Performance Of Anti-shock Loading During Petroleum-refining Catalyst Wastewater Treatment With Shortcut Nitrification Process

Petrochemical industry is one of important pillars of the national economy, and petroleum-refining catalyst takes up an indispensable position in the oil processing. The water quality of petroleum-refining catalyst wastewater is complex and fluctuated which contains high concentration of ammonia nitrogen, salt, alkali. The conventional treatment process performs poorly when the reactors is under shock loading. Therefore, efficient and stable treatment of petroleum-refining catalyst wastewater is important to the petrochemical industry.In this study, Sequencing Biofilm Batch Reactor(SBBR) and Sequencing Batch Reactor(SBR) were applied. The shortcut nitrification technology was used to deal with the petroleum-refining catalyst wastewater. Main study includes starting reactors, optimizing packing ratio and ensuring the limits of ammonia nitrogen, salt and p H shock loading. This study also compared different reactors’ removal efficiency. Besides, according to the study of p H shock loading experiment, it obtained the best alkali adding project which was used in pilot experiment.By adding petroleum-refining catalyst wastewater and K3 packing to build SBBR reactor after starting SBR reactor,the results show the process of biofilm colonization takes 35 cycles and the quality of biomembrane is 2400mg/L. The best pacing ratio is 35% considering economic factors. The removal rates of ammonia nitrogen and nitrite accumulation can reach 90%. The effluent meets national sewage effluent discharge standards 1b standard.In the test of shock loading, the study respectively adds ammonium chloride, sodium sulfate and sodium carbonate to simulate ammonia nitrogen, salt and p H shock loading. Under the condition of short aeration time, the SBR reactor can withstand the ammonia nitrogen shock loading limit is 1.3 times of the daily loading. SBBR reactor is 2 times of the daily loading. When the aeration time is longer, the limit of SBBR reactor is 3.4 times, and SBR reactor is 2.7 times. Under high salt shock loading, the anti-salt limit of SBBR and SBR reactor is 25g/L. When salinity domestication was carried out, SBBR reactor was able to adapt to the concentration range of 43g/L. The SND rate of the whole domestication process was first increased and then decreased, which reached the maximum when the salt content was 35g/L. When the domestication is over and decreased salt content, the total nitrogen removal rate of the wastewater can not be recovered. The volume loading was negatively correlated with salt content in the system. The anti-p H shock loading limit of SBBR reactor was 10.5, which increased by 0.5 compared with SBR reactor. When the p H was over 11, the rate of nitrite accumulation decreased sharply, and the nitration reaction was stopped.In this experiment, four kinds of adding alkali projects were set up, which were one-time, two-time, four-time and real time adding projects. The results show that the four kinds of projects can reach the sewage treatment standard all. The ammonia volume removal loading of real time adding project is highest, about 0.65 kg NH4+-N/(d·m3). It was approximately 0.6 kg NH4+-N/(m3·d) for two-time and four-time adding project. The ammonia volume removal loading of one-time adding project is lowest, at 0.55 kg NH4+-N/(d·m3). Considering the limits of device and the ammonia volume removal loading, two-time adding project was applied to the pilot reaction, and the removal effect of the reactor were similar with multiple-time adding project. Two-time adding project can be applied to practical engineering.Using shortcut nitrification technology, this study compared the operating efficiency of SBBR and SBR processes to deal with petroleum-refining catalyst wastewater. It was found that packing could be used to improve the stability and resistance of the system. The experiment results were successfully applied in pilot test, which reduced the difficulty of operation greatly. It is expected that the shock loading experiment results can provide a reference for the subsequent treatment of petroleumrefining catalyst wastewater.