Chapter 2 - Wastewater treatment as a process and a resource

Abstract

Wastewater treatment is a dynamic and complex process used to convert wastewater into an effluent that can be safely returned to the environment or directly reused. International standards are used as references to evaluate the safety of wastewater discharge, reclamation, and reuse. Significant progress has been made in terms of developing technical approaches to producing a quality and reliable water source according to the characteristics of the wastewater and end uses. Nowadays, wastewater treatment has entered a situation defined by recognition of the need to reduce global environmental impacts and enable long-term social sustainability. It is well-established that between 50% and 100% of lost resources are in wastewater. Thus, a complete wastewater treatment system should be focused on an efficient removal of various types of contaminants with a reduction of resource consumption (energy, chemicals, etc.). Besides conventional wastewater treatment schemes, there are many alternatives to enable lower energy consumption, recovery of valuable products inherent in the wastewater (i.e., nitrogen and phosphorus), and minimizing the impact of emerging pollutants (such as pharmaceuticals or endocrine disruptor substances). There are various options for combining these new technologies with those currently installed in wastewater treatment plant facilities. It is necessary to translate conventional technologies that remove contaminants from liquid or waste concentrated streams into those that recover valuable products to be reintroduced into production systems. This chapter reviews conventional schemes for urban and industrial wastewater treatment plants, emerging technological alternatives for minimization of resources consumption and recovery of valuable products, and future trends expected to contribute to the next generation of wastewater treatment plants.