A Study Of The Novel Biological Nitrogen Removal Process

The SHARON-ANAMMOX process is a new process for ammoniaremoval from wastewater, which includes two steps. In the partial nitrificationprocess, ammonium is first partially oxidized to nitrite under the anoxicconditions and in the anammox process, ammonium is oxidized to dinitrogengas by particular microorganisms with nitrite as the electron acceptor underthe anaerobic condition to realize the denitrification. The long-time run of thecombined process and the performances were studied, and the results andparameters were analyzed.The removal of COD and ammonia and the partial nitrification wererealized by changing the sludge state and adjusting the various parameters.The removal efficiency of ammonium and COD was 51.1% and 80%,respectively. The concentration of nitrite was much higher than nitrate in theeffluent. In addition, the heterotrophic bacteria in the partial nitrificationreactor could resist loading better than the autotrophic bacteria andpredominate in the reactor. In the later stage, the carriers were added in thereactor for the biofilm attachment and the removal efficiency increased. In thesame time, the effect of pH and DO on the two phase sludge was studied bybatch experiments. The COD concentration has the strong influence on theaccumulation of the nitrite and the partial nitrification. The attached sludgehas the strong adaptability to the experimental conditions and the COD shockloading.The results showed that the removal efficiency of ammonium, nitrite andCOD was 39.0%, 99.96% and 88.8%, respectively when the hydraulicretention time was 0.6 day. The initial purposes of the removal COD,ammonia and nitrite were realized finally on the whole. The anaerobicgranular sludge in the batch experiment endured the higher sludge loadingthan in the EGSB reactor and also had the higher removal efficiency ofammonia, nitrite, nitrate and COD. On the other hand, the comparison of theammonia removal by the anaerobic granular sludge with the aerobic sludge inthe batch experiment proved that anammox phenomenon was existed in thereactor. The results also indicated that heterotrophic bacteria had the strongercompetition capability and adaptability to the conditions than the autotrophicbacteria. The existence of organic carbon sources had remarkable effects onthe removal rate of ammonia. The different concentrations of COD had theobvious influence on the ammonia removal in the early batch experiments.The results also showed that COD had the effects on theSHARON-ANAMMOX combined process and we also got the relative ruleswhich had the academic and technical significances on the treatment ofmunicipal sewage.