| "National Economic and Social Development Five-Year Plan outline" proposed,by 2010,sulfur dioxide emissions reduction of 10%.Increase the capacity of existing coal-fired power plant desulfurization to 90%of the existing power plant emissions standards."National Environmental Protection" Eleventh Five-Year Plan "," also pointed out that the "Tenth Five-Year" Plan of environmental protection targets not all realize,sulfur dioxide emissions in 2000 increased by 27.8 percent,"Eleventh Five-Year" period of sulfur dioxide emissions in 2005 from 25.49 million tons of abatement 22,950,000 tons in 2010.Desulfurization has become the prevention of environmental pollution and ensure sustainable development an important task.With the bio-engineering techniques in recent years the rapid development of research and development of advanced,cost-effective biodesulfurization technology has become a hot research.The engineered strains for biological flue gas desulfurization technology, provides an effective foundation instrument.The author of this article screen several strains of bacteria which have better effect for degradation of sulfur dioxide from the bacterias which can degradate the sulfur dioxide gas through biotechnology.To study the degradation performance and the mechanism of sulfur dioxide gas,and try to find the bacterias of active growth, meanwhile,have the ability to degradate the sulfur dioxide highly efficient and rapidly, then used in the bio-trickling filter test.Experimental result shows that,in the mutagenesis experiments,T.f couldn't be made to resistant a low pH that processed by UV,nitrite and DES;T.f3 mutated by UV has the fastest oxidation rate of the Fe2+.two days before the original bacteria,the T.f25 mutated by nitrite can also completely oxidate Fe2+ in advance of the day;The T.f3 after UV mutagenesis transformed the SO32- most quickly,73%higher than the original bacteria in the 5th hour,the T.f40 mutated by DES followed by,39%higher than the original one in the 4th hour;None of the three mutagenic agent can make the T.f bacteria speed up the oxidation of Fe2+ with increasing its concentration,when the bacterias and the Fe2+ exist together,and both the Fe2+ and the SO32- are in low concentration,the speed of T.f3 mutated by UV oxidated SO32- is the quickest,that is 0.0071 g·L-1·min-1;In the experiment of bio-trickling filter,along with the increased inlet volume load,the volume removal load also increases,but the increasing rate continues to lower,and the shorter residence time,the worse purification;With the SO2 importing concentration increasing,its purification efficiency is gradual lowering of,and in a relatively short time,the T.f bacterias can't make use of the iron ion in the spray liquid effectively,so the two-oxidation system can't run effectively,lead to a relatively bad purifying;At the time of low spray density of recycling liquid,with increased amount of recycling liquid,purification efficiency increases at the same time,when spray density increases to 1.82 m3·m-2·h-1,purification efficiency reaches the highest,then with the continuing spray density increasing,the purification efficiency started to decrease;The end,the T.f bacterias can demonstrate a better desulfurization effect only when they under appropriate condition of pH,therefore,it's necessary to screen and train new Thiobacillus ferrooxidans of stronger adaptability and stability. |
