Journal ArticleDOI
Formation of disinfection by-products: Effect of temperature and kinetic modeling
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It was found that chloroform, DCAA, TCAA, DCAN and CH were detected at the considerable level of tens of μg L(-1), indicating that their occurrence levels in the finished water were more susceptible to temperature variations.About:
This article is published in Chemosphere.The article was published on 2013-01-01. It has received 64 citations till now.read more
Citations
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Journal ArticleDOI
Correlation between SUVA and DBP formation during chlorination and chloramination of NOM fractions from different sources.
TL;DR: Overall, SUVA is a good indicator for the formation of unknown DBPs, which indicates that UV absorbing compounds and aromatic carbon within NOM are the primary sources of precursors for unknownDBPs.
태양선택 흡수면의 Thermal Degradation
Abstract: When wood is exposed to elevated temperatures, changes can occur in its chemical structure that affect its performance. The extent of the changes depends on the temperature level and the length of time under exposure conditions. The changes in chemical structure may be manifested only as reduced strength, and hydroscopic water and volatile oil weight loss. In contrast, very drastic chemical changes may result in reduced strength and significant carbohydrate weight loss. At temperatures below 100°C, permanent reductions in strength can occur. The magnitude of the reduction depends on the moisture content, heating medium, exposure period and species. The strength degradation is usually not considered to result from the same thermal decomposition of the wood that occurs above 100°C, since no significant carbohydrate weight loss occurs. The strength degradation is probably due to depolymerization reactions, although little research has been done on the chemical mechanism. Reviews by Gerhards (1979, 1982, 1983) and Koch (1985) summarize reduction in strength at temperatures below 100oC (See Strength). If the wood has been treated with a chemical to reduce its flammability, more significant reductions in strength can occur at lower temperatures than for untreated wood. This is due to the presence of chemicals that catalyze the dehydration and depolymerization reactions. A review by Winandy (1987) summarizes the effects of elevated temperatures on strength properties of treated wood. At temperatures above 100oC, chemical bonds begin to break. The rate at which the bonds are broken increases as the temperature increases. Between 100°C and 200oC, noncombustible products, such as carbon dioxide, traces of organic compounds and water vapor, are produced. Above 200oC the celluloses break down, producing tars and flammable volatiles that can diffuse into the surrounding environment. If the volatile compounds are mixed with air and heated to the ignition temperature, combustion reactions occur. The energy from these exothermic reactions radiates to the solid material, thereby propagating the combustion, or pyrolysis, reactions. If the burning mixture accumulates enough energy to emit radiation in the visible spectrum, the phenomenon is known as flaming combustion (see Fire and Wood). Above 450oC all volatile material is gone. The residue that remains is an activated char that can be oxidized to carbon dioxide, carbon monoxide and water vapor. Oxidation of the char is referred to as afterglow. The thermal degradation of wood can be represented by two pathways (Fig. 1), one occurring at high temperatures (>300oC), the other at lower temperatures. These two competing reactions occur simultaneously. Fire retardants work by shifting degradation to the low-temperature pathway.
Journal ArticleDOI
Formation and toxicity of brominated disinfection byproducts during chlorination and chloramination of water: A review
TL;DR: Brominated disinfection byproducts may have higher health risks than their corresponding chlorinated DBPs and a potential role of an emerging alternate disinfectant, ferrate (FeVIO2− 4), in minimizing DBPs is briefly discussed.
Journal ArticleDOI
Disinfection by-products in drinking water: Occurrence, toxicity and abatement.
TL;DR: The efficiency of adsorption technique was found up to 90% for DBP removal from the water, and several regulations have been specified by world authorities like WHO, USEPA and Bureau of Indian Standard to protect human health.
Journal ArticleDOI
Prioritization of unregulated disinfection by-products in drinking water distribution systems for human health risk mitigation: A critical review
TL;DR: This review prioritizes some commonly occurring unregulated DBPs groups and species in DWDSs based on their concentration level, reported frequency, and toxicity using an indexing method to help water regulators to identify the most critical UR-DBPs species in the context of drinking water safety and provide them with useful information to develop guidelines or threshold limits.
References
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Journal ArticleDOI
Occurrence, genotoxicity, and carcinogenicity of regulated and emerging disinfection by-products in drinking water: a review and roadmap for research.
TL;DR: The brominated DBPs were the most genotoxic of all but have not been tested for carcinogenicity and highlighted the emerging importance of dermal/inhalation exposure to the THMs, or possibly other DBPs, and the role of genotype for risk for drinking-water-associated bladder cancer.
Journal ArticleDOI
Occurrence of a New Generation of Disinfection Byproducts
Stuart W. Krasner,Howard S. Weinberg,Susan D. Richardson,Salvador J. Pastor,Russell Chinn,Michael J. Sclimenti,Gretchen D. Onstad,Alfred D. Thruston +7 more
TL;DR: A survey of disinfection byproduct (DBP) occurrence in the United States was conducted at 12 drinking water treatment plants to obtain quantitative occurrence information for new DBPs (beyond those currently regulated and/or studied) for prioritizing future health effects studies.
Book ChapterDOI
Comparative mammalian cell toxicity of N-DBPs and C-DBPs
TL;DR: A quantitative, direct comparison amongst classes of drinking water disinfection by-products (DBPs), developed and calibrated in vitro mammalian cell cytotoxicity and genotoxicity assays to integrate the analytical biology with the analytical chemistry of these important environmental contaminants demonstrate the universality of the comparative toxicity of iodo- > bromo- » chloro-DBPs.
Journal ArticleDOI
Assessing DBP yield: uniform formation conditions
TL;DR: In this paper, a new chlorination approach has been developed for assessing disinfection byproduct (DBP) formation under constant, yet representative conditions, and the rationale used in the development of the uniform formation conditions (UFC) test and the results of a parametric sensitivity analysis are presented.
Journal ArticleDOI
Factors Affecting Formation of Haloacetonitriles, Haloketones, Chloropicrin and Cyanogen Halides During Chloramination
TL;DR: In this article, the effects of contact time, monochloramine dose, pH, temperature and bromide ion concentrations on the formation of disinfection by-products (DBPs) during chloramination were investigated using model solutions containing 5 mg/L (as DOC) Suwannee River natural organic matter (NOM).