Full-scale investigation of in-situ iron and alkalinity generation for efficient sulfide control

Ilje Pikaar; Markus Flugen; Hui-Wen Lin; Sirajus Salehin; Jiuling Li; Bogdan C Donose; Paul G Dennis; Lisa Bethke; Ian Johnson; Korneel Rabaey; Zhiguo Yuan

doi:10.1016/j.watres.2019.115032

Full-scale investigation of in-situ iron and alkalinity generation for efficient sulfide control

Water Res. 2019 Dec 15:167:115032. doi: 10.1016/j.watres.2019.115032. Epub 2019 Sep 5.

Authors

Ilje Pikaar¹, Markus Flugen², Hui-Wen Lin³, Sirajus Salehin⁴, Jiuling Li⁵, Bogdan C Donose⁶, Paul G Dennis⁷, Lisa Bethke⁵, Ian Johnson⁸, Korneel Rabaey⁹, Zhiguo Yuan⁵

Affiliations

¹ The University of Queensland, The School of Civil Engineering, QLD, 4072, Australia; The University of Queensland, Advanced Water Management Centre (AWMC), QLD, 4072, Australia. Electronic address: i.pikaar@uq.edu.au.
² The University of Queensland, The School of Civil Engineering, QLD, 4072, Australia.
³ Department of Agricultural Chemistry, National Taiwan University, Taiwan" to "Department of Agricultural Chemistry, National Taiwan University, Taipei, Taiwan.
⁴ The University of Queensland, The School of Civil Engineering, QLD, 4072, Australia; The University of Queensland, Advanced Water Management Centre (AWMC), QLD, 4072, Australia.
⁵ The University of Queensland, Advanced Water Management Centre (AWMC), QLD, 4072, Australia.
⁶ The University of Queensland, School of Chemical Engineering, St. Lucia, QLD, 4072, Australia.
⁷ The University of Queensland, School of Earth and Environmental Sciences, QLD, 4072, Australia.
⁸ The City of Gold Coast, 833 Southport Nerang Road, Nerang, QLD, 4211, Australia.
⁹ The University of Queensland, Advanced Water Management Centre (AWMC), QLD, 4072, Australia; Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, 9000, Ghent, Belgium.

PMID: 31546029
DOI: 10.1016/j.watres.2019.115032

Abstract

Hydrogen sulfide induced corrosion of concrete sewer pipes is a major issue for wastewater utilities globally. One of the most commonly used methods to combat hydrogen sulfide is the addition of ferric chloride. While a reliable and effective method, ferric chloride is acidic causing OH&S concerns as well as alkalinity consumption in sewage. This study investigates, under full-scale field conditions, an alternative method for sulfide control by in-situ electrochemical generation of iron ions using sacrificial iron electrodes. This method concomitantly produces alkalinity through cathodic OH^- generation, rather than consumption. The gaseous hydrogen sulfide concentrations at the discharge wet well of a real-life rising main (length: ∼1 km in, diameter: 150 mm) decreased from 173 ppm to 43 ppm (90 percentile of peak values), when a current of 0.86 A/m³ of sewage was applied. The 90 percentile peak H₂S value was further reduced to 6.6 ppm when the applied current was increased to 1.14 A/m³ sewage. Moreover, methane generation was almost completely inhibited from 25.3 ± 1.46 mg COD/L to 0.06 ± 0.04 mg COD/L. The overall cell voltage remained constant throughout the experimental period clearly showing the stability of the process. Detailed characterization of the down-stream sewer pipe biofilm revealed the complexity of the iron chemistry as the in-situ produced iron ions undergo transformation into a variety of iron species. Overall, this study demonstrates that in-situ generation of iron and alkalinity is an effective alternative method for hydrogen sulfide control in sewers.

Keywords: Electrochemistry; Hydrogen sulfide abatement; In-situ chemical generation; Real-life application; Sewer corrosion.

MeSH terms

Hydrogen Sulfide*
Iron*
Sewage
Sulfides
Wastewater

Substances

Sewage
Sulfides
Waste Water
Iron
Hydrogen Sulfide