Production of biogas and biofertilizer using anaerobic reactors with swine manure and glycerin doses

Abstract

This research aims to evaluate the development of biodigestion of swine manure with addition of glycerin doses, in order to promote a cleaner destination for both of these wastes in agroindustry, adopting different concentrations for a better relation of biogas production and biostabilized fertilizer. For this, five anaerobic biodigestors were developed, each reactor was fed with swine manure considering four treatments (5%, 10%, 15% and 20% vv−1 of glycerin). The physical-chemical parameters (temperature, pH, turbidity, solids series, total phosphorus, total nitrogen (Kjeldahl), and COD were evaluated every seven days, moreover the biogas production was monitored daily by a gasometer. The concentrations of Cu, Zn, Mn, Fe, Cd, Pb and Cr during hydraulic retention time (HRT) were determined by Flame Atomic Absorption Spectrometry (FAAS). Anaerobic co-digestion of swine and glycerin wastes didn't provided higher biogas production than the biodigestion without the addition of glycerin. The biogas production rates were impaired by the addition of glycerin doses higher than 5%, and the results demonstrate that the nutrient concentrations in the biostabilized waste are expressive for vegetal biofertilization, mainly for N, P, K, Ca, Mg and micronutrients such as Cu and Zn.