A short review on reverse osmosis pretreatment technologies

Jamaly, Sanaa; Darwish, N.N.; Ahmed, Iftikhar; Hasan, Shadi W.

doi:10.1016/j.desal.2014.09.017

Cited by 283 publications

(131 citation statements)

References 65 publications

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“…Similar to surface-water treatment, the low solids content in these applications allows the low-pressure membranes to be operated in the dead-end filtration mode with intermittent backwashing. The main advantages of membrane filtration compared to conventional pretreatments such as coagulation, flocculation, and sand filtration are improved water quality, smaller footprint, less chemical requirements, and consistent quality of the filtrate [38,39,52,53]. Higher energy demand and membrane fouling are the main disadvantages of having a membrane-filtration system for RO pretreatment.…”

Section: Pretreatment For Ro Desalination and Reclamationmentioning

confidence: 99%

The Performance and Fouling Control of Submerged Hollow Fiber (HF) Systems: A Review

et al. 2017

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Abstract:The submerged membrane filtration concept is well-established for low-pressure microfiltration (MF) and ultrafiltration (UF) applications in the water industry, and has become a mainstream technology for surface-water treatment, pretreatment prior to reverse osmosis (RO), and membrane bioreactors (MBRs). Compared to submerged flat sheet (FS) membranes, submerged hollow fiber (HF) membranes are more common due to their advantages of higher packing density, the ability to induce movement by mechanisms such as bubbling, and the feasibility of backwashing. In view of the importance of submerged HF processes, this review aims to provide a comprehensive landscape of the current state-of-the-art systems, to serve as a guide for further improvements in submerged HF membranes and their applications. The topics covered include recent developments in submerged hollow fiber membrane systems, the challenges and developments in fouling-control methods, and treatment protocols for membrane permeability recovery. The highlighted research opportunities include optimizing the various means to manipulate the hydrodynamics for fouling mitigation, developing online monitoring devices, and extending the submerged HF concept beyond filtration.

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Section: Pretreatment For Ro Desalination and Reclamationmentioning

confidence: 99%

The Performance and Fouling Control of Submerged Hollow Fiber (HF) Systems: A Review

et al. 2017

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“…Moreover, it was observed that the system with the activated carbon filter and cationic exchange resin filter pretreatments provided better fluoride rejection. The activated carbon and cationic exchange resin could have retained some ions contained in the feed solution, resulting in the low concentration polarization on the membrane surface [18,[23][24]. Consequently, higher fluoride rejection efficiency was obtained.…”

Section: Fig 2 Pure Water Permeability Of the Reverse Osmosis Membrmentioning

confidence: 99%

“…Pretreatment units can be added to enhance a system's defluoridation performance. In addition to its water pretreatment duties, a pretreatment unit can prevent the membrane from deterioration and foulants, and also expand the useful life of the membrane [17][18].…”

Section: Introductionmentioning

confidence: 99%

Effects of Activated Carbon and Cationic Exchange Resin Pretreatments on Groundwater Defluoridation by Reverse Osmosis Process

Chantharawong

Wongrueng

Rakruam

et al. 2017

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Abstract. The objective of this research was to study the effects of a pretreatment using activated carbon and cationic exchange resin on groundwater defluoridation by a reverse osmosis membrane. Actual groundwater containing a high fluoride concentration was collected and examined. Experiments were operated under controlled conditions: a transmembrane pressure of 0.6 MPa and temperature of 25 °C. The reverse osmosis system with activated carbon and cationic exchange resin pretreatments had higher fluoride removal than the one without the pretreatments, 97% compared to 95%, respectively. Additionally, the reverse osmosis system with the pretreatments also produced a higher permeate flux, 1.1 10 -5 compared 9.6 10 -6 m 3 /m 2 ·s without the pretreatment. When the reverse osmosis systems with and without pretreatments were fouled, they showed a decrease in fluoride rejection, as well as a permeate flux decline. After the fouled reverse osmosis membranes were chemically cleaned, the permeate flux recovery and the fluoride rejection of the osmosis system with the pretreatments improved. It could be concluded that the activated carbon and cationic exchange resin played an important role in improving the reverse osmosis system as they contributed to high fluoride rejection and high permeate flux.

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“…Furthermore, ferric chloride has a high ratio of cationic charge to total mass (Jamaly et al, 2014) that makes hydrolysis products more reactive and adsorptive with emulsified and semi-emulsified organic matter; e.g., oil and grease, natural and synthetic organic matter. The settled sludge volume of the ferric hydroxide formed from ferric chloride is reportedly 30-60% that of sulphate based coagulants (e.g., Fe 2 (SO 4 ) 3 ).…”

Section: Coagulationmentioning

confidence: 99%