Technoeconomic analysis, life cycle assessment and economic analysis of wastewater and sludge treatment systems

Wastewater treatment plants (WWTPs) have been developed as multifunctional systems responsible for the management and treatment of wastewater prior to its discharge into the aquatic environment. Improving the energy efficiency of WWTPs is a key factor for their sustainability performance; however, it is also crucial that their design is based on the combination of technologies capable of maintaining a balance between the desired quality of final streams (i.e., effluent, sludge, and gas emissions) and the recovery of resources (reclaimed water, fertilizers, and bioenergy). Within this framework, one of the central processes of the WWTPs within the water-energy nexus is the anaerobic digestion (AD) process, ideally suitable for the management of wastewater and solid waste with a high organic load. The objectives of AD are rooted in the underlying principle of circular economy in such a way that waste is valorized to produce bioenergy and biofertilizers.