Prevention of the Formation of N-nitrosodimethylamine (NDMA) During Wastewater Chlorination
Author: William Armistead Mitch
Publisher:
Published: 2003
Total Pages: 294
ISBN-13:
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Author: William Armistead Mitch
Publisher:
Published: 2003
Total Pages: 294
ISBN-13:
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Publisher:
Published: 2009
Total Pages:
ISBN-13:
DOWNLOAD EBOOKDiuron is a widely used phenylurea herbicide for control of broad leaf and annual grassy weeds for both agricultural and nonagricultural uses. With the combination of the heavy usage and its persistence in typical environmental conditions due to its physical and chemical properties, diuron has been observed frequently in California's water sources. In this study diuron is of concern due to the potential formation of N-nitrosodimethylamine (NDMA), a potent carcinogen that has been identified as an emerging disinfection byproduct (DBP) in drinking water. The first results identified that diuron is a specific NDMA formation precursor that arises from non-point sources, and highlighted the difficulties associated with determining the environmental safety of chemicals and their associated potential byproducts. The influence of additional nitrogen sources on the NDMA formation mechanism during chlorination of diuron was also studied with consideration that the dominant nitrogen-containing specie may vary between surface water and groundwater. The risks posed by representative concentrations of diuron and other reagents with respect to NDMA formation during chlorine-based disinfection may be limited even in the presence of multiple nitrogen species. A broader picture exploring the current and long-term effects of water quality on public health risks from DBP formation and drinking water treatment costs was investigated by considering the Sacramento-San Joaquin Delta system, one of the most important drinking water sources in California. The present DBPs with Delta supplies are manageable within the current treatment regulations. However, the management of Delta water as a drinking water supply would become more difficult and expensive due to a possible sea level rise in the future and western island failures, with residual health risks remaining from residual and unregulated DBPs after treatment. It is likely that water drawn directly from the Delta will pose a higher risk to public health and be more difficult to treat by conventional treatment technologies, indicating that modification of existing treatment operations or addition of new technologies may be required, with higher treatment costs.
Author: Frank Sacher
Publisher: International Water Assn
Published: 2008
Total Pages: 196
ISBN-13: 9781843392132
DOWNLOAD EBOOKThe objectives of the project were to identify str
Author: Khidir Hamad
Publisher:
Published: 2015
Total Pages: 82
ISBN-13:
DOWNLOAD EBOOKTarrant Regional Water District (TRWD) pumps untreated raw water from Richland Chambers and Cedar Creek reservoirs in East Texas to provide water to several customer cities including Arlington and Fort Worth. TRWD adds chloramines to the pipeline to combat biofilm growth, that reduces pipeline capacity and increases pumping costs, and to control zebra mussels, that clog intake structure screens and the pump wet wells. However, addition of chloramines leads to the formation of Nnitrosodimethylamine (NDMA), a potent carcinogen, by reaction of chloramines with nitrogenous organic precursors possibly present in the raw water. NDMA formation presents a challenge to TRWD because potential regulation of NDMA and other nitrosamines will force TRWD and other utilities alike to seek treatment options. Because post treatment removal of NDMA is ineffective and expensive, the best strategy is to optimize conditions to minimize NDMA formation and to eliminate nitrogenous NDMA precursors in the system. This research examines the effect of preformed chloramines and chlorine to ammonia mass ratio on NDMA formation in the District's current and future pipelines.
Author: Chetna Vasudeva
Publisher:
Published: 2018
Total Pages: 43
ISBN-13: 9780438752139
DOWNLOAD EBOOKAbstract: N-nitrosodimethylamine is a carcinogenic disinfection byproduct which can be reformed after wastewater treatment if appropriate conditions are present. In this study various NDMA formation precursors over a range of conditions have been studied to attempt to quantify this NDMA reformation potential. Efforts were made in this study to demonstrate the effect of time, pH, and multiple different precursor chemicals on the reformation process. Dimethylamine (DMA) has been demonstrated to be a precursor chemical, and was chosen as a standard for initial experiments. The concentration of this precursor was kept constant at 100 ppt (parts per trillion) and solutions at three different pH’s were tested over a 24-hour time period to see if any significant NDMA formation occurred. The impacts of various treated wastewater constituent chemicals including H2O2, monochloramine, dimethylhydrazine, etc. were also performed in this study. Significant difficulties occurred for the analysis of these samples, with large background interferences occurring in the method of analysis. Based on the data obtained, it appears that the formation potential of NDMA with DMA as a precursor was found to be the most efficient compound at basic pH (pH 9) and very basic (pH 13). This is consistent with the last step in wastewater remediation, where quicklime is added to the water to regulate the pH and for protection of distribution system. In addition, preliminary experiments were conducted using Ranitidine as a NDMA reformation precursor.
Author: Frank Sacher
Publisher: American Water Works Association
Published: 2008-01-01
Total Pages: 163
ISBN-13: 9781605730080
DOWNLOAD EBOOKNitrosamines are among the most toxic and carcinogenic chemical compounds known. Recently, N-nitrosodimethylamine (NDMA) has been identified as a possible water disinfection by-product and has been detected in water treatment plants in the US and Canada that use chloramines as a disinfectant. This report describes a research project on strategies for minimizing nitrosamine levels in drinking water. The research project focuses on the most prominent nitrosamine, NDMA, but also covers other aliphatic nitrosamines. Conclusions from the literature search and laboratory-scale experiments were the verified by full-scale tests in water utilities in the US, Australia, and Germany. The report lacks a subject index. Sacher is affiliated with DVGW-Technologiezentrum Wasser, Germany.
Author: Daniel Logan McCurry
Publisher:
Published: 2016
Total Pages:
ISBN-13:
DOWNLOAD EBOOKDisinfection of potable water is one of the great public health victories of the twentieth century, responsible for the avoidance of millions of deaths due to waterborne illness. However, application of disinfectants, typically chemical oxidants, leads to formation of hundreds of trace contaminants, often carcinogens, and consumption of chlorinated water has been epidemiologically linked to bladder cancer and certain birth defects. Eleven of these compounds are federally regulated in drinking water, but certain non-regulated disinfection byproducts (DBPs) are orders of magnitude more toxic than currently regulated compounds. Two specific DBPs, chloropicrin and N-nitrosodimethylamine (NDMA), are especially genotoxic, and are associated with nitrogen input into drinking water supplies. Wastewater-impacted drinking water and recycled wastewater are enriched in the precursors of these compounds, and their formation during potable water treatment is likely to grow, as wastewater increasingly contributes to the water supply. This thesis focuses on applying the tools of environmental organic chemistry to identify the chemical precursors and formation mechanisms of these compounds, leading to strategies for their control during water treatment. In particular, ozonation of primary and secondary amine compounds, leading to formation of nitro compound intermediates, was found be responsible for chloropicrin formation during water treatment. Secondary N-methylamines and primary amines geminal to facile leaving groups were particularly potent precursors, forming chloropicrin at up to 50% yield when exposed to ozone followed by chlorine. Based on this predominant formation pathway, chloropicrin precursors may be oxidized upstream of ozone addition to prevent chloropicrin formation. Strategies for controlling NDMA formation, a major concern during wastewater recycling, were developed based on an understanding of the chemical composition of NDMA precursors, and chloramines, the primary disinfectant applied during wastewater reuse. Minor modifications to wastewater recycling operations, in particular switching from low-pressure to medium-pressure mercury lamps for ultraviolet light treatment, and minor adjustments in the application of chloramines, were shown to dramatically reduce NDMA concentrations in final effluent. Finally, the effluent from a new, all-anaerobic wastewater treatment system was demonstrated to more efficiently remove trace contaminants and DBP precursors than conventional aerobic treatment, suggesting that this energy-saving technology may also be more suitable for water reuse than conventional treatment. These findings facilitate reducing the chronic health risk associated with consumption of (intentionally or unintentionally) recycled wastewater.
Author: Xianghua Luo
Publisher:
Published: 2006
Total Pages:
ISBN-13:
DOWNLOAD EBOOKN-nitrosodimethylamine (NDMA) is a chloramines disinfection by-product and probable carcinogen to human. The California state established a 10 ng/L action level for NDMA in drinking water. Analytical method of NDMA in waters at the trace level was developed using gas chromatography/mass spectrum with chemical ionization in the mode of selected ion storage coupled with solid phase extraction. It was found that 4 utilities in Missouri using monochloramine as disinfectant had NDMA higher than 10 ng/L in drinking water. Natural organic matter (NOM), especially the hydrophilic fraction of the NOM, was found to be a predominant NDMA precursors. Basic conditions and bromide ions favor NDMA formation in natural waters. The findings reported in this dissertation provide data on NDMA occurrences in drinking water and natural waters in Missouri. The results provide valuable information about NDMA precursors in natural waters and this information could be used in the further study of mitigating NDMA formation or removing NDMA precursors in drinking water utilities. The results on factors affecting on NDMA formation provide more information for water utilities to determine operation conditions to reduce and control NDMA formation.
Author: Stephanie Spahr
Publisher:
Published: 2016
Total Pages: 161
ISBN-13:
DOWNLOAD EBOOKMots-clés de l'autrice: water disinfection ; chloramination ; disinfection by-products ; N-nitrosodimethylamine (NDMA) ; compound-specific isotope analysis (CSIA) ; stable isotope fractionation.
Author: National Research Council
Publisher: National Academies Press
Published: 2012-07-17
Total Pages: 276
ISBN-13: 0309224624
DOWNLOAD EBOOKExpanding water reuse-the use of treated wastewater for beneficial purposes including irrigation, industrial uses, and drinking water augmentation-could significantly increase the nation's total available water resources. Water Reuse presents a portfolio of treatment options available to mitigate water quality issues in reclaimed water along with new analysis suggesting that the risk of exposure to certain microbial and chemical contaminants from drinking reclaimed water does not appear to be any higher than the risk experienced in at least some current drinking water treatment systems, and may be orders of magnitude lower. This report recommends adjustments to the federal regulatory framework that could enhance public health protection for both planned and unplanned (or de facto) reuse and increase public confidence in water reuse.