Evaluation of microorganisms responsible for the production of biogas in an anaerobic reactor that treats agro-industrial waste

Resumo

SummaryAgro-industrial effluents are composed of food waste and chemical compounds, discharged from industry with a high organic load, pH outside neutrality, with high COD and BOD, and with a high solids. If not treated, the agro-industrial effluent can cause serious damage to the river and the environment. Biological treatment, both aerobic and anaerobic, is widely used in the treatment of agro-industrial effluents. The objective of this work was to evaluate the communities of microorganisms in the anaerobic reactor treatment of agro-industrial effluent, investigating the efficiency of the system in the transformation of organic matter into biogas. All operating parameters of a full-scale anaerobic IC reactor of an agroindustry were monitored. The preliminary results showed that the organic load, pH, redox potential, temperature influence the performance of the reactor and consequently the generation of biogas. In relation to the biological sludge, the alkalinity was between 660 and 940, values that allow a good buffering of the medium, the volatile fatty acids were between 96 and 162 avoiding the acidification of the reactor, the temperature of 29 and 34ºC favored anaerobic digestion. The macronutrient analysis showed that the influent to the reactor had total nitrogen between 34.6 and 58.5 mg/L, P between 7.86 and 17mg/L and ammonia nitrogen between 9.34 and 12.5 mg/L, well meeting the need of anaerobic microorganisms. The volatile solids were between 58 and 85%, optimal values for biodegradability, with all these parameters well monitored, a COD removal between 72 and 84% was observed and the generation of biogas at an average of 1072 m³/d. It is concluded that for a good performance of an anaerobic reactor and efficiency in anaerobic digestion and biogas generation, it is necessary that the physicochemical parameters are well monitored.