Feasibility of solid-state anaerobic digestion and black soldier fly larvae composting for dairy cattle manure management

• Main Authors: Choon Yong Wee, 黃俊榕
• Other Authors: 蘇忠楨
• Format: Others
• Language: en_US
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/46727600618436651626

碩士 === 國立臺灣大學 === 動物科學技術學研究所 === 105 === The goal of this study was to evaluate the feasibility of applying a two-step biological treatment process, solid-state anaerobic digestion (SSAD) and black soldier fly larvae (BSFL) composting, to treat and recover energy from dairy cow manure. The feedstock for SSAD and BSFL experiments were dairy cow manure and digestate (i.e. anaerobically digested cow manure from SSAD reactors), respectively. The study of SSAD was to establish the optimal operation parameters. Thus, different ratios of inocula to feedstock (10, 30, and 50%) and with or without pH adjustment were tested for this study. For the study of BSFL, different feeding rates (25, 50, 75, and 100 mg/day/larvae) of digestate were applied for black soldier fly larvae composting experiments. In SSAD experiments, experimental results showed that the groups without pH adjustment regardless inoculation ratio of feedstock resulted in lower biogas, methane yield, and waste reduction than the groups with pH adjustment. Where the group 30% inoculation ratio (IR30) with pH adjustment had the highest theoretical methane productivity (626.1±28.7 L methane/kg-VS des) and ultimate methane yield (96.81±2.0 L methane/kg-VS load) (p<0.05). However, the group 50% inoculation ratio (IR50) with pH adjustment reached methane productivity peak at Day 5, which was 3 and 9 days faster than the 30 and 10% inoculation ratio (IR30 and IR10) with pH adjustment groups, respectively. The IR50 with pH adjustment group had the highest volatile solid removal efficiency of 20.2±2.4%. For BSFL experiments, the groups with feeding rate of 75 and 100 mg/day/larvae had the highest body weight change, which were 969.6±28.4 and 984.1±177.6%, respectively. However, removal efficiency of total solids (TS), volatile solids (VS), and nitrogen did not differ among treatments. Experimental results of this study showed that pH adjustment of feedstock was necessary during batch SSAD, where IR30 and IR50 groups achieved the highest specific methane production and waste removal efficiency. In addition, the BSFL composting enables further reduction of nutrients in the digestate of SSAD and promotes additional values of anaerobically digested dairy cow manure.