Study On Biodegradation Removal Of Hydrogen Sulphide And The Microbial Community Structure In Biotrickling Filter

A plate type-biotricking filter (PTBTF) and a biotrickling filter (BTF) packed with ether-based polyurethane foam were employed to remove H2S from waste gases. The start-up time and reactor performance were investigated for both reactors. The start-up procedures of the PTBTF and the BTF were finished by joint gas-liquid phase inoculation within14d and17d, respectively. Scanning electron microscopy (SEM) revealed that bacterial communities grew well on the carriers, and bacilliform and filamentous may be the dominant bacteria in the PTBTF and the BTF.When removal efficiency was90%, under the conditions of H2S inlet loading of65.7～1987.5mg·m-3and empty bed residence time (EBRT) of3.3-6s, both PTBTF and BTF could effectively degrade H2S, elimination capacity of PTBTF increased with EBRT. Colony forming unit analysis showed that the bio mass concentration in the PTBTF and BTF increased during the start-up stages of operation, and decreased with EBRT during the steady-state operation. The PTBTF was found that the microorganisms onto the packing carriers in upper, middle and lower layers increased significantly at the start-up state, and reached1.29×107,5.47×108, and1.07×109cells·g-1, respectively, in125d by the means of fluorescence staining. The BTF was found that the microorganisms onto the packing carriers in upper, middle and lower layers increased significantly at the start-up state, and reached2.49×108,5.56×108, and1.08×109cells—g-1, respectively, in125d by the means of fluorescence staining.The pressure drop and shock loads analysis showed that the pressure drops in the PTBTF and BTF were not high, however, the latter was higher than the former. Both PTBTF and BTF could recover the elimination capacity rapidly in response to shock loadings, however, the former was higher than the latter. The main products of SO42-and sulfur were determined for H2S degradation.In the PTBTF and BTF system, H2S-degrading process of the system followed the Michaelis-Menten kinetic model, R2values for H2S, were0.992and0.962, rmax values for H2S, were4219.4and632.9g·m-3·h-1respectively. Accordingly, Ks values for H2S, were2.152and0.306g·m-3, respectively. Process parameters, such as H2S inlet loading, inlet concentration, EBRT, moisture content, pH and spraying volume had effects on the H2S removal efficiency.For120d of starvation, when H2S was re-introduced, under the conditions of inlet H2S concentrations of400mg·m-3and EBRT of5s, the PTBTF was observed that10d was necessary to recover the RE of H2S, removal efficiency was98.7%and elimination capacities was257.1g·m-3·h-1; The BTF was observed that12d was necessary to recover the RE of H2S, removal efficiency was90.6%and elimination capacities was225.1g·m-3·h-1.The fingerprints of PCR-DGGE indicated that microbial population differed obviously during the start-up period. The bacterial communities had rich microbial population and stable community structure, implying little variation about the composition and diversity of microorganisms during the stable operation period. The sequencing results showed that in the PTBTF the dominant organisms responsible for H2S degradation were closely related to Acidithiobacillus thiooxidans, Pseudomonas fluorescens, Uncultured gamma proteobacterium, Amorphus, Ochrobactrum anthropi, Achromobacter piechaudii. And in the BTF the dominant organisms were closely related to Uncultured Acidithiobacillus, Frateuria, Uncultured bacterium, Pseudaminobacter, Methylosinus, Achromobacter xylosoxidans. There are two different types of microorganism bacteria dominants in two towers respectively.