Study On Performances Of Hydrogen Sulfide Removed In Bio-trickling Filter With Concentrations Of Ammonia Existence

In recent years,controlling and treating odor pollution has been became an urgent task at all over the world. Biotrickling filter treatment is used increasingly as a method for treating waste gases streams containing odors, especially for treating acid degradation products of H₂ S, because it is cost-effective, nutrients easy to add, pH value easy to adjust, the operation is simple, low pressure drop,and packing media not easy jam ect,compared with the conventional physical and chemical techniques.In the experiment, the sulfureted hydrogen is selected as the main pollutants and the efficient desulfurization bacteria of the biotrickling filter was screened and cultivated from sewage treatment plants deodorant system.There are many factors influence the reactor's purifying performance, such as the contaminant concentration,cumulative product,pressure drop, the empty bed retentiont ime,temperature,oxygen,pH value, the kinetic parameter and the recovery ability of the biotrickling filter,these need our study.The results showed the removal efficiency can reach over 95% when the concentration of inlet less than 2000mg/m³ and the retention time great than 45s. Because of Sulfate is the mainly product.with it accumulate,the pH lower.when the pH value of the original 7.7 dropped to 3.8, removal efficiency by the 97.83% down to 72.43%.and the optimal pH about 6⁷. The Vm is 66.7g H₂S m-3 h-1,In occasional overload condition running short time will not lead to a system crash, adjust inlet concentration can quickly restored the reactor processing ability. The system of biotrickling filter can recovered in 8h and 48h after stopping running at 1 week and 2 weeks ,respectively. Study on treatment of mixed gas containing Hydrogen sulfide and Ammonia was carried out in a bio-trickling filter which inoculated with deodorizing sulfide bacteria. The experimental results demonstrated that when the empty bed residence time was 34s; the concentration of hydrogen sulfide inlet were 800¹500mg/m³ and ammonia's concentration were less than 80mg/m³ respectively. Hydrogen sulfide and ammonia removal efficiency reached above 99% and 70% respectively. These data indicated that hydrogen sulfide was well removed by the bio-trickling filter and the removal efficiency was not affected by the low concentration of ammonia coexisted. However, hydrogen sulfide removal efficiency was suppressed significantly by ammonia in high concentration. In this biological system, microbial degradation and physical chemistry all play an important role in the process of treatment hydrogen sulfide and ammonia. Hydrogen sulfide was mainly oxidized into sulfate by deodorizing sulfide bacteria in these operating conditions. A part of ammonia was mainly removed in the form of ammonia sulfate in chemical reactions,and another part of ammonia were used as nitrogen source by sulfide bacterias and other microbes. The cycled liquid's pH value were not need adjust with low concentrations of ammonia existed in the bio-trickling filter.