Microbial exposure and health assessments in sanitation technologies and systems

The main objective of a sanitation system is to protect and promote human health. This is done by providing and maintaining a clean environment without faecal contamination and by adopting measures that break the cycle of disease transmission. To achieve the direct effects of containment and reduction of pathogenic organism the system should be technically appropriate, economically viable, socially acceptable, and institutionally manageable which are factors that all affect the health outcomes.

Human health and environmental impact are interlinked. When the products from a sanitary system should be considered as potential resources, either for food production or for energy generation, the health issues and aspects of risk reduction need to be accounted for in addition to the benefits of nutrient recovery.

In the technical improvement of existing sanitation systems or in the design and implementation of new ones, health risk considerations are crucial and should always be an integral part of the planning and decision making process. Here, human exposure through different routes and exposure reduction in the system context, against pathogens or where applicable hazardous substances, are central. The local relevant organisms or substances are prioritized in an initial “hazard identification” step (WHO, 2006). Different critical points of exposure in the full sanitation system, from the toilet, through the collection and treatment part of the system to the point of reuse or disposal should be accounted for. This also implies consideration for the downstream populations.

The aims of this publication are to:

• Highlight and examine the “Critical Exposure Points (CCPs)” in a sanitation system.
• Assess the health risks associated with the technologies that make up different sanitation systems.
• Exemplify the sanitation system gaps that may impact health outcomes.

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