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This paper investigates the influence of thermal pretreatment on kinetic parameters based on four kinetic models: Modified Gompertz, transference and logistic functions and first order equation. The kinetic modeling was applied on experimental results of previous study on producing methane from anaerobic digestion of Recycled Pulp and Paper Sludge (RPPS) under mesophilic conditions. We observed that the thermal pretreatment improve considerably improved the kinetic parameters mainly the methane production rate and the lag phase. Indeed, it can be noted that methane production rate μ increases significantly from a value of 4.72 to 16.27 Nml/h using logistic function for 1 g VS/L added load. Then the lag phase parameter λ has dramatically decreased from 5.46 to 1.04 h using logistic function for 1,5g VS/L added load. This means that the thermal pretreatment of RPPS accelerates the methane production process and saves time.

Food waste (FW) biotransformation into bioenergy has garnered a lot of scientific interest as a way to address the energy crisis and trash disposal issues. FW is converted into biogas, a gaseous combination of biomethane and carbon dioxide. In order to valorize FW, anaerobic digestion (AD) with combined pretreatment (hydrothermal (HT) and ultrasonic (US)) is used as a potential method. Three digesters were investigated: the control (unpretreated), HT(121°C) + US, and HT(134°C) + US, respectively. Based on changes in the combined pretreatment conditions, the paper assessed the methane productivity. Furthermore, kinetic modeling was evaluated with six kinetic models. The results show that the HT pretreatment at 121°C combined with US improves the volatile solid (VS) removal to 73 ± 5% and the methane yield to 529.7 ± 11 NmL/gVS. Both the Transference model and the first order have the greatest fits in terms of R2, and they also have the best fits in terms of relative errors, and methane production rate, respectively. The combined pretreatment has a positive impact on increasing methane yield as well as stabilizing the anaerobic digestion process. [ABSTRACT FROM AUTHOR]

This work aims to evaluate the technical and environmental feasibility of converting date palm waste from a Moroccan oasis into energy. In this study, two different scenarios were analysed. The first proposed scenario is the valorization of the date palm substrates using direct combustion (thermochemical conversion) to produce energy. The second proposed scenario is the valorization of the substrates using combined anaerobic digestion of the substrate and direct combustion of the digestate. In this study, two different date palm wastes are: empty fruit bunch (EFB) and palm leaflet (PL). The experimental lower heating values of the digestates studied are 12.93 and 12.71 MJ/kg, respectively. The results show that using Scenario 1, the estimated output energies for the EFB and PL waste were 1.13 and 1.17 MWh, respectively. Using Scenario 2, the EFB and PL output energies were 1.27 and 1.39 MWh, respectively. The study revealed that the combined process is possible as an alternative way to produce energy. Furthermore, combining anaerobic digestion and direct combustion of lignocellulosic waste can contribute to reducing greenhouse gas emissions. [ABSTRACT FROM AUTHOR]

Coffee is present in every street in the world and is without a doubt one of the most consumed beverages. Moreover, it is the third most consumed drink in the world. Recent estimations from the International Coffee Organization put. The world coffee production at about 6 million tons per year. Its uncontrolled disposal can cause environmental problems, but if handled properly, it can be processed into pellets, and used as an energy source. In the present study, the production of energy from coffee waste (CW) is an interesting alternative to traditional production lines. The objective of this study is to calculate the energetic potential (Ep), which can be generated by anaerobic digestion (AD) and thermochemical conversion (TC), of the organic fraction of CW in the city of Kenitra, Morocco. An elementary analysis allows us to estimate the calorific value by the TC. The lower and higher calorific values were estimated to be: 18.71 and 20.28 MJ/Kg, respectively. Ep results by AD and CT were 0.25 and 1.3 MWh/t, respectively. [ABSTRACT FROM AUTHOR]

Anaerobic digestion of the date palm empty fruit bunch is a promising technology for both solid waste management and biogas production. The date palm empty fruit bunch is a lignocellulosic waste that takes more time for degradation and has a low biodegradability, thus pretreatment is needed to improve anaerobic biodegradation. In this study, the substrate was pretreated with different ratios of alkali-NaOH: 6, 18 and 30% (w/w) (ratio weight of NaOH / weight of Volatile Solid) for 10 min at room temperature to evaluate the effect of high alkali concentration on the methane potential and biodegradability. The experiment was conducted in a 5 L batch reactor under mesophilic conditions (37 °C). The methane potential of the untreated substrate was 98.5 N mL/gVS. The best methane potential improvement of 104% was achieved in the treatment of 18% (w/w) (204 N mL/gVS) with a biodegradability of 50%. Besides, two kinetic models were used to fit the experimental methane potentials and to explore process parameters (Modified Gompertz and Transference function). The best fit for predicting the parameters of methane production was observed for the 18% (w/w) pretreatment using the transference function, with a maximum methane production rate of 5 N mL/gVS.d. [ABSTRACT FROM AUTHOR]