Design Considerations for Cost-Effective Ozone Mass Transfer in Sidestream Systems

Rakness, Kerwin L.; Hunter, Glenn; Lew, Julia; Mundy, Bill; Wert, Eric C.

doi:10.1080/01919512.2018.1424532

Cited by 12 publications

(5 citation statements)

References 4 publications

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“…The efficiency of the oxidation by ozonation also relies on the mass transfer of O 3 into the solution. The effectiveness of O 3 transferred from one phase to another across a gas–liquid interface is primarily influenced by four main factors, namely, gas flow rate, ozone concentration, large interface area (size of bubble), and water pressure (Rakness et al, 2018).…”

Section: Resultsmentioning

confidence: 99%

Effectiveness of ozonation with zirconium and tin tetrachloride for stabilized anaerobic landfill leachate treatment

Zakaria

Aziz

Alazaiza

2022

Water Environment Research

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Landfill leachate can threaten the environment and human life. Therefore, this study aims to investigate the efficiency of ozone (O 3 ), O 3 with zirconium tetrachloride (O 3 /ZrCl 4 ), and O 3 with tin tetrachloride (O 3 /SnCl 4 ) in remediating the stabilized anaerobic landfill leachate (SAL) from Alor Pongsu, Perak. Hydroxyl radical (OH•) is an important oxidizing agent in the ozonation process. Its presence was tested using tert-butyl alcohol. Results showed that using ZrCl 4 and SnCl 4 in ozonation boosted the generation of hydroxyl radical, thereby enhancing the oxidation process and pollutant removal inside the sample. The O 3 /ZrCl 4 mix at chemical oxygen demand (COD) to ZrCl 4 ratio of 1:1.5, pH 8-9, and 90-min reaction time resulted in the highest reduction rates of COD and color at 91.9% and 99.6%, respectively. All results demonstrated that the optimum performance occurred at alkaline conditions (pH > 8), proving that OH radicals primarily oxidized the pollutants through an indirect reaction pathway. The biodegradability (biochemical oxygen demand/COD) ratio was also considerably improved from 0.02 (raw) to 0.37 using O 3 /ZrCl 4 , compared with using O 3 alone and using O 3 / SnCl 4 , which only recorded 0.23 and 0.28, respectively, after the treatment. The study demonstrated that O 3 /ZrCl 4 was the most efficient combination. Practitioner Points• The O 3 /ZrCl 4 recorded the highest COD and color removals.• The O 3 /ZrCl 4 combination also recorded higher OH• concentrations.• The biodegradability of leachate (BOD 5 /COD ratio) improved from 0.02 to 0.37.

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Section: Resultsmentioning

confidence: 99%

Effectiveness of ozonation with zirconium and tin tetrachloride for stabilized anaerobic landfill leachate treatment

Zakaria

Aziz

Alazaiza

2022

Water Environment Research

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“…Because reactor hydraulics should approach plug flow for efficient disinfection and oxidation, there is limited room for changes. However, one factor that can influence bromate formation is the ozone mass-transfer (i.e., dissolution of gaseous ozone in water) method and design. , There are two major methods for ozone mass transfer: (i) fine bubble diffusion (FBD) and (ii) addition of a concentrated ozone solution through a sidestream. Alternative ozone injection methods, such as injection through membranes or as micro/nanobubbles, have been developed, though their ability to minimize bromate formation has not yet been evaluated. In FBD systems, the first chamber of an ozone contactor is used for ozone gas–liquid transfer (Figure a).…”

Section: Mitigationmentioning

confidence: 99%

Critical Review on Bromate Formation during Ozonation and Control Options for Its Minimization

Morrison

Hogard

Pearce

et al. 2023

Environ. Sci. Technol.

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Ozone is a commonly applied disinfectant and oxidant in drinking water and has more recently been implemented for enhanced municipal wastewater treatment for potable reuse and ecosystem protection. One drawback is the potential formation of bromate, a possible human carcinogen with a strict drinking water standard of 10 μg/L. The formation of bromate from bromide during ozonation is complex and involves reactions with both ozone and secondary oxidants formed from ozone decomposition, i.e., hydroxyl radical. The underlying mechanism has been elucidated over the past several decades, and the extent of many parallel reactions occurring with either ozone or hydroxyl radicals depends strongly on the concentration, type of dissolved organic matter (DOM), and carbonate. On the basis of mechanistic considerations, several approaches minimizing bromate formation during ozonation can be applied. Removal of bromate after ozonation is less feasible. We recommend that bromate control strategies be prioritized in the following order: (1) control bromide discharge at the source and ensure optimal ozone mass-transfer design to minimize bromate formation, (2) minimize bromate formation during ozonation by chemical control strategies, such as ammonium with or without chlorine addition or hydrogen peroxide addition, which interfere with specific bromate formation steps and/or mask bromide, (3) implement a pretreatment strategy to reduce bromide and/or DOM prior to ozonation, and (4) assess the suitability of ozonation altogether or utilize a downstream treatment process that may already be in place, such as reverse osmosis, for post-ozone bromate abatement. A one-size-fits-all approach to bromate control does not exist, and treatment objectives, such as disinfection and micropollutant abatement, must also be considered.

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“…The main costs of ozone operation relate to a combination of energy and oxygen consumption [12]. Usually, ozone is dissolved into the water phase via bubbling using various types of gas diffusers or side stream injection [13]. Knowledge and quantification of ozone mass transfer is crucial for the design of treatment operations [14].…”

Section: Introductionmentioning

confidence: 99%

A Single Tube Contactor for Testing Membrane Ozonation

Zoumpouli

Baker

Taylor

et al. 2018

Water

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A membrane ozonation contactor was built to investigate ozonation using tubular membranes and inform computational fluid dynamics (CFD) studies. Non-porous tubular polydimethylsiloxane (PDMS) membranes of 1.0–3.2 mm inner diameter were tested at ozone gas concentrations of 110–200 g/m3 and liquid side velocities of 0.002–0.226 m/s. The dissolved ozone concentration could be adjusted to up to 14 mg O3/L and increased with decreasing membrane diameter and liquid side velocity. Experimental mass transfer coefficients and molar fluxes of ozone were 2.4 × 10−6 m/s and 1.1 × 10−5 mol/(m2 s), respectively, for the smallest membrane. CFD modelling could predict the final ozone concentrations but slightly overestimated mass transfer coefficients and molar fluxes of ozone. Model contaminant degradation experiments and UV light absorption measurements of ozonated water samples in both ozone (O3) and peroxone (H2O2/O3) reaction systems in pure water, river water, wastewater effluent, and solutions containing humic acid show that the contactor system can be used to generate information on the reactivity of ozone with different water matrices. Combining simple membrane contactors with CFD allows for prediction of ozonation performance under a variety of conditions, leading to improved bubble-less ozone systems for water treatment.

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Design Considerations for Cost-Effective Ozone Mass Transfer in Sidestream Systems

Cited by 12 publications

References 4 publications

Effectiveness of ozonation with zirconium and tin tetrachloride for stabilized anaerobic landfill leachate treatment

Effectiveness of ozonation with zirconium and tin tetrachloride for stabilized anaerobic landfill leachate treatment

Critical Review on Bromate Formation during Ozonation and Control Options for Its Minimization

A Single Tube Contactor for Testing Membrane Ozonation

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