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. K E Y W O R D Smethane, organic matter, renewable energy

Energy recovery by anaerobic digestion of algal biomass from integrated microalgae/constructed wetland wastewater treatment

“…The growing search for energy generation alternatives to meet the global demand has increasingly raised the number of researches and debates in the scientific and technological spheres. Although fossil fuels are responsible for meeting most of this demand, factors such as environmental degradation and limited reserves make the use of this energy matrix finite and potentially polluting (Pacheco et al 2015 ; Hasan et al 2018 and Martens et al 2021 ).…”

“…Co-digestion can promote a better carbon/nitrogen (C/N) ratio, the main nutrients used by microorganisms in anaerobic digestion, ensuring that all the carbon available in the medium may be consumed by microorganisms (Konrad et al 2016a ). Researches on the generation of biogas have received growing attention in recent years, since besides being used as a renewable energy source for heat and energy generation, it can also generate fuel (biomethane), thus constituting a sustainable alternative to fossil fuels (Lantz 2012 ; León and Martín 2016 ; Hasan et al 2018 ). The production of biogas and biodiesel is growing rapidly, but neither has outpaced the production of bioethanol, mainly in Brazil.…”

“…Even so, the country has the potential to produce 10.9 billion m 3 of biogas for short-term use (INSTITUTO 17 2021 ). Studies show that the digestion of carbon-rich animal and/or vegetable residues, with residues that complement these substrates, has been widely used by industry with positive results in the generation of biogas, considered a sustainable technology as the process does not entail a net consumption of energy; the process is usually referred to as “co-digestion” (Zhang et al 2013 ; Capodaglio et al 2016b ; Hasan et al 2018 ). Other studies analyzed the proposal to generate biogas as an alternative for energy recovery in consolidated phytoremediation systems, such as the wastewater treatment through the use of macrophytes used in constructed wetlands, recovering energy by plant biomass (Prochnow et al 2005 ; Wöhler-Geske et al 2016 ; Roj-Rojewski et al 2019 ).…”