Gasoline Vapor Removal in Poraver Biofilter:Performance Characteristics and Biofilm Composition and Structure Changes

摘要

The study was focused on unleaded gasoline 95(octane value)vapor degradation in waste gases using a bench-scale biofilter with ID 50 mm and a bed height of 850 mm.First part comprises an acclimation period after inoculation of the Poraver packing with an enrichment mixed culture and operation parameters during loading test carried out by an increase of gasoline inlet concentrations.Evaluating separately a fractional removal rate and efficiency of aliphatic and aromatic gasoline components we proved that in a range of OL up to 17g.m~(-3).h~(-1)the removal efficiency of aromatic hydrocarbons kept almost constant at 90-85 % while that of aliphatic ones decreased from 60 to 30 %.Calculating the removal rate and efficiency for total petroleum hydrocarbons the values achieved were 20 g.m~(-3).h~(-1)and 60 %,respectively.Microbial analyses comprised the strains and genera identification of the inoculated enrichment mixed culture and of the biofilm after six months of gasoline degradation.From comparison it can be seen that due to a selection pressure in the biofilter significant reduction of the primary degraders and non-degraders occurred.A microscopic observation of the biofilm structure using SEM was carried out 10 days after the start of degradation and then after 6 months of operation.The observations proved a decrease of the present microbial species with prevalent Pseudomonas putida cells.Also the biofilm surface after six months was much more homogenous than after 10 days in operation.A production of an extracellular polymeric material trapping the cells was evident.