Removal of Cryptosporidium by high rate contact filtration: the performance of the Prospect Water Filtration Plant during the Sydney water crisis

摘要

In Sydney, Australia, during July, August and September 1998, three comprehensive boil water notices were issued in response to the detection of elevated concentrations of Giardia and Cryptosporidium in the water system. While the incidence of illness did not increase above background levels, the political impact of these events was sufficient to initiate a full-scale judicial inquiry. The treatment plants came under intense scrutiny, particularly the Prospect Water Filtration Plant, which provides for approximately 85% of Sydney's drinking water demand. As part of the investigation, detailed audits of the Prospect Plant were carried out and Cryptosporidium parvum seeding experiments were undertaken in a prototype plant in order to assess the removal capability of the Prospect filtration process. The overview of the Plant performance and the results of the Cryptosporidium seeding runs presented in this paper confirm that the Prospect Water Filtration Plant was achieving at least 3 logs pathogen removal prior to and during the contamination events. [References: 4]