Treatment Of Medium-ammonia Wastewater In SBR By Single-stage Partial Nitritation-anammox Process

The single-stage partial nitritation-anammox process based on anaerobic ammonium oxidation?Anammox?is a new biological nitrogen removal technology.Compared with the conventional nitrification/denitrification process,it has become a research hotspot in biological nitrogen removal field at home and abroad due to its advantages of no organics consumption,less aeration energy consumption and low sludge yield.Currently,the single-stage partial nitritation-anammox process has been successfully applied in ammonium-rich wastewaters,such as reject water,landfill leachate,livestock wastewater and so on.But studies on the use of this process to treat medium ammonia wastewater are still in exploration stage and rarely reported.Therefore,studying the start up and long stable operation of the single-stage partial nitritation-anammox process system has a great significance.In this study,a SBR was used to realize the stable operation of the single partial nitritation-anammox process under the dual inhibition of low dissolved oxygen and FA by intermittent aeration mode and to evaluate the nitrogen removal performance and microbial activity of AOB,NOB and Anammox.The microorganism in sludge is determined by using the FISH technique to the ecological characteristics of microorganisms on this basis.The main conclusions are as follows:?1?When the influent NH₄⁺-N concentration was 200 mg·L^-1,partial nitritation was achieved and maintained stably under under the dual inhibition of high FA and low DO concentration in SBR.The average effluent of NH₄⁺-N and NO₂^--N concentrations was108.66 mg·L^-11 and 85.90 mg·L^-1.The ratio of NO₂^--N_eff/NH₄⁺-N_effff was 0.80 close to1 and the NO₂^--N accumulation efficiency reach on 86%.?2?The stability of single-stage partial nitritation-anammox process was studied treating medium-ammonia wastewater in SBR under the oxygen concentration of0.2?0.4 mg·L-1 and the influent ammonia concentrations of 200 mg·L-1.The TN removal load was 0.24 kg·?m3·d?-1 with the total nitrogen removal rate was 75.83%.The start-up and stable operation of single-stage partial nitritation-anammox process was successfully realized.?3?FISH showed that AOB and Anammox bacteria were the dominant bacteria in SBR,and NOB was successfully inhibited which indicated the single-stage partial nitritation-anammox process system was proved to have good long-term operation stability from the perspective of microorganisms.?4?In the single-stage partial nitritation-anammox process,the increase of aeration will lead to the excessive proliferation of NOB.Subsequently,NOB can not be effectively inhibited even if the dissolved oxygen is reduced.The nitrogen removal performance of the SBR was seriously deteriorated by nitrate accumulation.?5?In order to increased total nitrogen removal,the intermittent aeration has been become continuous aeration,the TN removal efficiency was 50.97%.The nitrogen removal performance of the SBR was slightly recovery.