Improved anti-biofouling performance of pressure retarded osmosis (PRO) by dosing with chlorhexidine gluconate

Peng Fei Sun, Taek Seung Kim, Han Shin Kim, So Young Ham, Yongsun Jang, Yong Gyun Park, Chuyang Y. Tang, Hee Deung Park

Research output: Contribution to journalArticle

Abstract

Pressure retarded osmosis (PRO) is an emerging technology capable of extracting energy from salinity gradients of wastewater paired with SWRO brine. However, this process's performance is hindered by irreversible biofouling due to bacteria-containing wastewater and the sponge-like support layer of PRO membranes. In this study, chlorhexidine gluconate (CHG), a non-oxidizing biocide, was continuously added to feed solution to investigate its anti-biofouling performance during PRO. CHG showed higher anti-microbial and anti-biofilm activity than did other non-oxidizing biocides. Even at low dosages of CHG, water flux declines were greatly mitigated and benefited from the internal concentration polarization (ICP)-elevated concentrations within the active-support layer interface. CHG plays a critical role by inhibiting bacterial growth, and a 65–88% reduction of extracellular polymeric substances was achieved on the membrane surface and throughout the feed spacers. Membrane characterization demonstrated that the improved performance could be attributed to a consistent structural parameter and alleviation of ICP self-compensation effects. This study thus shows that a combination of biocide dosing and pressure assisted-osmotic backwashing can be a useful strategy for controlling biofouling during the PRO process.

Original languageEnglish
Article number114376
JournalDesalination
Volume481
DOIs
Publication statusPublished - 2020 May 1

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Keywords

  • Biofouling
  • Chlorhexidine gluconate (CHG)
  • Internal concentration polarization (ICP)
  • Pressure retarded osmosis (PRO)
  • Structural parameter (S)

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Science(all)
  • Water Science and Technology
  • Mechanical Engineering

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