§ 142.65 Variances and exemptions from the maximum contaminant levels for radionuclides.
(a)
(1) Variances and exemptions from the maximum contaminant levels for combined radium-226 and radium-228, uranium, gross alpha particle activity (excluding Radon and Uranium), and beta particle and photon radioactivity.
(i) The Administrator, pursuant to section 1415(a)(1)(A) of the Act, hereby identifies the following as the best available technology, treatment techniques, or other means available for achieving compliance with the maximum contaminant levels for the radionuclides listed in § 141.66(b), (c), (d), and (e) of this chapter, for the purposes of issuing variances and exemptions, as shown in Table A to this paragraph.
Table A—BAT for Radionuclides Listed in § 141.66
| Contaminant | BAT |
|---|---|
| Combined radium-226 and radium-228 | Ion exchange, reverse osmosis, lime softening. |
| Uranium | Ion exchange, reverse osmosis, lime softening, coagulation/filtration. |
| Gross alpha particle activity (excluding radon and uranium) | Reverse osmosis. |
| Beta particle and photon radioactivity | Ion exchange, reverse osmosis. |
(ii) In addition, the Administrator hereby identifies the following as the best available technology, treatment techniques, or other means available for achieving compliance with the maximum contaminant levels for the radionuclides listed in § 141.66(b), (c), (d), and (e) of this chapter, for the purposes of issuing variances and exemptions to small drinking water systems, defined here as those serving 10,000 persons or fewer, as shown in Table C to this paragraph.