Biogas generation related to carbon removal from anaerobic co-digestion of sludge, blood, and swine manure combined in different proportions: Production of biogas by anaerobic co-digestion

Abstract

This study evaluated, at a laboratory scale, samples composed of wastewater treatment sludge, blood, and swine manure, which were subjected to the process of anaerobic co-digestion. The goal of the study is to identify the reduction of organic loads through the removal of available carbon and its conversion to biogas. The results showed variation in hydraulic retention time, and that the total average volumes of biogas generated in 1-liter (L) reactors filled with 600 milliliters (ml) of samples, ranged from 3.37 to 18.76 L, with percentages of methane ranging between 57.9% and 71.1%. The largest volumes of biogas resulted from blends with lower percentages of swine manure, where the initial amounts of carbon in milligrams per liter (mg/L) were larger within the samples. All of the blends submitted to anaerobic treatment showed reductions in carbon content, and consequently, in chemical and biochemical oxygen demand, demonstrating that the efficiency of biodigesters in the treatment of waste is variable and related to physical–chemical factors, such as the amount of carbon available.