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GAC removal of organic nitrogen and other DBP precursors
Author(s) -
Chili ChaoAn,
Westerhoff Paul,
Ghosh Amlan
Publication year - 2012
Publication title -
journal ‐ american water works association
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.466
H-Index - 74
eISSN - 1551-8833
pISSN - 0003-150X
DOI - 10.5942/jawwa.2012.104.0090
Subject(s) - chemistry , dissolved organic carbon , effluent , chlorine , environmental chemistry , nitrogen , bromide , organic matter , total organic carbon , water treatment , activated carbon , inorganic chemistry , organic chemistry , adsorption , environmental engineering , environmental science
The increased mutagenicity of disinfection by‐products (DBPs) containing bromide (Br − ) and nitrogen requires a renewed evaluation of best available treatment technologies for DBP control. The aim of this article is to document the removal of organic nitrogen during granular activated carbon (GAC) treatment and to illustrate how GAC treatment alters DBP speciation. Rapid small‐scale column tests (RSSCTs) with GAC were conducted on pretreated surface water sources to evaluate the simultaneous removal of carbonaceous and nitrogenous DBP precursors: dissolved organic nitrogen (DON), dissolved organic carbon (DOC), organics absorbed by ultraviolet light at 254 nm (UV 254 ), and Br − . Simulated distribution system tests were conducted with RSSCT effluent samples throughout natural organic matter breakthrough, and free chlorine was used to evaluate the formation of halogenated carbonaceous and nitrogenous DBPs. GAC preferentially removed UV 254‐ absorbing material over DOC, which was removed more effectively than DON. Br − was not removed. Consequently, effluent ratios of Br − to DOC and Br − to DON changed during GAC treatment, and the ratio of brominated DBPs to chlorinated DBPs shifted during the GAC breakthrough cycle; brominated DBPs dominated earlier in the breakthrough of DOC. Neither DON nor nitrogenous DBP precursors were removed efficiently during GAC treatment.