Introduction

The book presents the state of knowledge and the future perspectives of anaerobic processes applied as mainstream treatment of domestic wastewater, which in the last few decades, due to the development of effective technologies such as the high-rate bioreactors, became competitive with the conventional aerobic process even in moderate climatic regions.The book consists of 12 chapters covering the main aspects related to the anaerobic treatment of domestic wastewater including engineering, microbiology, process monitoring and control, sustainability derived by energy and resource recovery, life-cycle assessment, and techno-economic analysis.Effective technologies namely upflow anaerobic sludge blanket bioreactors, membrane bioreactors, and granular and immobilized biomass systems, potentially able to achieve removal performance of high organics even at low temperatures, are presented in detail, and their status of application is reported.For the nutrient content of treated effluents, two alternatives are considered: their recovery, which is preferable to maximize the process sustainability, and low impact post-treatment solutions.Operational strategies to recovery energy and water are also discussed for different final use options.Concerning the drawback caused by the dissolved methane in the treated effluent, possible alternatives to enhance either its recovery within the process to maximize energy production or its use as an alternative carbon source to improve denitrification potential, avoiding in any case the emission of this powerful greenhouse gas, are critically analyzed.Constraints such as removal of microbial indicators (i.e., helminth eggs, pathogenic microorganisms, viruses) and fate of micropollutants are discussed to evaluate possible interventions for enhancing their removal.Feasibility of anaerobic treatment for domestic wastewater is also evaluated through life-cycle assessment and techno-economic analysis to define the real competitiveness with conventional activated sludge processes.At the end, the book will provide the reader all the information required to evaluate anaerobic processes as a feasible alternative in treating domestic wastewater, expected advantages in terms of sustainability, and the still open research questions, placing special emphasis on hot topics such as the fate of microplastics and antibiotic resistance in anaerobic systems.