AWWA ACE94135

N-nitrosodimethylamine (NDMA), classified as a probable human carcinogen, was initially detected in the water supply for the Town of Ohsweken, Ontario, Canada, in December 1989. NDMA has since been found regularly at levels above the Ontario Interim Maximum Acceptable Concentration of 9 ng/L (9 parts per trillion). This compound has appeared in treated water during winter months but has very rarely been detected in raw river water. Laboratory studies have demonstrated that this compound can be formed by emulation of the plant treatment. Optimization of treatment processes has improved treated water quality and reduced, but not eliminated NDMA. Laboratory studies aimed at inhibiting NDMA formation by alteration of conventional treatment methods have not consistently been successful. Ultraviolet (UV) irradiation is the only method examined to date which has consistently produced water with NDMA levels below detection. Full scale UV treatment has been working successfully at this location since December 1993. This report summarizes lab and pilot-scale UV work and gives details on full-plant scale UV treatment. Dosage requirements, costs and effectiveness of UV for degradation of NDMA are also discussed.

Product Details

Published:

01/01/1994

ISBN(s):

0898677742

Number of Pages:

8

File Size:

1 file , 330 KB