Corn silage was treated by white rot fungi (WRF) to investigate the effect of pretreatment on material's ability to produce methane in anaerobic digestion (AD). The selective fungi Pleurotus ostreatus and Dichomitus squalens promoted biogas generation, whereas the non-selective Trametes versicolor and Irpex lacteus had negative effect. Cumulative methane production after 10-day pretreatment with P. ostreatus at 28 °C rose 1.55-fold. The longer pretreatments of 30 and 60-days had smaller effect. When the pretreatment with P. ostreatus was carried out at 40 °C a high H2S release affected the AD process. Effect of WRF action dependent on the type of corn silage. With typical corn silage, the lignin depolymerisation raised the methane generation from 0.301 to 0.465 m3kgVS-1. In contrast, extensive decomposition of hemicellulose in hybrid corn silage deteriorated the effect of pretreatment on methane production.
- Klíčová slova
- Anaerobic digestion, Biological pretreatment, Corn silage, Pleurotus ostreatus, White rot fungi,
- MeSH
- anaerobióza MeSH
- kukuřice setá * MeSH
- methan MeSH
- siláž * analýza MeSH
- Trametes MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- methan MeSH
High-solid anaerobic digestion of the very small particle fraction of mechanically-sorted organic fraction of municipal solid waste (OFMSW) was examined in mesophilic digestion tests in a conventional laboratory (0.013 m3) and a pilot (0.300 m3) reactor. The non-biodegradable and recalcitrant molecules together with the low protein and starch contents of the small-particles of OFMSW limited the methane generation potential of substrate. In the conventional AD system, methane yields remained low at 0.139 m3kgVS-1 due to formation of a non-reacting layer on digestate surface, which restricted utilization of the available in OFMSW digestible organics. The absence of surface solid crust in the pilot unit favoured consumption of a greater proportion of volatile solids of the OFMSW. Dry AD was remarkably stable over the entire period and negligibly effected by the toxic H2S yields. Methane generation (0.167 m3kgVS-1) was increased 1.2-fold compared to the conventional system due to a better mixing of substrate and microorganisms achieved inside the pilot reactor, which led to an increase of the digested volatile organics. Digestate presented low stability and high heavy metal content, both of which restrain its implementation as soil conditioner or fertilizer in agriculture. A secondary co-digestion treatment may be required for the neutralization of digestate.
- Klíčová slova
- Anaerobic digestion, Dry process, Horizontal tube reactor, Mechanically-separated OFMSW, Mesophilic,
- MeSH
- anaerobióza MeSH
- bioreaktory MeSH
- laboratoře MeSH
- methan MeSH
- odpadky - odstraňování * MeSH
- tuhý odpad * analýza MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- methan MeSH
- tuhý odpad * MeSH
Mechanically-sorted organic fraction of municipal solid waste (OFMSW) was tested to determine its biogas and biomethane generation efficiency. Methane production capability of OFMSW was examined in biochemical methane potential (BMP) tests. The factors affecting the high-solid anaerobic digestion (AD) of feedstock were investigated in a series of long-term semi-continuous digestion tests performed at dry mesophilic and thermophilic conditions in a continuously rotating drum reactor with working volume of 0.013 m3. OFMSW presented low biogas and methane generation capacity due to its contained non-biodegradable components and the low proteins and starch proportions. Dry mesophilic AD allowed only a relatively limited fraction of OFMSW volatile solids to be consumed for biogas and methane production. Reducing particle size favoured utilization of higher proportions of the available digestible organic substances, and concurrently promoted biogas and biomethane generation rate. Stability of methane generation was also significantly improved by particle downsizing. Small particles compensated the limited mass transfer and restricted distribution of methane production intermediate metabolites caused by water absence in the dry AD system. Dry thermophilic AD converted sufficient quantity of OFMSWs biodegradable content. The average methane released from dry thermophilic AD (0.176 m3kgVS-1) was higher than that of dry mesophilic AD of fine particles (0.148 m3kgVS-1) and much higher than that of dry mesophilic AD of same grain size (0.114 m3kgVS-1). High temperature proved more suitable for anaerobically digesting mechanically-sorted OFMSW.
- Klíčová slova
- High-solid AD, Mesophilic, OFMSW, Particle size, Thermophilic,
- MeSH
- anaerobióza MeSH
- biopaliva analýza MeSH
- bioreaktory MeSH
- methan MeSH
- odpadky - odstraňování * MeSH
- tuhý odpad * analýza MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- biopaliva MeSH
- methan MeSH
- tuhý odpad * MeSH
Food waste collected exclusively from University restaurant was tested under anaerobic digestion (AD) conditions to determine its biomethane generation potential. The digestion characteristics of food waste were evaluated in BMP tests and in a conventional single-stage mesophilic CST Reactor. The suitability of psychrophilic two-stage AD to convert food waste was investigated by using a novel two-stage psychrophilic semi-continuous reactor, consisted of a vertically-oriented cylindrical reactor and a coaxially incorporated vertical tube able to spatially separate acidification from methanogenesis. Food waste presented significant methane generation performance under mesophilic conditions. Relatively high amounts of H2S released during process evolution did not have a significant effect on biogas production. For psychrophilic two-stage AD, H2S generated during start-up provoked reactor's instability only for a few days. The system was stable and operated at steady-state conditions over the course of the main AD. Higher amount of biogas was produced by the two-stage psychrophilic reactor (0.800 m3 kgVS-1) than the mesophilic single-stage system (0.751 m3 kgVS-1). However, the average methane quantities generated by the two systems were remarkably similar (0.444 and 0.440 m3 kgVS-1). Psychrophilic process was more efficient in utilizing higher proportions of volatile organics contained in substrate for methane generation than mesophilic operation. The low-temperature two-stage reactor was more energy-efficient than the mesophilic CSTR for digestion of food waste. Two-stage anaerobic digestion system operating under psychrophilic conditions might be an economically feasible option for efficiently digesting food waste.
- Klíčová slova
- Anaerobic digestion, BMP, Food waste, Mesophilic digestion, Psychrophilic digestion, Two-stage reactor,
- MeSH
- anaerobióza MeSH
- biopaliva MeSH
- bioreaktory * MeSH
- methan MeSH
- odpadky - odstraňování * MeSH
- potraviny MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- biopaliva MeSH
- methan MeSH
