Research On The Start-up Of Anammox Process And Its Treatment On Urban Sewage With Low C/N

Anaerobic ammonium oxidation (Anammox), one of the most economical biodenitrification technology, has much advantages such as high nitrogen removal efficiency, less oxygen demand, no external carbon source, and so on. The start-up of anammox process takes a long time due to the slow growth rate of anammox bacteria, limited the application of the precess. Besides, anammox bacteria was much likely to show the weakness in the competition for nitrite than denitrificans when organic matter existed in the system, thus affect the nitrogen removal performance.In this study, a novel rotating flat-sheet membrane bioreactor (RFMBR) was employed to start up anammox process. Through the comparison with a conventional membrane bioreactor (CMBR), the advantages of RFMBR in nitrogen removal performance and membrane fouling control were analyzed. Then, in view of the low C/N urban sewage, a combined reactor based on anammox technology was designed to investigate the cooperation of anammox bacteria and denitrification bacteria. The main research results are as follows:1) The anammox process was successfully started up within around16days in both bioreactors, with the final removal efficiency of ammonium and nitrite over92%.2) At the end of the experiment, the suspended solids (SS) in RFMBR and CMBR reached3567mg/L and3541mg/L, respectively; and the mean particle size of anammox granules in two reactors achieved899μm and809um, respectively. Besides, the granules in RFMBR possessed a more compact structure and secreted less EPS.3) At the end of the experiment, the trans-membrane pressure (TMP) reached4and16kPa in RFMBR and CMBR, respectively; and the thickness of biofilm formed on the membrane was35μm and120μm, respectively, indicating a much slower fouling rate in RFMBR than CMBR.4) The combined hydrolyze-DEAMOX process got stable after43days operation, and the removal efficiency of COD and ammonium were both over90%.5) Most of the organic matter was consumed in hydrolysis stage and nitrification stage, the amount of COD went into DEAMOX part was less than20%.6) The removal efficiency of COD, NH4+-N, NO2--N, and NO3--N was64.5%,96.6%,91.8%and86.1%, respectively, when the ratio of COD to ammonium was4.