Study On The Treatment Of Methanethiol By Two-phase Biotrickling Filter

Two-liquid bio-treatment technology is a new type of odor treatment technology.Adding silicone oil to circulating liquids accomplishes absorption of large amounts of hydrophobic odor pollutants in liquid phase,thus improving ability of bioreactors in removal of hydrophobic pollutants.Methanethiol is an intermediate product of aerobic decomposition of complex sulfides and plays a key role in metabolism of hydrophobic sulfur-based odors.Therefore,methanethiol and silicone oil served as representative hydrophobic odor and nonaqueous phase in hydrophobic odor removal test in a biotrickling filter,respectively.Main purposes of this study were as follows:to verify feasibility of adding silicone oil to circulating liquids;to comparatively investigate removal efficiency and impact load resistance of conventional biotrickling filters and two-liquid biotrickling filters;to explore the principle of deodorization and to establish dynamics model of deodorization;to study similarities and differences of microbial communities in two trickling filters using molecular biological techniques.The main conclusions included the following:?1?Solubility of methanethiol in silicone oil was 8.3 times higher than in water.Silicone oil did not dissolve SO₄^2-and was not biodegradable.?2?In comparison with conventional biotrickling filters,two-liquid biotrickling filters constantly showed better methanethiol removal efficiency under different empty bed residence time?EBRT?,inlet concentrations,or spraying loads.?3?Inhibition concentration of SO₄^2-measured 120 mg/L in conventional biotrickling filters compared with that at 180 mg/L in two-liquid biotrickling filters.?4?Based on capabilities for impact load resistance and system recovery,two-phase biotrickling filter performed better than conventional biotrickling filter.?5?When inlet concentration measured 0.4¹.0 mg/m³,and spraying load was510 L/?h·m²?,relation of EBRT and methanethiol removal rate in two-liquid biotrickling filter was?=1-¹_e0.1317Tfor the No.1 biotrickling filter and?=1-¹_e0.4092T0.4092T for the No.2 biotrickling filter.?6?When EBRT was 10 s,and spraying load measured 510 L/?h·m²?,relation of inlet concentration and methanethiol removal rate in two-liquid biotrickling filter was?=0.816+⁰₁₊₀..⁰²⁴_0003SGifor the No.1 biotrickling filter and?=0.774+⁰₁₊₀..¹⁷³_0018SGifor the No.2 biotrickling filter.?7?Methanethiol-degrading microorganisms in No.1 biotrickling filter were mainly heterotrophic,with Xanthomonas sp.as the most abundant at 7.45%.The No.2biotrickling filter primarily consisted of heterotrophic and autotrophic microorganisms with Xanthomonas sp.as the most abundant at 9.95%,followed by Thiobacillus sp.at 5.1%.Heterotrophic and autotrophic microorganisms work cooperatively in maintaining ecological advantages.