Nitrogen removal has been observed during soil aquifer treatment (SAT) at many
sites where nitrogen is primarily added to the soil as ammonia-nitrogen. A common
hypothesis for this nitrogen removal in SAT is the two-step process of
autotrophic nitrification and heterotrophic denitrification. However, few SAT
systems have the biological oxygen demand (BOD) to nitrogen (N) ratios that can
sustain heterotrophic denitrification. Most system conditions would result in
maximum heterotrophic nitrogen removal efficiencies of about 30%, whereas, much
higher nitrogen removal efficiencies have been observed in SAT systems. This
would suggest that some other mechanisms are responsible for the additional
nitrogen removal. Therefore, a proposed sustainable mechanism for denitrification
in SAT systems is anaerobic ammonium oxidation (Anammox). This paper reports the
results of batch tests used to assess the presence of anaerobic ammonium
oxidation in an SAT soil. These batch experiments compared the gas production and
ammonia and nitrate removal rates of the Anammox tests to heterotrophic
denitrification tests and blanks. The gas production results demonstrated that
autotrophic denitrification occurred in the Anammox test set. Typical
heterotrophic 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 the
CO2 gas production. This suggests that some other mechanism is responsible for
the denitrification observed. This preliminary experiment has identified the
presence of microbes and provides a basic testing method that can be employed in
future studies of the Anammox process during SAT. Includes 16 references, tables, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 190 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 13 |
| Published : | 01/01/2000 |
