Operator-Friendly Technique and Quality Control Considerations for Indigo Colorimetric Measurement of Ozone Residual

Rakness, Kerwin L.; Wert, Eric C.; Elovitz, Michael S.; Mahoney, Suzanne

doi:10.1080/01919510903467864

Cited by 28 publications

(16 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Therefore, leaving the bottles to sit overnight was sufficient to eliminate the ozone residual. Ozone concentration was measured using the indigo method (Rakness et al, 2010). Chloramine NDMA formation potential was evaluated based on a previously published method .…”

Section: Analytical Methods and Reagentsmentioning

confidence: 99%

N-nitrosodimethylamine (NDMA) formation from the ozonation of model compounds

et al. 2015

View full text Add to dashboard Cite

Nitrosamines are a class of toxic disinfection byproducts commonly associated with chloramination, of which several were included on the most recent U.S. EPA Contaminant Candidate List. Nitrosamine formation may be a significant barrier to ozonation in water reuse applications, particularly for direct or indirect potable reuse, since recent studies show direct formation during ozonation of natural water and treated wastewaters. Only a few studies have identified precursors which react with ozone to form N-nitrosodimethylamine (NDMA). In this study, several precursor compound solutions, prepared in ultrapure water and treated wastewater, were subjected to a 10 M excess of ozone. In parallel experiments, the precursor solutions in ultrapure water were exposed to gamma radiation to determine NDMA formation as a byproduct of reactions of precursor compounds with hydroxyl radicals. The results show six new NDMA precursor compounds that have not been previously reported in the literature, including compounds with hydrazone and carbamate moieties. Molar yields in deionized water were 61-78% for 3 precursors, 12-23% for 5 precursors and <4% for 2 precursors. Bromide concentration was important for three compounds (1,1-dimethylhydrazine, acetone dimethylhydrazone and dimethylsulfamide), but did not enhance NDMA formation for the other precursors. NDMA formation due to chloramination was minimal compared to formation due to ozonation, suggesting distinct groups of precursor compounds for these two oxidants. Hydroxyl radical reactions with the precursors will produce NDMA, but formation is much greater in the presence of molecular ozone. Also, hydroxyl radical scavenging during ozonation leads to increased NDMA formation. Molar conversion yields were higher for several precursors in wastewater as compared to deionized water, which could be due to catalyzed reactions with constituents found in wastewater or hydroxyl radical scavenging.

show abstract

Section: Analytical Methods and Reagentsmentioning

confidence: 99%

N-nitrosodimethylamine (NDMA) formation from the ozonation of model compounds

et al. 2015

View full text Add to dashboard Cite

show abstract

“…The ozone reaction continued until the residual ozone in the samples were completely consumed. The ozone concentration of stock solution and residual ozone concentration of samples were determined using indigotrisulfonate (ITS) method and the detailed procedure is described in the literature (Rakness et al, 2010).…”

Section: Ozonation Of Wastewater Effluentsmentioning

confidence: 99%

Predicting trace organic compound attenuation by ozone oxidation: Development of indicator and surrogate models

et al. 2017

View full text Add to dashboard Cite

“…Analytical methods. Dissolved ozone residuals were measured after steady-state operation had been achieved using method 4500-O3, Ozone by Indigo Colorimetric Method (Rakness et al 2010, Standard Methods 1999. Bromate concentrations were measured using liquid chromatography with tandem mass spectrometry (Snyder et al 2005).…”

Section: Methodsmentioning

confidence: 99%

Effect of Ozone Dissolution Systems on Ozone Exposure and Bromate Formation

Wert

Lew

Rakness³

2017

Journal AWWA

Self Cite

View full text Add to dashboard Cite

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.

show abstract

Operator-Friendly Technique and Quality Control Considerations for Indigo Colorimetric Measurement of Ozone Residual

Cited by 28 publications

References 5 publications

N-nitrosodimethylamine (NDMA) formation from the ozonation of model compounds

N-nitrosodimethylamine (NDMA) formation from the ozonation of model compounds

Predicting trace organic compound attenuation by ozone oxidation: Development of indicator and surrogate models

Effect of Ozone Dissolution Systems on Ozone Exposure and Bromate Formation

Contact Info

Product

Resources

About