351; 1096-0953
• DOI: 10.1016/j.envres.2023.117014

In recent years, bioleaching has emerged as a cost-effective technology for enhancing the dewaterability of sludge. However, the lengthy treatment time involved in sludge bioleaching processes limits daily treatment capacity for sludge. Here, a novel approach was developed through a short time of sludge bioleaching with A. ferrooxidans LX5 (A. f) and A. thiooxidans TS6 (A. t) followed by polyferric sulfate (PFS) flocculation (A. f + A. t + PFS). After 12.5 h of the A. f + A. t + PFS treatment (30% A. f, 10% A. t, 40 mg/g DS S0, 60 mg/g DS FeSO4•7H2O, and 120 mg/g DS PFS), the reduction efficiency of specific resistance to filtration (SRF) and sludge cake moisture content reached 94.0% and 11.6%, respectively, which were comparable to the results achieved through 24 h of completed bioleaching treatment. In pilot-scale applications, the mechanical dewatering performance was notably improved following A. f + A. t + PFS treatment, with the low moisture content of the treated sludge cake (∼59.2%). This study provides new insights into the A. f + A. t + PFS process and holds potential for developing efficient and promising sludge dewatering strategies in engineering application. [Display omitted] •Introducing PFS flocculation promoted sludge bioleaching dewatering efficiency.•Reduction efficiency of SRF reached 94.0% after 12.5 h of A. f + A. t + PFS treatment.•Bio-acidification, bio-substitution and PFS flocculation simultaneously occurred.•Co-driven bioleaching of A. ferrooxidans and A. thiooxidans caused low sludge pH.•In pilot-scale applications, the moisture content of treated sludge cake was ∼59.2%.