生物濾床處理廢棄物儲存場VOCs 廢氣之實場研究

Abstract

生物濾床處理廢棄物儲存場VOCs廢氣之實場研究 研究生：黃君逸＊ 指導教授： 蔡春進教授＊＊ 國立交通大學工學院產業安全與防災學程碩士班 摘 要 研究機構產生之有害事業廢棄物成份相當複雜，因此廢棄物儲存場內產生的廢氣成份亦十分複雜。廢棄物儲存場內逸散之揮發性有機物﹝Volatile organic compounds）可以經由排氣設施收集後，以生物濾床（Biofilter）處理以符合排放標準。本研究針對一廢棄物儲存場內的生物濾床進行研究, 其目的有三：1.瞭解實場最佳操作參數之設定。2.總碳氫化合物（Total hydrocarbons）的去除效率評估。3.對單一物種丁酮去除效率（Removal efficiency）及去除容量（Removal capacity）的評估。 本研究計畫分為三個階段，第一階段以培養濾床之處理能力為主，主要工作為：1.確定廢氣中無甲烷存在，證實濾床為好氧反應（Aerobic reaction）。2.馴養可分解丁酮之菌種，因菌種尚未馴養完成，丁酮之平均去除效率只有63.20﹪。 第二階段及第三階段以評估濾床之處理能力為主，主要工作為：1.評估濾床對THC的平均去除效率，結果發現第二階段為90.91﹪，第三階段為90.70﹪。2.在廢氣管道中製造各種濃度的丁酮廢氣，評估濾床對丁酮的平均去除效率，結果發現第二階段達90.12﹪，第三階段為91.43﹪。3.利用第2項的實驗結果計算體積質量負荷（Volumetric mass loading）及去除容量，以此2項數據製作曲線，得知濾床對丁酮的臨界去除容量為108g/m3/hr，最大整體去除容量為115g/m3/hr，超過此極限去除效率將隨之下降，由此可以推估濾床的各項設計參數。 由三個階段之各項操作參數統計資料得知：1.濾料的pH值宜控制在6.5至8.5。2.濾料含水率維持在65﹪至75﹪（濕基）。3.廢氣流量應控制在原設計範圍內。4.濾床壓力損失平均在20mBar以內，顯示濾料仍維持足夠的孔隙率。 以生物濾床處理VOCs廢氣是有效率且經濟的方法，本研究結果可以提供設計人員評估生物濾床對VOCs廢氣處理效率之標準研究模式，同時可以針對污染物種作去除容量實驗，評估濾床對該物種去除容量極限，以求取適宜之設計參數，達到最佳去除效率及最經濟的設置成本。

A Field Study of Biofilter for Treating VOCs in A Hazardous Waste Facility Student:Huang ,Chun-Yi* Advisor: Tsai Chuen-Jinn** Degree Program of Industrial Safety and Risk Management College of Engineering National Chiao Tung University Abstract The composition of hazardous wastes produced from research laboratories is very complicated so is the composition of the toxic gases that are produced in the hazardous waste storage facility. In the waste storage facility, the volatile organic compounds (VOCs) can be collected by an exhaust system and treated with a biofilter for meeting the governmental regulations. The purposes of this research are to study a biofilter treating VOCs for the following topics : 1. Understanding of the optimum operating parameters. 2.Evaluating the removal efficiency (RE) of total hydrocarbons (THC). 3.Evaluating the removal efficiency & removal capacity (RC) of methyl ethyl ketone. There are three stages for the study. The tasks for 1st stage are : 1. Analysis of exhaust gas to assure no methane in it and prove that the biofiltration process is an aerobic oxidation. 2.Growing and acclimation of microorganisms for MEK ,the average of RE for MEK is 63.20% because microorganisms having not been acclimated. The tasks for the 2nd & 3rd stages are : 1. Detecting the THC of inlet and outlet to evaluate RE. We found that the average of RE for the 2nd & 3rd stages are 90.91% and 90.70%, repectively. 2. Manually generated MEK vapors in the inlet of the biofilter and measured the pollutant concentrations in the inlet and outlet. The RE of MEK for the 2nd & 3rd stages was found to be 90.12% and 91.43%, respectively. 3. By the experimental data, the volumetric mass loading (VML) and RE were calculated for curve fitting . It was found that critical removal capacity of MEK is 108 g/m3/hr,maximum overall elimination capacity of MEK is 115 g/m3/hr, and the performance decays when the loading exceeds 115 g/m3/hr. In summary: 1. The optimum pH value of the filter media is from 6.5 to 8.5. 2. Proper moisture content should be maintained between 65% to 75% (wet base). 3. The exhaust flow rate shouldn’t exceed the design value. 4. The pressure drop has to be kept below than 20 mBar to ensure that the filter media have enough porosity. It is the most effective and economic method for treating VOCs by the biofiltration process. The study demonstrated a standard procedure for evaluating the biofilter for VOCs treatment. The study of RC for every pollutant to find out design parameters can achieve the best RE economically.