Bacteria Selection And Stuffing Modification In Bio-trickling Filter For Hydrogen Sulfide Decontamination

As living standards improve,people become more demanding on the quality of the environment,and more sensitive to stench.Bio-trickling filter has been widely used in removing odor pollution in recent years because of several advantages,such as simple, low capital and O & M easy.It is hoped to improve the efficiency of filter treatment by selection bacteria,stuffing and operating methods.Therefore experiments were designed as follow.Experiment on separating and screening of efficient bacterias which capable of degrading hydrogen sulfide;how to modify filler preparation;comparison experimental study on parameters of ceramic and modified ceramic;experiment on biological deodorizations of hydrogen sulfide(HzS) was conducted by using ceramic and modified ceramic as carrier in bio-trickling filter.Finally get some conclusion as follow:(1) There are several bacteria which capable of degrading hydrogen sulfide in the activated sludge of gold factory wastewater.Five heterotrophic bacterial strains were isolated after taming,separating and screening.(2) This experiment used a kind of ceramic as the carrier,choosing FeCl₃ as the modifying agent,we assume the way of high-temperature preparation to modify ceramic preparation.After confirming modifying conditions,density of modifying agent, roasting temperature,roasting time and pH value,we discover a kind of ceramic to reach the highest of the microbial membrane,which contains FeC13 with the density of 1.5mol/L,roasting temperature at 400 centigrade,roasting time of 4 hours as well as without sodium hydroxide.(3) It was found that modified ceramic is better than ceramic in the nature of the surface.Compared with ceramic,modified ceramic has more rough surface and the density increased 16.67 percent,the porosity increased 14.58 percent,the pH₀ changed from 0.7～2.2 to 8.5,the pH value of surface reduced 6.3.Modified ceramic is suitable for the growth of deodorization bacteria.Comparing with ceramic,bio-film forming time reduced 1/3 and the quality of deodorization bacteria increase 16 percent.(4)By using modified ceramic as carrier in bio-trickling filter,under the conditions of this experiment,the environmental and mass transfer conditions in the industrial application were:spray water one as spray water,pH of spray water from 6.5 to 7.5, volume of spray water from 2239 to 2737L/m_{(å¡«æ–™)}³Â·h;the operating conditions in the industrial application were:initial H₂S concentration below 4388mg/m³,gas flow less than 29.86m³/m_{(å¡«æ–™)}³Â·h,the residence time not less than 195s;the relevant load less than 131 gH₂S/m_{(å¡«æ–™)}³Â·h.Under this condition,the removing efficiency can more than 95%.(5) It was found that the height of packing affect the removing efficiency.The study shows that with the incoming hydrogen sulfide concentration at 124 mg/m³ to 4388 mg/m³,the removing efficiency in the under-layer is 70.4%,and in the both of the under-layer and middle-layer is up to 91%.Therefore,most of the pollutants are removed at the bottom of the bio-trickling filter.