TY - JOUR
T1 - Effect of Ozonation and Biological Activated Carbon Treatment of Wastewater Effluents on Formation of N-nitrosamines and Halogenated Disinfection Byproducts
AU - Chuang, Yi-Hsueh
AU - Mitch, William A.
PY - 2017/2/21
Y1 - 2017/2/21
N2 - Ozonation followed by biological activated carbon (O3/BAC) is being considered as a key component of reverse osmosis-free advanced treatment trains for potable wastewater reuse. Using a laboratory-scale O3/BAC system treating two nitrified wastewater effluents, this study characterized the effect of different ozone dosages (0-1.0 mg O3/mg dissolved organic carbon) and BAC empty bed contact times (EBCT; 15-60 min) on the formation after chlorination or chloramination of 35 regulated and unregulated halogenated disinfection byproducts (DBPs), 8 N-nitrosamines, and bromate. DBP concentrations were remarkably similar between the two wastewaters across O3/BAC conditions. Ozonation increased bromate, TCNM, and N-nitrosodimethylamine, but ozonation was less significant for other DBPs. DBP formation generally decreased significantly with BAC treatment at 15 min EBCT, but little further reduction was observed at higher EBCT where low dissolved oxygen concentrations may have limited biological activity. The O3/BAC-treated wastewaters met regulatory levels for trihalomethanes (THMs), haloacetic acids (HAAs), and bromate, although N-nitrosodimethylamine exceeded the California Notification Level in one case. Regulated THMs and HAAs dominated by mass. When DBP concentrations were weighted by measures of their toxic potencies, unregulated haloacetonitriles, haloacetaldehydes, and haloacetamides dominated. Assuming toxicity is additive, the calculated DBP-associated toxicity of the O3/BAC-treated chloraminated effluents were comparable or slightly higher than those calculated in a recent evaluation of Full Advanced Treatment trains incorporating reverse osmosis.
AB - Ozonation followed by biological activated carbon (O3/BAC) is being considered as a key component of reverse osmosis-free advanced treatment trains for potable wastewater reuse. Using a laboratory-scale O3/BAC system treating two nitrified wastewater effluents, this study characterized the effect of different ozone dosages (0-1.0 mg O3/mg dissolved organic carbon) and BAC empty bed contact times (EBCT; 15-60 min) on the formation after chlorination or chloramination of 35 regulated and unregulated halogenated disinfection byproducts (DBPs), 8 N-nitrosamines, and bromate. DBP concentrations were remarkably similar between the two wastewaters across O3/BAC conditions. Ozonation increased bromate, TCNM, and N-nitrosodimethylamine, but ozonation was less significant for other DBPs. DBP formation generally decreased significantly with BAC treatment at 15 min EBCT, but little further reduction was observed at higher EBCT where low dissolved oxygen concentrations may have limited biological activity. The O3/BAC-treated wastewaters met regulatory levels for trihalomethanes (THMs), haloacetic acids (HAAs), and bromate, although N-nitrosodimethylamine exceeded the California Notification Level in one case. Regulated THMs and HAAs dominated by mass. When DBP concentrations were weighted by measures of their toxic potencies, unregulated haloacetonitriles, haloacetaldehydes, and haloacetamides dominated. Assuming toxicity is additive, the calculated DBP-associated toxicity of the O3/BAC-treated chloraminated effluents were comparable or slightly higher than those calculated in a recent evaluation of Full Advanced Treatment trains incorporating reverse osmosis.
UR - http://www.scopus.com/inward/record.url?scp=85018426444&partnerID=8YFLogxK
U2 - 10.1021/acs.est.6b04693
DO - 10.1021/acs.est.6b04693
M3 - Article
C2 - 28092936
AN - SCOPUS:85018426444
SN - 0013-936X
VL - 51
SP - 2329
EP - 2338
JO - Environmental Science & Technology
JF - Environmental Science & Technology
IS - 4
ER -