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- Charles Banks
Microbiology of food waste digestion & effects of trace element - - PowerPoint PPT Presentation
Microbiology of food waste digestion & effects of trace element - - PowerPoint PPT Presentation
Microbiology of food waste digestion & effects of trace element additions Charles Banks Collected food waste Food waste preparation Commercial garbage grinder no water added Process flow diagram Domestic
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Food waste preparation
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Commercial garbage grinder – no water added
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Process flow diagram
Domestic kitchen food waste Restaurant waste Buffer storage tank Macerator pump Digester Digestate storage tank gas collector Biogas Digestate
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Digesters used early study
Mesophilic Thermophilic
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Demonstration plant
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Facts, speculation and interpretation
Accumulation of VFA after extended period
- f time
Something accumulating? Something depleted? Acetic acid peak replaced by propionic acid peak Loss of acetoclastic methanogens could lead to acetic acid peak Accumulation of ammonia Ammonia known to be toxic to acetoclastic methanogens Can carbon flow to methane in the absence of acetoclastic methanogens? Could have methane production from hydrogen and carbon dioxide (hydrogenotrophic route) Why does propionic acid accumulate? Uneven carbon chain length – breaks down to acetic and formic acids What is the significance of formic acid? Accumulation of formic acid will stop further breakdown of propionic acid Formic acid can only be used by hydrogenotrophic methanogens Is there a special enzyme system needed? Selenium and Tungsten possibly essential trace elements for formate reductase enzyme system Are these commonly added in trace element formulations? What is the concentration in food waste? Can we prove the theory Will need to look at combination of TE trials, metabolic assays and serotyping
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- −−−−−−−−−−−
- −−−+++−−−−−
- −−+−++−−−−−
- −−++−−−−−−−
- −+−−+−−−−−−
- −+−+−+−−−−−
- −++−−+−−−−−
- −++++−−−−−−
- +−−−−+−−−−−
- +−−++−−−−−−
- +−+−+−−−−−−
- +−++−+−−−−−
- ++−−++−−−−−
- ++−+−−−−−−−
- +++−−−−−−−−
- ++++++−−−−−
- +++++++−−−−
- +++++++++−−
- +++++++++++
- Fractional factorial design
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Acetic and Propionic acids degradation profiles
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75-litre digesters
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Organic loading rate (OLR)
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Volatile fatty acids profiles
Trace element supplementation stopped in Se,Mo,Co,W,Fe & Ni Se supplemented accidentally Started Supplementation with Se, Co & Ni Double Se supplementation concentration Started supplementation with Co as well. Returned the Se supplementation strength to original concentration
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Digestion efficiency
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Other digester parameters
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Trace element washout – estimating the critical dose
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TE required vs TE in the food waste
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Density gradient centrifugation – SEM images
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FISH images
Probe name Target group Probe sequence (5’3’) Fluorescent dye Fluorescent colour Formamide (%)
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Archaea Archaea Methanomicrobiales Methanosarcinaceae "!#! Methanosarcinales and Bacteria
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Conclusions (trace elements)
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Conclusions (Digester operation)
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Commercial scale
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