Biogas production from tannery solid wastes – Scale-up and cost saving analysis

Abstract

Abstract This work proposes a laboratory and semi-pilot scales procedure for the evaluation of biogas production potential and waste biodegradation efficiency from mixtures of solid wastes from tanneries as well as the evaluation of the energy saving. Leather shavings and sludge from wastewater treatment plants substrates were considered in the study. A theoretical model was employed for calculations of the disintegration kinetic constant (kdis). Biogas yields between 21 and 30 mL/kgVSS, maximum methane content of 59% v/v, and a TOC reduction between 68 and 76% were obtained on both scales. A linear consistency was found in the assessed scale up and a two-fold biodegradation rate to a five-fold volume of treated waste. In the conditions studied in semi-pilot scale, a midsize tannery could reduce 6.8% of electric and 1.6% of thermal energy consumption besides the great cost saving of disposal of this waste.