Effect of Amine-based Water Treatment Polymers on the Formation of N-nitrosodimethylamine (ndma) Disinfection By-product
Effect of Amine-based Water Treatment Polymers on the Formation of N-nitrosodimethylamine (ndma) Disinfection By-product

Author: Sang Hyuck Park

Publisher:

Published: 2008

Total Pages:

ISBN-13:

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In recent years, a compound N-nitrosodimethylamine (NDMA), a probable human carcinogen, has been identified as an emerging disinfection by-product (DBP) since its formation and detection were linked to chlorine-based disinfection processes in several water utilities in the U.S. and Canada. Numerous organic nitrogen compounds present in water may impact the formation of NDMA during disinfection. Amine-based water treatment polymers used as coagulants and flocculants have been suggested as potential NDMA precursors due to the presence of amine functional groups in their structures, as well as the possible presence of dimethylamine (DMA) residues in polymer products. To minimize the potential risk of NDMA associated with water treatment polymers, the mechanisms of how the polymers behave as NDMA precursors and their contribution to the overall NDMA formation under actual water treatment conditions need to be elucidated. This research involved a systematic investigation to determine whether amine-based water treatment polymers contribute to NDMA formation under drinking water and wastewater treatment conditions, to probe the involved reaction mechanisms, and to develop strategies to minimize the polymers NDMA formation potential. The investigation included five research tasks: (1) General screening of NDMA formation potential of commonly used amine-based water treatment polymers, (2) NDMA formation from amine-based water treatment polymers under relevant water treatment conditions, (3) Probing the mechanisms of NDMA formation from polyamine and PolyDADMAC, (4) Effect of water treatment processes on NDMA formation from amine-based water treatment polymers, and (5) Developing strategies to reduce polymers NDMA formation potential. Direct chloramination or chlorination of high doses of polymers in deionized water at longer than typical contact time was used in the general screening of the NDMA formation potential of water treatment polymers and in the studies to identify reaction mechanisms. On the other hand, realistic dosages of chloramines and polymers and contact time were used in simulating representative water treatment conditions to evaluate the contribution of polymers to the overall NDMA formation in real systems. On the basis of the study results, strategies were developed to reduce the NDMA formation potential of amine-based water treatment polymers, which include modification of polymer structures and treatment parameters.

Coagulation and Flocculation in Water and Wastewater Treatment
Coagulation and Flocculation in Water and Wastewater Treatment

Author: John Bratby

Publisher: IWA Publishing

Published: 2016-04-15

Total Pages: 538

ISBN-13: 1780407491

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Coagulation and Flocculation in Water and Wastewater Treatment provides a comprehensive account of coagulation and flocculation techniques and technologies in a single volume covering theoretical principles to practical applications. Thoroughly revised and updated this new edition has been progressively modified and increased in scope to cater for the requirements of practitioners involved with water and wastewater treatment. New topics in this new edition include : • activated sludge bulking and foaming control and enhanced bioflocculation; • algae removal and harvesting; • dissolved organic nitrogen (DON) removal; • inorganics removal; • turbidity and its measurement; • wastewater treatment by coagulation and chemically enhanced primary treatment (CEPT). The book presents the subject logically and sequentially from theoretical principles to practical applications. Successive chapters deal with, in turn, properties of materials present in waters and wastewaters; characteristics and types of coagulants commonly in use; mechanisms and practical implications of destabilization of waterborne material using metal coagulants and polyelectrolytes; considerations and requirements for coagulant addition at the rapid mixing stage; theoretical and practical considerations of flocculation; and details of experimental procedures for assessing primary coagulants, flocculant aids, sludge conditioners, and flocculation parameters. Numerous examples are included as appropriate. Treatment and disposal of sludges resulting from coagulation-flocculation related operations is dealt with in an Appendix. This important topic has been separated from the main text to avoid disturbing the continuum of the presentation. Coagulation and Flocculation in Water and Wastewater Treatment is a readable and useful resource for the water scientist and engineer. It is a convenient reference handbook providing numerous examples and appended information and it is a vital text for course material for undergraduate and postgraduate students.

Evaluation of N-Nitrosodimethylamine (NDMA) Formation at Varied PH and Conditions in Treated Wastewater
Evaluation of N-Nitrosodimethylamine (NDMA) Formation at Varied PH and Conditions in Treated Wastewater

Author: Chetna Vasudeva

Publisher:

Published: 2018

Total Pages: 43

ISBN-13: 9780438752139

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Abstract: 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.

The Llobregat
The Llobregat

Author: Sergi Sabater

Publisher: Springer

Published: 2012-06-02

Total Pages: 381

ISBN-13: 3642309399

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The Llobregat belongs to the most thoroughly studied rivers in Europe and is a paradigm of the confluence of human and natural disturbances in a single basin. Because of its location in a very densely populated region and its Mediterranean character, the Llobregat supports a mixture of irregular flow, water abstraction, excess nutrients, mining debris, and a wide array of pollutants. The aquatic organisms strive to survive in a dramatically changing river that passes through a succession of dams, weirs and channels. The long-term river monitoring as well as the research that has been carried out in the river for a long time have provided an extensive knowledge of these disturbances and their effects on the biological communities. This book highlights the available information, with emphasis on the hydrological, chemical and biological elements interspersed in the river. Experts in the field discuss the main nutrient patterns and pollutant occurrence and the responses of the biological quality elements as well as the river ecosystem to the overall natural and man-made influences.

Frontier Technology for Water Treatment and Pollutant Removal
Frontier Technology for Water Treatment and Pollutant Removal

Author: Puangrat Kajitvichyanukul

Publisher: IWA Publishing

Published: 2019-11-15

Total Pages: 242

ISBN-13: 1789061237

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Frontier technology in water treatment and pollutant removal is needed not only for maximizing water reuse but also for the rapid detection of contaminants in the recycled water. The UN announced the years 2018 to 2028 as the ‘International Decade for Action–Water for Sustainable Development’. To realize this mission, innovative and frontier technologies for water treatment and pollutant removal are important components. This book aims to serve as a platform for updating the scientific community with recent progress in this area, covering frontier technologies in analytical technique, physicochemical treatment, chemical treatment, and biological treatment. In Focus – a book series that showcases the latest accomplishments in water research. Each book focuses on a specialist area with papers from top experts in the field. It aims to be a vehicle for in-depth understanding and inspire further conversations in the sector.

Roles of Polydadmacs, Dithiocarbamates and Activated Carbons in Formation of N-nitrosamine Contaminants in Water
Roles of Polydadmacs, Dithiocarbamates and Activated Carbons in Formation of N-nitrosamine Contaminants in Water

Author: Lokesh Pradeep Padhye

Publisher:

Published: 2010

Total Pages:

ISBN-13:

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N-Nitrosamines are an emerging group of disinfection byproducts characterized by high carcinogenic risks at ng/L levels and by their frequent detection in water and wastewater treatment systems in the U.S. and other parts of the world. The overall goal of this research is to achieve a better understanding of the roles of common nitrosamine precursors in leading to N-nitrosamine formation in water and wastewater treatment systems. The specific objectives of this research are: (a) To probe the mechanisms of nitrosamine formation from commonly employed water treatment polymers, particularly polyDADMACs, during ozonation, (b) To evaluate the role of dithiocarbamate compounds as nitrosamine precursors in reaction with common water disinfection oxidants, and (c) To investigate the potential enhancement effect of activated carbons (AC) to promote transformation of amines to nitrosamines and identify the involved reaction mechanism. Results of this research show that, upon ozonation, polyDADMACs may yield N-nitrosodimethylamine (NDMA) at levels up to two orders of magnitude higher than current advisory guidelines for NDMA. Radical pathways may be responsible for the degradation of the quaternary ammonium ring groups in polyDADMACs to release of dimethylamine (DMA). Detection of significant amounts of nitrite after ozonation of polyDADMACs and DMA suggests the potential role of nitrosation pathway in NDMA formation. Study results also reveal dithiocarbamates as potent nitrosamine precursors with significant nitrosamine yields upon ozonation and monochloramination. Identification and quantification of reaction products suggest nitrosation and chlorinated-UDMH oxidation as primary reaction mechanisms in nitrosamine formation from ozonation and monochloramination of dithiocarbamates compounds, respectively. This research also demonstrates that many commercial AC materials may catalyze transformation of secondary amines to yield trace levels of N-nitrosamines under ambient aerobic conditions. This is a novel discovery with far-reaching implications because of the widespread usage of AC materials in numerous analytical and environmental applications. The study results show that the properties of AC materials and reaction conditions play a crucial role in the catalyzed nitrosamine formation and should be carefully selected to minimize analytical errors and undesirable nitrosamine formation in water samples. Overall, the mechanistic information obtained in this research will be useful for the water industry and research communities to develop more effective strategies to control undesirable nitrosamine formation in water and wastewater treatment systems and thus better protect the public health.