The effect of gas circulation on the performance of Anammox UASB reactor

The Performance of the Anammox reactor can be improved by enhancing mass transfer. Gas circulation was one of the methods. In this study, the influence of gas circulation on the performance of two Anammox reactors were investigated. One was floc sludge UASB system, the other was granular sludge UASB system. Obtained results showed that the removal efficiency of the floc sludge UASB couldn't be improved by using the gas circulation. And serious loss of sludge was also found. While in the granular UASB, the mixing characteristics of fluid was enhanced and the removal efficiency was also improved significantly by using the gas circulation. Furthermore, the gas circulation didn't cause washout of anammox granules and the deterioration of anammox process. In order to enhance the sludge settle ability as gas circulating, the structure of three-phase separator of the UASB need be improved to enhance the gas-sludge separation.