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Title 40Chapter ISubchapter DPart 141 → Subpart G


Title 40: Protection of Environment
PART 141—NATIONAL PRIMARY DRINKING WATER REGULATIONS


Subpart G—National Primary Drinking Water Regulations: Maximum Contaminant Levels and Maximum Residual Disinfectant Levels


Contents
§141.60   Effective dates.
§141.61   Maximum contaminant levels for organic contaminants.
§141.62   Maximum contaminant levels for inorganic contaminants.
§141.63   Maximum contaminant levels (MCLs) for microbiological contaminants.
§141.64   Maximum contaminant levels for disinfection byproducts.
§141.65   Maximum residual disinfectant levels.
§141.66   Maximum contaminant levels for radionuclides.

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§141.60   Effective dates.

(a) The effective dates for §141.61 are as follows:

(1) The effective date for paragraphs (a)(1) through (a)(8) of §141.61 is January 9, 1989.

(2) The effective date for paragraphs (a)(9) through (a)(18) and (c)(1) through (c)(18) of §141.61 is July 30, 1992.

(3) The effective date for paragraphs (a)(19) through (a)(21), (c)(19) through (c)(25), and (c)(27) through (c)(33) of §141.61 is January 17, 1994. The effective date of §141.61(c)(26) is August 17, 1992.

(b) The effective dates for §141.62 are as follows:

(1) The effective date of paragraph (b)(1) of §141.62 is October 2, 1987.

(2) The effective date for paragraphs (b)(2) and (b)(4) through (b)(10) of §141.62 is July 30, 1992.

(3) The effective date for paragraphs (b)(11) through (b)(15) of §141.62 is January 17, 1994.

(4) The effective date for §141.62(b)(16) is January 23, 2006.

[56 FR 3593, Jan. 30, 1991, as amended at 57 FR 31846, July 17, 1992; 59 FR 34324, July 1, 1994; 66 FR 7063, Jan. 22, 2001]

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§141.61   Maximum contaminant levels for organic contaminants.

(a) The following maximum contaminant levels for organic contaminants apply to community and non-transient, non-community water systems.

CAS No.ContaminantMCL (mg/l)
  (1)  75-01-4Vinyl chloride0.002
  (2)  71-43-2Benzene0.005
  (3)  56-23-5Carbon tetrachloride0.005
  (4)  107-06-21,2-Dichloroethane0.005
  (5)  79-01-6Trichloroethylene0.005
  (6)  106-46-7para-Dichlorobenzene0.075
  (7)  75-35-41,1-Dichloroethylene0.007
  (8)  71-55-61,1,1-Trichloroethane0.2
  (9)  156-59-2cis-1,2-Dichloroethylene0.07
  (10)  78-87-51,2-Dichloropropane0.005
  (11)  100-41-4Ethylbenzene0.7
  (12)  108-90-7Monochlorobenzene0.1
  (13)  95-50-1o-Dichlorobenzene0.6
  (14)  100-42-5Styrene0.1
  (15)  127-18-4Tetrachloroethylene0.005
  (16)  108-88-3Toluene1
  (17)  156-60-5trans-1,2-Dichloroethylene0.1
  (18)  1330-20-7Xylenes (total)10
  (19)  75-09-2Dichloromethane0.005
  (20)  120-82-11,2,4-Trichloro- benzene.07
  (21)  79-00-51,1,2-Trichloro- ethane.005

(b) The Administrator, pursuant to section 1412 of the Act, hereby identifies as indicated in the Table below granular activated carbon (GAC), packed tower aeration (PTA), or oxidation (OX) as the best technology treatment technique, or other means available for achieving compliance with the maximum contaminant level for organic contaminants identified in paragraphs (a) and (c) of this section:

BAT for Organic Contaminants Listed in §141.61 (a) and (c)

CAS No.ContaminantGACPTAOX
15972-60-8AlachlorX
116-06-3AldicarbX
1646-88-4Aldicarb sulfoneX
1646-87-3Aldicarb sulfoxideX
1912-24-9AtrazineX
71-43-2BenzeneXX
50-32-8Benzo[a]pyreneX
1563-66-2CarbofuranX
56-23-5Carbon tetrachlorideXX
57-74-9ChlordaneX
75-99-0DalaponX
94-75-72,4-DX
103-23-1Di (2-ethylhexyl) adipateXX
117-81-7Di (2-ethylhexyl) phthalateX
96-12-8Dibromochloropropane (DBCP)XX
95-50-1o-DichlorobenzeneXX
106-46-7para-DichlorobenzeneXX
107-06-21,2-DichloroethaneXX
75-35-41,1-DichloroethyleneXX
156-59-2cis-1,2-DichloroethyleneXX
156-60-5trans-1,2-DichloroethyleneXX
75-09-2DichloromethaneX
78-87-51,2-DichloropropaneXX
88-85-7DinosebX
85-00-7DiquatX
145-73-3EndothallX
72-20-8EndrinX
100-41-4EthylbenzeneXX
106-93-4Ethylene Dibromide (EDB)XX
1071-83-6GylphosateX
76-44-8HeptachlorX
1024-57-3Heptachlor epoxideX
118-74-1HexachlorobenzeneX
77-47-3HexachlorocyclopentadieneXX
58-89-9LindaneX
72-43-5MethoxychlorX
108-90-7MonochlorobenzeneXX
23135-22-0Oxamyl (Vydate)X
87-86-5PentachlorophenolX
1918-02-1PicloramX
1336-36-3Polychlorinated biphenyls (PCB)X
122-34-9SimazineX
100-42-5StyreneXX
1746-01-62,3,7,8-TCDD (Dioxin)X
127-18-4TetrachloroethyleneXX
108-88-3TolueneXX
8001-35-2ToxapheneX
93-72-12,4,5-TP (Silvex)X
120-82-11,2,4-TrichlorobenzeneXX
71-55-61,1,1-TrichloroethaneXX
79-00-51,1,2-TrichloroethaneXX
79-01-6TrichloroethyleneXX
75-01-4Vinyl chlorideX
1330-20-7XyleneXX

(c) The following maximum contaminant levels for synthetic organic contaminants apply to community water systems and non-transient, non-community water systems:

CAS No.ContaminantMCL (mg/l)
  (1)  15972-60-8Alachlor0.002
  (2) 116-06-3Aldicarb0.003
  (3) 1646-87-3Aldicarb sulfoxide0.004
  (4) 1646-87-4Aldicarb sulfone0.002
  (5)  1912-24-9Atrazine0.003
  (6)  1563-66-2Carbofuran0.04
  (7)  57-74-9Chlordane0.002
  (8)  96-12-8Dibromochloropropane0.0002
  (9)  94-75-72,4-D0.07
(10)  106-93-4Ethylene dibromide0.00005
(11)  76-44-8Heptachlor0.0004
(12)  1024-57-3Heptachlor epoxide0.0002
(13)  58-89-9Lindane0.0002
(14)  72-43-5Methoxychlor0.04
(15)  1336-36-3Polychlorinated biphenyls0.0005
(16)  87-86-5Pentachlorophenol0.001
(17)  8001-35-2Toxaphene0.003
(18)  93-72-12,4,5-TP0.05
(19)  50-32-8Benzo[a]pyrene0.0002
(20)  75-99-0Dalapon0.2
(21)  103-23-1Di(2-ethylhexyl) adipate0.4
(22)  117-81-7Di(2-ethylhexyl) phthalate0.006
(23)  88-85-7Dinoseb0.007
(24)  85-00-7Diquat0.02
(25)  145-73-3Endothall0.1
(26)  72-20-8Endrin0.002
(27)  1071-53-6Glyphosate0.7
(28)  118-74-1Hexacholorbenzene0.001
(29)  77-47-4Hexachlorocyclopentadiene0.05
(30)  23135-22-0Oxamyl (Vydate)0.2
(31)  1918-02-1Picloram0.5
(32)  122-34-9Simazine0.004
(33)  1746-01-62,3,7,8-TCDD (Dioxin)3 × 10−8

[56 FR 3593, Jan. 30, 1991, as amended at 56 FR 30280, July 1, 1991; 57 FR 31846, July 17, 1992; 59 FR 34324, July 1, 1994]

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§141.62   Maximum contaminant levels for inorganic contaminants.

(a) [Reserved]

(b) The maximum contaminant levels for inorganic contaminants specified in paragraphs (b) (2)-(6), (b)(10), and (b) (11)-(16) of this section apply to community water systems and non-transient, non-community water systems. The maximum contaminant level specified in paragraph (b)(1) of this section only applies to community water systems. The maximum contaminant levels specified in (b)(7), (b)(8), and (b)(9) of this section apply to community water systems; non-transient, non-community water systems; and transient non-community water systems.

ContaminantMCL (mg/l)
(1) Fluoride4.0
(2) Asbestos7 Million Fibers/liter (longer than 10 µm).
(3) Barium2
(4) Cadmium0.005
(5) Chromium0.1
(6) Mercury0.002
(7) Nitrate10 (as Nitrogen)
(8) Nitrite1 (as Nitrogen)
(9) Total Nitrate and Nitrite10 (as Nitrogen)
(10) Selenium0.05
(11) Antimony0.006
(12) Beryllium0.004
(13) Cyanide (as free Cyanide)0.2
(14) [Reserved]
(15) Thallium0.002
(16) Arsenic0.010

(c) The Administrator, pursuant to section 1412 of the Act, hereby identifies the following as the best technology, treatment technique, or other means available for achieving compliance with the maximum contaminant levels for inorganic contaminants identified in paragraph (b) of this section, except fluoride:

BAT for Inorganic Compounds Listed in Section 141.62(b)

Chemical NameBAT(s)
Antimony2,7
Arsenic41, 2, 5, 6, 7, 9, 125
Asbestos2,3,8
Barium5,6,7,9
Beryllium1,2,5,6,7
Cadmium2,5,6,7
Chromium2,5,62,7
Cyanide5,7,13
Mercury21,4,61,71
Nickel5,6,7
Nitrate5,7,9
Nitrite5,7
Selenium1,23,6,7,9
Thallium1,5

1BAT only if influent Hg concentrations ≤10µg/1.

2BAT for Chromium III only.

3BAT for Selenium IV only.

4BATs for Arsenic V. Pre-oxidation may be required to convert Arsenic III to Arsenic V.

5To obtain high removals, iron to arsenic ratio must be at least 20:1.

Key to BATS in Table

1 = Activated Alumina

2 = Coagulation/Filtration (not BAT for systems <500 service connections)

3 = Direct and Diatomite Filtration

4 = Granular Activated Carbon

5 = Ion Exchange

6 = Lime Softening (not BAT for systems <500 service connections)

7 = Reverse Osmosis

8 = Corrosion Control

9 = Electrodialysis

10 = Chlorine

11 = Ultraviolet

12 = Oxidation/Filtration

13 = Alkaline Chlorination (pH ≥8.5)

(d) The Administrator, pursuant to section 1412 of the Act, hereby identifies in the following table the affordable technology, treatment technique, or other means available to systems serving 10,000 persons or fewer for achieving compliance with the maximum contaminant level for arsenic:

Small System Compliance Technologies (SSCTs)1 for Arsenic2

Small system compliance technology Affordable for listed small system categories3
Activated Alumina (centralized)All size categories.
Activated Alumina (Point-of-Use)4All size categories.
Coagulation/Filtration5501-3,300, 3,301-10,000.
Coagulation-assisted Microfiltration501-3,300, 3,301-10,000.
Electrodialysis reversal6501-3,300, 3,301-10,000.
Enhanced coagulation/filtrationAll size categories
Enhanced lime softening (pH>10.5)All size categories.
Ion ExchangeAll size categories.
Lime Softening5501-3,300, 3,301-10,000.
Oxidation/Filtration7All size categories.
Reverse Osmosis (centralized)6501-3,300, 3,301-10,000.
Reverse Osmosis (Point-of-Use)4All size categories.

1Section 1412(b)(4)(E)(ii) of SDWA specifies that SSCTs must be affordable and technically feasible for small systems.

2SSCTs for Arsenic V. Pre-oxidation may be required to convert Arsenic III to Arsenic V.

3The Act (ibid.) specifies three categories of small systems: (i) those serving 25 or more, but fewer than 501, (ii) those serving more than 500, but fewer than 3,301, and (iii) those serving more than 3,300, but fewer than 10,001.

4When POU or POE devices are used for compliance, programs to ensure proper long-term operation, maintenance, and monitoring must be provided by the water system to ensure adequate performance.

5Unlikely to be installed solely for arsenic removal. May require pH adjustment to optimal range if high removals are needed.

6Technologies reject a large volume of water—may not be appropriate for areas where water quantity may be an issue.

7To obtain high removals, iron to arsenic ratio must be at least 20:1.

[56 FR 3594, Jan. 30, 1991, as amended at 56 FR 30280, July 1, 1991; 57 FR 31847, July 17, 1992; 59 FR 34325, July 1, 1994; 60 FR 33932, June 29, 1995; 66 FR 7063, Jan. 22, 2001; 68 FR 14506, Mar. 25, 2003; 69 FR 38855, June 29, 2004]

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§141.63   Maximum contaminant levels (MCLs) for microbiological contaminants.

(a) Until March 31, 2016, the total coliform MCL is based on the presence or absence of total coliforms in a sample, rather than coliform density.

(1) For a system that collects at least 40 samples per month, if no more than 5.0 percent of the samples collected during a month are total coliform-positive, the system is in compliance with the MCL for total coliforms.

(2) For a system that collects fewer than 40 samples per month, if no more than one sample collected during a month is total coliform-positive, the system is in compliance with the MCL for total coliforms.

(b) Until March 31, 2016, any fecal coliform-positive repeat sample or E. coli-positive repeat sample, or any total coliform-positive repeat sample following a fecal coliform-positive or E. coli-positive routine sample, constitutes a violation of the MCL for total coliforms. For purposes of the public notification requirements in subpart Q of this part, this is a violation that may pose an acute risk to health.

(c) Beginning April 1, 2016, a system is in compliance with the MCL for E. coli for samples taken under the provisions of subpart Y of this part unless any of the conditions identified in paragraphs (c)(1) through (c)(4) of this section occur. For purposes of the public notification requirements in subpart Q of this part, violation of the MCL may pose an acute risk to health.

(1) The system has an E. coli-positive repeat sample following a total coliform-positive routine sample.

(2) The system has a total coliform-positive repeat sample following an E. coli-positive routine sample.

(3) The system fails to take all required repeat samples following an E. coli-positive routine sample.

(4) The system fails to test for E. coli when any repeat sample tests positive for total coliform.

(d) Until March 31, 2016, a public water system must determine compliance with the MCL for total coliforms in paragraphs (a) and (b) of this section for each month in which it is required to monitor for total coliforms. Beginning April 1, 2016, a public water system must determine compliance with the MCL for E. coli in paragraph (c) of this section for each month in which it is required to monitor for total coliforms.

(e) The Administrator, pursuant to section 1412 of the Act, hereby identifies the following as the best technology, treatment techniques, or other means available for achieving compliance with the maximum contaminant level for total coliforms in paragraphs (a) and (b) of this section and for achieving compliance with the maximum contaminant level for E. coli in paragraph (c) of this section:

(1) Protection of wells from fecal contamination by appropriate placement and construction;

(2) Maintenance of a disinfectant residual throughout the distribution system;

(3) Proper maintenance of the distribution system including appropriate pipe replacement and repair procedures, main flushing programs, proper operation and maintenance of storage tanks and reservoirs, cross connection control, and continual maintenance of positive water pressure in all parts of the distribution system;

(4) Filtration and/or disinfection of surface water, as described in subparts H, P, T, and W of this part, or disinfection of ground water, as described in subpart S of this part, using strong oxidants such as chlorine, chlorine dioxide, or ozone; and

(5) For systems using ground water, compliance with the requirements of an EPA-approved State Wellhead Protection Program developed and implemented under section 1428 of the SDWA.

(f) The Administrator, pursuant to section 1412 of the Act, hereby identifies the technology, treatment techniques, or other means available identified in paragraph (e) of this section as affordable technology, treatment techniques, or other means available to systems serving 10,000 or fewer people for achieving compliance with the maximum contaminant level for total coliforms in paragraphs (a) and (b) of this section and for achieving compliance with the maximum contaminant level for E. coli in paragraph (c) of this section.

[78 FR 10347, Feb. 13, 2013]

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§141.64   Maximum contaminant levels for disinfection byproducts.

(a) Bromate and chlorite. The maximum contaminant levels (MCLs) for bromate and chlorite are as follows:

Disinfection byproductMCL (mg/L)
Bromate0.010
Chlorite1.0

(1) Compliance dates for CWSs and NTNCWSs. Subpart H systems serving 10,000 or more persons must comply with this paragraph (a) beginning January 1, 2002. Subpart H systems serving fewer than 10,000 persons and systems using only ground water not under the direct influence of surface water must comply with this paragraph (a) beginning January 1, 2004.

(2) The Administrator, pursuant to section 1412 of the Act, hereby identifies the following as the best technology, treatment techniques, or other means available for achieving compliance with the maximum contaminant levels for bromate and chlorite identified in this paragraph (a):

Disinfection byproductBest available technology
BromateControl of ozone treatment process to reduce production of bromate
ChloriteControl of treatment processes to reduce disinfectant demand and control of disinfection treatment processes to reduce disinfectant levels

(b) TTHM and HAA5. (1) Subpart L—RAA compliance. (i) Compliance dates. Subpart H systems serving 10,000 or more persons must comply with this paragraph (b)(1) beginning January 1, 2002. Subpart H systems serving fewer than 10,000 persons and systems using only ground water not under the direct influence of surface water must comply with this paragraph (b)(1) beginning January 1, 2004. All systems must comply with these MCLs until the date specified for subpart V compliance in §141.620(c).

Disinfection byproductMCL (mg/L)
Total trihalomethanes (TTHM)0.080
Haloacetic acids (five) (HAA5)0.060

(ii) The Administrator, pursuant to section 1412 of the Act, hereby identifies the following as the best technology, treatment techniques, or other means available for achieving compliance with the maximum contaminant levels for TTHM and HAA5 identified in this paragraph (b)(1):

Disinfection byproductBest available technology
Total trihalomethanes (TTHM) and Haloacetic acids (five) (HAA5)Enhanced coagulation or enhanced softening or GAC10, with chlorine as the primary and residual disinfectant

(2) Subpart V—LRAA compliance. (i) Compliance dates. The subpart V MCLs for TTHM and HAA5 must be complied with as a locational running annual average at each monitoring location beginning the date specified for subpart V compliance in §141.620(c).

Disinfection byproduct MCL (mg/L)
Total trihalomethanes (TTHM)0.080
Haloacetic acids (five) (HAA5)0.060

(ii) The Administrator, pursuant to section 1412 of the Act, hereby identifies the following as the best technology, treatment techniques, or other means available for achieving compliance with the maximum contaminant levels for TTHM and HAA5 identified in this paragraph (b)(2) for all systems that disinfect their source water:

Disinfection byproduct Best available technology
Total trihalomethanes (TTHM) and Haloacetic acids (five) (HAA5)Enhanced coagulation or enhanced softening, plus GAC10; or nanofiltration with a molecular weight cutoff ≤1000 Daltons; or GAC20

(iii) The Administrator, pursuant to section 1412 of the Act, hereby identifies the following as the best technology, treatment techniques, or other means available for achieving compliance with the maximum contaminant levels for TTHM and HAA5 identified in this paragraph (b)(2) for consecutive systems and applies only to the disinfected water that consecutive systems buy or otherwise receive:

Disinfection byproduct Best available technology
Total trihalomethanes (TTHM) and Haloacetic acids (five) (HAA5)Systems serving ≥10,000: Improved distribution system and storage tank management to reduce residence time, plus the use of chloramines for disinfectant residual maintenance
   Systems serving <10,000: Improved distribution system and storage tank management to reduce residence time

[71 FR 478, Jan. 4, 2006]

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§141.65   Maximum residual disinfectant levels.

(a) Maximum residual disinfectant levels (MRDLs) are as follows:

Disinfectant residualMRDL (mg/L)
Chlorine4.0 (as Cl2).
Chloramines4.0 (as Cl2).
Chlorine dioxide0.8 (as ClO2).

(b) Compliance dates—(1) CWSs and NTNCWSs. Subpart H systems serving 10,000 or more persons must comply with this section beginning January 1, 2002. Subpart H systems serving fewer than 10,000 persons and systems using only ground water not under the direct influence of surface water must comply with this subpart beginning January 1, 2004.

(2) Transient NCWSs. Subpart H systems serving 10,000 or more persons and using chlorine dioxide as a disinfectant or oxidant must comply with the chlorine dioxide MRDL beginning January 1, 2002. Subpart H systems serving fewer than 10,000 persons and using chlorine dioxide as a disinfectant or oxidant and systems using only ground water not under the direct influence of surface water and using chlorine dioxide as a disinfectant or oxidant must comply with the chlorine dioxide MRDL beginning January 1, 2004.

(c) The Administrator, pursuant to Section 1412 of the Act, hereby identifies the following as the best technology, treatment techniques, or other means available for achieving compliance with the maximum residual disinfectant levels identified in paragraph (a) of this section: control of treatment processes to reduce disinfectant demand and control of disinfection treatment processes to reduce disinfectant levels.

[63 FR 69465, Dec. 16, 1998, as amended at 66 FR 3776, Jan. 16, 2001]

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§141.66   Maximum contaminant levels for radionuclides.

(a) [Reserved]

(b) MCL for combined radium-226 and -228. The maximum contaminant level for combined radium-226 and radium-228 is 5 pCi/L. The combined radium-226 and radium-228 value is determined by the addition of the results of the analysis for radium-226 and the analysis for radium-228.

(c) MCL for gross alpha particle activity (excluding radon and uranium). The maximum contaminant level for gross alpha particle activity (including radium-226 but excluding radon and uranium) is 15 pCi/L.

(d) MCL for beta particle and photon radioactivity. (1) The average annual concentration of beta particle and photon radioactivity from man-made radionuclides in drinking water must not produce an annual dose equivalent to the total body or any internal organ greater than 4 millirem/year (mrem/year).

(2) Except for the radionuclides listed in table A, the concentration of man-made radionuclides causing 4 mrem total body or organ dose equivalents must be calculated on the basis of 2 liter per day drinking water intake using the 168 hour data list in “Maximum Permissible Body Burdens and Maximum Permissible Concentrations of Radionuclides in Air and in Water for Occupational Exposure,” NBS (National Bureau of Standards) Handbook 69 as amended August 1963, U.S. Department of Commerce. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies of this document are available from the National Technical Information Service, NTIS ADA 280 282, U.S. Department of Commerce, 5285 Port Royal Road, Springfield, Virginia 22161. The toll-free number is 800-553-6847. Copies may be inspected at EPA's Drinking Water Docket, 401 M Street, SW., Washington, DC 20460; or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal__register/code__of__federal__regulations/ibr__locations.html. If two or more radionuclides are present, the sum of their annual dose equivalent to the total body or to any organ shall not exceed 4 mrem/year.

Table A—Average Annual Concentrations Assumed To Produce: a Total Body or Organ Dose of 4 mrem/yr

1. RadionuclideCritical organpCi per liter
2. TritiumTotal body20,000
3. Strontium-90Bone Marrow8

(e) MCL for uranium. The maximum contaminant level for uranium is 30 µg/L.

(f) Compliance dates. (1) Compliance dates for combined radium-226 and -228, gross alpha particle activity, gross beta particle and photon radioactivity, and uranium: Community water systems must comply with the MCLs listed in paragraphs (b), (c), (d), and (e) of this section beginning December 8, 2003 and compliance shall be determined in accordance with the requirements of §§141.25 and 141.26. Compliance with reporting requirements for the radionuclides under appendix A to subpart O and appendices A and B to subpart Q is required on December 8, 2003.

(2) [Reserved]

(g) Best available technologies (BATs) for radionuclides. The Administrator, pursuant to section 1412 of the Act, hereby identifies as indicated in the following table the best technology available for achieving compliance with the maximum contaminant levels for combined radium-226 and -228, uranium, gross alpha particle activity, and beta particle and photon radioactivity.

Table B—BAT for Combined Radium-226 and Radium-228, Uranium, Gross Alpha Particle Activity, and Beta Particle and Photon Radioactivity

Contaminant BAT
1. Combined radium-226 and radium-228Ion exchange, reverse osmosis, lime softening.
2. UraniumIon exchange, reverse osmosis, lime softening, coagulation/filtration.
3. Gross alpha particle activity (excluding Radon and Uranium)Reverse osmosis.
4. Beta particle and photon radioactivityIon exchange, reverse osmosis.

(h) Small systems compliance technologies list for radionuclides.

Table C—List of Small Systems Compliance Technologies for Radionuclides and Limitations to Use

Unit technologies Limitations (see footnotes) Operator skill level required1 Raw water quality range and
considerations.1
1. Ion exchange (IE)(a)IntermediateAll ground waters.
2. Point of use (POU2) IE(b)BasicAll ground waters.
3. Reverse osmosis (RO)(c)AdvancedSurface waters usually require pre-filtration.
4. POU2 RO(b)BasicSurface waters usually require pre-filtration.
5. Lime softening(d)AdvancedAll waters.
6. Green sand filtration(e)Basic.
7. Co-precipitation with Barium sulfate(f)Intermediate to AdvancedGround waters with suitable water quality.
8. Electrodialysis/electrodialysis reversalBasic to IntermediateAll ground waters.
9. Pre-formed hydrous Manganese oxide filtration(g)IntermediateAll ground waters.
10. Activated alumina(a), (h)AdvancedAll ground waters; competing anion concentrations may affect regeneration frequency.
11. Enhanced coagulation/filtration(i)AdvancedCan treat a wide range of water qualities.

1National Research Council (NRC). Safe Water from Every Tap: Improving Water Service to Small Communities. National Academy Press. Washington, D.C. 1997.

2A POU, or “point-of-use” technology is a treatment device installed at a single tap used for the purpose of reducing contaminants in drinking water at that one tap. POU devices are typically installed at the kitchen tap. See the April 21, 2000 NODA for more details.

   Limitations Footnotes: Technologies for Radionuclides:

aThe regeneration solution contains high concentrations of the contaminant ions. Disposal options should be carefully considered before choosing this technology.

bWhen POU devices are used for compliance, programs for long-term operation, maintenance, and monitoring must be provided by water utility to ensure proper performance.

cReject water disposal options should be carefully considered before choosing this technology. See other RO limitations described in the SWTR Compliance Technologies Table.

dThe combination of variable source water quality and the complexity of the water chemistry involved may make this technology too complex for small surface water systems.

eRemoval efficiencies can vary depending on water quality.

fThis technology may be very limited in application to small systems. Since the process requires static mixing, detention basins, and filtration, it is most applicable to systems with sufficiently high sulfate levels that already have a suitable filtration treatment train in place.

gThis technology is most applicable to small systems that already have filtration in place.

hHandling of chemicals required during regeneration and pH adjustment may be too difficult for small systems without an adequately trained operator.

iAssumes modification to a coagulation/filtration process already in place.

Table D—Compliance Technologies by System Size Category for Radionuclide NPDWR's

Contaminant Compliance technologies1 for system size categories (population served) 3,300-10,000
25-500 501-3,300
1. Combined radium-226 and radium-2281, 2, 3, 4, 5, 6, 7, 8, 91, 2, 3, 4, 5, 6, 7, 8, 91, 2, 3, 4, 5, 6, 7. 8, 9.
2. Gross alpha particle activity3, 43, 43, 4.
3. Beta particle activity and photon activity1, 2, 3, 41, 2, 3, 41, 2, 3, 4.
4. Uranium1, 2, 4, 10, 111, 2, 3, 4, 5, 10, 111, 2, 3, 4, 5, 10, 11.

Note: 1Numbers correspond to those technologies found listed in the table C of 141.66(h).

[65 FR 76748, Dec. 7, 2000]

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