AWWA JAW64227

Biofilters seeded with mixed-culture nitrifiers from Lake Austin, Texas, and fed nutrient andLake Austin water biodegraded the four trihalomethanes (THMs) commonly found in treateddrinking water - bromoform, chloroform, dibromochloromethane, and dichlorobromomethane.THMs were degraded by cometabolism, and degradation increased with increased THMbromine substitution and increased total ammonia-nitrogen biodegradation. Overall, theseexperiments resulted in sustained THM removals ranging from 10 to 60% for varying operatingconditions. Three operational issues were also studied: THM product toxicity, nutrientlimitations, and monochloramine inhibition of ammonia and THM degradation. The cometabolismstability index represents a simple and useful parameter for evaluating the likelihood ofproduct toxicity problems in biofilter operation. Nutrient limitations (e.g., iron and copper)may exist for natural water sources, and supplemental nutrients may be needed to achievemaximum THM degradation rates. Influent monochloramine concentrations of 1 mg/L (orless) as Cl<;sub>;2<;/sub>; appear to be a good target for stable operation of developed biofilm. Includes 34 references, tables, figures.

Product Details

Edition:

Vol. 98 - No. 12

Published:

12/01/2006

Number of Pages:

13

File Size:

1 file , 370 KB