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 |
[FR Doc. C0-8155 Filed 8-11-00; 8:45 am]
BILLING CODE 1505-01-D