Influência dos ácidos voláteis na geração de biogás

Abstract

Given the essentiality of water for all living organisms survival, the search for efficient strategies of water reuse and effluent treatment is essential to avoid a water crisis scenario. The industrial effluents that are endowed with different characteristics and polluting loads, need treatment to atend the legal standards of release before being returned to the hydrographic network, so that they do not cause damage to human health and compromise environmental quality. Anaerobic digestion in biodigesters is often used for the treatment of industrial effluents and is a process that depends on specific associations of microorganisms wich degrade organic matter and produce biogas, but it is strongly influenced by environmental conditions. Some physical-chemical and biological parameters can act as indicators of the stability of the biodigestion process, among which volatile acidity can be highlighted. Volatile fatty acids are natural products of the anaerobic digestion process, but when in excess, they can inhibit the generation of methane, the main constituent of biogas, and lead to biodigester failure, as well as causing structural damage and incurring in additional costs. Therefore, the main of this research was evaluate the potential influence of volatile acids on the stability of the anaerobic digestion and the biogas generation in a biodigester of the milk dairy industry. We evaluated several physicochemical and biological parameters of the biodigester over a period of 12 months, as well as biogas production data, in order to show whether volatile acidity is related to the variation in biogas generation and may be a good indicator of process health. Data analisys was made in Program R. The results demonstrate that volatile acidity is negatively related to the productivity of the digester and affects the amount and concentration of methane in biogas. Parameters such as pH, COD and alkalinity proved to be important to control the excess of volatile acidity and maintain favorable environmental conditions for biogas generation in the evaluated reactor. Monitoring volatile acidity is an important strategy to guarantee biogas production as it is an indicator of the health and quality of the anaerobic digestion and, therefore, it is paramount to be considered in the process management.