Preliminary Study of Up-Flow Anaerobic Sludge Blanket (UASB) Technology for Energy Recovery from Domestic Wastewater

Abstract

New efforts are increasingly oriented towards the search for sustainable Waste Water Treatment Plant (WWTP) designs. The use of anaerobic digestion processes allows energy production during the treatment of wastewater. However, this technology has been poorly implemented for domestic wastewater due its low organic matter content. In this work, the generation of biogas from municipal wastewater has been studied through anaerobic digestion treatment. UASB effluent has been fed to a membrane photobioreactor (MPBR) where developed indigenous microalgae-bacteria consortia contributes to organic matter and nutrients recovery from digested wastewater and membrane allows continuous regenerated wastewater production as permeate stream. The study was performed at pilot scale making use of an Y configuration UASB, operated under psychrophilic conditions. In addition, the energy production potential of different valorisable substrates, which are residual streams from different treatment processes, was studied at lab scale: concentrate from direct ultrafiltration (DUF) membrane and sludge from conventional membrane bioreactors (MBR), in order to define the potentiality of technological trains with UASB reactors. Anaerobic digestion yields interesting results that should be considered, such as the fact that energy recovery in MBR is lower than that achieved in DUF, where a higher concentration of organic matter is obtained, and therefore, a greater energy obtainment is achieved.