Alternative TitleEffect of lignocellulosic components on the anaerobic digestibility of aquatic weeds and development of a predictive model of methane production
Note (General)Although the anaerobic digestion of aquatic weeds has been attempted all over the world, few studies focus on the relationship between anaerobic digestibility and chemical compositions. The biomass harvested from waterbody has variety of aquatic weeds species, and species composition and chemical composition in each species might vary with the change of season. In this doctoral thesis, development of the estimation method of annual methane productivity from seasonality of the chemical composition and species composition of harvested aquatic weeds was performed as follows: seasonal changes of the chemical compositions and estimation of monthly methane potential of harvested aquatic weeds from lake Biwa (Study 1), correlation analysis between chemical composition and anaerobic digestibility calculated by fitting to modified Gompertz model (Study 2). In study 1, among three species harvested in monthly from Spring to Fall, chemical composition was changed seasonally in two species, but another species did not change, indicating that life cycle of aquatic weeds affects the seasonality of the chemical composition. On the other hand, although methane yield were significantly varied, the difference was larger in each species: thus, methane potential of harvested aquatic weeds can be mainly determined depending on the species compositions. Estimation of monthly methane potential of aquatic weeds harvested from Lake Biwa was low in autumn to spring seasons (171?186 mL g-VS?1) due to the predominance of P. maackianus. In study 2, significant correlations were obtained between cellulose/lignin and ultimate methane yield, cellulose/hemicellulose and maximum methane production rate, and hemicellulose content and T80, respectively. From the equations explaining each kinetic parameters and annual estimated chemical compositions of harvested aquatic weeds, anaerobic digestibility was estimated. In Study 3, ADM1 was developed and simulated for the aquatic weeds biomass, incorporating these relationships. As a result, the ADM1 was able to estimate the methane production of water plant biomass with high accuracy. In the general discussion, the operational stability of the continuous treatment was estimated by the model and discussed for the social implementation of this treatment.
Collection (particular)国立国会図書館デジタルコレクション > デジタル化資料 > 博士論文
Date Accepted (W3CDTF)2023-10-11T15:41:03+09:00
Data Provider (Database)国立国会図書館 : 国立国会図書館デジタルコレクション