| In this study,the flocculation-inverted A~2/O process was used to treat domestic sewage.It mainly consists of the bioflocculation adsorption process,the inverted A~2/O process,and the hydrolytic acidification system.The test using bioflocculation adsorption process to strengthen the primary treatment of crude sewage.It can reduce the pollutant load of the follow-up biological treatment.The hydrolysis and acidification system can use the sludge of bioflocculation adsorption process for hydrolysis and acidification.It can provide a carbon source for biological treatment and optimize the performance of nitrogen and phosphorus removal.Before running the combined system,we should firstly start the inverted A~2/O process,then start the bioflocculation adsorption process,and finally start the hydrolysis acidification process.After the combination system is successfully started,we should optimize its parameters.The main research contents are as follows:1)Cultivation and domestication of sludge.By using the method of intermittent and continuous cultivation,after the concentration of sludge reaches the design requirements,the domestication of sludge need to be started.During sludge acclimation,the water intake was adjusted to the design value and the return flow rate was adjusted to 100%.If the effluent water reached the standard,the acclimation was successful.After that,the bioflocculation adsorption and hydrolysis process were started.2)After the reactor was successfully started,the dosage ratio of the acidified solution was optimized firstly.During this period,only the carbon source dosage of was changed,respectively:3L/h for the anoxic tank,and not for the anaerobic tank(Condition 1);2L/h for the anoxic tank,and 1L/h for anaerobic tank(Condition 2);1.5L/h for anoxic tank and anaerobic(Condition 3).After analysis,it is concluded that the removal of COD and ammonia nitrogen is not affected by the carbon source dosing ratio;the TN removal rate is reduced as the dosing ratio of the acidified solution in the hypoxic section decreases.Under condition 1,it's value of the effluent is more than what is required in the"urban sewage treatment plant pollutant discharge standard"(GB18918-2002)standard A.Under condition 2,the TN removal rate decreases by 6.65%,and under condition 3,the TN removal ratio is lowest;under the three working conditions,the TP removal rates were 65.43%,76.45%,and 67.8%.It can be seen that the TP removal rate is best under the working condition 2.3)After determining the optimal dosing ratio of the acidification solution,we need to study the impact of HRT on nitrogen and phosphorus removal.The study found that the removal rate of COD did not increase significantly.However,the removal rate of ammonia nitrogen increased from 85.73%to 96.28%,the change trend of TN removal was similar to the ammonia nitrogen,but the increase rate was not large.The removal of TP first increases and then decreases.After the optimal HRT was determined,the activated sludge reflux ratio was optimized.The study found that with the increase of activated sludge reflux ratio,the removal effect of flocculation adsorption tank on pollutants was increased,but the total effluent of the combined system was not improved.4)Finally,we study the effect of different acidification solution addition ratios on the nitrification and denitrification by using static experiment.The removal of COD and ammonia nitrogen and the rate of nitrification are not affected by the dosing ratio of the acidification solution.The rate of nitrification is only affected by the dissolved oxygen in the aerobic section.However,the denitrification rate can be affected by the dosing ratio of the acidification solution.The denitrification rate was the highest under condition 1.Under working condition 2,the accumulation of phosphate was the largest.Figure[35]table[7]reference[84]... |
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