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The formation of disinfection by-products (DBPs), including both nitrogenous disinfection by-products (N-DBPs) and carbonaceous disinfection by-products (C-DBPs), was investigated upon chlorination of water samples following two treatment processes: (i) coagulation-inclined plate sedimentation (IPS)-filtration and (ii) coagulation-dissolved air flotation (DAF)-filtration. The removal of algae, dissolved organic nitrogen (DON), dissolved organic carbon (DOC) and UV254 by coagulation-DAF-filtration was superior to coagulation-IPS-filtration. On average, 53%, 53% and 31% of DOC, DON and UV254 were removed by coagulation-DAF-filtration process, which were higher than 47%, 31% and 27% of that by coagulation-IPS-filtration process. Additionally, coagulation-IPS-filtration performed less well at removing the low molecular weight organics than coagulation-DAF-filtration process. The concentrations of chloroform, dichloroacetamide (DCAcAm) and dichloroacetonitrile (DCAN) formed during chlorination after coagulation-DAF-filtration reached their maximum values of 13, 1.5 and 4.7 μg L−1, respectively, and were lower than those after coagulation-IPS-filtration with the maximum detected levels of 17, 2.9 and 6.3 μg L−1. However, the trichloronitromethane (TCNM) concentration after the two processes was similar, suggesting that DON may have less of a contribution to TCNM formation than DCAcAm and DCAN. 相似文献
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Qian-Yuan Wu Yi-Jun Yan Yao Lu Ye Du Zi-Fan Liang Hong-Ying Hu 《Frontiers of Environmental Science & Engineering》2020,14(2):25
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Precursors and nitrogen origins of trichloronitromethane and dichloroacetonitrile during chlorination/chloramination 总被引:1,自引:0,他引:1
The formation of trichloronitromethane (TCNM) and dichloroacetonitrile (DCAN) was investigated during chlorination and chloramination of 31 organic nitrogen (org-N) compounds, including amino acids, amines, dipeptides, purines, pyrimidones and pyrroles. Tryptophan and alanine generated the greatest amount of TCNM during chlorination process and asparagine and tyrosine yielded the highest amount of TCNM during chloramination process. Tryptophan, tyrosine, asparagine, and alanine produced more DCAN than other org-N compounds regardless of chlorination or chloramination. TCNM and DCAN formation was higher by chlorination than by chloramination. NH2Cl:org-N molar ratios, reaction time, and pH affected N-DBPs formation in varying degrees. TCNM and DCAN yields were usually high during chloramination of tyrosine, asparagine, and methylpyrrole under the following reaction conditions: NH2Cl:org-N molar ratios greater than 10, reaction time for 1 d, and at pH 7.2. NH2Cl as a major nitrogen origin in TCNM and DCAN was confirmed via labeled 15N-monochloramine during chloramination of tyrosine, asparagine and methylpyrrole. In contrast, the majority of nitrogen in TCNM originated from glycine, and that in DCAN originated from pyrrole. Based on the intermediates identified by gas chromatography/mass spectrometry (GC/MS), a pathway scheme was proposed for TCNM and DCAN formation. 相似文献
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