| In order to improve the current status of the water environment and meet the requirements for water quality improvement,a sewage treatment plant in the south of China carried out the upgrading and upgrading work to upgrade the original MSBR process to the A~2O process to meet the requirements for quasi-IV water on the surface.After the completion of the upgrade project,this project investigates and evaluates the operation of the upgrade process,finds the problems existing in the operation of the water plant,and proposes corresponding solutions.It is difficult to treat and dispose of the remaining sludge in the sewage treatment plant,so the sewage treatment plant increased the sludge pyrolysis device to reduce the sludge.The sludge loss after the treatment exceeded 70%,but during the sludge reduction process,About 100 tons of sludge filtrate was generated and discharged into the biochemical section of the sewage treatment plant.The COD content of the sludge pressure filtrate can reach 25000 ? 60000 mg/L,and the ammonia nitrogen content is about 2500 m/ L.It is a high-concentration,difficultto-degrade organic wastewater.When it is added to the biochemical section of the sewage plant,it may cause certain water plant operation influences.Through investigation,it was found that after the sewage treatment plant was upgraded,the concentration of ammonia nitrogen,total phosphorus,total nitrogen,COD,and E.coli in the effluent could be stably reached the surface level IV without the sludge pressure filtrate being added to the biochemical section of the sewage treatment plant.Water requirements,compliance rates were 100%,98%,100%,95%,100%,and the entire water plant is operating well.When the sewage treatment plant's biochemical section started accepting sludge filtrate,the COD compliance rate of the effluent of the water plant dropped to 35.9%,while the compliance rates of other indicators remained basically unchanged.This indicates that the refractory organics of the sludge filtrate affect the removal of COD from the sewage treatment plant.In order to improve the biodegradability of the sludge press filtrate,reduce its COD content,and ensure that it will not affect the effluent quality after discharged into the biochemical section of the sewage plant,this topic proposes a method of using ferrocarbon microelectrolysis to treat the press filtrate.The iron-carbon micro-electrolysis test uses iron-carbon microspheres as a filler.The optimal reaction conditions for micro-electrolysis were determined through small-scale experiments: p H = 4,reaction time 4 h,and gas-water ratio 30: 1.At this time,the COD removal rate of micro-electrolysis Reached 35%.The biochemical test was carried out using micro-electrolyzed effluent.The test showed that the activated sludge system had a better effect on the mixed solution of iron-carbon micro-electrolyzed effluent and domestic sewage,and the COD concentration of the effluent could be controlled below 30 mg/L.The sludge from the pilot system of the A~2O process was inoculated directly from the water plant,and the system was successfully started in 7 days.The average removal rates of effluent COD,NH4 +-N,TN,and TP of the two systems were 90%,98%,70%,and 80%,and the average concentrations were 25 mg/L,0.15 mg/L,and 5.7 mg/L,0.6 mg/L.The pilot data show that the sludge pressure filtrate is beneficial to the removal of TN and TP in the system.The average concentration of TP and TN in the effluent of device 1 is 0.1 mg/L and 0.5 mg/L lower than that of device 2.The removal of ammonia nitrogen by the sludge pressure filtrate has no effect.Significant impact,the ammonia nitrogen effluent concentration of the two units can be maintained at a low level(?0.35 mg/L);the sludge pressure filtrate has a greater impact on the effluent COD,and the domestic sewage mixed with the pressure filtrate cannot reach the surface after being processed by the system The effluent requirements for quasi-IV water are about 10 mg/L above the standard.After the ferrocarbon micro-electrolysis treatment,the sludge pressure filtrate is discharged into the A~2O biochemical system.The effluent COD can meet the requirements of surface class IV water.The average COD concentration of the effluent is 24 mg/L.The COD removal efficiency of the entire system remains above 89%.Iron-carbon micro-electrolysis can effectively reduce the hardly degradable organic matter in the sludge pressure filtrate,and at the same time improve its biochemical properties,and ensure that the COD of the effluent of the biochemical system is ?30 mg/L. |
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