Reducing the Impacts of Biofouling in RO Membrane Systems through In Situ Low Fluence Irradiation Employing UVC-LEDs

Abstract

Biofouling is a major concern for numerous reverse osmosis membrane systems. UV pretreatment of the feed stream showed promising results but is still not an established technology as it does not maintain a residual effect. By conducting accelerated biofouling experiments in this study, it was investigated whether low fluence UV in situ treatment of the feed using UVC light-emitting diodes (UVC-LEDs) has a lasting effect on the biofilm. The application of UVC-LEDs for biofouling control is a novel hybrid technology that has not been investigated, yet. It could be shown that a low fluence of 2 mJ∙cm−2 delays biofilm formation by more than 15% in lab-scale experiments. In addition, biofilms at the same feed channel pressure drop exhibited a more than 40% reduced hydraulic resistance. The delay is probably linked to the inactivation of cells in the feed stream, modified adsorption properties or an induced cell cycle arrest. The altered hydraulic resistance might be caused by a change in the microbial community, as well as reduced adenosine triphosphate levels per cells, possibly impacting quorum sensing and extracellular polymeric substances production. Due to the observed biofilm attributes, low fluence UV-LED in situ treatment of the feed stream seems to be a promising technology for biofouling control.

Comparative Analysis of Conventional and Emerging Technologies for Seawater Desalination: Northern Chile as A Case Study

“…Dhakal et al [39] developed and demonstrated the applicability of the flow cytometry (FCM)-based bacterial growth potential (BGP) method to assess the biofouling potential in seawater (SW) RO systems using a natural microbial consortium. Sperle et al [40] reported the potential of UVC irradiation using the recently developed UV-LEDs as an in situ pretreatment strategy for biofouling control in RO or NF systems. In contrast to UV studies carried out previously, they tested if low fluences are sufficient to not only delay the biofilm formation but further lead to a reduced hydraulic resistance of the biofilm while approaching a severe biofouling state.…”

Cell density and extracellular matrix composition mitigate bacterial biofilm sensitivity to UV-C LED irradiation

“…For instance, LED lights are promising tools for in situ antimicrobial treatments along water distribution facilities such as plumbing installations and showerheads in order to prevent the development of opportunistic pathogens (Cates and Torkzadeh 2020 ). In addition, the installation of optical fibres within the plumbing network can provide a treatment solution for the internal surfaces of the pipes, as suggested by (Lanzarini-Lopes et al 2020 ), and also for reducing biofouling in membrane filtration systems (Sperle et al 2020 ).…”

A Practical Bacterial Biodosimetry Procedure to Assess Performance of Lab-Scale Flow-through Ultraviolet Water Disinfection Reactors

“…drinking and wastewater disinfection. However, applying UV disinfection for other applications like using UV irradiation as pre-treatment for biofouling control in membrane filtration systems, , E. coli may not be the ideal model organism. Biofilms often consist of noninfectious, nonmodel organisms, which to our knowledge have not been used as challenge organisms, yet.…”

“…This study aims to provide a standardized biodosimetry protocol for flow-through reactors and to elucidate critical steps that mitigate artifacts exploring new UV treatment designs with bacterial cells (using LEDs or conventional lamps). This is achieved by comparing the existing methods for flow-through UV reactors and the subsequent evaluation of the most important steps resulting in a standardized and reproducible biodosimetry protocol for the nonmodel organism, Aquabacterium citratiphilum , a Gram-negative bacterium found typically in drinking water biofilms around Europe with potential relevance for biofouling of high-pressure membrane treatment …”