Pilot-Scale and Full-Scale Evaluation of the Chlorine-Ammonia Process for Bromate Control During Ozonation

Wert, Eric C.; Neemann, Jeffrey J.; Johnson, David C.; Rexing, David J.; Zegers, Ronald E.

doi:10.1080/01919510701552883

Cited by 28 publications

(26 citation statements)

References 20 publications

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“…In 2003, preozonation began at both of these facilities to achieve Cryptosporidium inactivation using ozone dosages between 1.1 mg/L and 1.3 mg/L. Bromate is minimized below the Stage 1 D/DBP Rule MCL of 10 µg/L using ozone dose management at the AMSWTF, and chlorine-ammonia pretreatment at RMWTF (Wert et al, 2007). Free chlorine and ferric chloride are added at the rapid mix chamber and a free chlorine residual is maintained throughout the rest of the treatment process, which prevents biological activity in filters.…”

Section: Water Treatment Facilities and Distribution Systemmentioning

confidence: 99%

Effect of Ozonation on Trihalomethane and Haloacetic Acid Formation and Speciation in a Full-Scale Distribution System

Wert

Rosario‐Ortiz

2011

Ozone: Science & Engineering

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Disinfection by-product (DBP) formation was evaluated before and after ozone implementation at two full-scale drinking water facilities in Las Vegas, NV USA. The two treatment plants used preozonation for primary disinfection followed by direct filtration with subsequent chlorination for secondary disinfection. DBP data was evaluated from the finished water of the two treatment plants along with six locations in the distribution system. Results showed that preozonation reduced the formation of total trihalomethanes (TTHM) by up to 10 µg/L and the sum of five haloacetic acids (HAA5) by up to 5 µg/L. These reductions were primarily due to decreases in the diand trichlorinated DBPs such as chloroform, bromodichloromethane, and trichloroacetic acid. Ozonation appeared to shift the speciation of TTHMs and HAA5 to favor increased formation of the di-and tribrominated species such as bromoform, chlorodibromomethane, and dibromoacteic acid. A bromide mass balance showed that <30% of the raw water bromide was accounted for by the formation of TTHMs (8-21%), HAAs (2-3%) and bromate (5%). Reducing the concentration of THMs and HAAs is often not the primary purpose of ozonation, but it can assist utilities in meeting regulatory requirements during drinking water treatment.

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Section: Water Treatment Facilities and Distribution Systemmentioning

confidence: 99%

Effect of Ozonation on Trihalomethane and Haloacetic Acid Formation and Speciation in a Full-Scale Distribution System

Wert

Rosario‐Ortiz

2011

Ozone: Science & Engineering

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“…Therefore, it is unsurprising that bromate was poorly removed by GAC in treated wastewater containing 5 mg/L of DOC ( Table 1 ; see additional discussion on bulk parameters in the SI). Bromate mitigation strategies (e.g., pH depression, ammonia, chloramines, and hydrogen peroxide) involving bromide sequestration or manipulating the ozone/hydroxyl radical pathways have been studied for decades in drinking water applications ( Buffle et al., 2004 ; Pinkernell and Von Gunten, 2001 ; and Wert et al., 2007 ). However, these bromate mitigation strategies have only been limitedly studied in wastewater matrices ( Soltermann et al., 2017 ), which generally have much higher ozone demand.…”

Section: Resultsmentioning

confidence: 99%

Controlling disinfection byproducts from treated wastewater using adsorption with granular activated carbon: Impact of pre-ozonation and pre-chlorination

et al. 2020

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This study measured chlorine- and chloramine-reactive precursors using formation potential (FP) tests of nine U.S. Environmental Protection Agency (EPA) regulated and 57 unregulated disinfection byproducts (DBPs) in tertiary-filtered wastewater before and after pilot-scale granular activated carbon (GAC) adsorption. Using breakthrough of precursor concentration and of concentration associated calculated cytotoxicity and genotoxicity (by correlating known lethal concentrations reported elsewhere), the performance of three parallel GAC treatment trains were compared against tertiary-filtered wastewater: ozone/GAC, chlorine/GAC, and GAC alone. Results show GAC alone was the primary process, versus ozone or chlorine alone, to remove the largest fraction of total chlorine- and chloramine-reactive DBP precursors and calculated cytotoxicity and genotoxicity potencies. GAC with pre-ozonation removed the most chlorine- and chloramine-reactive DBP precursors followed by GAC with pre-chlorination and lastly GAC without pre-treatment. GAC with pre-ozonation produced an effluent with cytotoxicity and genotoxicity of DBPs from FP that generally matched that of GAC without pre-oxidation; meanwhile removal of toxicity was greater by GAC with pre-chlorination. The cytotoxicity and genotoxicity of DBPs from FP tests did not scale with DBP concentration; for example, more than 90% of the calculated cytotoxicity resulted from 20% of the DBPs, principally from haloacetaldehydes, haloacetamides, and haloacetonitriles. The calculated cytotoxicity and genotoxicity from DBPs associated with FP-chloramination were at times higher than with FP-chlorination though the concentration of DBPs was five times higher with FP-chlorination. The removal of DBP precursors using GAC based treatment was at least as effective as removal of DOC (except for halonitromethanes for GAC without pre-oxidation and with pre-chlorination), indicating DOC can be used as an indicator for DBP precursor adsorption efficacy. However, the DOC was not a good surrogate for total cytotoxicity and genotoxicity breakthrough behavior, therefore, unregulated DBPs could have negative health implications that are disconnected from general water quality parameters, such as DOC, and regulated classes of DBPs. Instead, cytotoxicity and genotoxicity correlate with the concentration of specific classes of unregulated DBPs.

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“…Preoxidation with chlorine dioxide (1 mg/L) has also been shown to minimize bromate formation by 75% (Newkirk et al 2006, Zhou & Neemann 2004. Chloramine-based pretreatment (0.1-0.5 mg/L) has been proved to reduce bromate by 65-95% through bromamine formation and reduced hydroxyl radical exposure (Benotti et al 2011, Wert et al 2007, Buffle et al 2004, von Gunten 2003.…”

Section: Introductionmentioning

confidence: 99%

Effect of Ozone Dissolution Systems on Ozone Exposure and Bromate Formation

Wert

Lew

Rakness³

2017

Journal AWWA

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Pilot‐scale data were generated to improve operational guidance for fine bubble diffusion (FBD) and sidestream addition (SSA) systems with respect to unaccounted‐for ozone exposure—i.e., concentration times time (C × T), and bromate formation during ozone dissolution. In FBD systems, results showed significant ozone dissolution C × T (0.31–2.85 mg‐min/L) and bromate formation (0.8–9.1 µg/L) occurring in the bubble column, which is not included in regulatory compliance C × T calculations. Utilities may consider taking contactors out of service to minimize contact time and corresponding bromate formation in the dissolution zone. In SSA systems, ozone dosages (7.2–18.6 mg/L) were transferred to approximately 20% of the overall plant flow for ~5 s, which produced bromate (2.6–5.7 µg/L). As the contact time exceeded the design guidance in the sidestream flow (>30 s), bromate formation became far more significant (40–140 µg/L). When the sidestream flow is operated with short contact times (~5 s), bromate formation can be minimized.

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Pilot-Scale and Full-Scale Evaluation of the Chlorine-Ammonia Process for Bromate Control During Ozonation

Cited by 28 publications

References 20 publications

Effect of Ozonation on Trihalomethane and Haloacetic Acid Formation and Speciation in a Full-Scale Distribution System

Effect of Ozonation on Trihalomethane and Haloacetic Acid Formation and Speciation in a Full-Scale Distribution System

Controlling disinfection byproducts from treated wastewater using adsorption with granular activated carbon: Impact of pre-ozonation and pre-chlorination

Effect of Ozone Dissolution Systems on Ozone Exposure and Bromate Formation

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