Research On Ammonia Nitrogen Removal And Reuse Technology Of Anaerobic Fermentation Biogas Slurry Of Chicken Manure And Maize Straw

Anaerobic fermentation is a popular way to treat agricultural waste and realize agricultural waste resource utilization nowadays.The anaerobic fermentation project can treat agricultural waste but also produce a large amount of biogas slurry.However,due to the high mass concentration of biogas slurry,reusing biogas slurry to the anaerobic fermentation system will inhibit the activity of anaerobic microorganisms,which in turn will affect the production of methane.In order to investigate the threshold of inhibition of high ammonia nitrogen concentration occurring in the anaerobic fermentation system and the parameters of methane ammonia nitrogen air blow-off for the purpose of methane reuse.Experiment with chicken manure and maize straw as anaerobic fermentation materials was carried out to establish the anaerobic fermentation inhibition threshold of ammonia nitrogen mass concentration for the start of inhibition of anaerobic fermentation was established by adding exogenous nitrogen sources to adjust the ammonia nitrogen mass concentration of the fermentation material.Using self-developed stripping device and carring out Single factor experiment and orthogonal statistical method to establish the process parameters of ammonia nitrogen removal.The de-nitrogenized biogas slurry is reused in the fermentation system,and the amount of de-nitrogenized biogas slurry reused is established through the analysis of system stability and biogas production performance indexes.The results showed that: the mass concentration of ammonia nitrogen in the anaerobic fermentation stock mixed according to the volatile solids mass ratio of 6:4 with chicken manure and maize straw was 1 224 mg/L,and the threshold value of3000 mg/L was obtained as the mass concentration of ammonia nitrogen to start inhibiting anaerobic fermentation by adding NH₄Cl exogenous nitrogen source;the process parameters for removing high concentration of ammonia nitrogen in the biogas using air blow-off were temperature 30℃,p H 10.5,gasliquid ratio 2 000,and air-liquid ratio 2.5 h,respectively.And the importance ranking of each factor was p H>temperature>gas-liquid ratio;100% reuse of biogas respectively.after denitrification had no effect on the stability and gas production performance of the fermentation system,and even promoted the fermentation efficiency with shortened start-up time and advanced peak biogas production.Therefore,reuse of biogas slurry after denitrification for anaerobic fermentation system could not only reduce environmental pollution,but also reduce water resources input,which was of great significance to realize reasonable utilization of biogas,promote stable and sustainable operation of biogas project and recycling of agricultural waste resources.