Test Study On The Effect Of Oxidation Factors On The Pretreatment Of Biogas Slurry For Drip Irrigation

Biogas slurry is the waste produced in the process of livestock and poultry breeding,and it is also a kind of high-efficiency organic liquid fertilizer.Realizing the efficient recycling of biogas slurry is an urgent need to realize the development of agricultural green and ecological recycling.The integration of biogas slurry,water and fertilizer is implemented with the help of drip irrigation technology.Irrigation is an important technical means to solve the problem of returning biogas slurry to the field,and it has broad application prospects.The use of pretreatment technology before the biogas slurry enters the drip irrigation system is the key to ensuring the stable and efficient operation of the drip irrigation system.Oxidation technology has always had the advantages of high efficiency in water treatment and no secondary pollution.The thesis explored the effects of combined technical measures such as ozone,hydrogen peroxide,and ultraviolet in the treatment of high-concentration biogas slurry after fermentation of cow manure,discussed the optimal reaction conditions for deep oxidation treatment of biogas slurry,and observed the oxidation treatment through laboratory experiments.The main conclusions obtained in the thesis are as follows:Taking the biogas slurry from the actual cattle manure fermentation as the research object,using single factor test and orthogonal test,four influencing factors were investigated,namely the initial pH value of the reaction,the dosage of H₂O₂,the UV（ultraviolet）irradiation time,and the O₃aeration time.The effect of that on the removal rate of SS（suspended matter）of the biogas slurry,the removal rate of clogging substances under different meshes,the distribution of clogging substances,and the retention rate of ammonia nitrogen.The test results show that the acidic environment is conducive to the removal of suspended solids,the removal of clogging substances under each mesh,and the improvement of the distribution of clogging substances,but it is not conducive to the retention of ammonia nitrogen;as the dosage of H₂O₂increases,the removal rate of SS and the content of each clogging substance are removed.Steady increase,improved distribution of clogging substances,and decreased ammonia nitrogen content;with the increase of UV irradiation time,the SS removal rate does not change significantly,the clogging substance content is stable in the early stage and the later removal rate increases,and the ammonia nitrogen content stabilizes slightly;With the increase of the O₃ventilation time,the SS removal rate first increased,then decreased,and then increased.The removal rate of the clogging substance content of each mesh increased steadily in the early stage,and remained stable in the later stage.The retention of ammonia nitrogen decreased in the early stage and increased in the later stage.The optimal parameter combination of biogas slurry oxidation is obtained by orthogonal test:the initial pH is 6,the dosage of H₂O₂is 25ml/L,the UV irradiation time is 2h,and the ventilation time of O₃is 75min,and the treatment effect is good.The best combination of oxidation of different COD biogas slurry treatment effect is good,there is better applicability.The oxidation treatment did not change the dominant species of biogas slurry at the phylum level,but the abundance of each species changed.After the treatment,the biogas slurry enters the drip irrigation system and the operation effect is obviously improved.The oxidation treatment delays the growth rate of the filter head loss and the instantaneous flow rate decline.The average relative flow of biogas slurry after treatment under time is higher than that of CK biogas slurry,which increases the CU value and prolongs the running time of drip irrigation.