Improved sulfide mitigation in sewers through on-line control of ferrous salt dosing

Ramon Ganigué; Guangming Jiang; Yiqi Liu; Keshab Sharma; Yue-Cong Wang; José Gonzalez; Tung Nguyen; Zhiguo Yuan

doi:10.1016/j.watres.2018.02.022

Improved sulfide mitigation in sewers through on-line control of ferrous salt dosing

Water Res. 2018 May 15:135:302-310. doi: 10.1016/j.watres.2018.02.022. Epub 2018 Feb 13.

Authors

Ramon Ganigué¹, Guangming Jiang², Yiqi Liu³, Keshab Sharma⁴, Yue-Cong Wang⁵, José Gonzalez⁶, Tung Nguyen⁷, Zhiguo Yuan⁸

Affiliations

¹ Advanced Water Management Centre, Building 60, Research Road, The University of Queensland, St. Lucia, Brisbane QLD 4072, Australia; Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, 9000 Ghent, Belgium. Electronic address: ramon.ganigue@ugent.be.
² Advanced Water Management Centre, Building 60, Research Road, The University of Queensland, St. Lucia, Brisbane QLD 4072, Australia. Electronic address: g.jiang@awmc.uq.edu.au.
³ Advanced Water Management Centre, Building 60, Research Road, The University of Queensland, St. Lucia, Brisbane QLD 4072, Australia; School of Automation Science & Engineering, South China University of Technology, Guangzhou, 510640, PR China. Electronic address: liuyiqi769@sina.com.cn.
⁴ Advanced Water Management Centre, Building 60, Research Road, The University of Queensland, St. Lucia, Brisbane QLD 4072, Australia. Electronic address: k.sharma@awmc.uq.edu.au.
⁵ Sydney Water Corporation, 1 Smith St, Parramatta, NSW 2150, Australia. Electronic address: yue-cong.wang@sydneywater.com.au.
⁶ Sydney Water Corporation, 1 Smith St, Parramatta, NSW 2150, Australia. Electronic address: jose.gonzalez@sydneywater.com.au.
⁷ Sydney Water Corporation, 1 Smith St, Parramatta, NSW 2150, Australia. Electronic address: tung.nguyen@nextgenwater.com.au.
⁸ Advanced Water Management Centre, Building 60, Research Road, The University of Queensland, St. Lucia, Brisbane QLD 4072, Australia. Electronic address: z.yuan@awmc.uq.edu.au.

PMID: 29477793
DOI: 10.1016/j.watres.2018.02.022

Abstract

Water utilities worldwide spend annually billions of dollars to control sulfide-induced corrosion in sewers. Iron salts chemically oxidize and/or precipitate dissolved sulfide in sewage and are especially used in medium- and large-size sewers. Iron salt dosing rates are defined ad hoc, ignoring variation in sewage flows and sulfide levels. This often results in iron overdosing or poor sulfide control. Online dosing control can adjust the chemical dosing rates to current (and future) state of the sewer system, allowing high-precision, stable and cost-effective sulfide control. In this paper, we report a novel and robust online control strategy for the dosing of ferrous salt in sewers. The control considers the fluctuation of sewage flow, pH, sulfide levels and also the perturbation from rainfall. Sulfide production in the pipe is predicted using auto-regressive models (AR) based on current flow measurements, which in turn can be used to determine the dose of ferrous salt required for cost-effective sulfide control. Following comprehensive model-based assesment, the control was successfully validated and its effectiveness demonstrated in a 3-week field trial. The online control algorithm controlled sulfide below the target level (0.5 mg S/L) while reducing chemical dosing up to 30%.

Keywords: Chemical dosing; Corrosion; Online control; Sewer systems; Sulfide control.

Publication types

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

MeSH terms

Algorithms*
Australia
Equipment Design
Ferrous Compounds / chemistry*
Hydrogen-Ion Concentration
Oxidation-Reduction
Reproducibility of Results
Sewage / chemistry*
Sulfides / chemistry*

Substances

Ferrous Compounds
Sewage
Sulfides