Study On The Performance Of The Removal Of N-butyl Acetate By Active Agent Enhanced Biotrickling Filter

The biological trickling filtration method is one of the best feasible methods for the treatment of low-and medium-concentration VOCs.However,due to its low mass transfer efficiency,the limitation of low bioavailability and biodegradation rate of pollutants greatly affects this environmentally friendly treatment technology.A common approach in recent years is to introduce active agents to increase the solubility of VOCs,thereby reducing mass transfer limitations.In this study,n-Butyl acetate was selected as the target pollutant,the optimal surfactant was screened and compounded in the biological trickling filter（BTF）,and metal ions were added to synergize to study the performance of the active agent-enhanced biological trickling filtration method for degrading n-Butyl acetate waste gas.The main results achieved are as follows:1)Add Tween-20,Tween-80,Triton X-100,SDBS,saponin and other surfactants to the domesticated bacterial liquid for screening.Surfactant of 80～150mg mg·L^-1 has a significant promoting effect on degrading bacteria;the dynamic experiment of the upper tower characterized by removal efficiency（RE）shows that Tween-80 and Triton X-100 have been screened out to improve the purification efficiency of n-Butyl acetate exhaust gas.（RE increased by 41.17%and 46.72%,respectively）;compound surfactant experiments show that when Tween-80 and Triton X-100 are 2:1,the OD₆₀₀ increment can reach 0.322,the RE is increased by 55.82%,and the removal capacity（EC）increased by 62.37 g·m^-3h^-1.2)6 kinds of metal ions were added to the acclimated bacterial liquid,and the OD₆₀₀increment value was ranked as Cu²⁺>Mn²⁺>Mg²⁺>Co²⁺>Ca²⁺>Zn²⁺,and Cu²⁺had the most obvious promoting effect on microorganisms.Experiments show that when the inlet concentration of n-Butyl acetate in the biological trickling filter tower is 2000 mg·m^-3 and the residence time（EBRT）is 60 s,Tween-80 and Triton X-100 are compounded at 2:1,and the concentration of Cu²⁺is added synergistically at 25 mg·L^-1.The RE can be increased to96.52%,which is 65.32%higher than that without the addition of surfactant and metal ions.3)By adjusting the intake concentration of BTF,EBRT,and inlet loading rate（ILR）,to evaluate the effect of compound surfactant synergistic Cu²⁺on BTF performance,the results show that BTF2(add compound surfactant and Cu²⁺)all perform well.It has better performance than BTF1（without adding active agent）,when the ILR value increases to 365g·m^-3h^-1,the RE can be stabilized at more than 60%under 30 s EBRT,which shows that the compound surface activity.The stability of BTF can be improved by combining with Cu²⁺.The community changes of BTF1 and BTF2 samples at the phylum level were analyzed by high-throughput sequencing,and it was found that the combination of surfactant and synergistic Cu²⁺could effectively improve the community structure.The PICRUSt function was used to predict the COG functional abundance and KEGG functional abundance statistical metabolic pathway of BTF2.The results showed that the abundance of BTF2functional protein species was beneficial to the growth and reproduction of the microbial community,and the carbon metabolism and amino acid biosynthesis in the KEGG pathway were two.This metabolic pathway is the main metabolic pathway of microorganisms,so that the biotrickling filter tower can have a stable and efficient degrading ability of n-Butyl acetate waste gas.