Operating Conditions of Bio-trickling Filter Deal with Hydrogen Sulfide and Study on Influence of Extracellular Polymeric
|School||Xi'an University of Architecture and Technology|
|Keywords||H2S Xanthomonas bio-trickling filter extracellular polymeric biomass|
Hydrogen Sulfide (H2S) is a toxic and harmful gas which hazard to humans and environment. H2S gas serious threat to personal safety and cause equipment corrosion. Biological deodorization method improved through continuous improvement to overcome the physical and chemical deficiencies. This method can maintain high removal efficiency of H2S gas, the way of biological control H2S gas as an important development at home and abroad.In this study, H2S gas will cleaning by bio-trickling filter, which filled with ceramic carrier and screening bacteria have efficient desulphurization to hanging on the carrier. When experimental operating conditions changed, we can get the best of working conditions, so as to promote industrialization and to provide operating parameters. Select the optimum method to extracting extracellular polymeric (EPS) from the bio-film surface. Analysis EPS components with the experimental operating conditions changed, then study the biological role of adsorption in the EPS.In the condition of temperature on 25-30℃, spray liquid volume of 1.25L/h, residence time is 130s, circulating fluid pH keep on neutral, when the use of basal medium for spraying, packing in a pH of 5.0 or more, intermittent time for ventilate 8h spray 1h, can keep bio-filter removal efficiency not less than 90%. Change the inlet gas flow, in four different gas residence time of 233s,130s,65s and 43s under the conditions of ventilation, stay for the 130s have a good removal efficiency. Bio-trickling filter volume load in 5.19-92.96g-H2S/m3·h range, removal efficiency can be maintained above 90%, the reactor has good resistance to impact load.Study EPS role in the biological treatment, you must be isolated it from the cell surface at first. There is no established standard of EPS extraction methods at present. Experimental selection of six commonly extraction methods to detach EPS, results show that ultrasonication in the ultrasonic power of 50W under ultrasound 4min get the best extraction efficiency. The environmental conditions of secretion largest Xanthomonas EPS is pH 6.0, temperature 32℃, bacteria ratio with medium of 7:100, metal salt solution dosage 3mL.With the increase of inlet concentration from 312mg/m3 to 4882mg/m3, EPS and protein content showed an overall increasing trend, growth rates reached 23% and 35%.Increasing ventilation will decrease the moisture content on filler surface, and then increase the secretion of EPS. Hydrophilic polysaccharides and other substances in EPS, such as the formation of bound water, can provide water for the microbe. Circulating fluid pH value decreased from 7-4, protein content reduced by about three-quarters. Every layer filler surface attached the EPS and biomass has a good positive correlation, EPS and volume load are positively correlated.