Review of the Reports of the Groups of Experts on Cryptosporidium in water Supplies and Publication of Additional Guidance.

Research Aims and Objectives To review the guidance and advice provided in the three reports of the Groups of Experts on Cryptosporidium in Water Supplies and identify whether any of the published guidance should be updated in the light of waterborne outbreaks of human cryptosporidiosis and other cryptosporidium-related water supply incidents that have occurred since the third report was published in 1998.

In particular the review should consider guidance and recommendations covering: i.

The occurrence of cryptosporidium in the environment and drinking water safety planning. ii.

Species of cryptosporidium that are pathogenic to humans, their occurrence in the environment and concentrations in drinking water likely to cause illness. iii.

The impact of raw water storage on the attenuation of cryptosporidium, risks associated with sources of cryptosporidium in catchments (for example human sewage discharges and animal husbandry) and short circuiting in reservoirs. iv.

Water treatment processes that remove or inactivate cryptosporidium, optimisation of these processes and operational good practice.

In particular recent developments in water treatment, for example membrane technology, UV treatment and enhanced coagulation/clarification processes (e.g.

CoCoDAF/ moving bed/ Actiflow filters/ cartridge filters). v.

Provision of continuous online monitoring of raw waters, final treated water and after intermediate stages of water treatment processes for turbidity and other relevant parameters, and triggers for response. vi.

Protection of treated water storage tanks from contamination, taking into account risks present in the environment and risks associated with severe weather events. vii.

Protection of water supply assets, in particular open structures containing partially treated water such as slow sand filters, from avian and mammalian access. viii.

Sampling methods for cryptosporidium and oocyst recovery for different sampling methods for raw and treated water