Development of bioreactor system for odors and water-soluble organic waste gases elimination

• Main Authors: Lin, Yueh-Hsien, 林岳賢
• Other Authors: Tseng, Ching-Ping
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/75667514151443614545

博士 === 國立交通大學 === 分子醫學與生物工程研究所 === 101 === This study used a bioreactor system with several effective strains, which were screened by our laboratory, for degradation of odors and water-soluble organic waste gases emitted from composting facilities and electronic industries, respectively. Some odorous substances are commonly found in composting facilities including nitrogen-containing compounds (ammonia, amines), sulfur-containing compounds (hydrogen sulfide, organic sulfur compounds) and short-chain fatty-acids (C2-C6). The first part of this study was based on previous laboratory- and pilot-scale studies of our group. We designed and established a large-scale modular bioreactor system which was 2,800 fold scaled-up from laboratory-scale in a big composting facility. The flow rate can achieve 34 CMM (cube meters per minute). During a long term operation period, this modular bioreactor system has been proven effective in eliminating odors, with a 97% removal efficiency for 96 ppm ammonia, a 98% removal efficiency for 220 ppm amines, and a 100% removal efficiency of other odorous substances, respectively. The monitoring of operation parameters indicated that this system was stable during a long term operational period. Specially, a low pressure drop (< 45 mmH2O m-1) was observed, indicating that the packing carrier in bioreactor units does not require frequent replacement. The monitoring of bacterial count, carbon dioxide concentrations, and nitrogen-containing metabolites showed that the odorous substances were certainly degraded by the strains and transformed to nitrate. Moreover, the recirculated water can be used as liquid fertilizer. Thus, this modular bioreactor system can be used in field applications to eliminate various odors with compact working volume. The widespread of acetone and isopropanol (IPA) emitted from semiconductor and optoelectronics industries release tens of thousand tons into the environment. In our preliminary studies, the removal efficiencies of 100 ppm acetone and IPA, either individual or mixed inlet, within a gas retention time (GRT) 30 seconds can achieve 99%. Therefore, the second part of this study inoculated some effective strains in three laboratory-scale bioreactor systems (biofilter, bioscrubber, modified column packed bioreactor) for elimination evaluation. The results showed that the removal efficiencies of acetone and IPA can achieve over 90% within all operational conditions by the biofilter and the modified column packed bioreactor. However, the removal efficiencies of acetone within high inlet loading (GRT 10 seconds, inlet concentration 300-800 ppm) achieved 80% to 90% by the bioscrubber. The bioscrubber type was considered for further pilot-scale test because of the removal efficiencies and cost consideration. Two pilot-scale bioscrubbers packed with raschigs established in a semiconductor and an optoelectronics factory, respectively. The results showed that the proper reactor design and the effective strains used in this study provided a stable removal efficiency of acetone over 90% within a 30-180 days period. To sum up, the large-scale bioreactor system was effective in odors elimination of composting facilities. The modular reactor units design with proper strains is feasible for various odor components, which can provide operational stability. Besides, the similar removal efficiencies between the laboratory-scale column packed bioreactor and the biofilter indicated that the proper design of liquid-gas contact channel within modified column can elevate the system effectiveness. Eventually, the results of pilot-scale application showed that the inoculated strains can eliminate acetone effectively, and the bioscrubber can be used with a proper reactor design in the future.