Abstract
The application of anammox for nitrogen removal from domestic wastewater was investigated in this study. In order to increase the treatment efficiency, polyurethane foam was used as an attached growth medium, and the organic loading rate was reduced by the high-efficiency solid-liquid separation device. Design and operational parameters such as the volumetric nitrogen loading rate to both the attached growth medium and the reactor, the substrate concentration, and agitation conditions were examined with actual sewage using a pilot-scale experimental apparatus. The main results obtained in this study were as follows; 1) the Kj-N loading rate should be kept less than 100 mg-N L-medium-1 h-1 from the viewpoint of sufficient nitrogen removal by anammox; 2) the T-N removal rate was approximately proportional to the square root of NH4-N concentration, therefore, the plug-flow style in the bioreactor was considered to be desirable for increasing the treatment efficiency; 3) it was also founded that aeration control based on the NO2-N concentration in the reactor was effective for simultaneous reaction of both nitritation and anammox; 4) the minimum agitation condition was required to avoid the suppression of the reaction rate. Operation under the minimum agitation condition should be adopted from the viewpoint of energy saving.
