Nutrient balance for anaerobic co-digestion of tannery wastes: Energy efficiency, waste treatment and cost-saving

The macronutrients ratio present in tannery wastes is normally not ideal for anaerobic digestion (AD). In most cases, it is necessary to add nutrients to obtain a more balanced AD process and to ensure favorable conditions for the growth and metabolism of microorganisms. The aim of this study was to verify the influence of the components of nutrient solution added to AD of tannery wastes with regard to the energy and waste treatment efficiency and to the cost-saving analysis. The findings provides better understanding of the nutritional requirement of co-AD of tannery wastes, with the highest value of biogas production of 30.14 mL/g of added VSS, besides representing a step in the search for a more balanced, efficient and viable process. The results obtained proving the competitiveness of co-AD of tannery wastes instead of disposing it in landfills (saving off about 71% in terms of electric consumption).