Integration of microalgae culturing within the wastewater scheme

This document provides an analysis of the potential improvements involved in the implementation of a microalgae culture integrated to the typical depurative cycle of a wastewater treatment plant. In particular, it is of interest the integration with the anaerobic digestion of the waste sludge, since the biogas produced from the anaerobic co-digestion of these feeds can be used to generate onsite electrical power or thermal heat to offset biomass processing and extraction processes. In fact, when both processes are integrated and operated simultaneously, the benefits to wastewater treatment are extended beyond the energy generation, including a considerably improvement of the effluent quality. For this purpose a Pilot plant scale culture was tested in order to define the operational parameter required for modeling this unit in an integrated scheme WWTP-PBR. From the simulations, it is evident the increase on produced biogas due to the co-digestion process, as well as the boost quality in the centrate stream. The outcomes confirm the potential of this scheme for improving the energy balance of the WWTP, but it is essential to go into deep in the optimization of the culture system, as well as the harvesting process, in order to avoid possible negative effects.