I&EC 51 |
| The removal of ammonium-nitrogen (NH4-N) from wastewater is of great importance to reduce the nitrogen loading to receiving water bodies. Liquid streams (rejection water) generated by the dewatering of anaerobically-digested sludges in New York City wastewater treatment plants contain ammonium-nitrogen in the range of 400mg/L – 1000 mg/L and can contribute a significant ammonium load to the wastewater plant. A biological process utilizing bacteria capable of the Anaerobic Ammonium Oxidation (ANAMMOX) reaction has proven to be capable of removing high levels of NH4-N from rejection water to acceptable levels. In the ANAMMOX reaction, ammonium and nitrite are converted to NO3- and N2 gas. In the treatment process, the ANAMMOX bacteria are coupled with aerobic ammonium-oxidizing bacteria (nitritation) in a sequencing batch reactor operated with pH-controlled intermittent aeration. During the aerated phase of the reaction cycle, a low dissolved oxygen concentration is maintained to only partially convert ammonium to nitrite and to restrict nitrite oxidation to nitrate. In the subsequent anoxic portion of the reaction cycle, the ANAMMOX bacteria perform the reaction shown above. Coupling nitritation and the ANAMMOX reaction reduces the oxygen requirements compared to a conventional biological nitrification process, which leads to lower energy demand and reduced operating costs. Since the ANAMMOX bacteria do not require an organic substrate as an electron donor, the nitritation/ANAMMOX process further reduces operating costs by eliminating the need for an external organic carbon source. This poster presents results of a 2000-gallon pilot reactor study in which the nitritation/ANAMMOX process was used to remove ammonium from rejection water generated at the NYC 26th Ward wastewater treatment facility. |
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IEC Poster Session
8:00 PM-10:00 PM, Tuesday, August 21, 2007 BCEC -- Exhibit Hall - B2, Poster
Division of Industrial & Engineering Chemistry |