Article

Bromate Formation During Ozonation of Drinking Water: A Response Surface Methodology Study

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Abstract

The use of ozone in water treatment encounters the bromate formation hindrance. If raw water contains bromide, bromate will be formed in the ozonation step. Because bromate is well known as a carcinogenic, it is very important to optimize the treatment process and minimize or eliminate the bromate formation. Response surface optimization methodology (three-variable, three-level experiment Box–Behnken design) was applied in a pilot plant to investigate the effect of operating conditions (pH, initial bromide concentration, and exposure time) on bromate ion formation. Results showed that most of the investigated water facilities have water that exceeds the international standards of bromate content. It also showed that bromate formation is maximum when the pH is close to 9. Bromate formation also favors higher initial bromide concentrations. However, further increase in initial bromide concentration will cause the bromate to be reduced to bromine (Br2) by excess bromide (Br−).Research highlights► Bromate formation was investigated during brackish water disinfection using ozone. ► Response surface optimization methodology was used to investigate the effect of operating conditions on bromate ion formation. ► Results also showed that bromate formation is maximum when the pH is close to 9. ► Bromate formation favors higher initial bromide concentrations. ► Further increase in initial bromide concentration will cause the bromate to be reduced to bromine (Br2) by excess bromide (Br−).

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... Gulf Cooperation Council (GCC) countries. The consumption of bottled drinking water has significantly increased in the past 20 years worldwide and is expected to continue to rise in the future (Aljundi, 2011;Doria, 2006). In Kuwait, the consumption of bottled water has increased from 50.2 to 76.1 L per capita between 1999and 2004(Al-Mudhaf et al., 2011Alsulaili et al., 2015). ...
... Bromate is not naturally found in water (Haiderkadhim, 2017). The presence of bromate is bonded with the availability of bromide (precursor for bromate) in the water sources (Aljundi, 2011;Othman et al., 2010). Bromide can occur naturally in seawater, or it can enter water sources by human activities such as industrial effluent discharges (Radwan et al., 2021;Siddiqui et al., 1995). ...
... In Saudi Arabia, Alsohaimi (2012) stated that 17% of the bottled drinking water samples were above the international MCL. Bromate concentrations in drinking water correlate with the amount of bromide, which is a precursor for bromate, in the water source (Aljundi, 2011;Othman et al., 2010). For instance, seawater has more bromide than freshwater (Alomirah et al., 2019). ...
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The study objectives were to assess bromate concentrations in bottled drinking water sold at retail in Kuwait and assess pH values relationship to bromate concentrations. A cross-sectional study was conducted in 2019 where 120 bottled water samples were collected from supermarkets across six governorates in Kuwait. Samples represented local brands that used distilled or mineral water as well as imported brands that used mineral water only. The samples were analyzed for bromate concentrations and pH values. The overall mean bromate concentration was 4.02 µg/L (95% CI: 3.35–4.69) with concentration of 4.45 µg/L in locally distilled water significantly (P < 0.05) higher than that in imported mineral water samples (i.e., 1.34 µg/L). The overall bromate percent positive was 41.7% (n = 120) with 35.8% in locally distilled samples, significantly higher than that in imported mineral samples (5.8%). None of the local mineral bottled water samples had detectable bromate. Bromate concentrations in our samples were within the international allowable limits of less than 10 µg bromate/L (except for one local distilled sample that contained 14.9 µg bromate/L). The mean pH value was 7.39 (95% CI: 7.33–7.45). There was no significant relationship between pH values and bromate concentrations in our samples. Our findings proved that local and imported bottled water sold at retail in Kuwait was bromate safe.
... Furthermore, ozone sanitation has been long used at municipal water purification facilities and bottled water plants (Loeb et al., 2012;Alsohaimi et al., 2015;Delpla et al., 2014). Nonetheless, if raw water contains bromide (Br − ), bromate (BrO 3 − ) will be formed during water ozonation (Aljundi, 2011;Wang and Chen, 2014) via complex mechanisms involving molecular ozone (O 3 ) and hydroxyl radical (OH•) reactions (Dorevitch et al., 2020). BrO 3 − is a toxic by-product with carcinogenic effects in humans -its maximum permitted concentration in drinking waters being 10 µg/L (Alsohaimi et al., 2015). ...
... BrO 3 − is a toxic by-product with carcinogenic effects in humans -its maximum permitted concentration in drinking waters being 10 µg/L (Alsohaimi et al., 2015). The presence of BrO 3 − in water is especially worrying since, unlike other by-products, it is not biodegradable, so biological treatments are not efficient in its removal (Aljundi, 2011). ...
Article
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This study was aimed at employing response surface methodology (RSM) for optimization of process variables and identifying optimal conditions for the adsorption of bromate (BrO3-) from contaminated water using multi-walled carbon nanotubes, based on iron hydr(oxide), Fe-CNTs nanocomposite. Fifteen experimental runs were conducted in batch mode to study the effect of individual as well as interactive process variables, i.e., pH, BrO3− initial concentration, and adsorbent dose, on the removal of BrO3− using Box–Behnken design (BBD) of RSM. The coefficient of determination (R2) at 98.34% indicated a good agreement between actual and predicted values. The main effect and contour plot were drawn to obtain the independent and interactive effect of operational variables on BrO3− uptake. A process optimization curve was drawn to determine the optimum operating conditions that lead to a desirable response. The optimum conditions for BrO3− adsorption using Fe-CNTs nanocomposite were found to be pH 2.0, initial BrO3− concentration of 10.0 mg/L, and adsorbent dose of 0.010 g per 50 mL solution.
... As an alternative to the comet assay, we have developed an automated version of the "Fluorimetric detection of Alkaline DNA Unwinding" (FADU) assay (Moreno-Villanueva et al., 2009, 2011. First described by Birnboim and Jevcak (1981), the method uses a highly alkaline pH for unwinding of genomic DNA in a cell lysate, starting at chromosome ends and sites of replication. ...
... In line with the literature (Speit et al., 2004), Figure 4B,D shows that Fpg recognizes both oxidative and methylation lesions. Since human 8-oxoguanine-DNA glycosylase recognizes only oxidative DNA lesions like 8-oxodG and formamidopyrimidine, Fpg could be replaced with this more specific glycosy-nated samples, which is of great interest, for example in the now more commonly used potentially genotoxic ozonation of water (Aljundi, 2011;Wu et al., 2019). We showed that KBrO 3 treatment selectively leads to Fpg-sensitive sites without direct induction of SBs. ...
... Since then, bromate formation has been often reported in bromide containing water treated by ozonation under different conditions, where the conversion ratio of bromide to bromate is in the range of 0.1e64.2% (wt/wt) (Aljundi, 2011). Bromate formation in water systems has attracted tremendous attention in recent years (Agus et al., 2009;Lv et al., 2019). ...
... Later, another study demonstrated that bromate formation during ozonation in drinking water was affected by pH, contact time, and initial bromide concentration. This research proved that the maximum formation of bromate occurred when pH was close to 9.0 (Aljundi, 2011). During ozonation of natural waters, bromate formation at concentrations ranging from 2 to 293 mg/L was reported under drinking water treatment conditions (Wang et al., 2018). ...
Article
Disinfection in water treatment and reclamation systems eliminates the potential health risks associated with waterborne pathogens, however it may produce disinfection by-products (DBPs) harmful to human health. Potentially carcinogenic bromate is a DBP formed during the ozonation of bromide-containing waters. To mitigate the problem of bromate formation, different physical/chemical or biological reduction methods of bromate have been investigated. Until now, adsorption-based physical method has proven to be more effective than chemical methods in potable water treatment. Though several studies on biological reduction methods have been carried out in a variety of bioreactor systems, such as in biologically active carbon filters and denitrifying bioreactors, the microbiological mechanisms or biochemical pathways of bromate minimization have not been clearly determined to date. Genetic analysis could provide a broader picture of microorganisms involved in bromate reduction which might show cometabolic or respiratory pathways, and affirm the synergy functions between different contributing groups. The hypothesis established from the diffusion coefficients of different electron donor and acceptors, illustrates that some microorganisms preferring bromate over oxygen contain specific enzymes which lower the activation energy required for bromate reduction. In addition, considering microbial bromate reduction as an effective treatment strategy; field scale investigations are required to observe quantitative correlations of various influencing parameters such as pH, ozone dose, additives or constituents such as ammonia, hydrogen peroxide, and/or chloramine, dissolved organic carbon levels, dissolved oxygen gradient within biofilm, and empty bed contact time on bromate removal or reduction.
... For instance, ozone-based AOPs could lead to the formation of bromate in bromide containing water. 259 Bromate is a genotoxic human carcinogen and nonbiodegradable compound. Therefore, a maximum acceptable contaminant level has been set as 10 mg L À1 for bromate by the United States, European Union, and World Health Organization. ...
... Therefore, a maximum acceptable contaminant level has been set as 10 mg L À1 for bromate by the United States, European Union, and World Health Organization. 259 However, two important strategies for bromate control during drinking water ozonation have been proposed, i.e., pH decrease and ammonia addition. 260 Similarly, SR-AOPs could lead to the formation of chlorate and bromate in chloride and bromide containing water. ...
... hydroxyl-ibuprofen and carboxy-ibuprofen) which may have similar or greater toxicity than the original compound (Ghauch et al., 2012). Also, if bromide ions are present in water, AOPs may lead to the formation of brominated by-products such as bromate and brominated organic compounds which are carcinogenic and genotoxic in nature (Aljundi, 2011). Ozonation of PhACs lead to the formation of by-products, which are at times as toxic or more toxic than the parent compound (Westerhoff et al., 2005). ...
... As a result, complete mineralization of organic matter is not attained. Presence of bromide ions may lead to the formation of brominated byproducts such as bromate and brominated organic compounds which are carcinogenic and genotoxic in nature (Aljundi, 2011). Also, oxidative reactions with ozone are relatively slow and selective therefore modifications of ozonation process have been considered to overcome the limitations (Nawrocki and Kasprzyk-Hordern, 2010). ...
... Optimization through factorial design and response surface methodology (RSM) has been a common practice in biotechnology (Kalil et al. 2000). RSM is widely applied in chemical (Aljundi 2011), biology (Trawczynska and Wojcik 2015), enzyme, and other fields for the optimization of all kinds of biochemical, biotechnological, and microbiological products (Beg et al. 2003). It minimizes experimentation and time and is far more efficient than traditional methods for optimizing such a process (Nie et al. 2013). ...
... With 5 experiments at the central level as replicates, the research included 17 total runs (Table 2). Based on the collected data (Table 2), regression analysis was used and was integrated into the aposteriori second-order polynomial model (Aljundi 2011) to analyze whether there was correlation between the factors and the response variables (Trinh and Kang 2011). The second-order quadratic model is shown as Eq. 1, ...
Article
The laccase-mediator system in laccase-aided chlorine dioxide bleaching of bagasse pulp was optimized using response surface methodology (RSM). The effects and interactions of the laccase enzyme dosage, the dosage of the mediator 1-hydroxybenzotriazole (HBT), and the reaction time on the adsorbed organic halogen (AOX) content of the wastewater as well as the brightness and kappa number of the pulp were examined. The optimal reaction conditions to achieve a balance of lower AOX content, higher brightness, and lower kappa number were as follows: laccase enzyme dosage of 20.3 U/g, HBT dosage of 1.51%, and reaction time of 154.5 min. Under these conditions, an AOX content of 20.67 mg/L, brightness of 58.94% ISO, and kappa number of 2.71 were observed. These results will offer a favorable option for pulp and paper mills as well as the natural environment and therefore provide a theoretical foundation for the industrial application of laccase in bleaching processes.
... The use of ozone in water treatment has been applied worldwide for many years to disinfect drinking water, and much research has been conducted recently in this area. Ozone has a powerful antibacterial ability due to its oxidizing capacity, and it is now widely applied to eliminate the pathogenic microorganisms in drinking water and at wastewater treatment plants (Aljundi 2011). When applied in water, ozone affects the permeability, enzymatic activity, and DNA of bacterial cells (Bitton 2005). ...
... The main drawbacks of ozone disinfection are the corrosive environment of the ozone disinfection system, the high cost for the initial setup, high electricity consumption, and the lack of any residual bactericidal effect. Ozone use in drinking water treatment can cause the formation of organic (aldehydes, carboxylic acids, and ketones) and inorganic (bromate) disinfection by-products in the presence of naturally occurring organic matter, anthropogenic contaminants, bromide, and iodide in water (Richardson et al. 1999;Beltràn 2004;Huang, Fang, and Wang 2005;Aljundi, 2011). ...
Article
The effect of ozonation on the microbial activities of domestic well drinking water was investigated, and the influence of the treatment conditions such as pH, temperature, ozone dose, and contact time was elucidated by comparing removal efficiencies. The results revealed that the disinfection of the microorganisms was related to an increase in contact time and thereby increases in Ct values with ozone. Higher ozone doses led to a large amount of microbial inactivation. The addition of hydroxyl and hydronium ions contributed greatly to the destruction of any microorganism in both acidic and basic mediums, achieving 25–88% efficiencies.
... Despite all of the advantages offered by ozonation processes [8][9][10][11][12][13], the formation of bromate remains a problem. Bromate ion (BrO 3 − ), a potential human carcinogen that is regulated in drinking water [14][15][16], is formed during the ozonation of bromide (Br − ) containing waters. ...
... It has been shown that bromate formation is influenced by a number of factors, including the concentration of bromide ion present in water, ozone dose, pH, contact time, and temperature [13,16,25,29,30]. The rate of formation of • OH in ozone systems is strongly pH dependent as the hydroxide ion initiates the formation of • OH in water [31], so pH can also influence bromate formation. ...
Article
The effect of the nature of the membrane surface, the presence of hydroxyl radical scavengers, and temperature, on bromate formation in a hybrid ozonation membrane filtration reactor was studied. The presence of tertiary butyl alcohol, a hydroxyl radical scavenger, suppressed the indirect bromate formation pathway and less bromate was formed. Bromate formation was less with the Mn oxide coated membrane than when using the uncoated TiO2 membrane. As the temperature was increased, bromate formation was enhanced, which was attributed to faster reaction rates. An empirical model was developed to predict bromate formation in a hybrid ozone-ceramic membrane filtration system. The model takes into account the effects of important experimental variables including initial bromide concentration, inlet ozone injection mass rate, pH, temperature, and reaction time. The coefficients in the model were determined using multiple linear regression with logarithmic transformations. The model indicated that bromate formation was favored at high bromide concentration, ozone dose, pH, and temperature. Good correlation was achieved between the model predictions and the experimental data.
... Normally, oxidative treatment by either chlorination or ozonation is applied to water to disinfect the product and eliminate taste and dour compounds [6]. Nonetheless, both oxidative water approaches result in the formation of non-desired and possibly carcinogenic brominated disinfection by-products (DBPs) such as brominated total trihalomethanes (TTHMs) and bromate BrO − 3 [5,7]. Altogether, removal methodologies aim to control the formation of brominated DBPs [8,9]. ...
Article
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The reuse and separation of nanomaterials from an aquatic solution is always challenging and may cause nanotoxicity if not separated completely. Nanomaterial immobilization on the surface of a macro-size material could be an effective approach to developing an efficient composite for groundwater purification. Herein, polyaniline and graphene oxide nanosheet immobilized granular tea waste (PANI/GO@GTW) has been synthesized to remove the anionic and cationic contaminants from groundwater. The synthesized materials were characterized by SEM, XRD, XPS, and FTIR spectroscopies. The optimization of experimental conditions was tested for bromide (Br−) removal from synthetic water. The results revealed that Br− adsorption behavior onto the synthesized materials was as follows: PANI/GO < PANI/GTW < PANI < PANI/GO@GTW. The optimum removal of Br− ions was observed at pH 3 with 90 min of saturation time. Br− adsorption onto PANI/GO@GTW followed the pseudo-first-order kinetic and Langmuir isotherm model, and electrostatic interaction was involved in the adsorption process. The optimum adsorption of Br− onto PANI/GO@GTW was found to be 26.80 m/g. The application of PANI/GO@GTW on real groundwater treatment demonstrated the effective removal of anion pollutants such as F−, Cl−, Br−, NO3−, and PO43−. This study revealed that PANI/GO@GTW successfully reduced Br− concentrations in synthetic and real groundwater and can be used for large-scale applications.
... [16][17] Therefore, Bajpai suggested the need of a detailed study on optimizing PAA dosage during pulp bleaching. 18 The optimization of process parameters through response surface methodology (RSM) is a common practice and widely utilized in various research fields, [19][20][21] being suitable for delignification and bleaching studies as well. 22 In comparison with traditional methods, RSM can minimize the number of experiments and save time. ...
Article
Pulp bleaching processes emit many toxic substances. Peracetic acid (PAA) has been long recognized as an efficient bleaching agent for cellulose pulps. In the present study, 20 runs were conducted using response surface methodology (RSM) through central composite design for optimization of peracetic acid treatment of hardwood pulp, as a pretreatment step before applying conventional bleaching. Three factors, namely temperature (50-80 °C), time (0.5-2.0 h) and PAA dose (0.5-2.0%), were investigated to find out their impact on the kappa number, yield, brightness and viscosity of the pulp. The findings revealed that the peracetic acid dose of 1.0% at 80 °C for 1.0 h was the most suitable to obtain pulp of kappa number 10.2, yield of 96.87%, brightness of 43.6% ISO and viscosity of 11.7 cP. FTIR analysis revealed that the peracetic acid pretreatment of the pulp led to lower lignin content, compared to untreated pulp, but also reduced the bleaching effluent parameters, such as BOD, COD, TDS, color and AOX, by 43.0%, 55.7%, 31.9%, 51.4% and 51.1%, respectively.
... The formation of bromate results from different oxidation processes of bromine, which include chlorination in the presence of sunlight/UV [86], ozonation [87] and sulphate-based oxidation [88,89]. However, it has been reported that the bromate formed during the chlorination treatment rapidly reacts with organic carbon present in the water treatment system to form other brominated disinfection by-products like bromoform [90,91]. ...
Chapter
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Due to the adverse health and environmental effects of halogen, based on oxyanions in water, the occurrence and distribution have been of great concern, worldwide. Therefore, in this chapter, the occurrence, chemical structure, the natural and anthropogenic sources of these oxyanions were appraised. The impacts on human health and the environment and their fate in water are carefully enunciated. Different techniques that have been developed for the determination of halogen-oxyanions in aqueous solutions are discussed. Finally, a perspective for future research on halogen-based oxyanions is provided, and the possible research gaps, which are begging for answers, are also highlighted.
... Bromate (BrO 3 − ) ions are stable in drinking water, which mainly originate from water disinfection by the direct and indirect paths of ozonation when bromide ions (Br − ) exist in water (Aljundi, 2011;Fischbacher et al., 2015). Bromate has been classified as Group 2B carcinogen to humans by the International Agency for Research on Cancer (IARC) due to it leading to oxidative deoxyribonucleic acid (DNA) damage (WHO, 2011). ...
Article
Bromate, a toxic by-product of bromide-containing drinking water after disinfecting with ozone, has attracted much attention in the past two decades. Traditional methods to activate zero-valent metals for reducing bromate are to eliminate their surface oxide layer by acid washing. In this work, for the first time, zero-valent Al (ZVAl) was surface treated by the following procedures including soaking, soaking and freeze-drying, soaking and heat-treating, and γ-Al2O3 covering Al particle surfaces (GCAP). It was found that all of above surface treated ZVAls have an obvious high efficiency for bromate reduction relative to pristine ZVAl. The bromate reduction rate is GCAP > soaking Al > freeze-drying Al > soaking and heat-treating Al > pristine Al, and using GCAP just 30 min is taken to completely reduce bromate to bromide in neutral solution. Mechanism analyses revealed that Al surface treating or covered by fine γ-Al2O3 phase can promote the hydration and breakage of Al surface passive oxide layer, resulting in a fast contact of inner Al with outside ions, leading to a high reduction rate of bromate in neutral solution. XPS analyses indicated that there are no bromate or bromide ions adsorbed on Al particle surfaces, implying that there is a high direct donating efficiency of electrons from inner Al to bromate ions in solution. Furthermore, GCAP has a good reusability and > 90% bromate can be reduced even it was reused up to 4 cycles.
... RSM is an assortment of statistical and mathematical tools that have proven valuable for multifactor optimization of various processes. (Aljundi, 2011) Box Behnken design (BBD) is a widely exploited form of RSM, particularly tailored for three levels (-1, 0, and +1). BBD is more efficient than other factorial designs including Central Composite Design (CCD) and requires fewer experiments (Kumar et al., 2016). ...
Article
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This research studied the possibility of using ozone to remove iron from groundwater. The optimum conditions were investigated using a Box-Behnken experiment design with statistical analysis by response surface technique. The three parameters investigated, pH (6.0-8.0), hardness (300-500 mg/L as CaCO3) and removal time (10 to 60 min) were independent parameters of iron removal. Data was examined for optimal conditions and included main effects and their interactions. Analysis of variance indicated that the proposed quadratic model successfully interpreted the experimental data with a coefficient of determination (R2) of 98.83% and adjusted R2 of 96.72%. Through this model, it could predict the iron removal efficiency under variable conditions. Furthermore, the optimum conditions were pH 6.99, hardness of 300 mg/L as CaCO3, and 10 min of reaction time. The predicted iron removal efficiency obtained from the model under the optimum conditions was 99.00%. The experiment confirmed that the optimum condition which validated the model’s accuracy of iron removal efficiency was 98.45%. The results showed that ozone can remove iron from groundwater.
... Therefore, RSM is considered as a handy tool for modeling and analysis of problems to evaluate the individual and interactive relationship between factors and responses. In this study, RSM is selected to investigate the synergistic effect of multiple preparation conditions on membrane performance and to determine the optimum conditions [16]. Box-Behnken design is a second-order design consisting of a collection of mathematical and statistical techniques that are useful for the modeling and analysis of problems. ...
Article
Polyelectrolyte multilayer films are currently used to modify the permeation and rejection properties of thin-film composite membranes (TFC). In this paper, response surface methodology was used to study the effect and synergies between interactive parameters essential for modification of the TFC membrane. TFC membranes were prepared using m-phenylenediamine and trimesoyl chloride and modified by spin-assisted layer-by-layer (LbL) technique using polyethyleneimine (PEI) and polyallylamine hydrochloride as the deposition polyelectrolytes. The Box–Behnken design of experiment (DOE) was applied to investigate the effect of preparation conditions (number of deposited layers, pH, the concentration of the polyelectrolyte solutions) on the performance of the modified reverse osmosis (RO) membranes. It was found that under saline feed conditions, higher permeate flux favors higher pH and higher PEI concentration, while salt rejection favors a similar concentration of both polyelectrolytes. In addition, the PEI concentration was found to have a stronger effect on the permeate flux than that of the number of bilayers since it enhanced the hydrophilic functional groups on the membrane surface. Analysis of variance results indicated that the developed models adequately represent the relationship between the studied variables. Optimization of the preparation conditions revealed that both polyelectrolytes must be used at their maximum concentration at a pH of 7.8 with 50 bilayers of the coating. The confirmation run showed a close correlation between the prediction using the DOE and the actual experimental data. This study demonstrated the potential application of DOE to the optimization of LbL RO membrane preparation conditions.
... Ozone increases production costs and requires control mechanisms to avoid overdosing reaching bacterial communities of the biofilters, the tanks or the farm staff. Moreover, ozonation may lead to the formation of organic and inorganic by-products such as aldehydes, ketones and bromate (Schroeder et al., 2015), some of which may be recalcitrant to subsequent biological filtration (Aljundi, 2011). Continued use of hazardous substances such as ozone and another disinfectants (e.g. ...
Article
Hydrogen peroxide (H2O2) treatment is an alternative for disinfection in aquaculture, which may be advantageous as it dissociates and disinfects while increasing water oxygen concentration. Yet, accurate dosing remains undeveloped in Recirculating Aquaculture Systems (RAS). Dosage requirements can depend on organic burden, stocking density, feeding frequency, salinity, temperature and biofilter performance. The present case study investigated the dual effect of H2O2 application for oxygen enrichment and disinfection when continuously applied to a RAS rearing European seabass. H2O2 addition equivalent to 2.4 and 15.8 H2O2 mg L-1 were applied for 4 h per day in three 5-days experiments. H2O2 was injected at the inlet of protein skimmer and/or the rearing tanks in or without combination with traditional disinfection methods. Water microbial load and oxygen saturation were determined, along with stress markers glucose and cortisol in blood plasma of fish. Doses of 15.8 mg L-1 H2O2 steadily increased oxygen levels in holding tank water from ∼50% to over 100% saturation while reducing microbial load (from 604.4 CFU ml-1 in the rearing tanks before dosing to 159.8 CFU ml-1 after application), achieving suitable conditions for commercial fish densities in RAS. The doses used had negligible impact on biofilter performance and did not affect the fish in terms of stress. Overall results indicate H2O2 is effective for disinfection and oxygenation of RAS systems when applied at appropriate dosage and we recommend the protein skimmer as the safest position in order to protect the bacterial community of the biofilters and the reared fish.
... Among the common optimization methods were (i) operating at an acidic pH (ii) lowering ozone dosage/contact time (iii) lowering of initial bromide content and (iv) addition of hydrogen peroxide to quench residual ozone. Tawabini and Zubair [36] reported that bromate formation was significantly reduced by lowering the pH of the groundwater to 6. Aljundi [37] stated that bromate formation during the ozonation process increased with pH, contact time and bromide concentration with the latter being the major governing factor. A pilot case study by Yang et al. [38], that compared the effectiveness of ozone as a pre-oxidation and a post-oxidation system for micro-pollutants removal, revealed that bromate formation can be significantly reduced from 2 mg/L to 0.006 mg/L, when ozone was used as a pre-oxidant. ...
Article
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Reuse of treated sewage effluent is an important option to overcome water scarcity. Conventional wastewater treatment methods are inadequate for the removal of several persistent contaminants such as pharmaceuticals and personal care products (PPCPs). In this study the removal of ibuprofen and gemfibrozil by ozonation and ozone/hydrogen peroxide (O3/H2O2) advanced oxidation process (AOP), as well as the formation of bromate were investigated at different temperatures and pH values. Complete removal of gemfibrozil and a maximum of 80% ibuprofen removal were achieved using ozone dosage of 1.5 mg/L with O3:H2O2 ratio of 1:0.25 in the O3/H2O2 process. The effect of temperature on the removal efficiency of these two compounds was found to be negligible from 25 to 40 ᵒC for both processes. pH effect from 6 to 9 was also found to be negligible for gemfibrozil removal, while ibuprofen had relatively lower removal by ozonation at pH 6 compared to higher pH values. Bromate formation was decreased to 0.012 mg/L when the pH was increased to 9. Increasing the temperature to 40 ᵒC also resulted in less bromate formation which was the lowest value obtained in this study at 0.0102 mg/L. Addition of H2O2 did not affect the formation of bromate and in some cases it was found to be slightly higher compared with ozonation treatment.
... It also has primary disinfection capability without any aqueous chemical by-products (Jain and Singh, 2012). The use of ozone can generate bromate in the presence of bromide, so it can produce by-products (Aljundi, 2011). The advantages and disadvantages of oxidizing agents are summarized in Fig. 4. ...
Article
Providing drinking water with safe arsenic levels in Latin American (LA) countries (a total of 22 countries) is a major current challenge. Arsenic's presence in water has been neglected for many decades since it was first reported ~100 years ago in Argentina. The major arsenic source in this region is geogenic. So far, arsenic has been reported in 15 LA countries. Arsenic concentrations in drinking water have been reported up to >200 fold (2000 μg/L) the WHO limit of 10 μg/L. About 14 million people in the arsenic affected LA countries depend on contaminated water characterized by >10 μg/L of arsenic. Low-cost, easy to use, efficient, and sustainable solutions are needed to supply arsenic safe water to the rural and peri-urban population in the affected areas. In the present study, >250 research articles published on various emerging technologies used for arsenic remediation in rural and peri-urban areas of LA countries are critically reviewed. Special attention has been given to arsenic adsorption methods. The manuscript focuses on providing insights into low cost emergent adsorbents with an implementation potential in Latin America. Natural, modified and synthetic adsorbents used for arsenic decontamination were reviewed and compared. Advantages and disadvantages of treatment methods are summarized. Adsorbent selection criteria are developed. Recommendations concerning emerging adsorbents for aqueous arsenic removal in LA countries have also been made.
... Ozonation is very efficient in removing contaminants from wastewater effluents but it can be responsible for multiple occupational health hazards like headaches, sore throats, irritation in eyes and nose. The residual ozone react with water containing bromite and produces bromate which is a potential genotoxic human carcinogen (Von Gunten and Hoign e, 1994;Kurokawa et al., 1990;Aljundi, 2011). Removal experiments on amoxicillin by UV and UV/H 2 O 2 have achieved 99% degradation in both the processes (Jung et al., 2012). ...
Article
Degradation of ciprofloxacin by using various advanced oxidation processes (AOPs) like UV, H2O2, UV/H2O2, modified Fenton (nZVI/H2O2) and modified photo-Fenton was studied at near neutral pH. The results revealed that direct photolysis (UV) resulted in 60% degradation with TOC removal of 4% in 120 min. Hydrogen peroxide (H2O2) resulted in 40% removal of ciprofloxacin in 100 min. However, different combinations of UV, H2O2 and nano zero valent iron particles (nZVI) resulted in 100% removal efficiency in 30–40 min with higher mineralization. Degradation of ciprofloxacin followed second order kinetics with highest rates for modified photo-Fenton process. Daughter products formed during the degradation were identified and pathways of degradation were established for different removal processes. Residual hydrogen peroxide concentrations were found to be very low when combined methods were applied. Response surface methodology (RSM) study shows that a nZVI:H2O2 ratio of 5:1 can achieve 99.30% removal in 120 min thus reducing the use of H2O2. The optimized combination in presence of UV light resulted in 100% degradation within 25 min.
... The valuesb 0 , b i , b ii and b ij are regression coefficients in the intercept, linear, quadratic and interaction terms, respectively. The value k is the number of design variables (Aljundi, 2011;Angelopoulos et al., 2013;Bezerra et al., 2008;Quanhong and Caili, 2005). The response functions for values of redox potential (E), pH and resistance (R) of EA solution production are presented in Table 1. ...
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This study examines the possibility of producing optimally electro-activated (EA) solutions using response surface methodology (RSM). RSM yielded models to predict solution properties as functions of the process parameters studied with very high coefficients of determination (R2 = 0.9393 to 0.9974), indicating the models provided high correlation between observed and predicted values. The effect of production parameters, such as salt concentration, current and exposure time on the properties of the solutions, was investigated. For oxidation-reduction potential, pH and resistance, salt concentration was the most significant factor followed by exposure time and current. Using a Derringer’s function, the best performance for the production of electro-activated solution was obtained at a current intensity of 200 mA in the presence of 0.05 M electrolyte after 38 and 60 min of treatment time, depending on which reactor configuration was used. The current investigation shows an agreement with the addition test of predicted data and confirms that the developed model equation can be used for prediction.
... As one of the technologies that can improve drinking water quality, ozonation is becoming increasingly popular. However, there will be disinfection by-products, such as bromate, formed during ozonation in bromide-containing raw water (Aljundi 2011;Jarvis et al. 2007;Van Staden et al. 2004). Bromate is a potential carcinogen and nephrotoxic compound to humans, regarded as the 2B carcinogen by the IARC (International Agency for the Research on Cancer) and brings a lot of problems to human health (Ahmad and Mahmood 2012;WHO 2004). ...
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Simulation studies in pure water were conducted to investigate the effect of nano-metal oxides on bromate (BrO3−) formation as catalysts and the catalytic mechanism. Results indicated that compared to ozonation alone, both nano-SnO2 and nano-TiO2 could inhibit the formation of bromate during ozonation process. The inhibition efficiency of BrO3− formation by nano-TiO2 enhanced with the increasing of ozone dosage and the decreasing of nano-TiO2 dosage, Br− concentrations and the pH value. Possible BrO3− minimization mechanism was that nano-TiO2 accelerated the decomposition of the dissolved O3 into OH radicals, which rapidly generated H2O2, and reduced HOBr/OBr− to Br−.
... Bromate is a genotoxic human carcinogen [6]. This bromate compound can cause loss of hearing, and decline of kidney and intestinal functions [7]. ...
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Disinfection process was applied as the last step of the water treatment to kill pathogenic bacteria in the water. However, according to several studies, the ozonation disinfection process could form undesired by-products. One of the by-products potentially affecting human life is bromate produced from bromide ionic-containing water. This study was carried out to examine the effect of raw water characteristics and pH on bromate formation. Also, the performance of bromate formation for a period of exposure time was analyzed. Raw waters taken from four different areas around Bandung were exposed to ozone introduced to a reactor with a flow rate of 2 L/min. The pH of the raw waters varied from 4, 7 to 10. The results show that there was no evidence of an initial bromide ion concentration, whereas a change in pH value gives a significantly different outcome. In acidic condition (pH of 4) the bromate formation tends to decrease, whereas when the pH value increases to a pH of 10, the bromate formation increases. Therefore, for drinking water with a neutral pH, when bromide ions are detected in the raw water, the drinking water may be toxic due to the presence of bromate.
... It is one of the strongest and most effective oxidizing agents of all chemical substances, capable of oxidizing many organic and inorganic compounds, and it can even deactivate pathogenic microorganisms. [46][47][48] However, disinfection by ozonation can lead to the formation of byproducts such as aldehydes, carboxylic acids, and ketones. 49 Some of these migrants, for example, acetaldehyde or formaldehyde, are known as mutagenic or carcinogenic agents. ...
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The ever-increasing popularity of bottled water means that it is important to analyze not only its mineral content but also, above all, its content of possible contaminants, especially the organic ones. In this respect, bottled waters are a special case, because apart from organic chemical contaminants derived from the well from which they were acquired, their secondary contamination is always possible, during treatment or storage or transport in unsuitable conditions (sunlight and elevated temperature). This paper describes how various factors, from the area around the well, and the method of drawing and treating water, to the manner in which the finished product is stored and transported may affect the quality of bottled waters. It also summarizes literature information on the levels of organic contaminants in various kinds of bottled water samples.Journal of Exposure Science and Environmental Epidemiology advance online publication, 24 October 2012; doi:10.1038/jes.2012.101.
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Due to its unique layered structure and inimitable physicochemical properties, MXene has been emerging as an essential candidate for the effective removal of organic and inorganic pollutants from wastewater. Accordingly,...
Chapter
Selenium is a metalloid and an essential micronutrient needed by animals and humans at low concentrations but extremely toxic at high concentrations. It is found in the natural environment and can be present in soil, food, air, plant, and water. The chemistry of Se is linked to its different chemical forms. Se mobility and toxicity are strongly dependent on its redox state; from highly soluble oxyanions like selenate, selenite, and hydroselenite to elemental Se. However, selenate and selenite are the two predominant Se species in the water system because of their high solubility and low adsorption by sediments and soil. This provides most techniques the platform to focus on the removal of both selenite and selenate among other Se species. This chapter is focused on the occurrence and effective management of Selenate and Selenite in water.
Chapter
Water security and sanitation are precursors for socio-economic development, survival of flora and fauna, food security and healthy ecosystems. However, when these are compromised, they tend to have an adverse effect on the health of the populace and the socio-economic development of the entire society. This chapter investigates global laws and economic policies aimed at the abatement of toxic oxyanions (e.g. nitrate, fluoride, perchlorate etc) in aqua systems. Using a non-doctrinal cum systematic analysis, the extent of legal and economic instruments in controlling, reducing and preventing toxic oxyanion pollutants in water was examined. Relevant international treaties and instruments were analysed including the Universal Declaration on Human Rights (UDHR) 1948, the International Covenant on Economic, Social and Cultural Rights (ICESCR) 1966, the United Nations Convention on the Laws of the Sea (UNCLOS) 1982 and the United Nations Convention on the Law of the Non-Navigational Uses of International Watercourses (UNWC) 1997. Moreover, the use of different command and control (CAC) and economic instruments (EI) were also studied. The findings revealed that the provisions of the legal instruments are not strong and clear enough to compel states to adopt adequate measures for the prevention of toxic oxyanion pollutants in marine areas. In addition, even though the CAC and EI approaches have been adopted for pollution abatement across countries, the latter appear to have gained wider acceptance, due to some of the advantages it offers over and above the former approach. Nevertheless, the chapter recommends the combination of regulatory and economic approaches as the way forward in achieving the abatement of toxic oxyanion in aqua systems. One of the recommended regulatory approaches is the amendment of existing treaties and instruments to incorporate stronger obligations on states, which will feasibly achieve effective measures for the reduction and control of toxic oxyanion pollutants. The justification for the eco-legal approach to control toxic oxyanion pollutants is to yield the best optimal outcome because none of the instruments can operate in isolation, especially in a dynamic and complex society. Both, complement and reinforce each other.
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Chapter
Nitrate is one of the most widespread toxic inorganic compounds in groundwater due to its high water solubility. High level of nitrate in potable water may poses serious risks to the environment and to human health. Heterogeneous photocatalysis has been widely used for water remediation and disinfection, however, less research studies, comparatively, have reported photocatalytic nitrate reduction because of the complexity of the mechanism of reaction. Mainly, nitrate photoreduction takes place directly via reaction with photo-generated electrons in the conduction band of the photocatalyst or by photo-produced reducing species under light irradiation. As a result, nitrate can be transformed into unpreferred by-products such as nitrite and ammonium, while the reduction into dinitrogen gas is much recommended due to its high importance. On the other hand, the issue of the re-oxidation of ammonium into nitrate has also been reported. The efficiency and selectivity of a photocatalytic system to reduce nitrate into dinitrogen depend on the operating parameters controlling the reaction, and more importantly, the selectivity strongly depends on the type of the photocatalytic nanomaterial. For this reason, a pool of studies have been performed in order to enhance the selectivity of nitrate reduction into dinitrogen by developing different kinds of nanomaterials. In this chapter, we examine: (i) the conventional technologies for nitrate removal/reduction, (ii) the effect of operating conditions on the photocatalytic nitrate reduction process, as well as (iii) the influence of the type of photoactive nanomaterial on the selectivity and the performance toward nitrate reduction.
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In the past two decades, ozone-based advanced oxidation processes, known as enhanced ozonation processes (EOPs), have been extensively investigated for the removal of emerging organic contaminants in water, such as pesticides, endocrine-disrupting compounds, and pharmaceuticals. EOPs offer an advantage by producing highly oxidizing radicals, such as hydroxyl radicals, to oxidize recalcitrant organic compounds. Although the EOPs are able to effectively remove emerging contaminants, several studies reported the formation of bromate, which has drawn significant attention because of its potential carcinogenicity. This issue becomes challenging for the utilization of EOPs on bromide containing water. Therefore, this work critically reviews and summarizes the mechanisms, influencing factors, advantages and disadvantages, and control strategies for bromate formation by four EOPs, i.e., peroxone and e-peroxone, photolytic ozonation, heterogeneous ozonation, and sonolytic ozonation. Various economic and technical characteristics of EOPs were also compared. Mathematical modeling, pilot and full-scale data, and secondary pollutant potential (toxic metals leaching from catalyst) have been identified as knowledge gaps, and future research should seek to address these issues.
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This paper investigates the fate of natural organic matter (NOM) during the full-scale drinking water treatment plant supplied by Danube river bank filtration. After the recent reconstruction of the plant, special attention was devoted to the effects of ozone dose and granulated activated carbon (GAC) filtration on the formation and behaviour of oxidation by-products (carbonyl compounds and bromate), as well as carbonaceous and nitrogenous chlorination by-products. For the oxidation of aromatic NOM moieties that absorb light at UV254, a lower ozone dose (1.0 g O3/m³) is sufficient, whereas to achieve a measurable reduction (about 20%) of total organic carbon, an ozone dose of 1.5 g O3/m³ is required. The content of carbonyl compounds in the water after ozonation increases relative to the content before oxidation treatment, and is up to 12 times higher in the case of aldehydes and up to 2 times higher in the case of carboxylic acids. Seasonal variations, including changes in temperature and the amount of precipitation, were also shown to affect the content of organic matter in the raw water, with slight effects on the quality of the treated water. In the winter, the organic matter content is slightly higher, meaning their transformation products aldehydes and carboxylic acids, are also higher during the winter than the summer.
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Drinking water is an important source of human exposure to bromate, an ubiquitous environmental contaminant and a suspect human carcinogen. Nevertheless, little is known with regard to bromate exposure from water produced by thermal desalination of seawater. The purpose of this study was to determine the occurrence of bromate in desalinated drinking water and groundwater from Kuwait and estimate associated exposure and health risks to consumers. In this study, 194 tap and ground water samples collected from Kuwait were analyzed for the presence of bromate and bromide (reduced form of bromine). Bromate was found in almost all tap water samples with a mean concentration of 19.6 μg/L, which is higher than the maximum acceptable contaminant level (MCL) of 10 μg/L. The mean concentration of bromide in tap water samples was 46.2 μg/L. In bottled water, lower mean bromate concentration was found (2.89 μg/L) with mean bromide levels at 76.1 μg/L. Saline brackish water had bromate concentration at 9.48 μg/L while bromate was not detected in saline groundwater/well water samples. The mean estimated daily intake (EDI) of bromate by the Kuwaiti population through tap water and commonly consumed bottled water was 21.7 μg/d and 3.21 μg/d, respectively. Among the five age groups, 3 to 5-year-old children had the highest EDI of bromate at 15.4 μg/d. The excess cancer risk due to ingestion of bromate in tap water was estimated to be 3.92 × 10-4, which is approximately one order of magnitude higher than the maximum acceptable level of risk (2× 10-5). This study highlights the significance of desalinated water as a source of bromate exposure.
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Chemical oxidation processes have been extensively utilized in disinfection and removal of emerging organic contaminants in recent decades. Some undesired byproducts, however, are produced in these processes. Of them, bromate has attracted the most intensive attention. It was previously regarded as a byproduct that typically occurred in ozone-based oxidation processes. However, for the past decade, bromate formation has been detected in other oxidation processes such as CuO-catalyzed chlorination, SO4--based oxidation, and ferrate oxidation processes. This review summarizes the occurrences, mechanisms, influencing factors, risk assessment, and control strategies of bromate formation in the four oxidation processes, i.e., ozone-based oxidation, chlorine-based oxidation, SO4--based oxidation, and ferrate oxidation. Besides, some unresolved issues for future studies are provided: (1) Clarification of the relative contributions of SO4- and Br to the oxidation of bromine for bromate formation in SO4--based oxidation processes; (2) evaluation of the role of different reactive species in the bromate formation in the process of UV/HOCl; (3) quantification of the dual role of alkalinity in bromate formation during ozonation; (4) assessment of the risks of bromate formation in SO4--based oxidation processes for practical applications; and (5) exploration of strategies for inhibiting bromate formation in SO4--based oxidation, UV/chlorine, and metal oxide-catalyzed chlorination processes.
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This paper presents the results of experimental study conducted to investigate the effects of different parameters on bromate formation in bottles of drinking water. The effects of various temperatures, storage times, pH and some water quality parameters including bromide, Total Organic Carbon (TOC) and Total Dissolved Solids (TDS) were investigated. Three different regional and international water bottles brands available in the United Arab Emirates (UAE) were selected. For each brand 36 Polyethylene Terephthalate (PET) bottles of water were used for the experimental study. It is concluded that the effects of storage time and temperature was negligible for all brands and that the effects of pH levels on bromate formation was noticeable. Increasing pH level increases the bromate formation for brands X and Y but decreases the bromate formation for Brand Z. It is also concluded the effect of TDS, TOC and turbidity on bromate formation was not significant.
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Wastewater containing Cr⁶⁺ with large water quantity and high levels of toxicity damaged human health through the food chain. Electric flocculation was one of the commonly used methods for heavy metals wastewater treatment, which was applied to remove Cr⁶⁺ from wastewater. In this study, response surface methodology (RSM) was used to investigate the effects of different operating conditions on the removal efficiency of Cr⁶⁺ by the electric flocculation with iron electrodes. Box-Behnken design (BBD) was used for the optimization of the electric flocculation process to evaluate the effects and interactions of process variables such as initial pH, the electrode distance, the current density and reaction time on the removal efficiency of Cr⁶⁺. The individual and interactive effects of the four main independent parameters (initial pH, the electrode distance, the current density and reaction time) by electric flocculation were investigated by the BBD. The optimum values were found to be 5.48, 2.51 cm, 87.55 A/m² and 25.6 min, respectively. Under this condition, the removal efficiency of Cr⁶⁺ reached to 99.34%.
Advanced reduction processes (ARPs) are treatment processes that involve combining reducing reagents and activating tools to produce highly reactive reducing free radicals. The process has proven effective for treating oxidized contaminants, and the effects of process variables on the degradation kinetics of various target contaminants have been investigated in our previous studies. In natural environments, natural organic matter (NOM) is found in surface or ground water. NOM absorbs UV light and can react with photochemically produced radicals, thus affecting target contaminant photochemical reactions and further influencing the efficiency of ARP. This study examines the impact of humic acid (HA) and Suwanee River NOM on bromate reduction rates with UV irradiation using a low-pressure mercury UV lamp. The effects of the sulfite dose, solution pH, and light intensity are studied and the pseudo-first-order rate constants in the presence of HA (kobs,HA) are compared to those observed in the absence of HA (kobs). At low HA concentrations of 1 mg L⁻¹, kobs,HA was larger than kobs however, kobs,HA was less than kobs at higher HA concentrations. Furthermore, kobs,HA did not increase with increasing sulfite doses in the presence of HA, which is unlike the behavior of kobs.
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While ozonation and biological activated carbon (O3/BAC) process was widely used in advanced water treatment, the control of ozonation by-product was one of the most important objects in water treatment. In this study, the filtered water of Huyan water plant, treating Yellow River water in Shanxi, was used as the raw water to investigate the control of ozonation by-products and the biological stability by O3/BAC process. Results showed that the bromate, formaldehyde and AOC concentration of ozonation effluent were increased, yet BAC filter could effectively reduce the concentration of the by-products. When ozone dosage was less than 3.5 mg/L, the bromate of BAC filter effluent was lower than 10 ug/L. And the formaldehyde was less than 20 ug/L in the whole range of ozone dosage. Moreover, the optimal ozone dosage for the highest AOC removal of 63.25% was 2.0 mg/L. The results could provide an operation parameter for Shanxi Yellow River water advanced treatment, thus to ensure the water quality safety.
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A series of batch experiments about adsorption of bromate onto three variable charge soils from Southern China was carried out. The adsorption behavior of bromate was estimated as a function of reaction time (0–240 min), and the concentration of bromate at a fixed value (100 μg/L) at 25, 35, and 45°C. Bromate adsorption increased with the rise of temperature, indicating that bromate adsorption onto the variable charge soils was an endothermic process. The pseudo-second-order kinetic equation was used to describe the kinetic data. The adsorption equilibrium time of BrO3– onto three soils was about 120 min and independent of the reaction temperature. The data of isotherm experiments fit well with the Langmuir model, which implied that monolayer adsorption was feasible during the sorption process. The data of the adsorption experiments at different reaction temperatures were used to calculate thermodynamic parameters. The thermodynamic parameters calculated suggest that bromate adsorption onto the variable charge soils from Southern China was a spontaneous, endothermic, and entropy-driven reaction as well as a physical adsorption process.
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In this study, for the first time, Zn–Fe(II)–Al layered double hydroxides (LDHs) with chloride intercalation were prepared and used in the removal of bromate from aqueous solutions. Batch experiments were performed, and the reactivity and mechanism were discussed with respect to the influence of various experimental such parameters as the effects of contact time, initial bromate concentration, the dose of Zn–Fe(II)–Al LDHs, pH and competing anions on bromate removal by Zn–Fe(II)–Al LDHs. The results show that bromate can be effectively removed by Zn–Fe(II)–Al LDHs. Starting from an initial concentration of 0.78 μmol/L, nearly 100% of bromate was removed in 0.5 h under neutral pH and with a dose of Zn–Fe(II)–Al LDHs of 0.5 g/L. Equilibrium was achieved within 1.5 h because bromide was adsorbed by the Zn–Fe(II)–Al LDHs samples during the reaction time. Mass balances provided strong evidence that bromide is the primary product via the reduction process. Moreover, results from materials characterization experiments indicated that the layered structures remained in the Zn–Fe(II)–Al LDHs samples collected after the reaction, indicating that Zn2+, Fe3+, Al3+ and interlayer chloride anions were not released.
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The worldwide consumption of bottled water has experienced an annual increase of 5.5% since 2004 and different authors have speculated that this is due to beliefs of superior flavor and health qualities of bottled water over tap water. The content of certain minerals varies by 2 to 6 orders of magnitude between bottled water brands. The major cations Ca, Mg, Na, and K can be found in concentrations up to 730, 450, 1900, and 270 mg/L but are usually below 100 mg/L; higher concentrations have only been found in some European and North American bottled water samples. The dominating anions are HCO3-, Cl-, and SO42-. Sensory evaluation and description of water strongly depend on personal preferences and sensitivities. The major cations can be detected by taste in concentrations down to 2 digits in the mg/L range; however, the intensity depends on which anions are present. Most cations add different degrees of salty, sour, sweet, and bitter tastes to water depending on their concentrations. Al, Ca, Cu, Fe, Mg, and Zn may introduce metallic, astringent, and irritative sensations and for Fe and Cu also retro-nasal odors may influence the metallic sensation. Drinking water with total dissolved solids in the range of 100 to 400 mg/L results in good sensory quality. Known off-flavor problems originate from by-products of ozonation and leaching of organics from bottling material which may also be enhanced by ozonation, and microbial by-products from the source water such as geosmin and 2-methylisoborneol, lubricants, or cleaning agents used in the bottling industry.
Article
The ozonation involved in drinking water treatment raises issues of water quality security when the raw water contains bromide (Br−). Br− ions may be converted to bromate (BrO3 −) during ozonation and some brominated disinfection by-products (Br-DBPs) in the following chlorination. In this study, the effects of ozone (O3) dosage, contact time, pH, and Br− and ammonia (NH3-N) concentrations on the formation of BrO3 − and Br-DBPs have been investigated. The results show that decreasing the initial Br− concentration is an effective means of controlling the formation of BrO3 −. When the concentration of Br− was lower than 100 μg/L, by keeping the ratio of O3 dosage to dissolved organic carbon (DOC) concentration at less than 1, BrO3 − production was effectively suppressed. The concentration of BrO3 − steadily increased with increasing O3 dosage at high Br− concentration (>900 μg/L). Additionally, a longer ozonation time increased the concentrations of BrO3 − and total organic bromine (TOBr), while it had less impact on the formation potentials of brominated trihalomethanes (Br-THMFP) and haloacetic acids (Br-HAAFP). Higher pH value and the presence of ammonia may lead to an increase in the formation potential of BrO3 − and Br-DBPs.
Article
Bromate formation has been identified as a significant barrier in the application of ozone during water treatment the downstream region of the Pearl River Basin that contains high levels of bromide. Seawater intrusion will increase bromide concentration in the inshore surface water. In this study, seawater intrusion in the Pearl River Basin was surveyed and modeling bromate formation during ozonation of the raw water affected by seawater intrusion was studied. Bromate formation models were developed to simulate the effects of the characteristics of water quality and the operating parameters of treatment processes on bromate formation during preozonation process and postozonation process. The results show that the downstream of the Pearl River Basin is affected seriously by seawater intrusion and the bromide mainly comes from seawater. Some empirical models were developed to estimate the concentration of bromate in ozonated surface raw water affected by seawater intrusion during the treatment process.
Article
Contamination of water due to bromate is a severe health hazard. The aim of the present study was to remove bromate from water using a crosslinked polystyrene based strongly basic anion exchange resin De-Acidite FF-IP. Batch experiments were performed to study the influence of various experimental parameters such as effect of pH, contact time, temperature, and effect of competing anions on bromate removal by De-Acidite FF-IP resin. At optimum parameters, the removal rate of bromate was very fast and 90% removal took place in 5 min and equilibrium was established within 10 min. The presence of competitive anions reduced the bromate adsorption in the order of Cl− > F− > CO > SO > NO > PO. The practical utility of this resin has been demonstrated by removing bromate in some of the commercial bottled water from Saudi Arabia. The level of bromate was determined using a very sensitive, precise and rapid method based on ultra-performance liquid chromatography-tendem mass spectrometry (UPLC-MS/MS).
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The oxidative removal of a diverse group of trace organic contaminants from surface water and wastewater was evaluated using ozone (O 3) and O 3 combined with hydrogen peroxide (O 3 /H 2 O 2). Target compounds included estrogenic and andro-genic steroids, pharmaceuticals, pesticides, and industrial che-micals. Bench-and pilot-scale experiments were conducted with surface water spiked with the target compounds and wastewater effluent containing ambient concentrations of target com-pounds. Full-scale water treatment plants were sampled before and after ozonation to determine if bench-and pilot-scale results accurately predict full-scale removal. In both drinking water and wastewater experiments, the majority of target compounds were removed by greater than 90% at O 3 exposures commonly used for disinfection. Atrazine, iopromide, meprobamate, and tris-chloroethylphosphate (TCEP) were the most recalcitrant compounds to oxidize using O 3 , with removals generally less than 50%. The addition of H 2 O 2 for advanced oxidation was of little benefit for contaminant removal as compared to O 3 alone. O 3 /H 2 O 2 provided a marginal increase in the removal of dilan-tin, diazepam, DEET, iopromide, and meprobamate, while decreasing the removal efficacy of pentoxifylline, caffeine, tes-tosterone, progesterone, and androstenedione. In wastewater experiments, O 3 and O 3 /H 2 O 2 were shown to remove in vitro estrogenicity. Collectively, these data provide evidence that O 3 is a highly effective oxidant for removing the majority of trace organic contaminants from water.
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Forty domestic and imported brands of bottled water were purchased in Manitoba, Canada and examined for total dissolved solids (TDS), chloride, sulfate, nitrate-nitrogen, cadmium, lead, copper, and radioactivity. The samples showed great variation in quality, and some exceeded the Canadian Water Quality Guidelines for drinking water for TDS, chloride, and lead. Carbonation, ozonation, and type of packaging were not associated with differences in metal levels, although carbonated samples tended to show higher TDS values. A number of deficiencies were found with respect to product labeling.
Article
This project studied bromate ion formation during ozonation of groundwater containing elevated bromide ion levels. Groundwater samples from aquifers in coastal areas were ozonated in a semi-batch reactor under typical ozonation conditions sufficient to inactivate microorganisms. Ozone dose and contact time played a significant role in bromate ion production. Bromate formation increased as the contact time increased under the same ozone dose. In addition, increasing the ozone dose while keeping a constant contact time resulted in increasing bromate formation. Further parameters that influenced the formation of bromate ions were the initial concentration of bromide ion and the product CT (ozone dose times contact time), which has been suggested as a control variable for effective ozonation. Empirical bromate formation models were developed in order to simulate the effect of water quality characteristics and treatment processes on bromate formation. The empirical models were capable of estimating the concentration of bromate ions in ozonated groundwater samples, which contain low concentrations of ammonia and dissolved organic carbon.
Article
Bromine chloride in the presence of chloride ion forms the dichlorobromate(I) ion, BrCl2-, where K-1 = [BrCl2-]/([BrCl(aq)][Cl-]) = 6.0 M(-1). Equilibrium constants (all at 25.0 degrees C, mu = 1.00 M) are also determined for K-2 = [Br2Cl-]/([BrCl(aq)][Br-]) = 1.8 x 10(4) M(-1), for K-3 = [Br2Cl-]/([Br-2(aq)][Cl-]) = 1.3 M(-1) and for K-4 = [Br-3(-)]/[Br-2(aq)][Br-] = 16.1 M(-1). UV absorption bands are resolved for BrCl2- at 232 nm (epsilon 32 700 M(-1) cm(-1)) and 343 nm (epsilon 312 M(-1) cm(-1)), for Br2Cl- at 245 nm (epsilon 24 900 M(-1) cm(-1)) and 381 nm (epsilon 288 M(-1) cm(-1)), and for Br-3(-) at 266 nm (epsilon 40 900 M(-1) cm(-1)). The UV spectral properties of Cl-2(aq), Cl-3(-), Br-2(aq), and Br- are examined and compared. The reaction between Cl-2(aq) and Br- to form BrCl2- occurs at the diffusion-controlled limit; the rate constant, (7.7 +/- 1.3) x 10(9) M(-1) s(-1), is measured by the pulsed-accelerated-flow method. The rapid formation of BrCl2- can be used as an analytical method for trace bromide ion, where as little as 10(-5) mol % Br- can be detected in aqueous solutions of HCl or chloride salts.
Article
Using a combination of spectral identification techniquesgas chromatography coupled with low- and high-resolution electron-impact mass spectrometry (GC/EI-MS), low- and high-resolution chemical ionization mass spectrometry (GC/CI-MS), and infrared spectroscopy (GC/IR)we identified many drinking water disinfection byproducts (DBPs) formed by ozone and combinations of ozone with chlorine and chloramine. Many of these DBPs have not been previously reported. In addition to conventional XAD resin extraction, both pentafluorobenzylhydroxylamine (PFBHA) and methylation derivatizations were used to aid in identifying some of the more polar DBPs. Many of the byproducts identified were not present in spectral library databases. The vast majority of the ozone DBPs identified contained oxygen in their structures, with no halogenated DBPs observed except when chlorine or chloramine was applied as a secondary disinfectant. In comparing byproducts formed by secondary treatment of chlorine or chloramine, chloramine appeared to form the same types of halogenated DBPs as chlorine, but they were generally fewer in number and lower in concentration. Most of the halogenated DBPs that were formed by ozone−chlorine and ozone−chloramine treatments were also observed in samples treated with chlorine or chloramine only. A few DBPs, however, were formed at higher levels in the ozone−chlorine and ozone−chloramine samples, indicating that the combination of ozone and chlorine or chloramine is important in their formation. These DBPs included dichloroacetaldehyde and 1,1-dichloropropanone.
Article
Kinetic simulations have been tested by laboratory experiments to evaluate the major factors controlling bromate formation during ozonation of waters containing bromide. In the presence of an organic scavenger for OH radicals, bromate formation can be accurately predicted by the molecular ozone mechanism using published reaction rate data, even for waters containing ammonium. In the absence of scavengers, OH radical reactions contribute significantly to bromate formation. Carbonate radicals, produced by the oxidation of bicarbonate with OH radicals, oxidize the intermediate hypobromite to bromite, which is further oxidized by ozone to bromate. During drinking water ozonation, molecular ozone controls both the initial oxidation of bromide and the final oxidation of bromite. OH radical reactions contribute to the oxidation of the intermediate oxybromine species. Bromate formation in advanced oxidation processes can be explained by a synergism of ozone and OH radicals.
Article
Response surface methodology was employed to optimize medium composition for the production of cyclic adenosine 3',5'-monophosphate (cAMP) with Microbacterium sp. no. 205. A fractional factorial design (2(11-7)) was applied to evaluate the effects of different components in the medium. K(2)HPO(4), MgSO(4) and NaF were found to significantly influence on the cAMP production. The steepest ascent method was used to access the optimal region of the medium composition. The concentrations of the three factors were optimized subsequently using central composite design and response surface methodology. The optimal medium composition to achieve the optimal cAMP production was determined (g/L): K(2)HPO(4), 12.78; MgSO(4), 3.53 and NaF, 0.18. The corresponding cAMP concentration was 8.50 g/L, which was about 1.8-fold increase compared with that using the original medium. Validation experiments were also carried out to prove the adequacy and the accuracy of the model obtained. The cAMP fermentation in 5L fermenter reached 9.87 g/L.
Article
Potassium bromate (KBrO3) is an oxidizing agent that has been used as a food additive, mainly in the bread-making process. Although adverse effects are not evident in animals fed bread-based diets made from flour treated with KBrO3, the agent is carcinogenic in rats and nephrotoxic in both man and experimental animals when given orally. It has been demonstrated that KBrO3 induces renal cell tumors, mesotheliomas of the peritoneum, and follicular cell tumors of the thyroid. In addition, experiments aimed at elucidating the mode of carcinogenic action have revealed that KBrO3 is a complete carcinogen, possessing both initiating and promoting activities for rat renal tumorigenesis. However, the potential seems to be weak in mice and hamsters. In contrast to its weak mutagenic activity in microbial assays, KBrO3 showed relatively strong potential inducing chromosome aberrations both in vitro and in vivo. Glutathione and cysteine degrade KBrO3 in vitro; in turn, the KBrO3 has inhibitory effects on inducing lipid peroxidation in the rat kidney. Active oxygen radicals generated from KBrO3 were implicated in its toxic and carcinogenic effects, especially because KBrO3 produced 8-hydroxydeoxyguanosine in the rat kidney. A wide range of data from applications of various analytical methods are now available for risk assessment purposes.
Article
Oxidative damage caused by potassium bromate (KBrO3), a rat renal carcinogen, was investigated using in vitro preparations of rat renal proximal tubules (RPT) and renal nuclear fractions. Release of lactate dehydrogenase and decrease of SH-group content in RPT (1 mg protein/ml) by KBrO3 (0.5-5 mM) in a concentration- and time-dependent manner were observed. Peroxidized arachidonic acid and 8-hydroxydeoxyguanosine (8-OH-dG) levels in RPT were increased after administration of 2 and 5 mM KBrO3. 8-OH-dG formation was observed after incubation of renal nuclei with a lipid-peroxiding system, autooxidized methyl linolenate, or KBrO3. These findings provide support for involvement of lipid peroxidation in producing oxidized DNA damage by KBrO3 directly to RPT, the target site for renal carcinogenesis.
Article
Bromate formation during ozonation of bromide-containing natural waters is somewhat inversely connected to the ozone characteristics: an initial fast increase followed by a slower formation rate. During the initial phase mostly OH radical reactions contribute to bromate formation,whereas in the secondary phase both ozone and OH radicals are important. To minimize bromate formation several control options are presented: ammonia addition, pH depression, OH radical scavenging, and scavenging or reduction of hypobromous acid (HOBr) by organic compounds. Only the two first options are applicable in drinking watertreatment. By both methods a similar effect of a bromate reduction of approximately 50% can be achieved. However, bromate formation during the initial phase of the ozonation cannot be influenced by either method. Ammonia (NH3) efficiently scavenges HOBrto NH2Br. However, this reaction is reversible which leads to higher required NH3 concentrations than expected. The rate constant kNH2Br for the hydrolysis of NH2Br by OH- to NH3 and OBr- was found to be 7.5-10(6) M(-1) s(-1). pH depression shifts the HOBr/ OBr- equilibrium to HOBr and also affects the ozone chemistry. The effect on ozone chemistry was found to be more importantfor bromate formation. For a given ozone exposure, the OH radical exposure decreases with decreasing pH. Therefore, for pH depression the overall oxidation capacity for a certain ozone exposure decreases which in turn leads to a smaller bromate formation.
Article
Ozone is an excellent disinfectant and can even be used to inactivate microorganisms such as protozoa which are very resistant to conventional disinfectants. Proper rate constants for the inactivation of microorganisms are only available for six species (E. coli, Bacillus subtilis spores, Rotavirus, Giardia lamblia cysts, Giardia muris cysts, Cryptosporidium parvum oocysts). The apparent activation energy for the inactivation of bacteria is in the same order as most chemical reactions (35-50 kJ mol(-1)), whereas it is much higher for the inactivation of protozoa (80 kJ mol(-1)). This requires significantly higher ozone exposures at low temperatures to get a similar inactivation for protozoa. Even for the inactivation of resistant microorganisms, OH radicals only play a minor role. Numerous organic and inorganic ozonation disinfection/oxidation by-products have been identified. The by-product of main concern is bromate, which is formed in bromide-containing waters. A low drinking water standard of 10 microg l(-1) has been set for bromate. Therefore, disinfection and oxidation processes have to be evaluated to fulfil these criteria. In certain cases, when bromide concentrations are above about 50 microg l(-1), it may be necessary to use control measures to lower bromate formation (lowering of pH, ammonia addition). Iodate is the main by-product formed during ozonation of iodide-containing waters. The reactions involved are direct ozone oxidations. Iodate is considered non-problematic because it is transformed back to iodide endogenically. Chloride cannot be oxidized during ozonation processes under drinking water conditions. Chlorate is only formed if a preoxidation by chlorine and/or chlorine dioxide has occurred.
Article
The major disinfection by-products (DBPs) resulting from ozone treatment of polluted surface water were investigated. By-products of either health concern or which may contribute to biological instability of treated drinking water were investigated. The major DBPs were analyzed in two fractions: carbonyl compounds and brominated organic compounds. The natural organic matter (NOM) was also isolated and fractionated from polluted water for subsequent ozonation and DBPs identification under conditions of typical drinking treatment. The main identified carbonyl compounds were low molecular weight carboxylic acids, benzoic compounds, aliphatic aldehydes and odorous aldehydes, respectively. Brominated organics were also found in ozonated water, including bromoform (CHBr3), monobromoacetic acid (MBAA), dibromoacetic acid (DBAA), 2,4-dibromophenol (2,4-DBP) and dibromoacetonitrile (DBAN), respectively. It was also found that the characteristic of organic precursors have significant influences on brominated organic by-products formation. Humic acid demonstrated the highest CHBr3, DBAA and 2,4-DBP formations, whereas hydrophilic neutral produced less CHBr3 and 2,4-DBP than the rest of the organic fractions but produced the highest amount of DBAN. In addition to the other target compounds, a total of 59 different organic compounds were detected by means of gas chromatograph/high-resolution electron-impact mass spectrometry (GC/EI-MS) detection and tentatively identified using mass spectral library searching, mainly aromatics, acids/esters, alcohols, aldehydes, phthalates and amines/amino acids were analyzed. The percentage of elimination or formation levels reached during ozonation is also discussed in this study.
Article
Potassium bromate (KBrO3) is a chemical oxidizing agent found in drinking water as a disinfection byproduct of surface water ozonation. Chronic exposures to KBrO3 cause renal cell tumors in rats, hamsters and mice and thyroid and testicular mesothelial tumors in rats. Experimental evidence indicates that bromate mediates toxicological effects via the induction of oxidative stress. To investigate the contribution of oxidative stress in KBrO3-induced cancer, male F344 rats were administered KBrO3 in their drinking water at multiple concentrations for 2-100 weeks. Gene expression analyses were performed on kidney, thyroid and mesothelial cell RNA. Families of mRNA transcripts differentially expressed with respect to bromate treatment included multiple cancer, cell death, ion transport and oxidative stress genes. Multiple glutathione metabolism genes were up-regulated in kidney following carcinogenic (400 mg/L) but not non-carcinogenic (20 mg/L) bromate exposures. 8-Oxodeoxyguanosine glycosylase (Ogg1) mRNA was up-regulated in response to bromate treatment in kidney but not thyroid. A dramatic decrease in global gene expression changes was observed following 1mg/L compared to 20 mg/L bromate exposures. In a separate study oxygen-18 (18O) labeled KBrO3 was administered to male rats by oral gavage and tissues were analyzed for 18O deposition. Tissue enrichment of 18O was observed at 5 and 24 h post-KBr18O3 exposure with the highest enrichment occurring in the liver followed by the kidney, thyroid and testes. The kidney dose response observed was biphasic showing similar statistical increases in 18O deposition between 0.25 and 50 mg/L (equivalent dose) KBr18O3 followed by a much greater increase above 50 mg/L. These results suggest that carcinogenic doses of potassium bromate require attainment of a threshold at which oxidation of tissues occurs and that gene expression profiles may be predictive of these physiological changes in renal homeostasis.
Article
Bromate reduction by Fe(0) was investigated under various conditions in batch tests. The bromate was primarily reduced to bromide ions with possible adsorption onto iron. Bromate reduction by Fe(0) can be described by pseudo-first-order kinetics. The differences in surface areas, numbers of reactive sites, impurities, pretreatment methods and numbers of repeated uses of iron affected the rates of bromate reduction through reducing or accumulating a passive oxide film on the iron surface. The reduction of bromate was significantly affected by only the dissolved oxygen content at supersaturated concentrations or by decreasing the pH from 6 to 5. Increasing the temperature increased the bromate reduction rate, which followed the Arrhenius relationship with activation energy of 52.6 kJmol(-1) and the reduction rate increased with increased mixing rates. These observations indicate that bromate reduction by iron is a surface-mediated process and diffusion to the surface is essential. Under the test conditions, modest inhibitory effects on bromate reduction by Fe(0) from nitrite, chlorate and bicarbonate were observed and the inhibitory effect from phosphate was relatively larger. Enhanced reactivity of Fe(0) to bromate was observed in the presence of nitrate or sulfate. These findings suggest that bromate reduction by Fe(0) can be an effective method for bromate control.
Article
Bormate (BrO3(-)) is a carcinogenic chemical produced in ozonation or chlorination of bromide-containing water. Although its formation in seawater with or without sunlight has been previously investigated, the formation of bromate in dilute solutions, particularly raw water for water treatment plant, is unknown. In this article, the results of bench scale tests to measure the formation rates of bromate formation in dilute solutions, including de-ionized water and raw water from Yangtze River, were presented in dark chlorination and ultraviolet (UV)/chlorination processes. And the effects of initial pH, initial concentration of NaOCl, and UV light intensity on bromate formation in UV/chlorination of the diluted solutions were investigated. Detectable bromate was formed in dark chlorination of the two water samples with a relatively slow production rate. Under routine disinfecting conditions, the amount of formed bromate is not likely to exceed the national standards (10 microg/L). UV irradiation enhanced the decay of free chlorine, and, simultaneously, 6.6%--32% of Br was oxidized to BrO3(-). And the formation of bromate exhibited three stages: rapid stage, slow stage and plateau. Under the experimental conditions (pH = 4.41--11.07, Ccl2 = 1.23--4.50 mg/L), low pH and high chlorine concentration favored the generation of bromate. High light intensity promoted the production rate of bromate, but decreased its total generation amount due to acceleration of chlorine decomposition.
Determination of inorganic oxyhalide disinfection byproduct anions and bromide in drinking water using ion chromatography with the addition of a post column reagent for trace bromate analysis, Application Note
  • Dionex
Dionex, Determination of inorganic oxyhalide disinfection byproduct anions and bromide in drinking water using ion chromatography with the addition of a post column reagent for trace bromate analysis, Application Note, 136, Dionex Corporation, Sunnyvale, CA, USA, 2000.
Statistics Informed Decisions Using Data, Pearson Education
  • M Sullivan
M. Sullivan, Statistics Informed Decisions Using Data, Pearson Education, New Jersey, 2004.
  • D Delker
  • G Hatch
  • J Allen
  • B Crissman
  • M George
  • D Geter
  • S Kilburn
  • T Moore
  • G Nelson
  • B Roop
  • R Slade
  • A Swank
  • W Ward
  • A Deangeol
D. Delker, G. Hatch, J. Allen, B. Crissman, M. George, D. Geter, S. Kilburn, T. Moore, G. Nelson, B. Roop, R. Slade, A. Swank, W. Ward, A. DeAngeol, Molecular biomarkers of oxidative stress associated with bromate carcinogenicity, Toxicology 221 (2006) 158-165.