Effects of Oxidation Reduction Potential and Organic Compounds on Anammox Reaction in Batch Cultures

Abstract

The present study investigates the effect of oxidation-reduction potential (ORP) and organic compounds on specific anaerobic ammonium oxidation activity (SAA) using batch experiments. The batch tests were based on the measurement of nitrogen gas production. The relationship between ORP and dissolved oxygen (DO) concentration was found to be ORP (mV) = 160.38 + 68 log [O2], where [O2] is the DO concentration in mg/L. The linear relationship obtained between ORP and SAA (R 2 = 0.99) clearly demonstrated that ORP can be employed as an operational parameter in the Anammox process. At ORP value of-110 mV, the SAA was 0.272 ± 0.03 g N2-N (g VSS)-1 d-1. The investigation also revealed inhibitory effect of glucose on the SAA while acetate concentration up to 640 mg COD/L (corresponding to 10 mM) had stimulating effect on the SAA. However, acetate concentration beyond 640 mg COD/L had inhibitory effect on the Anammox activity. The results indicated that nitrogen rich wastewaters containing low level organic matter could be better treated by Anammox microorganisms in real-world conditions after some acidification process.