Distribution and removal of Giardia and Cryptosporidium in water supplies in Germany

Abstract

This study has been conducted, to estimate the distribution of Giardia and Cryptosporidium in German water supplies and the removal efficiency of surface water treatment plants for Giardia and Cryptosporidium by conventional treatment. Water samples from six surface water treatment plants in different parts of Germany were simoultaneously examined for Giardia and Cryptosporidium. Investigations for both parasites were carried out in the period from July 1993 until December 1995. The results confirmed the occurrence of Giardia and Cryptosporidium in surface and raw water, in intermediate steps after treatment, in back wash water, in the first filtrate and in final water. Giardia or Cryptosporidium or both have been found in 76.2% of the investigated raw water sources. The average number of the detected Giardia cysts was 88.2/100 1 (max. 1314/100 1), and the average number of Cryptosporidium oocysts was 116/100 1 (max. 1081/100 1). In the intermediate steps (including flocculation and several steps of filtration), Giardia or Cryptosporidium or both have been found in 33.3% (50/150) of the samples. 14.9% of drinking water samples (7/47) were positive for Giardia (max. 16.8/100 1) and 29.8% (14/47) were positive for Cryptosporidium (max. 20.8/100 1). Overall, Giardia and Cryptosporidium, or both were detected in 38.3% of the drinking water samples. The parasites have been found in nearly all of the investigated backwash water samples. The filtrate of a rapid sand filter was analysed immediately after filter backwashing during the ripening period of the filter. Good elimination results were obtained by optimizing relevant water treatment process, but a low flocculant dose following sudden variation in the raw water quality, causes a breakthrough of Cryptosporidium into the treated water. Although water treatment technologies are effective to remove Giardia and Cryptosporidium, the results clearly show that Giardia and Cryptosporidium evade the filter barries in the absence of visible treatment deficiencies and low turbitidy level, and contaminate final water.

Waterborne transmission of protozoan parasites: A worldwide review of outbreaks and lessons learnt

“…Giardia and Cryptosporidium (oo)cysts have been detected in selected German surface and drinking waters (Gornik & Exner 1991;Karanis et al 1998). Limited data are available regarding the occurrence and distribution of pathogenic protozoa in water in southern and eastern European countries.…”

Detection of Cryptosporidium parvum Oocysts in Environmental Water in Hokkaido, Japan.

“…method modified by Karanis et al [13][14][15]. The EPA method has been used in several studies in the U.S.A. and England [3,17,19] and Karanis et al have adapted this method for analysis of samples in Germany [13,15] and Greece [16].…”

“…The EPA method has been used in several studies in the U.S.A. and England [3,17,19] and Karanis et al have adapted this method for analysis of samples in Germany [13,15] and Greece [16]. The filtration method involved filtering large quantities of environmental water using Micro Wynd Cuno yarn wound cartridge filters.…”

A Survey ofCryptosporidiumOocysts in Water Supplies during a 10-Year Period (2000-2009) in Seoul

“…These oocysts have been reported to be present in worldwide water environments [6][7][8]. In South Korea, there have recently been several reports on the cases of cryptosporidiosis [9,10] in humans and animals, although there have been no documented public outbreaks associated with drinking water.…”