Simultaneous use of caustic and oxygen for efficient sulfide control in sewers

Hui-Wen Lin; Yang Lu; Ramon Ganigué; Keshab R Sharma; Korneel Rabaey; Zhiguo Yuan; Ilje Pikaar

doi:10.1016/j.scitotenv.2017.05.225

Simultaneous use of caustic and oxygen for efficient sulfide control in sewers

Sci Total Environ. 2017 Dec 1:601-602:776-783. doi: 10.1016/j.scitotenv.2017.05.225. Epub 2017 Jun 1.

Authors

Hui-Wen Lin¹, Yang Lu¹, Ramon Ganigué², Keshab R Sharma¹, Korneel Rabaey³, Zhiguo Yuan¹, Ilje Pikaar⁴

Affiliations

¹ The University of Queensland, Advanced Water Management Centre (AWMC), QLD 4072, Australia.
² Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, 9000 Ghent, Belgium.
³ 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.
⁴ The University of Queensland, Advanced Water Management Centre (AWMC), QLD 4072, Australia; The University of Queensland, The School of Civil Engineering, QLD 4072, Australia. Electronic address: i.pikaar@uq.edu.au.

PMID: 28578235
DOI: 10.1016/j.scitotenv.2017.05.225

Abstract

Periodic caustic shock-loading is a commonly used method for sulfide control in sewers. Caustic shock-loading relies on the elevation of the sewage pH to ≥10.5 for several hours, thereby removing sewer pipe biofilms as well as deactivating SRB activity in the remaining biofilm. Although a widely used method, SRB activity is often not completely inhibited, and as such sulfide is still being generated. Here, we propose and experimentally demonstrate an innovative approach which combines caustic with oxygen, another commonly used method, as a dosing strategy for overcoming the drawbacks of caustic shock-loading. Six laboratory-scale rising main reactors were subjected to three dosing schemes over a period of three months, namely (i) simultaneous caustic and oxygen addition, (ii) caustic addition and (iii) no chemical addition. Our results showed that the combination of caustic and oxygen achieved efficient sulfide control, leading to a prolonged biofilm recovery period in between caustic shocks. In addition, methane emissions were reduced to a negligible level compared to caustic treatment only. To translate the findings to real-life application, the key parameters obtained during the long-term lab-scale experiments were subjected to extensive simulation studies using the SeweX model under a wide range of conditions commonly found in sewers. Overall, this study highlights the potential of periodic shock-loading and intermittent oxygen injection as combined dosing strategy for efficient sulfide control in sewers.

Keywords: Caustic shock-loading; Dynamic modelling; Oxygen; Sewer corrosion; Sulfate reducing bacteria; Sulfide abatement.