Study On The Treatment Of Volatile Organic Waste Gas By Immobilized Microorganism

The components of VOCs which with carcinogenic, teratogenic and mutagenic effects are complex, It causes great harm to human health especially by benzene, toluene and xylene. Biological method will be widely used in the field of VOCs governance, not only for the VOCs dealed with effectively, but also for the probably of the disadvantages in the traditional processing technology will be overcomed. In the experiment, benzene, toluene, xylene were used as VOCs, fungi with degradation ability to the BTEX were acclimated and screened. The growth metabolism of fungi and the condition of degradation of BTEX were optimized, the degradation efficiency of fungi in the water and air were measured. At the same time, the optimization conditions of degrading fungi buried by SA, PVA and the removal efficiency of immobilized microorganism particles as biofilter packing of different concentrations of BTEX were studied.The results of Benzene degradation fungi by acclimation and screening:The sludge in the benzene series matter near the factory emissions large separation of domestication was selected as the source, with benzene, toluene, xylene, as the sole substrate, in the conditions of aerobic shock. Two strains respectively named the NO.l and NO.2with benzene degradation ability of fungi were domesticated, screened and separated, and preliminarily identified as mould Penicillium and Talaromyces. The optimum conditions of growth and degradation of the NO.1fungus is C:N=5:1, temperature is30℃, pH is5, and with the best biological quantity of5.5mL bacteria suspension (50mL basal medium). It entered the logarithmic growth phase in3days, and then entered the decline phase in5days. Degradation effect of the NO.1fungus to BTEX in water was methyl benzene> benzene> xylene. The highest degradation efficiency respectively were87.39%,85.21%,81.47%. The optimum conditions of growth and degradation of the NO.2fungus is C:N=5:1, temperature is30℃, pH is6, and with the best biological quantity of5.5mL bacteria suspension (50mL basal medium). Degradation effect of the NO.2fungus to BTEX in water was methyl benzene> benzene> xylene. The highest degradation efficiency respectively were86.30%,83.34%,82.40%; the degradation effect of the two strains of fungi to BTEX in the air was 60%～80%.In this experiment, the influence of the immobilized material, method, concentration ratio effect on immobilization of fungi were system studied.through the selection of materials, optimization, parameter determination. And compared to immobilized particle stability, mass transfer and degradation effect, and the applicable conditions to NO.1fungi chemistry embedment were determine:The concentration of PVA is6%, SA is2%, activated carbon is1%, with2%calcium chloride saturated boric acid, reaction24h. At the same time, measure the degradation efficiency to BTEX with embed particles as biofilter packing, the results show that:(1)The degradation efficiency of bio trickling filter is55%～78%;(2)The purification efficiency of biofilter increases with the increase of the concentration of BTEX entrance, at the same residence time, similar entrance concentration conditions, the methyl benzene owned the highest purification efficiency but the xylene to the lowest;(3)For the BTEX, the same trend of purification efficiency was with the similar concentration, the purification efficiency decreases with the residence time shorter. With the residence time cut short, the reduce rate of purification efficiency gradually increased with benzene entrance concentration increased. Considering the economic and technical factors, residence time of103.6s was finally chosen.