Study On Treatment Of Villagesewage By Under The Soilsewage Treatment System

The sewage treatment technology of under the filed optimized traditional istewater anaerobic treatment,and added aerobic biological treatment,through the combination of anaerobic and aerobic biological treatment systems,achieved highly denitrified wastewater treatment.Through the actual sewage production test,the sewage treatment regulation and influencing factors of the process were tested.This experiment conducted a pilot study on the treatment of rural domestic sewage by the sewage treatment system under the field,and draw the following conclusions:(1)According to the statistics of rural sewage discharge,it is found that the village has a distinct three peaks in one day,which appear in the morning from6:00-7:00,11:00-12:00,and 17:00.00-18:00,within one week,the peak of sewage discharge appeared on the weekend.The displacement on Wednesday,Wednesday and Thursday did not change much.The daily variation coefficient is Kd = 1.2,the time variation coefficient Kh = 1.11,and the total change coefficient is Kz = 1.34,the total variation coefficient Kz10 = 2.24 in 10 minutes,the total variation coefficient Kz5 =2.45 in 5 minutes,the total variation coefficient Kz1 = 2.71 in 1 minute,and the total variation coefficient is K'z=2.15,indicating the maximum hour within the peak flow rate.There are large fluctuations,which have a great impact on the design of the sewage pipe network and the operation of the sewage plant;(2)Determining the optimal hydraulic retention time of anoxic and aerobic sections based on the system's final effluent removal rate: the COD concentration in the sewage influent range is 74 mg/L?117 mg/L,and the ammonia influent concentration of the sewage influent range is 13.75 mg/L? 20.35 mg/L,the total nitrogen concentration of sewage influent ranged from 17.79 mg/L to 32.17 mg/L,the p H ranged from 7 to 8,the average water temperature is 24.6 ?,the reflux ratio is200%,and the controlled influent flow rate is 10 m3/h.The test shows that the hydraulic retention time has no effect on the removal of COD and ammonia nitrogen,and has a great influence on the removal of total nitrogen.In the condition(2),the removal rate of total nitrogen is 13% higher than condition(1),The hydraulic retention time in the anoxic section is 5.5h,and the hydraulic retention time in the aerobic section is 7.6h.the sewage treatment effect is the best.(3)Under the condition that the HRT of the hypoxic segment is 5.5h and theHRT of the aerobic segment is 7.6h,investigate the changing rules of pollutants in the treatment systems.The average water temperature of 23 ?,an average COD concentration of 102 mg/L,an average ammonia nitrogen concentration of 15.3 mg/L,and an average total nitrogen concentration of 22.88 mg/L,the average turbidity is9.92 NTU,the average removal rate of COD is 85.3%,the average removal rate of ammonia nitrogen is 88%,the average removal rate of total nitrogen is 59%,and the removal of COD is in the anoxic section.Initial degradation occurred,the removal rate is 36%,and further removed in the aerobic section;ammonia nitrogen also degraded in the anoxic section.The anoxic section is not strictly anoxic environment due to reflux,and the average removal rate of ammonia nitrogen in the anoxic section is 30.77%.The removal of total nitrogen mainly occurs in the anoxic section,and the aerobic section is also removed,but the removal rate is low;During temperature acquisition,the minimum temperature 3?,the highest temperature is 35?,the lowest water temperature in the system is 9.5?,the maximum water temperature is 28.1?,winter temperature is lower than the water temperature inside the system,when the temperature fluctuates,the water temperature in the system will not change much;TCOD and SCOD have not obvious proportional relationship.(4)The degradation kinetics of COD in the field of the experimental sewage treatment system is the first-order reaction.When the reaction temperature is 17?28?,the degradation rate k is between 0.1396?0.1796,which can be used in practical applications.Considering 0.1498d-1,the empirical rate equation for COD degradation is Ct=exp(0.097-84.1e-1854.5/Tt)C0;at the location of the experimental project,the average ammonia concentration of the influent is 15.3mg/L,by fitting the ammonia nitrogen concentration with the change of reaction time,it is determined that the ammonia nitrogen degradation rate and ammonia nitrogen concentration are one level;when the water temperature is between 13?28?,the degradation rate k value is between 0.1396?0.1812,in practical application.In the case of 0.1779d-1 ammonia nitrogen degradation rate equation: St=exp(0.1147-22.7e-1457.4/Tt)S0;COD reaction activation energy is 15KJ·mol-1,and ammonia nitrogen reaction activation energy is12KJ·mol-1.Therefore,there is physical adsorption in the process of treating COD and ammonia nitrogen in sewage treatment system under the filed.