AWWA WQTC64090

The objectives of this slide presentation were to: evaluate impacts of UV/Cl₂ on theformation of seven classes of disinfection byproducts (DBPs) includingTHMs, HAAs, HANs, CP, TCP,Haloacetamides, and TOX;Greater Cincinnati Water Works (GCWW) water from three locations;influent to carbon contactors (GACI);effluent from carbon contactors (CSW);effluent from the oldest carbon contactor (CN7);LPHO and MP UV were used @ 40, 105,and 140 mJ/cm². The testing protocol included: all samples at all doses were tested atconditions simulating GCWW'soperations;30º C, pH 8.6, 3-days retention time tosimulate summer conditions;one set of testing was conducted at 10and 20ºC using MP-UV (at 140 mJ/cm²) tosimulate winter conditions; all samples were shipped to DukeUniversity, where UV exposure, and 3-day plant simulation conditions weremaintained; and,at the end of the simulation conditions,samples were dechlorinated.Samples were then shipped to UMASSwhere all the DBP analyses wereperformed. Conclusions were that:UV treatment did not substantially changewater samples' tendency to form THMs,HAAs, haloacetonitriles, and the closelyassociated haloacetamides, or TOX under theconditions tested;no difference between LP and MP lamps forthese DBPs was observed; and,the higher concentrations of DCA at 30ºCwere likely due to the higher rate of DCANdegradation, therefore higher rate offormation; LP UV did not cause an increase in CPformation under all test conditions;CP increased as a result of MP UV treatmentby about 0.9 µg/L under worst conditions(30ºC and 140 mJ/cm²) for carbon contactedwater; the only drinking water standard for CP is in the State of California;an action level of 50 µg/L (37 µg/L T&Othreshold) was included in a March 1986 listof DHS action; this was revised to 56 µg/L in2002 and now referred to as historic archivedadvisory level.There is also a NIOSH standard of 100 ppb,based on its action as an eye irritant.It is very likely that impact of CP will beinsignificant for drinking water disinfectiondoses. Finally, at normal disinfection doses ofUV, chlorine, and pH there doesn'tseem to be much increase in the DBPsstudied.

Product Details

Edition:

Vol. - No.

Published:

11/01/2006

Number of Pages:

28

File Size:

1 file , 640 KB