Removal of the waterborne protozoan parasites Cryptosporidium and Giardia by photochemical processes, ultrasound and adsorption onto granular activated carbon

Abstract

Cryptosporidium and Giardia are two important genera of intestinal protozoan parasites that infect a wide range of vertebrate hosts, including humans. The route of transmission for these enteropathogens is the faecal-oral route, directly from person to person or animal to person, or indirectly via contaminated food and water, being the latter the most common route. They cause the self-limited illnesses cryptosporidiosis and giardiosis, which symptoms depend on the immunity status of the host, varying from asymptomatic to diarrhoea, malaise or fatigue, abdominal pain, anorexia and weight loss. The infective forms, oocysts and cysts (oo/cysts), are highly resistant to environmental conditions and to the conventional disinfection treatments of water. Thus, oo/cysts have been reported to occur in different types of water (surface water, drinking water, wastewater) being identified in waterborne outbreaks worldwide. Therefore, new technologies that enhance or optimize conventional methods are needed. This chapter reviews the current knowledge about the efficacy of different technologies that can be applied in the removal of Cryptosporidium and Giardia from water such as photochemical advanced oxidation processes (AOPs), ultrasound (a non-photochemical AOPs) and granular activated carbon adsorption