1Chemical Engineering Department, Federal University of Rio Grande do Sul, Brasil
2Institute of Basic Health Sciences (ICBS), Microbiology Department, Federal University of Rio Grande do Sul, Brasil
*Corresponding author: Caroline Borges Agustini, Chemical Engineering Department, Leather and Environment Laboratory, Federal University of Rio Grande do Sul, Brazil, Ph: 55 (51) 3308-3638; Email: firstname.lastname@example.org
Submission: February 05, 2018;Published: February 23, 2018
ISSN 2637-8035Volume1 Issue1
The main solid wastes from tanneries are wet-blue shavings (chrome tanned leather) and sludge emitted mainly from waste-water treatment plants (WWTP). The main degradation process that occurs on solid media is anaerobic digestion. In this process the main products are methane (CH4), which has a high calorific value, and carbon dioxide (CO2); together these gases compose the emitted biogas. Methanogens, which are strict anaerobes, are responsible for the last step of anaerobic digestion and it is through their metabolism that methane is generated. The aim of this study was to evaluate the interference of oxygen on methane yield in the biogas produced in the controlled biodegradation of leather industry solid waste where in oxygenation occurred through a momentary exposure to atmospheric oxygen. Biodegradation of the solid waste residue was carried out in bench bioreactors and each bioreactor was momentarily exposed to atmospheric oxygen by opening the top cover for 10min at different degradation times. To determine the composition of the gases produced during the biodegradation, a gas chromatograph was used. The results showed that methane production started before the oxygen was completely consumed in all assays. Each bioreactor showed a different behavior after its momentary exposure to atmospheric oxygen and the behavior was strongly linked to the availability of nutrients. When the oxygen exposure occurred at a stage when there were still adequate nutrients, methanogenesis could recover but when the oxygen exposure was made after the nutrients were depleted, methane formation did not recover.
Keywords: Anaerobes; Biogas; Methane; Oxygen; Tannery