1. Managing Cryptosporidium Risk

2. 2 Risk Assessment All stages of the process need to be examined Catchment Source Treatment Distribution Consumer’s premises

3. 3 Starting Point? Methodology recommended by NDSC and EPA contained in the EPA Handbook 2004 Catchment, source and treatment processes examined in detail A risk score is produced adjusted for the population served

4. 4 Catchment risk score Animals within the catchment Agricultural practices within the catchment Discharges to the catchment/water source Water source type Catchment inspections Raw water intake management for direct abstractions

5. 5 Treatment and Supply Risk Score Water treatment processes Treatment works monitoring of coagulation and filtration Treatment works operational practices

6. 6 Final Weighted Risk Assessment Score (Catchment Risk Score + Treatment & Supply Risk Score) x Population weighting factor 0.4 x log 10 (population served by the supply)

7. 7 Water Supply Risk Classification (from EPA Handbook) ClassificationFinal Risk Assessment Score Very High Risk>100 High Risk76-100 Moderate Risk50-75 Low risk<50

8. 8 Monitoring - Can Risk be reduced? - Continuous monitoring min 40 l/hr - Less than 1 oocyst/10 litres Very High / High Risk

9. 9 Reducing Risk Catchment Apply Nitrates Regs. Identify potential pollution locations Fence off water sources Catchment inspections Automatic shutdown for poor source quality Implement action plan to prevent pollution Monitor effectiveness of action plans

10. 10 Reducing Risk Treatment Plant & Supply Provide appropriate treatment barrier Maintain plant within design throughput Avoid by-passing filters Optimise pH for coagulation/sedimentation Avoid disturbing sludge blanket Maintain filter media above minimum level After backwash, run to waste until turbidity is satisfactory

11. 11 Reducing Risk Do not return filter backwash water without membrane filtration Monitor turbidity in filtered water and maintain at lowest possible level Identify capital works requirements

12. 12 Reducing Risk Distribution Network Inspect and clean out service reservoirs regularly Prohibit grazing of reservoir sites by livestock Significant leaks should be repaired promptly Reduce overall leakage level

13. 13 Outbreaks 5 in Ireland (Mullingar, Ennis, Roscommon, Carlow & Galway) 61 in England & Wales 1993 to 2005 involving 7118 cases 12 No. > 200 cases (greater than Galway) Milwaukee (1993, 100 deaths), Sydney (1998, 3m people),

14. 14 In Conclusion….. Risk assessment helps to focus resources and identify where testing is needed Provide barrier to crypto breakthrough and monitor effectiveness Documented quality management system Best to be prepared