| As the closer trade among countries and the increasing total number of ships,the emission standards proposed by IMO are more and more stringent and ship wastewater treatment process is ready to be upgraded.This experiment intends to use the A-OMBBR process coupled with the electrocoagulation process to figure out the treatment efficiency and mechanism of the process treats ship's domestic sewage.This coupling process combines the advantages of MBBR process with large biomass,impact load and electrocoagulation process with high efficiency of dephosphorization.At the same time,the process runs by the mode of intermittent aeration.The start-up optimization and the influencing factors of the A-OMBBR reactor system were been studied,and the results that the optimal working conditions of the process and the removal path of each substance during the process operation are obtained in this study.The composition and distribution of biomes in the reactor were also explored.The main reaction zone of the small test reactor was simulated by the beaker test.The filling ratio,porosity and hydrophilic of the filler were investigated during the startup stage to explore the effect on startup time and removal efficiency.The results show that the large filling rate and small porosity can improve biofilm volume,but don't conducive to system fluidization and microbial membrane renewal.Hydrophilicity has a positive effect on the membrane rate,but it also sacrifices the physical adsorption performance of the loaded activated carbon.Finally,when the process starts with the original packing of 1.5×1.5×1.5cm,30% filling rate and 25 PPI,it can be successfully startup in 11 dwith the removal efficiencies of COD,ammonia nitrogen,total nitrogen and total phosphorus were 95.00%,99.22%,84.21%,61.74%.The effects of C/N ratio,drainage ratio and number of stop exposures on the various materials removal efficiency of A-OMBBR process were investigated.The experiment found that the consumption of dissolved oxygen and carbon source will be affected by the C/N ratio.The increase of the drainage ratio affects the activity and removal efficiency of the microorganisms distributed in the outer layer of the filler and the free activated sludge,and the divided COD in intermittent aeration can effectively solve the problem of carbon source competition in the process of nitrogen and phosphorus removal.The working conditions of the whole process were optimized.Under the conditions of drainage ratio 0.3,stop exposure 3 and electric field strength 0.52 V/cm,the removal efficiencies of COD,ammonia nitrogen,total nitrogen and total phosphorus were 94.05%,99.86%,94.71% and 95.61%.Through the exploration of the relationship among electric field and microorganisms and the removal path of various substances in the system,it is found that the electric field has two functions that were enhancing microbial activity and electrocoagulation to remove pollutants.The result of sludge in the filler and sludge in the main reaction zone by scanning electron microscopy and microbial community detection were analyzed.It showed that the bacterial of nitrifying and denitrifying mainly accumulates in the packed sludge.The denitrifying bacteria in the filler account for 13.7% of the system.The system has the genetic characteristics of anti-shock load and rapid recovery. |
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