Methane Productivity of the Major Animal Waste Types

Abstract

ABSTRACT METHANE production using animal waste is becoming economically feasible for intermediate to large scale animal production operations. No general economic assessment can be made, however, since each individual application of the technology must be evaluated as construction methods, labor costs and alternative energy values vary from one production facility to another. The methane yield from a fermentation plant, however, will be relatively constant from site to site, given the same waste type and operating conditions. The expected methane yield from a fermentation plant is needed to evaluate the site-specific economics and for on-site energy use planning and development. The methane productivity of the four major animal waste types has been studied by computer simulation using a validated dynamic mathematical model of the methane fermentation process. Methane productivity is reported on two bases: (a) yield per unit total solids loaded (m^CH4/Mg TS) and (b) yield per unit animal live weight (mCH4/Mg LW-day). Results indicate that there are large differences between the waste types and that poultry waste produces the highest yield for animal LW while dairy waste is the least productive on a LW and TS basis.