Fig. 3.4: Stanchion barn with floating gutter
Fig. 3.5: Cow-cubicle barn with floating gutter
Fig. 3.6: Piggery with group bays (no litter)
Fig. 3.7: Slurry storage and composting
Fig. 3.8: Flow diagram for integral farming with a biogas plant
Fig. 3.9: Site plan of the Bouake Ecofarm in Cote d'Ivoire
Fig. 4.1: Balancing the-energy demand with the biogas production
Fig. 5.1: Three-stage anaerobic fermentation
Fig. 5.2: Gas yield as a function of temperature and retention time (fT,RT-curves)
Fig. 5.3: The batch-feed principle vs the continuous-feed principle
Fig. 5.4: The fermentation channel vs the complete-mixed digester
Fig. 5.5: Slurry flow for various configurations of feed, discharge and stirring
Fig. 5.6: Floating-drum plant with internal guide frame
Fig. 5.7: Water-jacket plant with external guide frame
Fig. 5.8: Cylindrical plant design for quarrystone masonry construction
Fig. 5.9: Basic function of a fixed-dome biogas plant
Fig. 5.10: Fixed-dome plant with cenkal entry hatch
Fig. 5.11: Fixed-dome plant with suspended dome
Fig. 5.12: Horizontal balloon-type biogas plant
Fig. 5.13: Earth-pit plant with plastic-sheet gasholder
Fig. 5.14: Ferrocement biogas plant
Fig. 5.15: Horizontal biogas plant (KVIC shallow design)
Fig. 5.16: Mixing pit
Fig. 5.17: Mixing pit, gutter and toilet drain pipe
Fig. 5.18: Inlet and outlet for fixed-dome and floating-drum plants
Fig. 5.19: Forces acting on a spherical-dome digester
Fig. 5.20: Level line, excavation and foundation
Fig. 5.21: Construction of a spherical dome from masonry
Fig. 5.22: Construction of a metal gasholder with internal guide frame
Fig. 5.23: Construction of a fixed-dome gasholder
Fig. 5.24: Entry hatch of a fixed-dome biogas plant
Fig. 5.25: Sealing the masonry with paraffin
Fig. 5.26: Separate, mobile, plastic-sheet gasholder
Fig. 5.27: Gas pipe, valves and fittings of a biogas plant
Fig. 5.28: Gas valves and fittings: U-tube pressure gauge, water trap with drain valve, U-tube water
separator, "gravel pot" flashback arrestor
Fig. 5.29: Ferric-hydrate gas purifier
Fig. 5.30: Schematic drawing of a biogas burner and its parts
Fig. 5.31: Various types of biogas burners
Fig. 5.32: Schematic drawing of a biogas lamp
Fig. 5.33: Schematic drawing of a radiant heater
Fig. 5.34: Schematic drawing of an incubator
Fig. 5.35: Various gas mixers for spark-ignition and diesel engines
Fig. 5.36: Consumption of diesel and biogas by a 10-kW engine
Fig. 5.37: Energy shares of an internal-combustion engine
Fig. 5.38: Measuringinstruments for biogas field tests
Fig. 6.1: Basic principle of organic wastewater treatment
Fig. 6.2: Biogas plant in Ferkessedougou - system OEKOTOP
Fig. 7.1: Water-seal testing of a digester
Fig. 7.2: Seal testing (water and gas) of a fixed-dome plant
Fig. 7.3: Gas-seal testing of a metal-gasholder
Fig. 7.4: Pressure testing a gas pipe
Fig. 8.1: Basic elements of an economic analysis
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