C0-8155. National Primary Drinking Water Regulations: Long Term 1 Enhanced Surface Water Treatment and Filter Backwash Rule

Correction

In proposed rule document 00-8155 beginning on page 19046 in the issue of Monday, April 10, 2000, make the following correction:

On pages 19057 and 19058, Table II.7 is corrected to read as follows:

Table II.7.—Cryptosporidium Occurrence in Filter Backwash and Other Recycle Streams

Name/location of study	Number of samples (n)	Type of sample	Cyst/oocyst concentration	Number of treatment plants sampled	Reference
Drinking water treatment facilities	2	backflush waters from rapid sand filters	sample 1: 26,000 oocysts/gal (calc. as 686,900 oocysts/100L)	2	Rose et al. 1986.
			sample 2: 92,000 oocysts/gal (calc as 2,430,600 oocysts/100L)
Thames, U.K.,	not reported	backwash water from rapid sand filter	Over 1,000,000 oocysts/100L in backwash water on 2/19/89	1	Colbourne 1989.
			100,000 oocysts/100L in supernatant from settlement tanks during the next few days
Potable water supplies in 17 States	not reported	filter backwash from rapid sand filters (10 to 40 L sample vol.)	217 oocysts/ 100 L (geometric mean)	not reported	Rose et al. 1991.
Name/location not reported	not reported	raw water initial backwash water	7 to 108 oocysts/100L detected at levels 57 to 61 times higher than in the raw water	not reported not reported	LeChevallier et al. 1991c.
Bangor Water Treatment Plant (PA)	Round 1: 1 (8-hour composite)	raw water filter backwash supernatant recycle	6 oocysts/100L 902 oocysts/100L. 141 oocysts/100L.	1	Cornwell and Lee 1993.
	Round 2: 1 (8-hour composite)	raw water filter backwash supernatant recycle	140 oocysts/100L 850 oocysts/100L. 750 oocysts/100L.	1	Cornwell and Lee 1993.
Moshannon Valley Water Treatment Plant	Round 1: 1 (8-hour composite)	raw water spent backwash supernatant recycle sludge	13 oocysts/100L 16,613 oocysts/100L. 82 oocysts/100L. 2,642 oocysts/100L.	1	Cornwell and Lee 1993.
	Round 2: 1 (8-hour composite)	raw water supernatant recycle	20 oocysts/100L 420 oocysts/100L.	1	Cornwell and Lee 1993.
Plant “C”	11 samples using continuous flow centrifugation; 39 samples using cartridge filters	backwash water from rapid sand filters; samples collected from sedimentation basins during sedimentation phase of backwash water at depths of 1, 2, 3, and 3.3 m	continuous flow: range 1 to 69 oocysts/100 L; 8 of 11 samples positive cartridge filters: ranges 0.8 to 252/100 L; 33 of 39 samples positive	1	Karanis et al. 1996.
Pittsburgh Drinking Water Treatment Plant	24 (two years of monthly samples)	filter backwash	328 oocysts/ 100 L (geometric mean); (38 percent occurrence rate) non-detect-13,158 oocysts/100L.	1	States et al. 1997.
“Plant Number 3”	not reported	raw water spent backwash	140 oocysts/100L 850 oocysts/100L.	not reported	Cornwell 1997.
“Plant C” (see Karanis, et al., 1996)	12 50	raw water backwash water from rapid sand filters	avg. 23.2 oocysts/100L (max. 109 oocysts/100L) in 8 of 12 samples avg. 22.1 oocysts/100L (max. 257 oocysts/100L) in 41 of 50 samples	1	Karanis et al 1998 (Table 8, p. 14).
“Plant A”	1	rapid sand filter (sample taken 10 min. after start of backwashing)	150 oocysts/100L