WHO Recommendations for HWTS Technology Performance Evaluation: The Nuts and Bolts

Transcription

1 WHO Recommendations for HWTS Technology Performance Evaluation: The Nuts and Bolts Prof. Mark D. Sobsey, PhD Department of Environmental Sciences and Engineering Gillings School of Global Public Health University of North Carolina Chapel Hill, NC USA 1

2 Overview Introduction to WHO Guidelines for Drinking-water Quality Water safety plans Household water treatment and safe storage (HWTS) International Network Criteria to evaluate technologies/methods National policies and regulations Challenges in HWTS and future needs

3 WHO Guidelines for Drinking-water Quality: Background History '84/'85 1 st edition published; th edition published Aim -Protection of human health -Support setting of national standards and regulations Approach Health risk/benefit, advisory in nature, multiple barriers, incremental improvements Target audience Policy makers, regulators, water suppliers, implementers Risk Framework, health based -Risk assessment, i.e. quantitative microbial risk assessment (QMRA)

4 A Framework for Safe Drinking Water: WHO Guidelines for Drinking Water Quality Health-based targets (National regulatory body) Water Safety Plans (Water utility; water provider) Independent surveillance (Surveillance agency)

5 Household Water Treatment and Safe Storage (HWTS) One (interim) way to achieve safe water: treat it at point-of-use (POU) Fills a gap in the water supply sector for safe water at POU (Now) Empowers communities and households to achieve safe water themselves, at home Included in the WHO GDWQ Embraced by WHO and other stakeholders Promoted globally International WHO Network BUT..Which ones really work?

6 International Network on HWTS Initiated by WHO in 2003; as of 2011 co-hosted with UNICEF Over 100 participating organizations (international organizations, NGOs, governments, private entities, academia,... Phase II Strategy ( ) aims to: Support national policy and framework development Strengthen evidence base Evaluate and disseminate best practices in implementation Realize tangible results in scaling-up

7 Overview of WHO Recommendations on HWT Performance Goal: Protect the health of HWTS users, increase access to safe water Audience: certification organizations, governments, regulators, evaluators, manufacturers and implementers Target pathogens: viruses, bacteria and protozoa Derivation of targets: Based on Guidelines for Drinkingwater Quality risk-based approach QMRA models, DALYs, log 10 microbe reductions Tiered approach: Highly protective > protective > interim Lab protocols: Performance verification methods Provides a rational basis to find out and know what works, in principle and in context

8 Performance Criteria Rating Highly protective (10-6 DALYs/ P/yr) Protective (10-4 DALYs/ P/yr) Interim Log 10 reduction: bacteria Log 10 reduction: viruses Log 10 reduction protozoa Examples: Boiling, ultrafilters, combined technologies Examples: Membrane (micro) filters, flocculant-disinfectant Achieves protective target for two classes of pathogens and results in health gains Examples: Chlorine, ceramic filters, biosand filters

9 Labelling, Certification and Regulation (WHO does not endorse or certify technologies) Procter and Gamble, Coag-Floc P&G packets have been proven to eliminate disease causing microorganisms. P&G packets result in removal of more than % of intestinal bacteria (including those that cause cholera), 99.99% of intestinal viruses (including those that cause hepatitis A) and 99.9% of protozoa. P&G packets remove dirt and other pollutants. P&G packets are considered an effective technology by the World Health Organization. Hindustan Unilever, Microfilter Effective against bacteria and protozoa. Cascade Design, Microfilter % removal of bacteria and 99.99% removal of viruses, 99.9% protozoa Meets EPA standards for virus and bacteria removal. Recommendations: Locally developed and understood, supply sufficient information to make "informed choice"

10 Challenges in HWTS and Future Needs Improving correct and consistent use Ensuring vulnerable groups have access to clean drinking-water (HWTS is one solution) Communicating health benefits within greater global health community (HIV/AIDs & TB, malaria, nutrition, and respiratory diseases) Ensuring national policies and strategies support selection of optimal devices and make them available in high risk areas Utilizing effective delivery and financing mechanisms (cost-recovery, partial subsidy, full-subsidy, good commercial marketing, etc.) WHO/ R Granich

11 Further Information WHO HWT Performance Recommendations water/en/index.html WHO Drinking-water Guidelines Network (UNC communications portal) Acknowledgements: Maggie Montgomery and Jennifer de France, World Health Organization, Geneva

12 Thank You Questions? Stanford University/Amy Pickering