Study On The Performance Of Biological Aerated Filter Comprised Of Bamboo Biochar And Ceramic Pellet For Piggery Wastewater Treatment

The rapid development of farming industry in South Xinjiang has led to the increasing pollution problem of farming wastewater.The existing anaerobic digestion treatment technology cannot meet the relevant standards for wastewater farm reuse,and there is an urgent need to find an efficient and low-cost biological treatment process for farming wastewater.In this experiment,bamboo charcoal,ceramic pellets and their combinations were used as fillers for the aeration biofilter,and the simulated nitrogen and phosphorus recovery process effluent was used as the treatment object.The comparative study of the film hanging start-up performance of the aeration biofilter with different fillers was conducted,and the effects of dissolved oxygen and copper on the operating performance of the aeration biofilter were also investigated,and the deep treatment process for farming wastewater was designed with the goal of resource recovery.The following conclusions were mainly drawn:（1）Three biofilm reactors（Z-BAF,T-BAF and ZT-BAF,respectively）with bamboo charcoal,ceramic pellets and mixed fillers were started up by composite inoculation with hanging membranes at a hydraulic retention time（HRT）of 6 h,a temperature of 23-26℃and an air-to-water ratio of 5:1.After 26,18 and 13 days of biofilm incubation,the chemical oxygen demand（COD）removal rates of Z-BAF,T-BAF and ZT-BAF were stabilized at about 50%,55%and 70%,respectively,while the ammonia nitrogen（NH₄⁺-N）removal rates were all stabilized at more than 80%,among which,ZT-BAF with bamboo charcoal-vitrified mixed filler showed the best film-hanging performance.（2）Under the high NH₄⁺-N concentration gradient（36.9-221.6 mg/L）hanging conditions,the NH₄⁺-N removal rate of ZT-BAF increased from a minimum of 87.1%to a maximum of 98.9%during the period of gradual increase of NH₄⁺-N concentration from 100 mg/L to 220 mg/L without any significant decrease,while the average removal rate of ZT-BAF was higher than that of Z-BAF and T-BAF during this period.The average removal rate of ZT-BAF was higher than that of Z-BAF and T-BAF,i.e.,ZT-BAF was more resistant to NH₄⁺-N load impact,indicating that ZT-BAF with bamboo charcoal-granular hybrid filler performed better than Z-BAF and T-BAF with a single filler in terms of film initiation under high NH₄⁺-N concentration.（3）Compared with DO concentrations of 1.5-2.5 mg/L,BAF had better pollutant removal performance at DO concentrations of 3.0-4.0 mg/L.Under this condition,the average removal rates of COD were 93.1%,91.4%and 91.8%,NH₄⁺-N were 55.9%,55.7%and 82.6%,and TP were 36.1%,78.1%and 93.0%for Z-BAF,T-BAF and ZT-BAF,respectively,and the effluent quality could meet the livestock farming wastewater discharge The effluent quality can meet the livestock and poultry farming wastewater discharge standard.（4）Z-BAF,T-BAF and ZT-BAF all showed some tolerance and adaptability to low concentrations of copper ions（0.6 mg/L）.The COD removal rate of each reactor did not show significant changes after the copper ion concentration was increased,but the average NH₄⁺-N removal rates of Z-BAF,T-BAF and ZT-BAF decreased from 75.6%,89.0%and 88.8%to 67.0%,removal rates of Z-BAF,T-BAF and ZT-BAF decreased from 75.6%,89.0% and 88.8% to 67.0%,65.1%and 80.0%,respectively,and ZT-BAF decreased the least,indicating that the tolerance and adaptability of ZT-BAF best.（5）Under the normal operating conditions of the tandem process,the water quality of pig methane can meet the standard of agricultural irrigation water after a series of treatments,and the basic economic cost of treating each cubic meter of pig methane is 1.521 RMB through basic economic analysis,which basically realizes the efficient treatment and resource reuse of farming methane.