TABLE 4.

Estimated removal efficiencies for Cryptosporidium oocysts and Giardia cysts at three STW

Parameter	Result for STW:
	B	F	V
No. of influent and effluent samples collected on the same day	30a	25a	15b
No. of influent samples containing Cryptosporidium oocysts	27	18	15
No. of effluent samples containing Cryptosporidium oocysts	13	20	10
No. of sample pairs to estimate Cryptosporidium removal efficiency	13	16	10
Extrapolated mean concn of Cryptosporidium (oocysts/liter) in influent	485	3,145	770
Extrapolated mean concn of Cryptosporidium (oocysts/liter) in effluent	230	3,300	370
No. of influent samples containing Giardia cysts	30	25	15
No. of effluent samples containing Giardia cysts	16	25	11
No. of sample pairs to estimate Giardia removal efficiency	16	25	11
Extrapolated mean concn of Giardia (cysts/liter) in influent	9,520	5,620	3,420
Extrapolated mean concn of Giardia (cysts/liter) in effluent	506	5,880	480
Estimated % removal efficiency of Cryptosporidium oocysts by STW	50	0	50
Estimated % removal efficiency of Giardia cysts by STW	95	0	85

^aSamples were collected over an 18-month period.

^bSamples were collected over an 8-month period.