AWWA ACE54332

Cincinnati Water Works (CWW) has one of the world's largest granular activated carbon (GAC) facilities with on-site reactivation. Therefore, CWW had the unique opportunity to examine the effects of multiple reactivations on GAC structure and adsorption. Additionally, the GAC was segregated by reactivation age for a number of years making the examination of specific reactivation scenarios feasible. Over the course of seven months CWW and Penn State studied three GAC contactors containing virgin GAC, GAC reactivated five times and GAC reactivated twelve times. The physical characteristics andadsorption capabilities of these GACs were examined and reactivation strategies developed. Benzene isotherms batch tests were used to model synthetic organic chemicals potentially found in the raw water. No significant difference was seen in benzene adsorption among the GACs even after twelve times reactivation. However, the five and twelve times reactivated carbons were very similar in adsorption capability while the virgin GAC was slightly better. The GAC contactors were loaded from the top of the bed to the bottom and after about seven months in service there appeared to be some desorption of the natural organic matter at the top of the GAC bed. This desorption allowed for better benzene adsorption in the top layer near the end of the contactor run. Although the GAC may have suffered some slight loss of benzene adsorption capacity through reactivation, the loss does not appear substantive. This data indicates that all the GACs tested will provide adequate spillprotection for the Cincinnati Water Works. Includes 2 references, tables, figures.

Product Details

Edition:

Vol. - No.

Published:

06/01/2001

Number of Pages:

20

File Size:

1 file