Abstract
Currently, the worldwide growth population has led to several environmental and societal challenges: rising global demand for food and energy, industrial and green revolutions, use of fossil fuels, increasing concentrations of greenhouse gases in the atmosphere, global climate change, demand for renewable energy sources, etc. The concept of sustainable development through the production of renewable energy and alternative value-added products through the valorization of agricultural residues and biomasses is a promising route for this environmental and energetic issues. The objectives of my thesis project were the following ones: 1) valorization of Moroccan biomass & residues by pyrolysis process for objective to produce activated biochars for effluent detoxification and agriculture application , 2) valorization of Moroccan residues using anaerobic digestion in CSTR lab pilot for biogas production, 3) coupling of anaerobic digestion (AD) and pyrolysis for maximizing energy recovery from pyrolysis of solid digestate, and 4) coupling liquid digestate and biochar (from solid digestate) for agronomic purpose. The results demonstrated that the “one pot activation/pyrolysis approach” of red macro-algae residue and olive pomace using chemical and mechanical activations could improve the properties of biochar through generating surface functional groups and specific surface area compared to inactivated ones. In parallel the results also showed the efficiency of activation depends on the nature and type of biomass; the olive pomace biochar activated by ball milling showed the most promising result with a maximum adsorption capacity of methylene blue of 32 mg/g compared to 3 mg/g for the inactivated one. The continuous anaerobic co-digestion of Quinoa residues (45 %VS) with wastewater sludge (55 %VS) demonstrated a good stability and a methane production of 219 NL CH4/ kg VS. The coupling of AD and pyrolysis through pyrolysis of solid digestate showed a potential opportunity to maximize energy through the production of syngas and bio-oils which showed a calorific value range between 11-13 MJ/Nm3 and 28-34 MJ/kg, respectively. The coupling of biochar and liquid digestate (170 kg UN/ha) depicted potential use as agronomic support for growing plants, this combination did not negatively impact relative seed germination and improved aerial dry biomass production up to 27.5 % (50 tons/ha) and 25 % (25 tons/ha) for wheat and tomato plants respectively, compared to the trial using liquid digestate alone. Finally, co-application of biochar with liquid digestate significantly increased the ammonia volatilization by 64 % compared to the trial using liquid digestate alone but had no impact on C and N mineralization.