Study On Removal Of Styrene By A Biotrickling Filter

A vertical biotrickling filter and a horizontal biotrickling bed designed by the laboratory were used as experimental devices and styrene was the target pollutant.The packing materials were high-quality ceramics with size of 8-10mm and 20ppi（per pore inch）polyurethane sponges in the vertical and horizontal biotrickling filter,respectively.Activated sludge from the second sedimentation tank of Gaobeidian Sewage Treatment Plant was domesticated as the source of bacteria.The performance,carbon balance and the microbial community structure in the reactors were investigated.The selected predominant bacteria was used to start up the vertical biotrickling filter.The start-up period rans 45 days,and the removal efficiency reached 100%when the empty bed resident time（EBRT）was 67s and inlet concentration was about350 mg/m³.During the stable operation of the reactor,the removal load was up to108.53 g/（m3·h）.After short-term stagnation,the activity of microorganism recovered within fastest two days,and the optimal spraying amount of nutrient solution was90m L/h.The nutrient solution p H range was 6.0-7.0,and the maximum pressure drop of the tower was 30Pa.The tower had a good operating performance without blockage.In the carbon balance investigation,the CO₂ production increased with the increase of the inlet concentration.C-CO₂ accounted for the highest proportion of the total input carbon mass.The screened styrene dominant bacteriawere used to start the horizontal biotrickling bed with polyurethane sponges that had two structures.The reactor started-up successfully within 35 days,and the removal efficiency was stable at 100%under the conditions of the EBRT of 73s and an inlet concentration of 350mg/m³.During stable operation,the pressure drop was 0.After restarting,the microorganisms could quickly recover activity and had a good robustness.The performance between BTF1（15cm*15cm*5cm structured polyurethane sponge）and BTF2（5cm*5cm*5cm structured polyurethane sponge）showed that under the same process conditions,the BTF2 could quickly started-up successfully and the performance was well.During the stable operation of two towers,the major dominant bacteria in the genus level were Pseudomonas,Gemmobacter and Acinetobacter etc.The Pseudomonas had the highest relative abundance in the microbial community.The proportions of Gemmobacter and Acinetobacter increased when the reactor encountered an unfavorable external environment,which could increase the resistance to adverse environments.Factors such as inlet concentration and removal load in the different layers had an impact on changes in microbial communities.