Study On Biological Degradation Of NO From Gas Streams Used Hollow Ceramic Sphere Filter

The air pollution caused by nitrogen oxides emission has become a major global environmental problem. The air pollution not only brings serious harm to human life, but also damages the ecological environment, increasing the formation of acid rain and photochemical smog, etc. With the increasing hazards of nitrogen oxides, the people of the world are trying to find and study the control and treatment method of nitrogen oxides.The experiment uses hollow ceramic ball as the filter media in biological treatment of NO. First, we research the relevant factors of the hollow ceramic ball in the biological denitrification process and chelate absorption– biological reduction process. Second, we analyze the transfer process of NO in the two methods. The operating conditions of this experiment are as follows: The microorganism which is from municipal wastewater treatment plant can be acclimated to degradation the nitrogen oxides.We use the glucose and methanol as the carbon sources. The recycle liquid flow rate is from 0.5L/h to 2 L/h. The gaseous flow rate is from 100 L/h to 400 L/h. The influx gas concentration is from 100mg/m~3 to 600 mg/m~3. The main experimental findings are as follows:1 The biological denitrification which takes hollow ceramic ball as the filter media can purify NO.The experiment results are as follows: When the system is running stable, the removal efficieny of NO is more than 80%. The glucose is more suitable than methanol as the carbon source in this system. The removal efficieny of nitrogen oxides will decrease with the increase of the gaseous flow rate. The recycle liquid flow rate has little effect on the purification of the system. The height of filter media of this system is divided into four layers. The bottom layer of this system is the most efficient in the NO treatment, which can achieve 50%. The removal efficiency of the above three layers is about 40%. The oxygen has a greater impact on the purification efficiency in this system. When the oxygen in this system is approximately 0, the system's removal efficiency can reach 86% or more. However, when the oxygen in this system increases to 3%, the removal efficiency of this system decreases from 86% to 65%. The removal efficiency of this system reduced to 50% when the oxygen increases to 5%.The height of the filter media has a greater impact on the system's removal efficiency by Orthogonal Experiment. The height of the filter media has the relative weight of 53.47%. The best operating conditions of this system are as follows: The glucose is more suitable as the carbon source. The recycle liquid flow rate is 0.5L / h. The gaseous flow rate is 300 L / h. The number of the filter media is four.2 The chelate absorption– biological reduction which takes hollow ceramic ball as the filter media can purify NO.The experiment results are as follows: The removal efficiency of NO can reach more than 90% when we use a new chelating agent. The removal efficiency of this system stabilizes at more than 85% when the absorption fluid recycles more than three times. The glucose is more suitable than methanol as the carbon source in this system. The lower the gas-liquid ratio, the higher the efficiency of the purification system.The oxygen has a greater impact on the purification efficiency in this system. When the oxygen in this system is approximately 0, the system's removal efficiency can reach more than 90%. However, when the oxygen in this system increases to 5%, the removal efficiency of this system is only 30%～40%.The results of the experiment show that it is feasible to purify the nitrogen oxides useing hollow ceramic sphere as the filter media in the two methods. It also has a reference value for the popularization of the biological degradation.