AWWA WQTC60653

The objectives of this study are to understand the interactions of disinfection byproducts (DBPs) with natural organic matter (NOM)and flocs during conventional treatment, focusing on the solid / liquid phase formation ofDBPs, and to characterize and quantify the extent of DBPs that form under chlorine andchlorine dioxide preoxidant application. A bench-scale jar testing apparatus was used to simulate the full-scale conventionaltreatment process. A modified jar with limited headspace was used in all experiments tominimize the loss of volatile DBPs. Tests were conducted at 20°C ± 1°C with aluminumsulfate (Al₂(SO₄)₃ · 14H₂O, alum) as the coagulant, and preliminary tests were performed toselect the alum dose needed to meet US Environmental Protection Agency's (USEPA) enhanced coagulation total organic carbon (TOC) removalrequirements. Jar tests were run to simulate rapid mix, taperedflocculation and sedimentation. This research plan utilized four waters. The source waters were selectedfrom distinct geographical locations within the United States to encompass a spectrum of rawwater quality, such as turbidity and NOM concentration as measured by total organic carbon(TOC). Alum was dosed from a stock concentration of 20 g/L prepared from Fisher Scientificcertified grade aluminum sulfate. The oxidants that were used in the study were taken fromthe following stock solutions: chlorine 3675 mg/L; and, chlorine dioxide 2000 mg/L,generated on site at Colorado State University, Fort Collins, Colorado. Adsorbable organic halogens (AOX) measurements were conducted using aMitsubishi model TOX-10 using a modified Standard Method 5320B. Trihalomethanes(THMs) and haloacetic acids (HAAs) were analyzed using a HP GC 6890 applying amodified USEPA Method 551.1 and a modified Standard Method 6251 B, respectively. The experimental approach included chlorine, natural organic matter, floc and disinfection byproduct interactions during coagulation. Includes 3 references, tables, figures.

Product Details

Edition:

Vol. - No.

Published:

11/15/2004

Number of Pages:

12

File Size:

1 file , 350 KB