ARE CURRENT WASTEWATER TREATMENTS ENOUGH TO AVOID PUBLIC HEALTH PROBLEMS IN TUNISIA

The reuse of treated wastewater in irrigation and to refill the aquifer became a common strategy in Tunisia to palliate the lack of water resources. However, sewage treatment processes currently used are only partially effective to remove viruses and consequently discharge of contaminated treated wa...

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Published inCurrent politics and economics of Africa Vol. 10; no. 1; pp. 79 - 107
Main Authors Ouardani, Imen, Aouni, Mahjoub, Romalde, Jesús L
Format Journal Article
LanguageEnglish
Published Hauppauge Nova Science Publishers, Inc 01.01.2017
Subjects
Agriculture
Aquifers
Chemical oxygen demand
Epidemiology
Freshwater resources
Gastroenteritis
Genetic diversity
Health hazards
Health problems
Health surveillance
Healthy food
Hepatitis
Hepatitis A
Irrigation
Population growth
Public health
Reuse
Risk reduction
Rotavirus
Sewage disposal
Socioeconomic factors
Surveillance systems
Systematic review
Viral infections
Virology
Viruses
Wastewater
Water treatment
Tunisia
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Summary:The reuse of treated wastewater in irrigation and to refill the aquifer became a common strategy in Tunisia to palliate the lack of water resources. However, sewage treatment processes currently used are only partially effective to remove viruses and consequently discharge of contaminated treated wastewater is a potential source of viral infections. Hepatitis A virus (HAV), hepatitis E virus (HEV), norovirus (NoV), rotavirus (RV), enterovirus (EV), astrovirus (AsV), sapovirus (SaV), adenovirus (AdV) and aichi virus (AiV) are, among enteric viruses, the major waterborne pathogens, predominantly transmitted via the faecal-oral route, and important agents implicated in gastroenteritis or hepatitis outbreaks. They are released in large quantities in raw wastewater and can survive for long periods in several environments which present an important public health hazards. Due to their persistence and low infectious dose, enteric viruses can easily infect people via water or food. Although Tunisia is considered as an endemic country for enteric viruses, routine surveillance of viral wastewater quality is not performed and data on viral epidemiology are limited. In this review we provide an overview on the prevalence of the most common enteric viruses in wastewater from different regions of Tunisia including socioeconomic data and seasonal distribution when available. Indeed, efficiency of different wastewater treatment processes for viral reduction is discussed in order to evaluate the risk associated to the wastewater in the country. Data show that RV, HAV, EV and NoV are constantly present in both raw and treated wastewater with high prevalence. Differences in the incidence of these viruses in wastewater within the country are linked to variations in socioeconomic and sanitary conditions, geographic area and climate. We describe also the genetic diversity of multiple pathogenic enteric viruses in sewage. Different viral reduction rates are observed demonstrating the difficulty of the present biological treatments to provide virus-free wastewater effluents. This review contributes to the understanding of the epidemiology of enteric viruses in Tunisia and underlines the need of an environmental surveillance program and official viral controls for treated wastewater. Therefore, efforts should focus on the enhancing of sewage treatment technologies to avoid a social and public health hazard.
ISSN:1098-4070