Chapter 1 - Wastewater to R3 – resource recovery, recycling, and reuse efficiency in urban wastewater treatment plants

Abstract

Wastewater is traditionally viewed as an unwanted material that must be treated prior to discharge to protect public health and the environment. However, due to dwindling natural resources, water utilities, engineers, and researchers have started to look at wastewater as a valuable feedstock for resource and energy recovery. Wastewater contains valuable resources such as water, nutrients, and energy – that, if recovered safely and effectively, can have economic and environmental benefits. Potable and nonpotable water recovery from wastewater gives an extra level of certainty and security to water supplies in the face of a changing climate. The recovery of nutrients (i.e., nitrogen and phosphorus) and energy emerges as another revenue for wastewater treatment plants. While water recovery has achieved an upward trajectory in both technology development and full-scale applications, the nutrient and energy recovery has recently received great attention from both the scientific community and industry stakeholders. This book chapter aims to provide a state-of-the-art perspective on the paradigm shift from wastewater treatment to wastewater R3 - reuse, recovery, and resource efficiency. Nutrients and embedded energy in domestic wastewater were reviewed followed by different technologies applied to recover nitrogen and phosphorus. Energy recovery through biogas production from anaerobic digestion and reactive nitrogen was also scrutinized. While several technologies have been reviewed separately in this chapter, the combination of various technologies is likely the key to achieve water, nutrient, and energy recovery.