AWWA REUSE52086

Nitrogen removal has been observed during soil aquifer treatment (SAT) at manysites where nitrogen is primarily added to the soil as ammonia-nitrogen. A commonhypothesis for this nitrogen removal in SAT is the two-step process ofautotrophic nitrification and heterotrophic denitrification. However, few SATsystems have the biological oxygen demand (BOD) to nitrogen (N) ratios that cansustain heterotrophic denitrification. Most system conditions would result inmaximum heterotrophic nitrogen removal efficiencies of about 30%, whereas, muchhigher nitrogen removal efficiencies have been observed in SAT systems. Thiswould suggest that some other mechanisms are responsible for the additionalnitrogen removal. Therefore, a proposed sustainable mechanism for denitrificationin SAT systems is anaerobic ammonium oxidation (Anammox). This paper reports theresults of batch tests used to assess the presence of anaerobic ammoniumoxidation in an SAT soil. These batch experiments compared the gas production andammonia and nitrate removal rates of the Anammox tests to heterotrophicdenitrification tests and blanks. The gas production results demonstrated thatautotrophic denitrification occurred in the Anammox test set. Typicalheterotrophic denitrification would result in the production of CO2 and N2 gases.The observed N2 gas production in the Anammox test set did not correlate with theCO2 gas production. This suggests that some other mechanism is responsible forthe denitrification observed. This preliminary experiment has identified thepresence of microbes and provides a basic testing method that can be employed infuture studies of the Anammox process during SAT. Includes 16 references, tables, figures.

Product Details

Edition:

Vol. - No.

Published:

01/01/2000

Number of Pages:

13

File Size:

1 file , 190 KB