| Since the 21st century, the energy neutral wastewater treatment processes, based on ANAMMOX, have been research focuses in the field of wastewater treatment in order to conserve energy, reduce emissions and deal with the global climate change. However, the slow growth rate and strict growth environment of AMX lead to some problems of the application of novel nitrogen removal processes, such as long start-up time and limiting scope of application. In this study, high-efficiency and low-consumption biotechnology named AnHA and SNAD integration process was designed to treat municipal sewage in order to remove TN and COD simultaneously. The main research content included the analysis of influencing factors, the determination of optimal operating parameters, the characterization of microorganisms, the fitting of quadratic models and the feasibility of the intergation process. Some findings of this study are as follows:(1) AnHA process used as a pretreatment of municipal sewage could create good conditions for SNAD process. On the one hand, it could degrade some COD and decrease the C/N. On the other hand, it could produce VFAs, which have limited activity inhibitions on AMX and could be used as organic carbon sources for DNB. In this study, an up-flow non-woven biofilm reactor was investigated to operate this process. The result of microbiological characteristic showed that Clostridium and Bacteroides were dominant in the reactor. Based on the Taguchi orthogonal array, the main components of VFAs were acetic acid, propionic acid and n-butyric acid. Moreover, the suitable conditions were HRT=1.5 h, pH=8.5, influent COD=100 mg/L and influent NH4+-N=30 mg/L. The removal efficiency of COD and the effluent VFAs/COD were 27.15% and 89.21%, respectively. In addition, the C/N was decreased from 3.5 to 2.5.(2) The existence of a suitable dose of GO (≤2.86 g/(gVSS L)) was an alternative for shortening start-up time of ANAMMOX process by enhancing the activity of AMX. The increase of anaerobic ammonium oxidizing activity was related to the dose of GO. However, when the GO dose went beyond the optimum value, the ANAMMOX process for nitrogen removal was comparatively inhibited. The results of batch tests showed that the favorable GO dose in this study was 2.86 g/(gVSS L), and the anaerobic ammonium oxidizing activity increased by approximately 10.26%. Moreover, the start-up time of ANAMMOX process was decreased by 10 d, and the removal efficiency of TN was 76%.(3) SNAD process could be used to treat municipal sewage for simultaneous TN and COD removal. A non-woven rotating biological contactor was investigated to operate this process. The characterization of bacteria revealed that AOB, accounting for 65.13%, was the main bacteria in the outer layer of biofilm. Most of AMX and DNB exist in the inner layer of biofilm, accounting for 47.17% and 38.91%, respectively. Modified quadratic models described the variation of COD and TN removal efficiency as functions of C/N and DO as variables through RSM. The results showed that the optimum operating conditions were C/N=2.3 and DO=0.2 mg/L. The COD and TN removal efficiency were 83.12% and 79.13%, respectively.(4) Based on the results of this study and the data of a local municipal wastewater treatment plant, the simple energy and running cost analysis of AnHA and SNAD integration process have been studied. The results showed that the energy consumption was approximately 0.16 kW·h/m3 and the running cost was about 0.21 yuan/m3. The environmental and economic benefits is remarkable. |
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