Avaliação do dimensionamento de um reator UASB de Estação de Tratamento de Esgoto em Fortaleza-CE

Abstract

Nowadays, there is a great concern regarding the treatment and final destination of sewage, due to problems related to human health and the environment. Sewage Treatment Plants (STPs) are systems developed to treat these sanitary effluents, generally, based on anaerobic or aerobic biological processes. Today, anaerobic systems for digestion of organic matter and energy production already have their use stabilized. However, the maintenance and evaluation of the operating parameters of biological reactors are very important to ensure their proper functioning. In this perspective, the aim of the present study was to analyze operational parameters of the UASB reactor of the Sewage Treatment Station Alameda das Palmeiras, in Fortaleza-Ceará. For this, the Specific Methanogenic Activity (SMA test) of the sludge from the UASB reactor was determined. In addition, the hydraulic retention time and the organic and hydraulic loads applied in the reactor were analyzed, based on the sewage flows and on the Chemical Oxygen Demand (COD). The CH4 production rate per sludge mass (SMA) was 0.385gDQO-CH4/g STV.d, a value corresponding to the ranges recorded for digesters assessed on a laboratory scale and even higher than other similar studies. Considering the average monthly flows, the COD values affluent to the system and the operational parameters studied in this work, it could be verified that there were significant differences between the average values of the evaluated parameters defined in the UASB reactor project and the real values, measured in the STP. This allows us to state that the reactor was oversized during the analyzed period.