以生物濾床處理含MTBE 廢氣之效率評估

Performance of a Biofilter in MTBE Removal

本研究之主要目的乃以改良式生物濾床系統，進行含MTBE（methyl tertiary butyl ether）廢氣之處理效率評估，同時探討生物濾床之操作條件對MTBE 去除效率之影響。研究結果顯示，本生物濾床於42 天之馴化啟動階段其去除效率皆可維持在80% 以上，而最大分解能力則可達18 g MTBE‧m-3‧h-1，約為其他處理MTBE 生物濾床的2-3 倍。當循環水流量由10 ml/min增加至40 ml/min 時，MTBE 之去除效率由72% 提升至約86%，顯示足夠含水量有助於提升生物濾床之去除效率，但再提高循環水流量至50、60 ml/min 時，則去除效率分別下降至83% 與78%，由此顯示過高含水率易造成濾床內部產生阻塞（clogging）或管流（channeling）現象，因而導致去除效率之下降。當濾床之停留時間為188 秒及於進流濃度為50 ppm 時，系統之去除效率可達99% 以上，因此較長之接觸時間將使得微生物具有充足的時間以分解MTBE。 The objectives of this study were to determine the effectiveness of a laboratory-scale biofilter in the removal of MTBE (methyl tertiary butyl ether) and to investigate the effects of operating parameters on biofilter performance. The experimental results show that MTBE removals exceeded 80% during operation throughout the 42-day biofilter acclimation period. The maximum elimination capacity (EC) of the biofilter was about 18 g MTBE‧m-3‧h-1. Furthermore, MTBE removal efficiency increased from 72% to 86% as the liquid feeding rate (LFR) increased from 10 to 40 ml/min. However, the removal efficiency dropped to 78% as the LFR increased to 60 ml/min. It is believed that high moisture contents in the biofilter caused the reduction of the mass transfer rate, leading to the decrease in removal efficiencies. More than 99% removal efficiencies were achieved for inlet MTBE concentration at 50 ppm with the highest empty-bed residence time (EBRT). Hence, MTBE removal efficiency increases while EBRT increases.