| Summary: | 碩士 === 國立交通大學 === 生物科技學系 === 107 === Pig feeding and compost are two primary means to deal with kitchen waste in Taiwan at the moment. Due to the outbreak of African swine fever, feeding pigs on food waste might be the loopholes in prevention and control of African swine fever. Consequently, it has been gradually banned. kitchen waste composting leads to Not In My Back Yard since the foul odors generated by compost diffuse to surroundings, which results in the difficulty in finding the place to do so.
The anaerobic digestion can effectively decompose organic matters of kitchen waste, and biogas produced in the process of decomposition can be utilized as a renewable energy source in order to maximize the benefits of reusing waste. Also, the odors in an anaerobic environment can easily be controlled. A wet anaerobic digester, which consumes much water and requires complex process, is commonly used to tackle the anaerobic digestion of kitchen waste in Taiwan. In this study, our aim is to develop a dry anaerobic digestion requiring less pretreatment and water usage. By using single-phase dry anaerobic system, we can evaluate biogas yields under various operating parameters.
The results indicated all the solids content increased and the oil content reduced when the kitchen waste filtered out soup. That is, the decrease in inhibiting long-chain fatty acids helps to promote growth of biogas. The re-circulation frequency rate of 40 L/1Hr and substrate/inoculum ratio of 2 yielded the most methane which is 0.324 L/g VSfed for 25 days. Through successive operation in several batches, the production of methane would be inhibited when ammonia concentration reached 4000 mg/L and salt concentration reached 30 g/L. In microbial community analysis, hydrolytic bacteria (Williamwhitmania taraxaci), acidogenic bacteria (Acholeplasma vituli、Ammoniphilus resinae) and acetotrophic methanogens (Methanosaeta concilii) increased when raising re-circulation frequency rate. In conclusion, this system provides comparatively simple pretreatment, less leachate, low equipment cost, and no difficulty in operation and maintenance.
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