REMOVAL OF OOCYSTS OF CRYPTOSPORIDIUM FROM PRIVATE WATER SUPPLIES - ASSESSMENT OF POINT-OF-USE FILTERS Final Report to the Department of the Environment, Drinking Water Inspectorate
Report No DWI0376

Feb 1995

SUMMARY

The performance of three point-of-use filters was assessed in terms of their ability to remove Cryptosporidium oocysts from water. The three filters tested were an in-line ceramic cartridge filter, a jug filter using four ceramic cartridges and a Memcor Memtec filtration unit set up in cross flow mode.

Three trials were performed in which the filters were challenged with water of different turbidities (high, medium and low) each containing 1 x lO^4 oocysts per litre over a period of 7 days. The in-line ceramic cartridge filter and the jug filter excluded oocysts during the high and medium turbidity trials but low numbers were detected in the effluents during the low (tap water) turbidity trial. The cross flow unit excluded oocysts from the filtrate throughout these trials.

Another series of trials was established to assess the ability of the filters to exclude oocysts when challenged with a large spike under water hammer (hydraulic shock) conditions, using three separate water turbidities (high, medium and low). The jug filter alone, of the three filters tested, failed to exclude oocysts during these trials, when low numbers were detected in the effluent from the low turbidity trial only.

Copies of this report may be available as an Acrobat pdf download under the 'Pre 2000 Reports' heading on the DWI website.