ÉVALUATIONS PHYSICO-CHIMIQUE ET ÉNERGÉTIQUE DE LA BIOMÉTHANISATION EXPÉRIMENTALE APPLIQUÉE AUX EFFLUENTS D’ÉLEVAGES INTENSIFS GÉNÉRÉS EN TUNISIE

Abstract

This study, carried out in the Tunisian conditions, proposes to deepen the analysis of certain operating parameters of implemented digesters used to treat cowpat experimentally (four laboratory pilot), focusing especially on the effect of the variation of various physical and chemical conditions (temperature, agitation, nature of the substrate, ...) of the discontinuous anaerobic digestion, on the quantitative production of gas. In addition, four other experimental digesters continuously fed by poultry droppings (different depending on their rate of DM) were followed to assess the quantitative and qualitative gas productivity. A physico-chemical diagnosis (pH and Dry Matter: DM) was also undertaken throughout the fermentation process (start-up and production phases). It has been found that quantitative gas productivity is less interesting in the case of digesters discontinuously supplied with cowpat. The amount of experimental cattle biogas produced is variable according to the adopted digestion parameters. It’s maximum in front of a high temperature (35°C) and mechanical agitation of the inserted substrate (substrate mixed with inoculum). For the four poultry digesters, it is more important with the increase of the raised DM concentration. Similarly, the digester at 8% of DM (supplied with poultry droppings) is more efficient in terms of quantity and quality of gas (methane content and calorific value).