| In the process of treating urban sewage,it is often affected by carbon sources,which results in unsatisfactory treatment effects,and the effluent does not meet the discharge standards;in the actual domestic wastewater treatment,more external carbon sources are added,which increases the treatment cost.In order to reduce the addition of external carbon sources,this experiment used a biological flocculation adsorption series inverted A~2/O combined process device.The sludge in the primary sedimentation tank of hydrolysis provides a carbon source.The main research contents under the combined operating conditions of the optimal carbon source ratio and the internal and external reflux ratios are as follows:(1)First,the optimal external reflux ratio of the combined system is determined under the condition of the optimal carbon source dosage.The change of the external reflux ratio has a small effect on the removal of COD.The effluent is less than 50mg/L,and the removal rates are 89.76%,90.89%,and89.61%on average.Ammonia nitrogen is not greatly affected by the sludge reflux ratio.The removal rates of ammonia nitrogen under the three external reflux ratio operating conditions are 96.94%,97.28%,and 96.89%,respectively.When the external reflux ratio is 200%,the combined system has a better removal effect on TP.The average total phosphorus concentration in the effluent was 0.44mg/L,and the average removal rate reached 88.18%.When the external reflux ratio is 200%,the nitrogen removal efficiency is the highest,reaching a removal rate of 72.34%,and the effluent meets the discharge standard of Grade A.(2)The second is to study the pollutant removal effect of the combined system,the COD and TP concentration changes along the way,the material balance of carbon and phosphorus,and the discussion of the correlation between COD and TOC in the effluent under the optimal working conditions.Under the optimal external reflux ratio,the removal rates of COD,ammonia nitrogen,total phosphorus and total nitrogen by the combined system were 90.79%,97.3%,87.14%and 72.29%,respectively.The monitoring of the COD and TP concentrations of each unit found that the COD concentration gradually decreased after treatment in each reaction tank,and each reaction tank had a certain degradation of COD;and the total phosphorus concentration in the anaerobic tank was extremely high and the total phosphorus Almost all removal is done in the aerobic tank.Calculated from the material balance equation,the carbon balance rate is 89.78%,and the phosphorus balance rate is 78.68%.The equation between COD and TOC calculated by least squares analysis is COD=2.2TOC+9.85,the correlation coefficient r=0.805,and the correlation is verified by the correlation coefficient method.(3)Finally,in order to compare with the combined system,the effect of pollutant removal when only the inverted A~2/O process was run was studied.The single inverted A~2/O process removes COD and ammonia nitrogen better,and the removal effect of TN and TP is worse than that of the combined system.It can only reach Grade B standard of"Emission Standard of Pollutants for Urban Sewage Treatment Plants",and the effluent concentration is 16.50mg/L,0.98mg/L,the removal rates were 61.99%and 75.59%,respectively.Figure[25]table[8]reference[82]... |
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