Clean Energy and Resource Recovery. Wastewater Treatment Plants as Biorefineries, Volume 2 - Chapter 2: Energy and resources recovery from wastewater treatment systems

Conventional wastewater treatment plants (WWTPs) are progressively looked upon as resource recovery facilities (RRFs), reflecting the worth of energy, nutrients and other resources, besides vindicating the required effluent quality. Though, WWTPs clean wastewater and lessen water pollution; but, while doing so, they also contribute to air pollution and need energy/material input with associated emissions. However, energy recovery (e.g., biogas, heat) and resource recovery (e.g., extracellular polymers, bioplastics, cellulose fibers, nutrients) allow us to counterbalance the negative environmental impacts of wastewater treatment. Several environment friendly approaches for resource recovery from WWT system have established their utility in optimizing WWTP operation to accomplish improved effluent quality at lower costs; they also constitute a useful tool to support the transition of WWTPs into water resource recovery facilities that maximize the valorization of products recovered from the wastewater. This article critically discusses the recent developments, opportunities, market possibilities, and barriers in the resource recovery from WWTP. Wastewater can not only dampen the effects of water shortages by means of water reclamation, but it also provides the medium for energy and nutrient recovery to further offset the extraction of precious resources.