Regu P. Regunathan PhD ReguNathan & Associates, Inc. Technical Consultant to WQA 10 Aug 2011

Guidelines released Released in June 2011 after considerable reviews and discussions Intended Audiences are: National Certifiers Regulatory Authorities Researchers Manufacturers & Implementers Arranged in 3 short Sections and 4 detailed Appendices

Tiered Approach One of the most contentious subject by reviewers Modified from original proposal but still retained the essence of the concept. Interim Target approach has been altered significantly. Based on WHO’s regularly and extensively used target levels of DALY (Disability Adjusted Life Years) Quantitative Microbial Risk Assessment (QMRA) was employed to estimate Health based Performance Targets

DALY Measure to estimate burdens of disease and injuries Health effects weighed - 0 (good health) to 1 (death) Years of life lost due to mortality = YLL Years of life lived with disability = YLD DALY = YLL + YLD 10⁻⁶ DALY/person/year = loss of 365 healthy days/one million/year = 1 excess case of cancer/ people drinking water over 70 years

Target Pathogens Selected Bacteria - Campylobacter jejuni Virus – Rotavirus Protozoa - Cryptosporidium

Tiers presented Highly Protective ⁻⁶ DALY /person/year Protective ⁻⁴ DALY/person/year Interim Achieves “protective” targets for two classes of pathogens & results in health gains in applications.

Health Based HWT Performance Targets Target Log reduction - Bacteria Log reduction - Virus Log Reduction - Protozoa Highly Protective≥4≥5≥4 Protective≥2≥3≥2 InterimAchieves “protective” targets for two classes of pathogens & results in health gains

Derivation of Targets using QMRA Based on known sets of data and several assumptions Pathogens selected had been cited in GDWQ of WHO along with being involved in several outbreaks Pathogen levels in raw water calculated on the basis of adding wastewater to a concentration of 0.01% Daily water consumption, probability of infection by each pathogen, risk of diarrheal illness, and susceptible population were all assumed for the calculations of the DALY and thus these target levels

Technologies described in Appendices Chemical Disinfection (chlorine, bromine, iodine, chlorine dioxide, ozone, etc. Filters of all types (Membrane, ceramic, Granular, etc) Solar Disinfection UV Thermal Technologies Coagulation, precipitation and settling Combination of relevant technologies

Protocol Details Two types of test waters similar to EPA protocol Differentiation of protocols based on technology Alternate indicator microbes suggested (E. coli, MS2, C. perfringens spores, inert particles, etc.) But not very detailed directions for carrying out the actual tests with the selected pathogens or suggested alternates Mostly guidelines for development of national regulations and protocols along with certification approaches

Potentially Simpler Approach Present approach for interim targets appears well thought out and appropriate compared to earlier 1/1/1 log reductions proposed. Had to make several assumptions to reach these two tiers and targets. Any different assumptions would have lead to very different results Could have decided on ONE suggested goal to be reached by different countries. 10⁻⁵ DALY/person/year could have been selected as the only one approach This approach would have lead to targets of 3/4/3 for bacteria/virus/ protozoa. If one gets 4 logs of virus reduction along with 3 logs of protozoan reduction that technology would have easily also achieved 6 logs or more of bacteria reduction. Same as EPA protocol of 6/4/3!!!