

@article {8729,
	title = {{GIARDIA CYSTS AND CRYPTOSPORIDIUM OOCYSTS AT SEWAGE TREATMENT WORKS IN SCOTLAND, UK}},
	journal = {Water Research},
	volume = {34},
	number = {8},
	year = {2000},
	pages = {2310{\textendash}2322},
	abstract = {{\DH}A three year study on Cryptosporidium oocysts and Giardia cysts in sewage was conducted with emphasis upon: (1) development and assessment of techniques for sampling and processing sewage for these parasites; (2) a {\textregistered}eld study in which six sewage treatment works (STW) were assessed for removal of these parasites from the liquid phase; and (3) assessment of eect of sewage treatment on survival/destruction of Cryptosporidium oocysts. In sampling, grab samples were superior to {\textregistered}ltered samples. In concentration and clari{\textregistered}cation of samples, the most ecient technique was that in which sample manipulation was minimised. Although calculated parasite removal eciency varied for both parasites and between and within STW, some consistent patterns were observed. First, Giardia cyst removal was signi{\textregistered}cantly greater than Cryptosporidium oocyst removal. Second, most parasite removal occurred during secondary treatments, rather than during primary settlement. Third, no signi{\textregistered}cant dierence between ecacy of activated sludge treatment and trickling {\textregistered}lters at parasite removal was detected. Also, in one STW which utilised tertiary sewage treatment, most removal from the liquid phase occurred during preceding treatment stages. Finally, one STW had signi{\textregistered}cantly higher removal eciencies of both parasites than the other {\textregistered}ve STW investigated. Low numbers of viable oocysts were detected at both in{\textasciimacron}uent and euent. Survival was monitored by introducing oocysts, in containers bounded by semi-permeable membranes, into various environments within one STW. The results demonstrated that, over one week, none of the environments tested had a deleterious eect on oocyst viability, with the exception of the sludge-holding tank. Results are discussed in relation to other published work on Cryptosporidium and Giardia in sewage and recommendations for further areas of research on this subject are made. 7},
	keywords = {Cryptosporidium, Cysts, Giardia, Oocysts, Protozoan parasites, removal eciency, Sampling, Survival, {\DH}sewage},
	author = {Robertson, L J and Paton, C A and Campbell, A T and Smith, P G and Jackson, M H and Gilmour, R A and Black, S E and Stevenson, D A and Smith, H V}
}
