Estratégias para predominância de organismos acumuladores de fósforo em sistemas de lodo ativado e respirometria aplicada à biodesfosfatação

Abstract

In recent years there has been an intensified studies on the biological removal of phosphorus from wastewater and as a result, a breakthrough in the understanding of the microbial groups involved in this process. This was possible due to the availability of different laboratory techniques for the identification and quantification of these organisms that often is associated with molecular biology. As part of sanitary engineering, new approaches can be inserted to enable the determination of operating parameters that support rational projects, such respirometry combined with mathematical modeling of microbial metabolisms. Furthermore, the possibility of identifying the predominance of phosphorus accumulating organisms (PAO) by means of techniques available and low cost is attractive in countries such as Brazil. For this reason, nine activated sludge systems were operated with different strategies to stimulate not only the predominance of PAO, in four of these systems as well as in other settings, the prevalence of other bacterial groups as glycogen storage batteries (GAO), heterotrophic ordinary (OHO) and mixed populations. Five tools based on physico-chemical and respirometric tests were used to assess the prevalence of different populations from stoichiometric ratios and kinetic data. The PAO predominance strategy that got the most attention in average temperature of 25°C, which consisted of a system that promoted denitrification via nitrite using exclusively propionate as organic carbon source. From the data obtained was built an array of predominance of PAO, also using mixed sludge, OHO and GAO comparatively. The results obtained in this study can be applied in rational models and optimized projects and support other biotechnological applications.