Evaluation of the COD and the C/N ratio in the anaerobic treatment of fruit and vegetable wastes

Abstract

Daily, there are generated large quantities of fruit and vegetable wastes on wholesale fruit and vegetable markets, local orthofruit shops and supermarkets. The excessive generation of these wastes can cause environmental problems. So, the aim of this study was to evaluate the anaerobic biodegradation of fruit and vegetable wastes by the COD and C/N ratio monitoring. The wastes were collected in a central distribution market for food, shredded, blended, inoculated with sewage sludge and characterized. The waste was characterized in terms of organic carbon, soluble and total COD and Kjeldahl nitrogen, so it was put in an anaerobic reactor for the biological degradation that was monitored during 300 days. The results show that during the experiment, the degradation of the organic material wasn´t possible, because of the low COD and C/N ratio removal. Probably, this fact was caused by the physical aspect of the waste, such as a semi-solid paste. A dilution or the addition of higher concentrations of sewage sludge could facilitate the biodigestion process.