以生物活性碳(BAC)滴濾床處理硫化氫及氨氣廢氣之研究

Abstract

本研究將養豬場廢水篩選到除臭效果佳之異營性硫氧化菌（Pseudomonas putida CH11）和氨氧化菌(Arthrobacter oxydans CH8)以農產廢棄物製成之顆粒活性碳(GAC)為擔體進行共固定化，由於活性碳具高吸附性、菌體易附著、高保濕性、高緩衝能力、高硬度及低壓損等優點，且可由農場棄物資源再生，具經濟價值和環保觀念，故極適合作為生物濾床之擔體，本研究將共固定化後之生物擔體填充至模場(Pilot scale)生物滴濾床中，進行硫化氫和氨氣之去除實驗，探討去除特性、代謝產物及去除效率，並將此系統之排放濃度設定於「空氣污染防治法」所規定之周界環境標準(Ambient air standard)以下，以滿足及應付趨嚴之空氣品質標準，符合空氣污染物排放標準。 在氨氣之去除實驗方面，整個操作期長達138天，去除效率100%時，臨界負荷(Critical loading)為2.78 g-N/m3/h。而最大進氣負荷約為16.12 g-N/m3/h (R%=45 %)。此外，在無質傳影響及氧氣濃度限制下利用Pseudo Michaelis-Menten動力式進行分析，活性碳生物反應系統中代謝氨氣之飽和常數(ks)為43 ppm，最大去除效率(Vm)為0.20 (g-N/kg dry AC/day)，此系統主要是產物為有機氮。在硫化氫之去除實驗方面，整個操作期長達172天，臨界負荷(Critical loading)為6.80 g-S/m3/h。而最大進氣負荷約為18.74 g-S/m3/h (R%=56 %)。經由動力分析，可得此系統代謝硫化氫之飽和常數(ks)為33 ppm，最大去除效率(Vm)為0.38 (g-S/kg dry AC/day)，此系統主要產物為硫元素。 由結果可知，本系統可高效率同時去除硫化氫/氨氣共存污染物，由於系統在環境溫度15及35℃時仍然有如26℃時之去除效率，因此極適合應用於台灣本土產業之廢氣處理，且操作過程系統pH值穩定，濾床無酸化現象發生，溼度控制容易，壓損小且不會因操作時間長而劇增，系統可操作至少達半年以上，無須更換濾料，因此本生物滴濾床系統極富經濟性、安全性和優越性。

Heterotrophic sulfur-oxidizing Pseudomonas putida CH11 and ammonia oxidizer Arthrobacter oxydans CH8, were co-immobilized with granular activated carbon (GAC) to remove H2S and NH3. Since GAC has many advantages, such as high adsorption capacity, easy attachment for bacteria, high buffer capacity and low pressure loss, it is suitable to be the media of the biofilter. In this study, we co-immobilized microoganism with GAC to form biofilm on the bead, and then packed into the pilot-scale biofilter system to control NH3 and H2S emission. The effect of operating parameters, including retention time, temperature, and inlet gas concentration on the removal efficiency capacity and kinetic analysis was evaluated. The emission of upper limits was set to reach Taiwan’s current ambient air standard of NH3 and H2S. In ammonia removal experiments, during the continuous operation of 140 days, the critical loading was 2.78 g-N/m3/h, that the removal efficiency can be reached 100%. The maximum inlet loading of ammonia was 16.12 g-N/m3/h (R%=45%). Also, kinetic analysis was derived from the Pseudo Michaelis-Menten equation, which the saturation constant and the maximum removal rate were calculated to be Ks = 43 ppm and Vm = 0.20 g-N/m3/h. The main metabolic product of NH3 oxidation was organic nitrogen. In hydrogen sulfide removal experiments, during the continuous operation of 172 days, the critical loading was 6.80 g-S/m3/h that the removal efficiency can be reached 100%. The maximum inlet loading of hydrogen sulfide was 18.74 g-N/m3/h (R%=56%) The saturation constant and the maximum removal rate of hydrogen sulfide were calculated to be Ks = 33 ppm and Vm = 0.38 g-S/m3/h, respectively. The main metabolic product of H2S oxidation was elemental sulfur. The results of the study indicate that the biotrickling filter has high efficiency to remove NH3 and H2S waste gas. In addition, the system also maintained at high removal efficiency at 15℃ or 35℃ experimental temperature as it worked under 26℃. Therefore, this system will be suitable to operate in Taiwan for waste gas treatment under different climate and seasons. During long operation period, the high operation stability, no obvious acidification , low environmental impact and low pressure loss as well as the reasonably high removal efficiency suggest that the bio-reactor is a promoting technology for treatment waste gas.