Page 11: Guidelines for Canadian Drinking Water Quality: Guideline Technical Document - Enteric Protozoa: Giardia and Cryptosporidium

Appendix A: CT tables for the inactivation of Giardia lamblia cysts by chlorine, chlorine dioxide, chloramine and ozone at various temperatures

1a) Chlorine: 99.9% (3 log) inactivation

Table A.1. CT values (in mg•min/L) for 99.9% (3 log) inactivation of *Giardia lamblia* cysts by free chlorine at 0.5°C
Residual (mg/L)	pH
Residual (mg/L)	6.0	6.5	7.0	7.5	8.0	8.5	9.0
< 0.4	137	163	195	237	277	329	390
0.6	141	169	200	239	286	342	407
0.8	145	172	205	246	295	354	422
1.0	148	176	210	253	304	365	437
1.2	152	180	215	259	313	376	451
1.4	155	184	221	266	321	387	464
1.6	157	189	226	273	329	397	477
1.8	162	193	231	279	338	407	489
2.0	165	197	236	286	346	417	500
2.2	169	201	242	297	353	426	511
2.4	172	205	247	298	361	435	522
2.6	175	209	252	304	368	444	533
2.8	178	213	257	310	375	452	543
3.0	181	217	261	316	382	460	552

Table A.2. CT values (in mg•min/L) for 99.9% (3 log) inactivation of Giardia lamblia cysts by free chlorine at 5°C
Residual (mg/L)	pH
Residual (mg/L)	6.0	6.5	7.0	7.5	8.0	8.5	9.0
< 0.4	97	117	139	166	198	236	279
0.6	100	120	143	171	204	244	291
0.8	103	122	146	175	210	252	301
1.0	105	125	149	179	216	260	312
1.2	107	127	152	183	221	267	320
1.4	109	130	155	187	227	274	329
1.6	111	132	158	192	232	281	337
1.8	114	135	162	196	238	287	345
2.0	116	138	165	200	243	294	353
2.2	118	140	169	204	248	300	361
2.4	120	143	172	209	253	306	368
2.6	122	146	175	213	258	312	375
2.8	124	148	178	217	263	318	382
3.0	126	151	182	221	268	324	389

Table A.3. CT values (in mg•min/L) for 99.9% (3 log) inactivation of *Giardia lamblia* cysts by free chlorine at 10°C
Residual (mg/L)	pH
Residual (mg/L)	6.0	6.5	7.0	7.5	8.0	8.5	9.0
< 0.4	73	88	104	125	149	177	209
0.6	75	90	107	128	153	183	218
0.8	78	92	110	131	158	189	226
1.0	79	94	112	134	162	195	234
1.2	80	95	114	137	166	200	240
1.4	82	98	116	140	170	206	247
1.6	83	99	119	144	174	211	253
1.8	86	101	122	147	179	215	259
2.0	87	104	124	150	182	221	265
2.2	89	105	127	153	186	225	271
2.4	90	107	129	157	190	230	276
2.6	92	110	131	160	194	234	281
2.8	93	111	134	163	197	239	287
3.0	95	113	137	166	201	243	292

Table A.4. CT values (in mg•min/L) for 99.9% (3 log) inactivation of *Giardia lamblia* cysts by free chlorine at 15°C
Residual (mg/L)	pH
Residual (mg/L)	6.0	6.5	7.0	7.5	8.0	8.5	9.0
< 0.4	49	59	70	83	99	118	140
0.6	50	60	72	86	102	122	146
0.8	52	61	73	88	105	126	151
1.0	53	63	75	90	108	130	156
1.2	54	64	76	92	111	134	160
1.4	55	65	78	94	114	137	165
1.6	56	66	79	96	116	141	169
1.8	57	68	81	98	119	144	173
2.0	58	69	83	100	122	147	177
2.2	59	70	85	102	124	150	181
2.4	60	72	86	105	127	153	184
2.6	61	73	88	107	129	156	188
2.8	62	74	89	109	132	159	191
3.0	63	76	91	111	134	162	195

Table A.5. CT values (in mg•min/L) for 99.9% (3 log) inactivation of *Giardia lamblia* cysts by free chlorine at 20°C
Residual (mg/L)	pH
Residual (mg/L)	6.0	6.5	7.0	7.5	8.0	8.5	9.0
< 0.4	36	44	52	62	74	89	105
0.6	38	45	54	64	77	92	109
0.8	39	46	55	66	79	95	113
1.0	39	47	56	67	81	98	117
1.2	40	48	57	69	83	100	120
1.4	41	49	58	70	85	103	123
1.6	42	50	59	72	87	105	126
1.8	43	51	61	74	89	108	129
2.0	44	52	62	75	91	110	132
2.2	44	53	63	77	93	113	135
2.4	45	54	65	78	95	115	139
2.6	46	55	66	80	97	117	141
2.8	47	56	67	81	99	119	143
3.0	47	57	68	83	101	122	146

Table A.6. CT values (in mg•min/L) for 99.9% (3 log) inactivation of *Giardia lamblia* cysts by free chlorine at 25°C
Residual (mg/L)	pH
Residual (mg/L)	6.0	6.5	7.0	7.5	8.0	8.5	9.0
< 0.4	24	29	35	42	50	59	70
0.6	25	30	36	43	51	61	73
0.8	26	31	37	44	53	63	75
1.0	26	31	37	45	54	65	78
1.2	27	32	38	46	55	67	80
1.4	27	33	39	47	57	69	82
1.6	28	33	40	48	58	70	84
1.8	29	34	41	49	60	72	86
2.0	29	35	41	50	61	74	89
2.2	30	35	42	51	62	75	90
2.4	30	36	43	52	63	77	92
2.6	31	37	44	53	65	78	94
2.8	31	37	45	54	66	80	96
3.0	32	38	46	55	67	81	97

1b) Chlorine: 90% (1 log) inactivation

Table A.7. CT values (in mg•min/L) for 90% (1 log) inactivation of *Giardia lamblia* cysts by free chlorine at 0.5°C
Residual (mg/L)	pH
Residual (mg/L)	6.0	6.5	7.0	7.5	8.0	8.5	9.0
< 0.4	46	54	65	79	92	110	130
0.6	47	56	67	80	95	114	136
0.8	48	57	68	82	98	113	141
1.0	49	59	70	84	101	122	146
1.2	51	60	72	86	104	125	150
1.4	52	61	74	89	107	129	155
1.6	52	63	75	91	110	132	159
1.8	54	64	77	93	113	136	163
2.0	55	66	79	95	115	139	167
2.2	56	67	81	99	118	142	170
2.4	57	68	82	99	120	145	174
2.6	58	70	84	101	123	148	178
2.8	59	71	86	103	125	151	181
3.0	60	72	87	105	127	153	184

Table A.8. CT values (in mg•min/L) for 90% (1 log) inactivation of *Giardia lamblia* cysts by free chlorine at 5°C
Residual (mg/L)	pH
Residual (mg/L)	6.0	6.5	7.0	7.5	8.0	8.5	9.0
< 0.4	32	39	46	55	66	79	93
0.6	33	40	49	57	68	81	97
0.8	34	41	49	58	70	84	100
1.0	35	42	50	60	72	87	104
1.2	36	42	51	61	74	89	107
1.4	36	43	52	62	76	91	110
1.6	37	44	53	64	77	94	112
1.8	38	45	54	65	79	96	115
2.0	39	46	55	67	81	98	118
2.2	39	47	56	68	83	100	120
2.4	40	48	57	70	84	102	123
2.6	41	49	58	71	86	104	125
2.8	41	49	59	72	88	106	127
3.0	42	50	61	74	89	108	130

Table A.9. CT values (in mg·min/L) for 90% (1 log) inactivation of *Giardia lamblia* cysts by free chlorine at 10°C
Residual (mg/L)	pH
Residual (mg/L)	6.0	6.5	7.0	7.5	8.0	8.5	9.0
< 0.4	24	29	35	42	50	59	70
0.6	25	30	36	43	51	61	73
0.8	26	31	37	44	53	63	75
1.0	26	31	37	45	54	65	78
1.2	27	32	38	46	55	67	80
1.4	27	33	39	47	57	69	82
1.6	28	33	40	48	58	70	84
1.8	29	34	41	49	60	72	86
2.0	29	35	41	50	61	74	88
2.2	30	35	42	51	62	75	90
2.4	30	36	43	52	63	77	92
2.6	31	37	44	53	65	78	94
2.8	31	37	45	54	66	80	96
3.0	32	38	46	55	67	81	97

Table A.10. CT values (in mg·min/L) for 90% (1 log) inactivation of *Giardia lamblia* cysts by free chlorine at 15°C
Residual (mg/L)	pH
Residual (mg/L)	6.0	6.5	7.0	7.5	8.0	8.5	9.0
< 0.4	16	20	23	28	33	39	47
0.6	17	20	24	29	34	41	49
0.8	17	20	24	29	35	42	50
1.0	18	21	25	30	36	43	52
1.2	18	21	25	31	37	45	53
1.4	18	22	26	31	38	46	55
1.6	19	22	26	32	39	47	56
1.8	19	23	27	33	40	48	59
2.0	19	23	28	33	41	49	59
2.2	20	23	28	34	41	50	60
2.4	20	24	29	35	42	51	61
2.6	20	24	29	36	43	52	63
2.8	21	25	30	36	44	53	64
3.0	21	25	30	37	45	54	65

Table A.11. CT values (in mg·min/L) for 90% (1 log) inactivation of *Giardia lamblia* cysts by free chlorine at 20°C
Residual (mg/L)	pH
Residual (mg/L)	6	6.5	7.0	7.5	8.0	8.5	9.0
< 0.4	12	15	17	21	25	30	35
0.6	13	15	18	21	26	31	36
0.8	13	15	18	22	26	32	38
1.0	13	16	19	22	27	33	39
1.2	13	16	19	23	28	33	40
1.4	14	16	19	23	28	34	41
1.6	14	17	20	24	29	35	42
1.8	14	17	20	25	30	36	43
2.0	15	17	21	25	30	37	44
2.2	15	18	21	26	31	38	45
2.4	15	18	22	26	32	38	46
2.6	15	18	22	27	32	39	47
2.8	16	19	22	27	33	40	48
3.0	16	19	23	28	34	41	49

Table A.12. CT values (in mg·min/L) for 90% (1 log) inactivation of *Giardia lamblia* cysts by free chlorine at 25°C
Residual (mg/L)	pH
Residual (mg/L)	6.0	6.5	7.0	7.5	8.0	8.5	9.0
< 0.4	8	10	12	14	17	20	23
0.6	8	10	12	14	17	20	24
0.8	9	10	12	15	18	21	25
1.0	9	10	12	15	19	22	26
1.2	9	11	13	15	18	22	27
1.4	9	11	13	16	19	22	27
1.6	9	11	13	16	19	23	28
1.8	10	11	14	16	20	23	29
2.0	10	12	14	17	20	24	29
2.2	10	12	14	17	21	25	30
2.4	10	12	14	17	21	25	31
2.6	10	12	15	18	22	26	31
2.8	10	12	15	18	22	26	32
3.0	11	13	15	18	22	27	32

1c) Chlorine: 68.4% (0.5 log) inactivation

Table A.13. CT values (in mg·min/L) for 68.4% (0.5 log) inactivation of *Giardia lamblia* cysts by free chlorine at 0.5°C
Residual (mg/L)	pH
Residual (mg/L)	6.0	6.5	7.0	7.5	8.0	8.5	9.0
< 0.4	23	27	33	40	46	55	65
0.6	24	28	33	40	48	57	68
0.8	24	29	34	41	49	59	70
1.0	25	29	35	42	51	61	73
1.2	25	30	36	43	52	63	75
1.4	26	31	37	44	54	65	77
1.6	26	32	38	46	55	66	80
1.8	27	32	39	47	56	68	82
2.0	28	33	39	48	55	70	83
2.2	28	34	40	50	59	71	85
2.4	29	34	41	50	60	73	87
2.6	29	35	42	51	61	74	89
2.8	30	36	43	52	63	75	91
3.0	30	36	44	53	64	77	92

Table A.14. CT values (in mg·min/L) for 68.4% (0.5 log) inactivation of *Giardia lamblia* cysts by free chlorine at 5°C
Residual (mg/L)	pH
Residual (mg/L)	6.0	6.5	7.0	7.5	8.0	8.5	9.0
< 0.4	16	20	23	28	33	39	47
0.6	17	20	24	29	34	41	49
0.8	17	20	24	29	35	42	50
1.0	18	21	25	30	36	43	52
1.2	18	21	25	31	37	45	53
1.4	18	22	26	31	38	46	55
1.6	19	22	26	32	39	47	56
1.8	19	23	27	33	40	48	58
2.0	19	23	28	33	41	49	59
2.2	20	23	28	34	41	50	60
2.4	20	24	29	35	42	51	61
2.6	20	24	29	36	43	52	63
2.8	21	25	30	36	44	53	64
3.0	21	25	30	37	45	54	65

Table A.15. CT values (in mg·min/L) for 68.4% (0.5 log) inactivation of *Giardia lamblia* cysts by free chlorine at 10°C
Residual (mg/L)	pH
Residual (mg/L)	6.0	6.5	7.0	7.5	8.0	8.5	9.0
< 0.4	12	15	17	21	25	30	35
0.6	13	15	18	21	26	31	36
0.8	13	15	18	22	26	32	38
1.0	13	16	19	22	27	33	39
1.2	13	16	19	23	28	33	40
1.4	14	16	19	23	28	34	41
1.6	14	17	20	24	29	35	42
1.8	14	17	20	25	30	36	43
2.0	15	17	21	25	30	37	44
2.2	15	18	21	26	31	38	45
2.4	15	18	22	26	32	38	46
2.6	15	18	22	27	32	39	47
2.8	16	19	22	27	33	40	48
3.0	16	19	23	28	34	41	49

Table A.16. CT values (in mg·min/L) for 68.4% (0.5 log) inactivation of *Giardia lamblia* cysts by free chlorine at 15°C
Residual (mg/L)	pH
Residual (mg/L)	6.0	6.5	7.0	7.5	8.0	8.5	9.0
< 0.4	8	10	12	14	17	20	23
0.6	8	10	12	14	17	20	24
0.8	9	10	12	15	18	21	25
1.0	9	11	13	15	18	22	26
1.2	9	11	13	15	19	22	27
1.4	9	11	13	16	19	23	28
1.6	9	11	13	16	19	24	28
1.8	10	11	14	16	20	24	29
2.0	10	12	14	17	20	25	30
2.2	10	12	14	17	21	25	30
2.4	10	12	14	18	21	26	31
2.6	10	12	15	18	22	26	31
2.8	10	12	15	18	22	27	32
3.0	11	13	15	19	22	27	33

Table A.17. CT values (in mg·min/L) for 68.4% (0.5 log) inactivation of *Giardia lamblia* cysts by free chlorine at 20°C
Residual (mg/L)	pH
Residual (mg/L)	6.0	6.5	7.0	7.5	8.0	8.5	9.0
< 0.4	6	7	9	10	12	15	19
0.6	6	8	9	11	13	15	18
0.8	7	8	9	11	13	16	19
1.0	7	8	9	11	14	16	20
1.2	7	8	10	12	14	17	20
1.4	7	8	10	12	14	17	21
1.6	7	8	10	12	15	18	21
1.8	7	9	10	12	15	18	22
2.0	7	9	10	13	15	18	22
2.2	7	9	11	13	16	19	23
2.4	8	9	11	13	16	19	23
2.6	8	9	11	13	16	20	24
2.8	8	9	11	14	17	20	24
3.0	9	10	11	14	17	20	24

Table A.18. CT values (in mg·min/L) for 68.4% (0.5 log) inactivation of *Giardia lamblia* cysts by free chlorine at 25°C
Residual (mg/L)	pH
Residual (mg/L)	6.0	6.5	7.0	7.5	8.0	8.5	9.0
< 0.4	4	5	6	7	8	10	12
0.6	4	5	6	7	9	10	12
0.8	4	5	6	7	9	11	13
1.0	4	5	6	8	9	11	13
1.2	5	5	6	8	9	11	13
1.4	5	6	7	8	10	12	14
1.6	5	6	7	8	10	12	14
1.8	5	6	7	8	10	12	14
2.0	5	6	7	8	10	12	15
2.2	5	6	7	9	10	13	15
2.4	5	6	7	9	11	13	15
2.6	5	6	7	9	11	13	16
2.8	5	6	8	9	11	13	16
3.0	5	6	8	9	11	14	16

2. Chlorine dioxide

Table A.19. CT values (in mg·min/L) for inactivation of *Giardia*, pH 6.0-9.0
Log inactivation	Water temperature (°C)
Log inactivation	1	5	10	15	20	25
0.5	10	4.3	4	3.2	2.5	2
1	21	8.7	7.7	6.3	5	3.7
1.5	32	13	12	10	7.5	5.5
2	42	17	15	13	10	7.3
2.5	52	22	19	16	13	9
3	63	26	23	19	15	11

3. Chloramine

Table A.20. CT values ^{Table 1 Footnote a} (in mg·min/L) for inactivation of *Giardia*, pH 6.0-9.0
Log inactivation	Water temperature (°C)
Log inactivation	1	5	10	15	20	25
Table 1 Footnotes Table 1 Footnote 1 Values estimated from monochloramine data. Return to Table 1 footnote a referrer
0.5	635	365	310	250	185	125
1	1270	735	615	500	370	250
1.5	1900	1100	930	750	550	375
2	2535	1470	1230	1000	735	500
2.5	3170	1830	1540	1250	915	625
3	3800	2200	1850	1500	1100	750

4. Ozone

Table A.21. CT values (in mg·min/L) for inactivation of *Giardia*
Log inactivation	Water temperature (°C)
Log inactivation	≤ 1	5	10	15	20	25
0.5	0.48	0.32	0.23	0.16	0.12	0.08
1	0.97	0.63	0.48	0.32	0.24	0.16
1.5	1.5	0.95	0.72	0.48	0.36	0.24
2	1.9	1.3	0.95	0.63	0.48	0.32
2.5	2.4	1.6	1.2	0.79	0.60	0.4
3	2.9	1.9	1.43	0.95	0.72	0.48

Report a problem or mistake on this page

Please select all that apply:

A link, button or video is not working

It has a spelling mistake

Information is missing

Information is outdated or wrong

Login error when trying to access an account

I can't find what I'm looking for

Other issue not in this list

Date modified:: 2013-04-17