Biofouling control by UV/H2O2 pretreatment for brackish water reverse osmosis process
23 Aug 2018-Vol. 4, Iss: 9, pp 1331-1344
TL;DR: In this paper, the potential of medium pressure (MP)-UV/H2O2 as a pretreatment step to control brackish water RO biofouling caused by indigenous microorganisms was evaluated.
Abstract: UV applied with H2O2 is a well-known advanced oxidation process (AOP) for degradation of trace organic compounds. However, the UV/H2O2 process has scarcely been documented as a disinfection method for brackish or seawater applications or particularly as a potential reverse osmosis (RO) biofouling control tool in varied treatment scenarios. The objective of this paper is to evaluate the potential of medium-pressure (MP)-UV/H2O2 as a pretreatment step to control brackish water RO (BWRO) biofouling caused by indigenous microorganisms. UV/H2O2 pretreatment significantly reduced total heterotrophic counts. Consequently, the quantity of biofilm cells and extracellular polymeric substances (EPS) following UV/H2O2 pretreatment was significantly lower than that obtained after the control and the singular UV pretreatment steps. This is attributed to the additive or synergistic effect of MP UV light, H2O2 and ˙OH radicals. Hence, UV/H2O2 has a high potential as a biofouling control tool in BWRO desalination systems. Higher H2O2 concentrations may achieve improved biofouling control due to enhanced radical formation and higher H2O2 residual effect.
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01 Jan 2018
TL;DR: A comprehensive review of the role of polymeric membranes in the treatment of wastewater to potable water quality and highlight recent advancements in separation processes is provided in this paper, where the authors provide a background and history of the potable reuse process chains, pretreatment steps, and advanced oxidation processes.
Abstract: Conventional water resources in many regions are insufficient to meet the water needs of growing populations, thus reuse is gaining acceptance as a method of water supply augmentation. Recent advancements in membrane technology have allowed for the reclamation of municipal wastewater for the production of drinking water, i.e., potable reuse. Although public perception can be a challenge, potable reuse is often the least energy-intensive method of providing additional drinking water to water stressed regions. A variety of membranes have been developed that can remove water contaminants ranging from particles and pathogens to dissolved organic compounds and salts. Typically, potable reuse treatment plants use polymeric membranes for microfiltration or ultrafiltration in conjunction with reverse osmosis and, in some cases, nanofiltration. Membrane properties, including pore size, wettability, surface charge, roughness, thermal resistance, chemical stability, permeability, thickness and mechanical strength, vary between membranes and applications. Advancements in membrane technology including new membrane materials, coatings, and manufacturing methods, as well as emerging membrane processes such as membrane bioreactors, electrodialysis, and forward osmosis have been developed to improve selectivity, energy consumption, fouling resistance, and/or capital cost. The purpose of this review is to provide a comprehensive summary of the role of polymeric membranes in the treatment of wastewater to potable water quality and highlight recent advancements in separation processes. Beyond membranes themselves, this review covers the background and history of potable reuse, and commonly used potable reuse process chains, pretreatment steps, and advanced oxidation processes. Key trends in membrane technology include novel configurations, materials and fouling prevention techniques. Challenges still facing membrane-based potable reuse applications, including chemical and biological contaminant removal, membrane fouling, and public perception, are highlighted as areas in need of further research and development.
201 citations
30 Aug 2019
TL;DR: There are three suggested areas of additional research offering promising, polyamide membrane-targeted biofouling minimization that are discussed, and proactive cleaning, which aims to control the extent of bioFouling by cleaning before it negatively affects membrane performance, shows potential for low- to middle-risk systems.
Abstract: Reverse osmosis and nanofiltration systems are continuously challenged with biofouling of polyamide membranes that are used almost exclusively for these desalination techniques. Traditionally, pretreatment and reactive membrane cleanings are employed as biofouling control methods. This in-depth review paper discusses the mechanisms of membrane biofouling and effects on performance. Current industrial disinfection techniques are reviewed, including chlorine and other chemical and non-chemical alternatives to chlorine. Operational techniques such as reactive membrane cleaning are also covered. Based on this review, there are three suggested areas of additional research offering promising, polyamide membrane-targeted biofouling minimization that are discussed. One area is membrane modification. Modification using surface coatings with inclusion of various nanoparticles, and graphene oxide within the polymer or membrane matrix, are covered. This work is in the infancy stage and shows promise for minimizing the contributions of current membranes themselves in promoting biofouling, as well as creating oxidant-resistant membranes. Another area of suggested research is chemical disinfectants for possible application directly on the membrane. Likely disinfectants discussed herein include nitric oxide donor compounds, dichloroisocyanurate, and chlorine dioxide. Finally, proactive cleaning, which aims to control the extent of biofouling by cleaning before it negatively affects membrane performance, shows potential for low- to middle-risk systems.
66 citations
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...[385] investigated using an AOP using MP-UV with peroxide for biofouling control of brackish water RO processes....
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TL;DR: The review scans research articles published in 2018 on physico-chemical processes for water and wastewater treatment for membrane technology, granular filtration, flotation, adsorption, coagulation/flocculation, capacitive deionization (CDI), ion exchange (IEX), and oxidation.
Abstract: By summarizing 187 relevant research articles published in 2019, the review is focused on the research progress of physicochemical processes for wastewater treatment. This review divides into two sections, physical processes and chemical processes. The physical processes section includes three sub-sections, that is, adsorption, granular filtration, and dissolved air flotation, whereas the chemical processes section has five sub-sections, that is, coagulation/flocculation, advanced oxidation processes, electrochemical, capacitive deionization, and ion exchange. PRACTITIONER POINTS: Totally 187 research articles on wastewater treatment have been reviewed and discussed. The review has two major sections with eight sub-topics.
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...To control biofouling in RO (BWRO) treating brackish water, Lakretz et al. (2018) pretreated the influent with...
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...To control biofouling in RO (BWRO) treating brackish water, Lakretz et al. (2018) pretreated the influent with medium‐pressure (MP)‐UV/H2O2....
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TL;DR: In this article, the effect of ultraviolet (UV) disinfection on reverse osmosis (RO) membrane fouling was investigated and the mechanism was also revealed in this study. And the morphology of the fouled RO membranes indicated serious biofouling in all groups.
30 citations
References
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TL;DR: In this article, the rate constants for over 3500 reaction are tabulated, including reaction with molecules, ions and other radicals derived from inorganic and organic solutes, and the corresponding radical anions, ⋅O− and eaq−, have been critically pulse radiolysis, flash photolysis and other methods.
Abstract: Kinetic data for the radicals H⋅ and ⋅OH in aqueous solution,and the corresponding radical anions, ⋅O− and eaq−, have been critically pulse radiolysis, flash photolysis and other methods. Rate constants for over 3500 reaction are tabulated, including reaction with molecules, ions and other radicals derived from inorganic and organic solutes.
9,887 citations
TL;DR: The analysis of aqueous H 2 O 2 at concentrations as low as 1 μM is conveniently done by the I 3 - method, which is based on the spectrophotometric determination of I 3, formed when H 2 o 2 is added to a concentrated solution of I -. At 351 nm, E max (I 3 - ) was measured to be 26 450 M -1 cm -1.
Abstract: The analysis of aqueous H 2 O 2 at concentrations as low as 1 μM is conveniently done by the I 3 - method, which is based on the spectrophotometric determination of I 3 - formed when H 2 O 2 is added to a concentrated solution of I - . At 351 nm, E max (I 3 - ) was measured to be 26 450 M -1 cm -1 . By contrast, an apparent value of 25 800 M -1 cm -1 was determined from a calibration of the I 3 - method against titration by permanganate. The difference could only be partially accounted for by the equilibrium between I 3 - , I 2 , and I -
802 citations
TL;DR: Kinetic modeling of phenol destruction demonstrated that RHS contributed significantly to phenol Destruction, mitigating the impact of HO* scavenging, and the formation of halogenated byproducts was minimal.
Abstract: Advanced oxidation processes (AOPs) generating nonselective hydroxyl radicals (HO*) provide a broad-spectrum contaminant destruction option for the decontamination of waters. Halide ions are scavengers of HO* during AOP treatment, such that treatment of saline waters would be anticipated to be ineffective. However, HO* scavenging by halides converts HO* to radical reactive halogen species (RHS) that participate in contaminant destruction but react more selectively with electron-rich organic compounds. The effects of Cl-, Br-, and carbonates (H2CO3+HCO3-+CO3(2-)) on the UV/H2O2 treatment of model compounds in saline waters were evaluated. For single target organic contaminants, the impact of these constituents on contaminant destruction rate suppression at circumneutral pH followed the order Br->carbonates>Cl-. Traces of Br- in the NaCl stock had a greater effect than Cl- itself. Kinetic modeling of phenol destruction demonstrated that RHS contributed significantly to phenol destruction, mitigating the impact of HO* scavenging. The extent of treatment efficiency reduction in the presence of halides varied dramatically among different target organic compounds. Destruction of contaminants containing electron-poor reaction centers in seawater was nearly halted, while 17beta-estradiol removal declined by only 3%. Treatment of mixtures of contaminants with each other and with natural organic matter (NOM) was evaluated. Although NOM served as an oxidant scavenger, conversion of nonselective HO* to selective radicals due to the presence of anions enhanced the efficiency of electron-rich contaminant removal in saline waters by focusing the oxidizing power of the system away from the NOM toward the target contaminant. Despite the importance of contaminant oxidation by halogen radicals, the formation of halogenated byproducts was minimal.
697 citations
TL;DR: “biofilm-enhanced osmotic pressure” plays a dominant role in RO biofouling, with scanning electron microscope images of dead cells and biofilm supporting these proposed mechanisms.
586 citations