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Abstract Steam gasification of char derived from spent mushroom substrate was carried out in thermobalance coupled with mass spectrometer, in the temperature range of 800–900 °C and the steam concentration from 10 to 50 vol%. Syngas production was influenced by temperature and steam concentration. The highest yield of H 2 production (42.9 mol H 2 /kg) was achieved at temperature of 800 °C and steam concentration of 50 vol%. The composition of the generated gas was strongly influenced by the water-gas shift reaction. The grain model was used to describe the kinetics of gasification of the char and the calculated activation energy was equal to 99.0 kJ/mol. The low activation energy of the gasification process was caused by a high content of mineral compounds in the char. The obtained results indicate the potential for gasification of the spent mushroom substrate and found to be an initial and important stage in the development of the gasification process in mushroom production plants. Highlights • Spent mushroom substrate showed high potential for utilization by steam gasification. • The highest yield of H 2 was attained at 800 °C and steam concentration of 50 vol%. • Grain model appeared to be the most suitable to describe the kinetics of gasification. • Low activation energy (99.0 kJ/mol) was caused by high content of minerals. [ABSTRACT FROM AUTHOR]

In this study the municipal solid waste degradation processes in simulated landfill bioreactors under aerobic and anaerobic conditions is investigated. The effect of waste aeration on the dynamics of the aerobic degradation processes in lysimeters as well as during anaerobic processes after completion of aeration is presented. The results are compared with the anaerobic degradation process to determine the stabilization stage of waste in both experimental modes. The experiments in aerobic lysimeters were carried out at small aeration rate (4.41 ⋅ 10 −3 l min −1 kg −1 ) and for two recirculation rates (24.9 and 1.58 l m −3 d −1 ). The change of leachate and formed gases composition showed that the application of even a small aeration rate favored the degradation of organic matter. The amount of CO 2 and CH 4 released from anaerobic lysimeter was about 5 times lower than that from the aerobic lysimeters. Better stabilization of the waste was obtained in the aerobic lysimeter with small recirculation, from which the amount of CO 2 produced was larger by about 19% in comparison with that from the aerobic lysimeter with large leachate recirculation. [ABSTRACT FROM AUTHOR]

Dark fermentation of kitchen wastes was studied in batch bioreactors, with no pH adjustment, to evaluate the effect of the initial organic load on the process performance in terms of volatile fatty acids and H 2 production. Initial organic load of the kitchen wastes ranged from 4.1 to 48.2 gVS/L. Acetic and butyric acids were produced in the largest amount. At the initial organic load of 48.2 KW gVS/L the highest concentration of volatile fatty acids was 9.81 g/L. The maximum production yield of H 2 (76.1 mL/gVS) was found for the initial organic load of kitchen wastes at 14.3 gVS/L. The carbon balance calculation showed that the maximum CO 2 yield of 0.34 gC/gC was attained in the bioreactor with the initial organic load of 14.3 gVS/L. The microbiological analysis revealed that the predominant microorganisms in the dark fermentation process were Bacteroidetes , Firmicutes, Spirochaetes and WWE1 at phyla level. [ABSTRACT FROM AUTHOR]

Abstract: Biomass from Miscanthus giganteus, Sida hermaphrodita and Sorghum Moensch was treated with Fenton’s reagent for 2 hours under optimal conditions (pH=3, mass ratio of [Fe2+]:[H2O2] equals 1:25 for Miscanthus and Sorghum and 1:15 for Sida). The degrees of delignification were 30.3%, 62.3% and 48.1% for the three plant species, respectively. The volatile fatty acids concentration after chemical pretreatment was high enough for production of biogas with a high methane content. Combined chemical oxidation and enzymatic hydrolysis with cellulase and cellobiase led to glucose contents of above 4g/L. Among the tested plants, the highest biogas production (25.2Ndm3/kg TS fed) with a 75% methane content was obtained with Sorghum Moensch. The results of the three-step process of biomass degradation show the necessity of applying a chemical pretreatment such as oxidation with Fenton’s reagent. Moreover, the coagulation of residual Fe3+ ions is not required for high biogas production. [Copyright &y& Elsevier]