Marco Gottardo

Mesophilic and thermophilic anaerobic digestion of the liquid fraction of pressed biowaste for high energy yields recovery

Deep separate collection of the organic fraction of municipal solid waste generates streams with relatively low content of inert material and high biodegradability. This material can be conveniently treated to recovery both energy and material by means of simplified technologies like screw-press and extruder: in this study, the liquid fraction generated from pressed biowaste from kerbside and door-to-door collection was anaerobically digested in both mesophilic and thermophilic conditions while for the solid fraction composting is suggested. Continuous operation results obtained both in mesophilic and thermophilic conditions indicated that the anaerobic digestion of pressed biowaste was viable at all operating conditions tested, with the greatest specific gas production of 0.92m(3)/kgVSfed at an organic loading rate of 4.7kgVS/m(3)d in thermophilic conditions. Based on calculations the authors found that the expected energy recovery is highly positive. The contents of heavy metals and pathogens of fed substrate and effluent digestates were analyzed, and results showed low levels (below End-of-Waste 2014 criteria limits) for both the parameters thus indicating the good quality of digestate and its possible use for agronomic purposes. Therefore, both energy and material were effectively recovered.

Dark fermentation optimization by anaerobic digested sludge recirculation: effects on hydrogen production.

Dark Fermentation Optimization by Anaerobic Digested Sludge Recirculation: Effects on Hydrogen Production Marco Gottardo*, Cristina Cavinato , David Bolzonella, Paolo Pavan a University Ca’Foscari of Venice, Department of Environmental Science, Informatics and Statistics, Calle Larga Santa Marta, Dorsoduro 2137 – 30123, Venice, Italy University of Verona, Department of Biotechnology, Strada le Grazie 15 – 37134 37134, Verona, Italy. marco.gottardo@unive.it

Recent developments in biohythane production from household food wastes: A review

Biohythane is a hydrogen-methane blend with hydrogen concentration between 10 and 30% v/v. It can be produced from different organic substrates by two sequential anaerobic stages: a dark fermentation step followed by a second an anaerobic digestion step, for hydrogen and methane production, respectively. The advantages of this blend compared to either hydrogen or methane, as separate biofuels, are first presented in this work. The two-stage anaerobic process and the main operative parameters are then discussed. Attention is focused on the production of biohythane from household food wastes, one of the most abundant organic substrate available for anaerobic digestion: the main milestones and the future trends are exposed. In particular, the possibility to co-digest food wastes and sewage sludge to improve the process yield is discussed. Finally, the paper illustrates the developments of biohythane application in the automotive sector as well as its reduced environmental burden.

Hydrogen and Methane Production from Biowaste and Sewage Sludge by Two Phases Anaerobic Codigestion.

The two phases anaerobic codigestion of biowaste and sewage sludge is the key to implementing the integrated treatment approach of municipal wastewater and organic fraction of municipal solid waste. In addition to increasing the production of biogas, the joint treatment of biowaste and wastewater allows to obtain readily biodegradable carbon source, an additive promoter of the denitrification stages and biological phosphorous removal. In order to develop a two-phase anaerobic codigestion process optimized for hydrogen and methane production, implementable in a wastewater treatment plant (WWTP), in the present study a pilotscale experimental apparatus was used to verify the feasibility and performance of the process. The addition of small amounts (5 – 10 %) of H2 to rich CH4 biogas improves the quality of gas combustion while reducing CO2 emissions. The experimental test was carried out at pilot scale using two stirred reactors both maintained at thermophilic temperature and semi-continuously fed. Nor chemicals neither recirculation were used to control the pH in first phase. The study lasted 50 days in which there were no evidences of any instability in the process. It was confirmed the possibility to obtain a stable hydrogen production with a specific hydrogen production of 40 L per kgTVS fed and a specific methane production in the second phase of 320 L per kgTVS fed. The biogas produced has a composition characterized by a stable presence of hydrogen over 5 %.

Ammonia Concentration and Ph Control in Pilot Scale Two-phase Anaerobic Digestion of Food Waste for Hydrogen Production: Focus on Start-up

Ammonia Concentration and pH Control in Pilot Scale TwoPhase Anaerobic Digestion of Food Waste for Hydrogen Production: Focus on Start-up Cristina Cavinato*, Marco Gottardo, Federico Micolucci, David Bolzonella, Paolo Pavan. a University Ca’ Foscari of Venice, Department of Environmental Sciences, Informatics and Statistics, via Torino, Mestre Venezia, Italy. University of Verona, Department of Biotechnology, Strada le Grazie 15, Verona, Italy. cavinato@unive.it.

Bioprocess Network for Solid Waste Management

The anaerobic digestion process is a well-known and still growing technology. It has been implemented in full scale in several waste and wastewater treatment plants.