Insights into the molecular compositions of CX3 - ScienceDirect
By the results of significant and strong correlations between AOM molecules and DBP formation potentials, the typical precursors of DCAN or TCP were observed to be the molecules with relatively high O/C (0.5–0.8) and low H/C (0.9–1.8) ratios, while different precursors of TCM were obviously determined.
Insights into the molecular compositions of CX3 - ScienceDirect
Therefore, in this study, the objectives are to explore the specific precursors of dichloroacetonitrile (DCAN), trichloromethane (TCM) and trichloroacetone (TCP) as well as its molecular properties of these DBP precursors. Firstly, the DBP formation potentials during chlorination were measured.
Assessing the chemical compositions and disinfection byproduct
The chemical composition and formation of carbonaceous and nitrogenous DBPs of biofilms were continuously monitored every 21 days for 168 days and correlated with the derived EEM-PARAFAC components. Results indicated that all biofilm samples comprised mostly of protein-like components (90%), and to a lesser extent, humic-like components (10%).
Characteristics of low and high SUVA precursors
DBPs formed by NOMchlorine reactions are highly complicated, involving oxidation of macromolecules, substitution of chlorine into intermediates, further decarboxylation, and hydrolysis to form final by-products with low molecular weight ( Reckhow and Singer, 1985; Dickenson et al., 2008; Yang et al., 2008; Bond et al., 2009 ).
Assessing the chemical compositions and disinfection byproduct
The chemical composition and formation of carbonaceous and nitrogenous DBPs of biofilms were continuously monitored every 21 days for 168 days and correlated with the derived EEM-PARAFAC components. Results indicated that all biofilm samples comprised mostly of protein-like components (90%), and to a lesser extent, humic-like components (10%).
- Are disinfection by-products (DBPs) formed during water treatment a problem?
- Disinfection by-products (DBPs) formed upon water treatment is an emerging issue worldwide. While monitoring of DBP precursors can easily be achieved for high specific UV absorbance (SUVA) organic (>6 L/mg·m), low and extremely low SUVA precursors (<2 L/mg·m) are difficult to monitor or even to predict their DBP formation behaviour.
- What is a DBP disinfection byproduct?
- DBPs are generally formed by the reaction of disinfectants such as chlorine with organic precursors present in source water; these organic precursors are mainly called natural organic matter (NOM) and NOM acts as a forerunner to DBPs. Some of the chlorination disinfection byproducts are shown in Table 1.
- What is the role of DBP precursors in water treatment?
- Understanding the diverse nature of DBP precursors is critical for developing more effective water treatment strategies. This includes not only optimizing the disinfection process to minimize DBP formation but also implementing pre-treatment measures to reduce the concentration of precursors in the water.
- How are DBP precursors determined?
- In general, DBP precursors in drinking water sources can be determined using DBP FP tests, in which source water samples are dosed with a stoichiometric excess of specific disinfection agents (e.g., chlorine or chloramines) for a reaction time that is designed to maximize DBP formation under certain reaction conditions , .
- How do nom characteristics affect DBP formation?
- This study investigated the relationships among NOM characteristics, such as molecular weight (MW), fluorescence, and chemical composition, with DBP formation resulting from the chlorination of relatively high and low SUVA precursors.
- How do DBPs form?
- Unlike most other drinking water contaminants, DBPs form from disinfectant application within the plant, as a result of the final drinking water treatment process (disinfection) and continue to form throughout the distribution system, such that control strategies necessarily focus on minimizing their formation.
