Skip to Main Content
 

Global Search Box

 
 
 

ETD Abstract Container

Abstract Header

Technical, Microbial, and Economic Study on Thermophilic Solid-state Anaerobic Digestion of Lignocellulosic Biomass

Lin, Long
http://rave.ohiolink.edu/etdc/view?acc_num=osu1500505570855855

Abstract Details

2017, Doctor of Philosophy, Ohio State University, Environmental Science.
Yard trimmings (leaves, grass, wood chips, etc.) are abundant lignocellulosic biomass wastes, which need to be treated and/or utilized properly. Composting is a conventional approach to divert yard trimmings from the landfill. Alternatively, solid-state anaerobic digestion (SS-AD) can convert yard trimmings to biogas and digestate. It is promising to develop thermophilic SS-AD that can both produce energy and reduce waste to treat yard trimmings. This research included five inter-related projects: 1) examination of performance of thermophilic SS-AD and composting of yard trimmings with liquid anaerobic effluent as inoculum; 2) evaluation of the effect of yard trimmings on thermophilic SS-AD and prediction of methane yield based on feedstock component ratios; 3) development of a sequential batch thermophilic SS-AD with recirculated digestate as inoculum; 4) investigation of microbial community dynamics in the sequential batch thermophilic SS-AD; and 5) techno-economic comparison of thermophilic SS-AD and composting of yard trimmings. The first project showed that composting had higher degradation than SS-AD, while over half of the degraded carbon was converted to methane in SS-AD. Both SS-AD and composting generated nutrient-rich (N, P, K) end products with different dominant nitrogen forms, which may require different land application methods. The second project showed that digesting yard trimmings mixture alleviated inhibitors and increased methane yield compared to digesting single components. The favorable performance was obtained with equal fractions of the three components. Concentrations of volatile fatty acids (VFA) and ammonia varied with component ratios and correlated with system performance. A mixture design model was established to predict methane yield with good agreement. A sequential batch thermophilic SS-AD of yard trimmings was successfully developed with recirculated digestate as the inoculum in the third project. At substrate-to-inoculum ratio of 1, sequential batch SS-AD gradually reached steady state by 3 runs (30 days/run) with increases in both methane yields and cellulose degradation, indicating that recirculating digestate could be feasible to establish long term SS-AD. At steady state, about half of the digestate was recirculated as the inoculum. The fourth project showed microbes in sequential batch SS-AD shifted substantially toward a stable state with increased diversity in the first 3 runs. Recirculating digestate as inoculum also selectively enriched Firmicutes and Methanothermobacter to enhance degradation of lignocellulosic biomass and adaption of the microbial community to high VFA levels, suggesting that recirculating SS-AD might be an effective way for inoculation. Finally, a techno-economic comparison was conducted between commercial-scale SS-AD and composting at 20,000 MT/year. Composting was shown to be more economically competitive than SS-AD. SS-AD had higher capital cost but lower labor cost than composting. With financial incentives, SS-AD was shown to be slightly more profitable than composting. Both systems were most sensitives to plant size and tipping fees. The results of this research indicate that thermophilic SS-AD of yard trimmings is technically feasible and its economics could be comparable with composting with some financial incentives. The knowledge obtained from these studies could be used to assist in the optimization and scale-up of SS-AD and enhance the renewable energy from lignocellulosic biomass.
Zhongtang Yu (Advisor)
Harold Keener (Advisor)
Frederick Michel (Committee Member)
Ajay Shah (Committee Member)
231 p.
Agricultural Engineering; Environmental Engineering; Environmental Science
Anaerobic digestion, composting, lignocellulosic biomass, thermophilic, solid waste management, inoculation, microbial community dynamics, techno-economic analysis, process modeling

Recommended Citations

Citations

  • Lin, L. (2017). Technical, Microbial, and Economic Study on Thermophilic Solid-state Anaerobic Digestion of Lignocellulosic Biomass [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1500505570855855

    APA Style (7th edition)

  • Lin, Long. Technical, Microbial, and Economic Study on Thermophilic Solid-state Anaerobic Digestion of Lignocellulosic Biomass. 2017. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1500505570855855.

    MLA Style (8th edition)

  • Lin, Long. "Technical, Microbial, and Economic Study on Thermophilic Solid-state Anaerobic Digestion of Lignocellulosic Biomass." Doctoral dissertation, Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1500505570855855

    Chicago Manual of Style (17th edition)

osu1500505570855855
633
© 2017, some rights reserved.Creative Commons License Technical, Microbial, and Economic Study on Thermophilic Solid-state Anaerobic Digestion of Lignocellulosic Biomass by Long Lin is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License. Based on a work at etd.ohiolink.edu.
This open access ETD is published by The Ohio State University and OhioLINK.