ABSTRACT
This chapter summarizes the main characteristics of wastewater treatment processes, especially those suitable for use in developing countries, from the perspective of their potential to produce an effluent suitable for safe agricultural irrigation; it thus concentrates on pathogen removal and nutrient conservation. Wastewater treatment processes are divided into two principal categories: ‘natural’ systems which do not rely on the consumption of large amounts of electrical energy and which are therefore more suitable for use in developing countries; and conventional electromechanical systems which are wholly energy-dependent and which, if used in low income regions, require high levels of financial investment for their construction and skilled manpower for their successful operation and maintenance. The removal of viral, bacterial, protozoan and helminthic pathogens achieved by the most commonly used natural and conventional treatment processes are detailed, and recommendations are made for process selection.
