AWWA WQTC69420

Chlorination in drinking water systems has been instrumental in decreasing waterbornediseases. However, free chlorine can interact with organics in the water to formregulated disinfection byproducts (DBPs). Therefore, many water utilities are switchingto chloramines to reduce the levels of DBPs. Chloraminated systems can suffer fromnitrification when free ammonia is converted to nitrite and then nitrate. Nitrificationepisodes in chloraminated drinking water distribution systems are thought to be causedby autotrophic nitrifiers. An observation has been that there is an increase inheterotrophic bacterial abundance during nitrification, and the study hypothesis is thatheterotrophs may also be contributing to nitrification since it is known that these bacteriaare capable of nitrification in many environments.In a reactor that simulates premise plumbing, nitrification was found to beaffected minimally by chlorite treatment, suggesting a possible contribution to thenitrification process by organisms other than autotrophic bacteria. A heterotrophicnitrifying bacteria was isolated from the effluent of this reactor.The isolation of organisms such as the one in this study can provide a positivecontrol for the design of a molecular method to track heterotrophic nitrification and thuspossibly predict nitrification events in the DWDS. Likely gene targets for trackingheterotrophic nitrification include the heterotrophic ammonia monooxygenase (AMO)gene and the heterotrophic hydroxylamine oxidoreductase (HAO). Includes 25 references.

Product Details

Edition:

Vol. - No.

Published:

11/01/2008

Number of Pages:

7

File Size:

1 file , 770 KB