Análise da recuperação de recursos em sistemas de lodo granular aeróbio: oportunidades e obstáculos dentro do tratamento de esgoto

Abstract

Aerobic granular sludge (AGS) is one of the most studied biological sewage treatment technologies in the last decade. Examples of resource recovery in full-scale sewage treatment plants (STP) with this technology have been reported recently, in addition to several other opportunities that could be better explored. Therefore, this review presents the state of the art of the main products capable of recovering the AGS, the possibilities, and the challenges. In the liquid phase, the water may be reused for irrigation and urban reuse, for example. In the solid phase, the application of sludge in agriculture is an interesting possibility, but we must pay attention to the adsorption of pollutants in the biosolid due to the high concentration of extracellular polymeric substances (EPS) that tend to concentrate many pollutants. In the gaseous phase, generating biogas by the anaerobic digestion of excess sludge is possible, but there are difficulties due to the low biodegradability of the aerobic granules. Thus, recovering resources in AGS reactors may further favor the application of these technologies in STPs, since it would help reduce operational costs, considered high, in relation to other technological routes employed in Brazil and in other developing countries, by the aeration, automation, and supervisory systems, among others.