Measuring Biofouling Potential in SWRO Plants with a Flow-Cytometry-Based Bacterial Growth Potential Method

Abstract

Measuring the bacterial growth potential of seawater reverse osmosis (SWRO) feed water is an issue that is receiving growing attention. This study developed and demonstrated the applicability of the flow-cytometry (FCM)-based bacterial growth potential (BGP) method to assess the biofouling potential in SWRO systems using natural microbial consortium. This method is relatively fast (2–3 days) compared to conventional bioassays. The effect of the potential introduction of nutrients during measurement has been studied thoroughly to achieve the lowest measure value of about 45,000 cells/mL, which is equivalent to about (10 µg-C glucose/L). The BGP method was applied in two full-scale SWRO plants that included (i) dissolved air flotation (DAF) and ultra-filtration (UF); (ii) dual-media filtration (DMF) and cartridge filter (CF), which were compared with the cleaning frequency of the plants. A significant reduction (54%) in BGP was observed through DAF–UF as pre-treatment (with 0.5 mg Fe3+/L), while there was a 40% reduction by DMF–CF (with 0.8 mg Fe3+/L). In terms of the absolute number, the SWRO feed water after DAF–UF supports 1.5 × 106 cells/mL, which is 1.25 times higher than after DMF–CF. This corresponds to the higher cleaning-in-place (CIP) frequency of SWRO with DAF–UF compared to DMF–CF as pre-treatment, indicating that the BGP method has an added value in monitoring the biofouling potential in SWRO systems.

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

“…Low alginate concentrations (25 mg/L) limited NF/RO fouling, but high concentrations (100 mg/L) appeared to promote calcite scaling. 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.…”

Phosphorus Concentration in Water Affects the Biofilm Community and the Produced Amount of Extracellular Polymeric Substances in Reverse Osmosis Membrane Systems

“…Fluorescence intensity was collected at FL1 = 533 ± 30 nm, FL3 > 670 nm, with sideward-and forward-scattered light intensities also being obtained. All data were processed with the BD Accuri CFlow ® software [46,47]. Electronic gating was used to select SYBR green-labeled signals to quantify the total bacterial cell count following the procedure described by Hammes and Egli, (2005) [48].…”

Enhanced Anti-Biofouling Properties of BWRO Membranes via the Deposition of Poly (Catechol/Polyamine) and Ag Nanoparticles

“…However, a significant obstacle to the high performance of RO technology is membrane biofouling, which impacts the water flux and the lifetime of membrane filters and modules [ 1 , 2 , 3 , 4 , 5 ]. Recently, several methods have been developed to monitor biofouling in RO systems, such as assimilable organic carbon (AOC), the membrane biofilm formation rate (mBFR) and bacterial growth potential (BGP) [ 6 , 7 ]. Many pretreatment processes have also been employed to decrease the fouling of RO membranes, such as the chlorination of feed water, ultrafiltration and microfiltration [ 8 , 9 , 10 ].…”