Effect of biochar addition on anaerobic digestion of laying hen manure

• Ano de defesa: 2019
• Autor(a) principal: Andrade, Willian Rufino
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Universidade Federal de Viçosa
• Palavras-chave em Português: Resíduos de animais - Reaproveitamento; Resíduo como combustível; Biogás; Construções Rurais e Ambiência
• Link de acesso: https://locus.ufv.br//handle/123456789/27349

Anaerobic digestion is considered one of the most antique and suitable methods for waste treatment from urban and rural areas. It usually involves the action of a variety of fermentative microorganisms that metabolize and generates sub products used as precursors for biogas production. It is known that in spite of its appealing benefits, such as biogas and digestate generation, anaerobic plants require proper control of monitoring parameters that can directly affect the overall efficiency of the treatment system. Parameters such as pH, total ammonia nitrogen, alkalinity, volatile fatty acids and organic matter should always be well managed in order to maximize microorganism’s activity and increase biogas production. Excess of total ammonia nitrogen for instance is one of the main reasons for anaerobic digestion failure since it can strongly affect fermentative microorganism’s activity. Some wastes are known for its problematic regarding high concentration of total ammonia nitrogen, for instance, laying hen manure. Recent research has shown interesting improvement in terms of mitigating the excess total ammonia nitrogen throughout the anaerobic digestion process. Improvements could come from adoption of anaerobic codigestion, dilution of residues with water, addition of zeolite, charcoal, activated carbon and biochar. The use of an adsorbent substance such as biochar as a component in the anaerobic digestion process is new and may have a positive impact on the anaerobic digestion process allowing better stability and overall equilibrium of fermentation reactions. In order to provide new and concrete results to the literature, the present study proposed to assess the use of biochar in the anaerobic digestion of hen manure as a way to mitigate negative and inhibitory effects, expecting better equilibrium regarding monitoring parameters, and possible increase in the biogas yield. Two different assays were carried out to assess different inclusions (at 2.5, 5.0, and 7.5%) of biochar in substrates of batch anaerobic reactors formed by laying hen manure diluted in water at 5 and 7% of total solids, respectively. From both experiments, it is possible to understand that biochar has great potential to be used as buffering substance in anaerobic reactors, however, regarding biogas production its use did not display a positive effect on biogas yield.