Coupling Process Of Partial Nitrification And Anammox For Treatment Of Sludge Liquor

Sludge liquor, which is characterized by high concentration of ammonium,low alkalinity and low C/N ratio. The conventional biological nitrification-denitrification cannot to achieve the processing request for this kind of waste water. Therefor it is important that researching and developing new nitrogen removal biotechnology. In resent years, the new biotechnologies such as ANAMMOX (Anaerobic Ammonium Oxidation), NITRITATION, CANON process have been the focus of research all around the world. Whereas the most new nitrogen removal processes have been limited in laboratory scale.The sludge liquor was studied in this paper. The partial nitrification was achieved and and maintained stably in the aerobic carrier biofilm reactor under normal temperature and the high DO. At the same time, the ANAMMOX bioreactor can be started-up by cultivating autotrophic nitrifying biofilm first. The combine the nitritation reactor and the ANAMMOX reactor to achieve the completely autotrophic nitrogen removal over bitrite. The coupling process has advantages of no need of organic carbon addition, low oxygen consumption and energy consumption.The main results were as follows:The partial nitrification was achieved and maintained stably in the aerobic reactor under normal temperature(15～29℃),the high DO(6～9mg/L) and long SRT, by the selective inhibition action of free ammonia to nitrite oxidation bacteria. The partial nitrification maintained stably in the aerobic reactor and nitration was about eighty percent when FA concentration was in the range of 1.0～10.3mg/L, in the 130 days prior to operation of the process. The nitration up to 97.7% when the influent ammonia loading rate(ALR) was 1.15 kg/m3·d. The effluent nitrite/ammonia ratio was about 1.25 when the average influent ammonia, influent ALR and influent ratio of alkalinity and ammonia were 315.80mg/L, 0.43 kg/m3·d and 5.25, respectively. So the effluent of partial nitrification process provided the influent substrate demand for the following ANAMMOX process.The start-up of the ANAMMOX bioreactor by autotrophic nitrifying biofilm was studied. The ANAMMOX bioreactor can be initiated within 110 days when cultivating autotrophic nitrifying biofilm before the start-up of the bioreactor. At the 200th day, the volumetric loading rates of NH4+-N and NO2--N are 0.526 kg/m3·d and 0.536 kg/m3·d respectively. At the beginning of the start-up phase, the effluent pH value is lower than the influent pH value, but gradually, the effluent pH becomes higher than the influent pH value as the pH value of the liquid in the bioreactor is alkaline. Between the 110th and 200th day, the ratio of the NH4+-N removal, the NO2--N removal and the NO3--N production is 1:1.1:0.33. In the start-up course of ANAMMOX bioreactor, by the variation of the ratio of the NH4+-N removal and the NO2--N removal and the NO3--N production, the effluent and influent pH can demonstrate the start-up progression of the bioreactor. Besides, the ANAMMOX bioreactor has greater advantages at improving the immobilized of ANAMMOX bacteria and reducing the outflow of bacteria.The effluent nitrite/ammonia ratio has a vital role to improve nitrogen removal efficiency of couping process. When influent ALR and alkalinity/ammonia ratio were respectively 1.16 kg/m3·d and 5.1, effluent ratioof nitrite to ammonia of the nitritation reactor was about 1.2 and total nitrogen removal efficiency of the ANAMMOX reactor was about 83.8%. The couping process achieved autotrophic nitrogen removal and without adding organic carbon source, so the noval adapt to water characteristics of digested sludge liquor.