Study Of Advanced Treatment Of Piggery Biogas Slurry By Micro-electrolysis Coupled With Denitrification Sludge Based On A/O Process

The rapid development of livestock and poultry has brought about increasingly serious environmental issues in China.The environmental agencies have put strain on monitoring pollutants produced from the industry of the livestock and poultry,and improved the higher limitation of pollutants emssion.Therefore,it is widely known that more and more reseachers focus on developing the treatment technologies of low-cost and high-efficiency in order to meet severe environmental protection requirements.The combination of anaerobic digestion and A/O process is a commonly used treatment method for livestock and poultry breeding wastewater.However,a single biological treatment technology of A/O process is diff-icult to meet emission standards with the shortage like the low B/C of piggery biogas slurry produced by anaerobic digestion,containing heavy metals,hormones,antibiotic residues,and other biological toxins and bio-refractory organic contaminations.This research focuses on the goal of achieving the target discharge of piggery biogas slurry and carrying out a research of removal technology of eff-icient and economical nitrogen and carbon.A single iron-carbon microelectrolysis technique was used to treat the biogas slurry under different initial pH conditions and the effects were compared.The feasibility of the microelectrolysis technology for the treatment of biogas slurry was studied.Moreover,based on the actual A/O operation of the proect,a small simulation device was set up in the laboratory and the effects of micro-electrolysis and enhanced denitrification were studied.During the study,it was found that using the two-stage A/O process to treat the actual biogas slurry,the concentration of nitrate nitrogen and COD in the effluent was high and did not meet the emission standards.In the research of laboratory two-stage A/O process,denitrification sludge coupled with iron-carbon micro-electrolysis was used to intensify the two-stage A/O process for the treatment of pig farm biogas slurry.The effluent COD,ammonia nitrogen,nitrite nitrogen and nitrate nitrogen The average concentrations were 42.5 mg/L,2.4 mg/L,1.7 mg/L,and 9.8 mg/L,respectively,and all the indicators met the emission standards.The nitrogen removal mechanism was explored by analyzing the composition of microbial communities in the sludge and using bioinformatics analysis techniques.The results showed that the core denitrifying bacteria in the two-stage A/O process and denitrifying sludge mainly include Nitrosomonadaceae,Nitrospira,Candidatus Brocadia,Pseudomonas,Thermomonas,Thiobacillus,Paracoccus,Thauera.After the analysis of the collinear network,it was found that the relationship of most of these core denitrifying bacteria was positively correlated,which indicating that these bacteria had a good synergistic effect.This research studies and develops post-processing techniques for the widely used A/O process.It is of great significance to improve the effect of removing nitrogen and carbon from biogas slurry and accelerating large-scale engineering application.