Methane production by anaerobic digestion of Bermuda grass

Conference · Thu Jan 01 04:00:00 EST 1981 · ACS Symp. Ser.; (United States)

OSTI ID:5167862

Klass, D L; Ghosh, S

Bermuda grass (Cynodon dactylon) is one of the high-yield warm-season grasses that has been suggested as a promising raw material for conversion to methane. Experimental work performed with laboratory digesters to study the anaerobic digestion of Coastal Bermuda grass harvested in Louisiana and having a C/N ratio of 24 is described. Methane yields of about 1.9 SCF/lb of volatile solids (VS) added were observed under conventional mesophilic high-rate conditions. When supplemental nitrogen additions were made, the methane yields increased. This observation along with the compositional data compiled on the grass used in this work indicated that the nitrogen content of the unsupplemented grass was insufficient to sustain high-rate digestion at the higher yield level. However, as the C/N ratio was reduced by addition of ammonium chloride, the methane yield continually increased up to 3.5 SCF/lb added at the lowest C/N ratio examined (6.3) even after relatively high concentrations of ammonium nitrogen were measured in the effluent. It appears that the added nutrient had a stimulatory effect on methane production above the point where nitrogen was not limiting. Thermophilic digestion with supplemental nitrogen additions afforded methane yields of about 2.7 SCF/lb VS added. Carbon and energy balances were calculated and the relative biodegradabilities of the organics were estimated. It was concluded from this work that Coastal Bermuda grass can be converted to high-methane gas under conventional anaerobic digestion conditions. The performance of the particular lot of grass studied was substantially improved by supplemental nitrogen additions. (Refs. 12).

• Research Organization: Inst. of Gas Technology, 3424 South State St., Chicago, IL 60616
• OSTI ID: 5167862
• Conference Information: Journal Name: ACS Symp. Ser.; (United States) Journal Volume: 144
• Country of Publication: United States
• Language: English

Related Subjects

09 BIOMASS FUELS
090122* -- Hydrocarbon Fuels-- Preparation from Wastes or Biomass-- (1976-1989)
140504 -- Solar Energy Conversion-- Biomass Production & Conversion-- (-1989)
ALKANES
ANAEROBIC DIGESTION
BENCH-SCALE EXPERIMENTS
BIOCONVERSION
BIOSYNTHESIS
CARBON
DIGESTION
ELEMENTS
ENERGY BALANCE
GRASS
HYDROCARBONS
MANAGEMENT
METHANE
NITROGEN
NONMETALS
ORGANIC COMPOUNDS
PERFORMANCE
PLANTS
PROCESSING
SYNTHESIS
THERMODYNAMICS
WASTE MANAGEMENT
WASTE PROCESSING
YIELDS