| The technology of strengthening nitrogen removal and sludge reduction in wastewater treatment is a hot topic in current water pollution control.In this experiment,the hydrolysis-denitrification +AO combination process was used to study the water inlet of a municipal wastewater treatment plant in Beijing.The sludge reduction was achieved with high efficiency denitrification,and the operation effect was good.The scale of the test is the scale of pilot test,and the daily processing capacity is 48 m3/d.The water intake of the system was low,and the mean value of COD/TN was about 3.37,and that of BODS/TN was lower than 1.7.During the operation,the average concentration of COD,NH4+-N and SS of the system was 29.85 mg/L,0.57 mg/L and 6.81 mg/L respectively.The mean removal rate was 87.97%,99.04%and 85.68%respectively,which was better than the first-grade A emission standard.The average concentration of the system effluent TN and TP was 19.01 mg/L and 6.2 mg/L respectively,with an average removal rate of 75.53%and 37.58%respectively.During the period of enhanced nitrogen removal from April 16 to October 31,the average concentration of effluent TN in the system was 14.68 mg/L.During the process of chemical enhanced dephosphorization,the TP concentration of the system was 0.151 mg/L.After the strengthening measures,the system effluent TN and TP are also better than the national grade A emission standard.On the problem of denitrification of the strengthening system,the study was carried out on several aspects,such as hydrolytic acidification,strengthening of denitrification,carbon source and active sand filter.The content of VFA was increased after hydrolysis of water by hydrolysis,which provided a high quality carbon source for the system.The reflux ratio was increased by 75%,100%,120%and 150%to enhance the anti-nitrification function of the hydrolyzed tank.During the period,the mean removal efficiency of nitrate nitrogen was 37.18 g/h,40.08 g/h,44.17 g/h and 66.6 g/h.Sodium acetate with 26 mgCOD/L was added to the active sand filter,and its removal efficiency of NO3--N increased by 163.73%.During the enhanced denitrification of activated sand filter,the average removal amount of TN was 9.286 mg/L.Wash sand wastewater to return to the best oxygen pool,ensure that the system sludge has no outside row.In this paper,the sludge changes in the three structures of the hydrolytic pool,the AO section and the secondary sedimentation tank were analyzed,and the sludge yield coefficient was calculated to measure the effect of sludge reduction.During the operation period,the total sludge amount increased from 101.99 kg to 492.19 kg.The total amount of sludge is increasing,and the proportion is changed.During the whole test phase,the yield coefficient of the sludge was 0.112 gMLSS/gCOD,which was much lower than that of the sewage plant.In the study of biological predation and intensified sludge reduction,the indigenous biological water earthworm in the experimental system of sludge inoculation was found to be the best when the inoculation concentration was 800 bar/L,and the reduction value of individual sludge was as high as 0.135 mg/d.The macrogenomic sequencing of microorganism in the system was carried out and the biological community,gene and enzyme level were studied.The results showed that Nitrospiraceae and Rhodocyelaceae were the dominant bacteria of the system.It is of great significance to the formation of granular sludge,strengthening of denitrification and sludge reduction. |
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