The Effect of Up-Flow Rate on the Nitrogen Treatment Efficiency and Sludge Characteristics of ANAMMOX Process with Up-Flow Anaerobic Sludge Bed Reactor

Anaerobic ammonia oxidation (ANAMMOX) technology is a novel biological nitrogen removal technology with potential applications for the treatment of nitrogenous wastewater treatment prospects. Most of the literature explores the growth environment of anaerobic ammonia-oxidizing bacteria and total nitrogen removal efficiency but the influence of reactor operating conditions (such as up-flow rate) on the treatment efficiency and sludge growth property of anaerobic ammonia-oxidizing bacteria is rarely discussed. Therefore, the purpose of this study is to discuss the effect of up-flow rate on the treatment efficiency and sludge property of the anaerobic ammonia oxidation treatment procedure adopting up-flow anaerobic sludge bed (UASB) as a reactor. The results show that up-flow rate has a significant effect on sludge concentration and sludge growth rate. The highest sludge concentration and maximum sludge growth rate could be obtained at the up-flow rate of 3.21 m/h. According to the analysis results of the sludge concentration, we speculate that when the flow rate was lower than 3.21 m/h, the sludge particles did not easily collide with each other to produce a larger sludge floc. On the contrary, when the up-flow rate was higher than 3.21 m/h, the larger sludge floc could be decomposed by the shear force. The sludge concentration was reduced by these two reasons. On the other hand, the average total nitrogen volume removal rates in test runs 1 through to 4 were 0.18 g-N/m3/d, 0.19 g-N/m3/d, 0.20 g-N/m3/d and 0.20 g-N/m3/d at up-flow rates from 1.95 m/h to 3.70 m/h, respectively. Therefore, the treatment efficiency was not affected by the up-flow rate in these operating conditions.