Assessing pretreatment and seawater reverse osmosis performance using an ATP-based bacterial growth potential method

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.

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Monitoring Biofouling Potential Using ATP-Based Bacterial Growth Potential in SWRO Pre-Treatment of a Full-Scale Plant

Membranes ◽

10.3390/membranes10110360 ◽

2020 ◽

Vol 10 (11) ◽

pp. 360

Author(s):

Almotasembellah Abushaban ◽

Sergio G. Salinas-Rodriguez ◽

Moses Kapala ◽

Delia Pastorelli ◽

Jan C. Schippers ◽

...

Keyword(s):

Bacterial Growth ◽

Full Scale ◽

Growth Potential ◽

Feed Water ◽

Potential Growth ◽

Dissolved Air Flotation ◽

Particulate Fouling ◽

Seawater Reverse Osmosis ◽

Pre Treatment ◽

Modified Fouling Index

Several potential growth methods have been developed to monitor biological/organic fouling potential in seawater reverse osmosis (SWRO), but to date the correlation between these methods and biofouling of SWRO has not been demonstrated. In this research, the relation between a new adenosine triphosphate (ATP)-based bacterial growth potential (BGP) test of SWRO feed water and SWRO membrane performance is investigated. For this purpose, the pre-treatment of a full-scale SWRO plant including dissolved air flotation (DAF) and two stage dual media filtration (DMF) was monitored for 5 months using BGP, orthophosphate, organic fractions by liquid chromatography coupled with organic carbon detection (LC-OCD), silt density index (SDI), and modified fouling index (MFI). Results showed that particulate fouling potential was well controlled through the SWRO pre-treatment as the measured SDI and MFI in the SWRO feed water were below the recommended values. DAF in combination with coagulation (1–5 mg-Fe3+/L) consistently achieved 70% removal of orthophosphate, 50% removal of BGP, 25% removal of biopolymers, and 10% removal of humic substances. Higher BGP (100–950 µg-C/L) in the SWRO feed water corresponded to a higher normalized pressure drop in the SWRO, suggesting the applicability of using BGP as a biofouling indicator in SWRO systems. However, to validate this conclusion, more SWRO plants with different pre-treatment systems need to be monitored for longer periods of time.

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Measuring Bacterial Growth Potential of Ultra-Low Nutrient Drinking Water Produced by Reverse Osmosis: Effect of Sample Pre-treatment and Bacterial Inoculum

Frontiers in Microbiology ◽

10.3389/fmicb.2020.00791 ◽

2020 ◽

Vol 11 ◽

Author(s):

Mohaned Sousi ◽

Sergio G. Salinas-Rodriguez ◽

Gang Liu ◽

Jan C. Schippers ◽

Maria D. Kennedy ◽

...

Keyword(s):

Drinking Water ◽

Reverse Osmosis ◽

Bacterial Growth ◽

Growth Potential ◽

Bacterial Inoculum ◽

Pre Treatment

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Biofouling potential using ATP-based bacterial growth potential method

Assessing Bacterial Growth Potential in Seawater Reverse Osmosis Pretreatment: Method Development and Applications ◽

10.1201/9781003021940-4 ◽

2019 ◽

pp. 77-110

Author(s):

Almotasembellah Mustafa Jawdat Abushaban

Keyword(s):

Bacterial Growth ◽

Potential Method ◽

Growth Potential

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Characterization of seawater reverse osmosis fouled membranes from large scale commercial desalination plant

10.31221/osf.io/96zj5 ◽

2019 ◽

Author(s):

Chem Int

Keyword(s):

Reverse Osmosis ◽

Large Scale ◽

Retention Rate ◽

Local Level ◽

Microscopic Analysis ◽

Transmembrane Pressure ◽

Hydraulic Permeability ◽

Seawater Reverse Osmosis ◽

A Chain

The objective of this work is to study the ageing state of a used reverse osmosis (RO) membrane taken in Algeria from the Benisaf Water Company seawater desalination unit. The study consists of an autopsy procedure used to perform a chain of analyses on a membrane sheet. Wear of the membrane is characterized by a degradation of its performance due to a significant increase in hydraulic permeability (25%) and pressure drop as well as a decrease in salt retention (10% to 30%). In most cases the effects of ageing are little or poorly known at the local level and global measurements such as (flux, transmembrane pressure, permeate flow, retention rate, etc.) do not allow characterization. Therefore, a used RO (reverse osmosis) membrane was selected at the site to perform the membrane autopsy tests. These tests make it possible to analyze and identify the cause as well as to understand the links between performance degradation observed at the macroscopic scale and at the scale at which ageing takes place. External and internal visual observations allow seeing the state of degradation. Microscopic analysis of the used membranes surface shows the importance of fouling. In addition, quantification and identification analyses determine a high fouling rate in the used membrane whose foulants is of inorganic and organic nature. Moreover, the analyses proved the presence of a biofilm composed of protein.

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