5 Epa as Course Coag and Ppt Processes Yujungchang

Coagulation-Filtration - Chwirka & Thomson*Arsenic Removal by Coagulation & Precipitation ProcessesPresentation Prepared by:Joe Chwirka - Camp Dresser & McKee ([email protected])Bruce Thomson - University of New Mexico ([email protected])Presented by: YuJung Chang HDR Engineering, Inc.

Coagulation-Filtration - Chwirka & Thomson

Coagulation-Filtration - Chwirka & Thomson*IntroductionArsenic removal by coagulation & filtration is effective for many applicationsPresentation will discuss:Chemistry of the processVariables affecting process performance (especially pH & coagulant dose)Process variationsCoagulation & granular media filtrationCoagulation & membrane filtrationDesign considerations


Coagulation-Filtration - Chwirka & Thomson*Acid-Base Chemistry of As(V)


Chart2

0.99440803170.00559196730.0000000010

0.94675969520.05324021020.00000009470

0.6400609030.35993269640.00000640060

0.15095676580.84889227740.00015095680

0.01744161730.98081422090.00174416170

0.00174416170.98081421660.01744161730.0000000044

0.00015095670.84889195550.15095670860.0000003792

0.00000640050.35992690960.64005061250.0000160773

0.00000009470.05322755180.94653459480.0002377587

0.0000000010.00557803430.99193034840.0024916164

00.00054826130.97496180540.0244899333

00.00004494250.79920407120.2007509862

00.00000160120.2847467930.7152516058

00.00000002150.03828650310.9617134754

00.00000000020.00396528560.9960347142

H3AsO4

H2AsO4-

HAsO42-

AsO43-

H3AsO4

H2AsO4-

HAsO42-

AsO43-

pH

Fraction

As(V)

pHH+H3AsO4H2AsO4-HAsO42-AsO43-log[H3As]log[H2As-]log[HAs2-]log[As3-]log[H+]log[OH-]

01.00E+009.94E-015.59E-039.94E-102.50E-21-5.00E+00-7.25E+00-1.40E+01-2.56E+010-14

11.00E-019.47E-015.32E-029.47E-082.38E-18-5.02E+00-6.27E+00-1.20E+01-2.26E+01-1-13

21.00E-026.40E-013.60E-016.40E-061.61E-15-5.19E+00-5.44E+00-1.02E+01-1.98E+01-2-12

31.00E-031.51E-018.49E-011.51E-043.79E-13-5.82E+00-5.07E+00-8.82E+00-1.74E+01-3-11

41.00E-041.74E-029.81E-011.74E-034.38E-11-6.76E+00-5.01E+00-7.76E+00-1.54E+01-4-10

51.00E-051.74E-039.81E-011.74E-024.38E-09-7.76E+00-5.01E+00-6.76E+00-1.34E+01-5-9

61.00E-061.51E-048.49E-011.51E-013.79E-07-8.82E+00-5.07E+00-5.82E+00-1.14E+01-6-8

71.00E-076.40E-063.60E-016.40E-011.61E-05-1.02E+01-5.44E+00-5.19E+00-9.79E+00-7-7

81.00E-089.47E-085.32E-029.47E-012.38E-04-1.20E+01-6.27E+00-5.02E+00-8.62E+00-8-6

91.00E-099.92E-105.58E-039.92E-012.49E-03-1.40E+01-7.25E+00-5.00E+00-7.60E+00-9-5

101.00E-109.75E-125.48E-049.75E-012.45E-02-1.60E+01-8.26E+00-5.01E+00-6.61E+00-10-4

111.00E-117.99E-144.49E-057.99E-012.01E-01-1.81E+01-9.35E+00-5.10E+00-5.70E+00-11-3

121.00E-122.85E-161.60E-062.85E-017.15E-01-2.05E+01-1.08E+01-5.55E+00-5.15E+00-12-2

131.00E-133.83E-192.15E-083.83E-029.62E-01-2.34E+01-1.27E+01-6.42E+00-5.02E+00-13-1

141.00E-143.97E-222.23E-103.97E-039.96E-01-2.64E+01-1.47E+01-7.40E+00-5.00E+00-140

log Ct =-5

log K1 =-2.250.0056234133

log K2 =-6.750.0000001778

log K3 =-11.60

As(V)

H3AsO4

H2AsO4-

HAsO42-

AsO43-

log[H3As]

log[H2As-]

log[HAs2-]

log[As3-]

log[H+]

log[OH-]

pH

log Concentration

As(III)

H3AsO4

H2AsO4-

HAsO42-

AsO43-

H3AsO4

H2AsO4-

HAsO42-

AsO43-

pH

Fraction

As(III) Solubility

pHH+alpha-oH2AsO4-HAsO42-AsO43-log[H3As]log[H2As-]log[HAs2-]log[As3-]log[H+]log[OH-]

01.00E+001.00E+006.03E-104.68E-221.82E-35-5.00E+00-1.42E+01-2.63E+01-3.97E+010-14

11.00E-011.00E+006.03E-094.68E-201.82E-32-5.00E+00-1.32E+01-2.43E+01-3.67E+01-1-13

21.00E-021.00E+006.03E-084.68E-181.82E-29-5.00E+00-1.22E+01-2.23E+01-3.37E+01-2-12

31.00E-031.00E+006.03E-074.68E-161.82E-26-5.00E+00-1.12E+01-2.03E+01-3.07E+01-3-11

41.00E-041.00E+006.03E-064.68E-141.82E-23-5.00E+00-1.02E+01-1.83E+01-2.77E+01-4-10

51.00E-051.00E+006.03E-054.68E-121.82E-20-5.00E+00-9.22E+00-1.63E+01-2.47E+01-5-9

61.00E-069.99E-016.02E-044.67E-101.82E-17-5.00E+00-8.22E+00-1.43E+01-2.17E+01-6-8

71.00E-079.94E-015.99E-034.65E-081.81E-14-5.00E+00-7.22E+00-1.23E+01-1.87E+01-7-7

81.00E-089.43E-015.68E-024.41E-061.72E-11-5.03E+00-6.25E+00-1.04E+01-1.58E+01-8-6

91.00E-096.24E-013.76E-012.92E-041.14E-08-5.20E+00-5.42E+00-8.53E+00-1.29E+01-9-5

101.00E-101.41E-018.52E-016.61E-032.57E-06-5.85E+00-5.07E+00-7.18E+00-1.06E+01-10-4

111.00E-111.52E-029.14E-017.09E-022.76E-04-6.82E+00-5.04E+00-6.15E+00-8.56E+00-11-3

121.00E-129.18E-045.53E-014.29E-011.67E-02-8.04E+00-5.26E+00-5.37E+00-6.78E+00-12-2

131.00E-131.41E-058.49E-026.59E-012.56E-01-9.85E+00-6.07E+00-5.18E+00-5.59E+00-13-1

141.00E-144.36E-082.63E-032.04E-017.93E-01-1.24E+01-7.58E+00-5.69E+00-5.10E+00-140

log Ct =-5

log K1 =-9.220.0000000006

log K2 =-12.110

log K3 =-13.410

As(III) Solubility

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

H3AsO4

H2AsO4-

HAsO42-

AsO43-

H3AsO3

H2AsO3-

HAsO32-

AsO33-

log[H3As]

log[H2As-]

log[HAs2-]

log[As3-]

log[H+]

log[OH-]

pH

log Concentration

As(V) Solubility

0000

0000

0000

0000

0000

0000

0000

0000

0000

0000

0000

0000

0000

0000

0000

H3AsO3

H2AsO3-

HAsO32-

AsO33-

alpha-o

H2AsO4-

HAsO42-

AsO43-

pH

Fraction

As vs S

pHH+Alpha3As2O3Arsenolite (As2O3)As2O3Claudetite (As2O3)Alpha1-SAs2S3Orpiment (As2S3)

01.00E+001.00E+002.02E-01-0.692.19E-01-0.667.94E-088.92E-09-8.05

11.00E-011.00E+002.02E-01-0.692.19E-01-0.667.94E-078.92E-09-8.05

21.00E-021.00E+002.02E-01-0.692.19E-01-0.667.94E-068.92E-09-8.05

31.00E-031.00E+002.02E-01-0.692.19E-01-0.667.94E-058.92E-09-8.05

41.00E-041.00E+002.02E-01-0.692.19E-01-0.667.94E-048.92E-09-8.05

51.00E-051.00E+002.02E-01-0.692.19E-01-0.667.88E-038.96E-09-8.05

61.00E-069.99E-012.02E-01-0.692.19E-01-0.667.36E-029.34E-09-8.03

71.00E-079.94E-012.03E-01-0.692.20E-01-0.664.43E-011.27E-08-7.90

81.00E-089.43E-012.14E-01-0.672.32E-01-0.638.88E-013.40E-08-7.47

91.00E-096.24E-013.24E-01-0.493.51E-01-0.469.88E-011.50E-07-6.82

101.00E-101.41E-011.43E+000.151.55E+000.199.99E-011.07E-06-5.97

111.00E-111.52E-021.33E+011.121.44E+011.161.00E+001.04E-05-4.98

121.00E-129.18E-042.20E+022.342.38E+022.381.00E+001.27E-04-3.89

131.00E-131.41E-051.43E+044.161.55E+044.191.00E+002.70E-03-2.57

141.00E-144.36E-084.63E+066.675.02E+066.709.99E-011.08E-01-0.97

logKsp

log K1 =-9.220.0000000006-1.39-1.32logK1 =-7.17.94E-08-61.02

log K2 =-12.1104.07E-024.79E-02logK2 =-171.00E-179.55E-62

log K3 =-13.410

Reactions:

Arsenolite & Claudetite:

As2O3 + 3H2O = 2H3AsO3

Orpiment:

As2S3 + 6H2O = 3HS- + 2H3AsO3 + 3H+

As vs S

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

Arsenolite (As2O3)

Claudetite (As2O3)

Orpiment (As2S3)

pH

log Concentration

U(VI)

pHH+Alpha3AlAsO4AlAsO4Ca3(AsO4)2Ca3(AsO4)2CrAsO4CrAsO4Cu3(AsO4)2Cu3(AsO4)2Fe3(AsO4)2Fe3(AsO4)2FeAsO4FeAsO4Mn3(AsO4)2Mn3(AsO4)2LaAsO4LaAsO4

01.00E+002.50E-212.52E+022.402.99E+088.481.76E+000.251.72E+055.243.98E+066.601.59E+000.203.28E+066.526.55E-01-0.18

11.00E-012.38E-188.16E+000.914.88E+066.695.71E-02-1.242.81E+033.456.50E+044.815.15E-02-1.295.35E+044.732.12E-02-1.67

21.00E-021.61E-153.14E-01-0.509.79E+044.992.20E-03-2.665.63E+011.751.30E+033.111.98E-03-2.701.07E+033.038.16E-04-3.09

31.00E-033.79E-132.04E-02-1.693.69E+033.571.43E-04-3.842.12E+000.334.91E+011.691.29E-04-3.894.05E+011.615.32E-05-4.27

41.00E-044.38E-111.90E-03-2.722.13E+022.331.33E-05-4.881.23E-01-0.912.84E+000.451.20E-05-4.922.34E+000.374.95E-06-5.31

51.00E-054.38E-091.90E-04-3.721.35E+011.131.33E-06-5.887.75E-03-2.111.79E-01-0.751.20E-06-5.921.48E-01-0.834.95E-07-6.31

61.00E-063.79E-072.04E-05-4.699.27E-01-0.031.43E-07-6.845.33E-04-3.271.23E-02-1.911.29E-07-6.891.02E-02-1.995.32E-08-7.27

71.00E-071.61E-053.14E-06-5.509.79E-02-1.012.20E-08-7.665.63E-05-4.251.30E-03-2.891.98E-08-7.701.07E-03-2.978.16E-09-8.09

81.00E-082.38E-048.16E-07-6.091.94E-02-1.715.71E-09-8.241.12E-05-4.952.59E-04-3.595.15E-09-8.292.13E-04-3.672.12E-09-8.67

91.00E-092.49E-032.52E-07-6.604.75E-03-2.321.77E-09-8.752.73E-06-5.566.32E-05-4.201.59E-09-8.805.21E-05-4.286.56E-10-9.18

101.00E-102.45E-028.04E-08-7.091.20E-03-2.925.63E-10-9.256.93E-07-6.161.60E-05-4.805.08E-10-9.291.32E-05-4.882.09E-10-9.68

111.00E-112.01E-012.81E-08-7.553.41E-04-3.471.97E-10-9.711.96E-07-6.714.54E-06-5.341.77E-10-9.753.74E-06-5.437.31E-11-10.14

121.00E-127.15E-011.49E-08-7.831.59E-04-3.801.04E-10-9.989.16E-08-7.042.12E-06-5.679.39E-11-10.031.74E-06-5.763.87E-11-10.41

131.00E-139.62E-011.28E-08-7.891.33E-04-3.888.98E-11-10.057.67E-08-7.121.77E-06-5.758.10E-11-10.091.46E-06-5.843.34E-11-10.48

141.00E-149.96E-011.26E-08-7.901.30E-04-3.888.83E-11-10.057.51E-08-7.121.74E-06-5.767.96E-11-10.101.43E-06-5.843.28E-11-10.48

logKsp

log K1 =-2.250.0056234133-15.8-18.9-20.11-35.1-28.28-20.2-28.7-20.97

log K2 =-6.750.00000017780000002.00E-290

log K3 =-11.60

Data from Norman (1998), pg. 191

U(VI)

00000000

00000000

00000000

00000000

00000000

00000000

00000000

00000000

00000000

00000000

00000000

00000000

00000000

00000000

00000000

CrAsO4

FeAsO4

Ca3(AsO4)2

Fe3(AsO4)2

Mn3(AsO4)2

Cu3(AsO4)2

AlAsO4

LaAsO4

AlAsO4

Ca3(AsO4)2

CrAsO4

Cu3(AsO4)2

Fe3(AsO4)2

FeAsO4

Mn3(AsO4)2

LaAsO4

pH

log Concentration

Dependence of As phase on pe, pH, & [HS-]

Rx: As2O3 + 4H+ + 2HS- + 2e- = As2S2 + 3H2O

log K =50.45

logSt4710

014.1210.875.22

-104.120.87-4.78

Sulfide SystemAlpha1Alpha1Alpha1

pK1 =7.10.00079369780.44268836620.9987425577

pK2 =17

000

000

pH = 4

pH = 7

pH = 10

As2O3

As2S2

log [Total S(-II)]

pe

pHH+alpha-olog[H3As]log[H2As-]log[HAs2-]log[As3-]

01.00E+009.90E-01-5.00E+00-7.00E+00-1.40E+01-2.60E+01

11.00E-019.09E-01-5.04E+00-6.04E+00-1.20E+01-2.30E+01

21.00E-025.00E-01-5.30E+00-5.30E+00-1.03E+01-2.03E+01

31.00E-039.09E-02-6.04E+00-5.04E+00-9.04E+00-1.80E+01

41.00E-049.89E-03-7.00E+00-5.00E+00-8.00E+00-1.60E+01

51.00E-059.89E-04-8.00E+00-5.00E+00-7.00E+00-1.40E+01

61.00E-069.09E-05-9.04E+00-5.04E+00-6.04E+00-1.20E+01

71.00E-075.00E-06-1.03E+01-5.30E+00-5.30E+00-1.03E+01

81.00E-089.09E-08-1.20E+01-6.04E+00-5.04E+00-9.04E+00

91.00E-099.89E-10-1.40E+01-7.00E+00-5.00E+00-8.00E+00

101.00E-109.89E-12-1.60E+01-8.00E+00-5.00E+00-7.00E+00

111.00E-119.09E-14-1.80E+01-9.04E+00-5.04E+00-6.04E+00

121.00E-125.00E-16-2.03E+01-1.03E+01-5.30E+00-5.30E+00

131.00E-139.09E-19-2.30E+01-1.20E+01-6.04E+00-5.04E+00

141.00E-149.90E-22-2.60E+01-1.40E+01-7.00E+00-5.00E+00

log Ct =-5

log K1 =-20.01

log K2 =-70.0000001

log K3 =-120

-5.0024353766-7.2524353766-14.0024353766-25.6024353766

-5.0237602389-6.2737602389-12.0237602389-22.6237602389

-5.1937787001-5.4437787001-10.1937787001-19.7937787001

-5.8211474173-5.0711474173-8.8211474173-17.4211474173

-6.7584132459-5.0084132459-7.7584132459-15.3584132459

-7.7584132478-5.0084132478-6.7584132478-13.3584132478

-8.821147582-5.071147582-5.821147582-11.421147582

-10.1937856825-5.4437856825-5.1937856825-9.7937856825

-12.0238635084-6.2738635084-5.0238635084-8.6238635084

-14.0035188222-7.2535188222-5.0035188222-7.6035188222

-16.0110123977-8.2610123977-5.0110123977-6.6110123977

-18.0973423124-9.3473423124-5.0973423124-5.6973423124

-20.5455411585-10.7955411585-5.5455411585-5.1455411585

-23.4169542986-12.6669542986-6.4169542986-5.0169542986

-26.4017255251-14.6517255251-7.4017255251-5.0017255251

H3AsO4

H2AsO4-

HAsO42-

AsO43-

log[H3As]

log[H2As-]

log[HAs2-]

log[As3-]

pH

log Concentration

Coagulation-Filtration - Chwirka & Thomson*Acid-Base Chemistry of As(III)


Chart3

0.99999999940.000000000600

0.9999999940.00000000600

0.99999993970.000000060300

0.99999939740.000000602600

0.99999397440.000006025600

0.99993974770.000060252300

0.99939780280.00060219670.00000000050

0.99401044830.00598950520.00000004650

0.94316431830.05683127010.00000441150

0.62381967880.37588852750.00029178240.0000000114

0.1413949660.85198892160.00661353940.000002573

0.01516265580.91364035970.07092106950.000275915

0.00091785920.55306485230.42931499690.0167022915

0.00001408510.08487099170.65880862590.2563062974

0.00000004360.0026272930.20394286160.7934298018

H3AsO3

H2AsO3-

HAsO32-

AsO33-

alpha-o

H2AsO4-

HAsO42-

AsO43-

pH

Fraction

As(V)


01.00E+009.94E-015.59E-039.94E-102.50E-21-5.00E+00-7.25E+00-1.40E+01-2.56E+010-14

11.00E-019.47E-015.32E-029.47E-082.38E-18-5.02E+00-6.27E+00-1.20E+01-2.26E+01-1-13

21.00E-026.40E-013.60E-016.40E-061.61E-15-5.19E+00-5.44E+00-1.02E+01-1.98E+01-2-12

31.00E-031.51E-018.49E-011.51E-043.79E-13-5.82E+00-5.07E+00-8.82E+00-1.74E+01-3-11

41.00E-041.74E-029.81E-011.74E-034.38E-11-6.76E+00-5.01E+00-7.76E+00-1.54E+01-4-10

51.00E-051.74E-039.81E-011.74E-024.38E-09-7.76E+00-5.01E+00-6.76E+00-1.34E+01-5-9

61.00E-061.51E-048.49E-011.51E-013.79E-07-8.82E+00-5.07E+00-5.82E+00-1.14E+01-6-8

71.00E-076.40E-063.60E-016.40E-011.61E-05-1.02E+01-5.44E+00-5.19E+00-9.79E+00-7-7

81.00E-089.47E-085.32E-029.47E-012.38E-04-1.20E+01-6.27E+00-5.02E+00-8.62E+00-8-6

91.00E-099.92E-105.58E-039.92E-012.49E-03-1.40E+01-7.25E+00-5.00E+00-7.60E+00-9-5

101.00E-109.75E-125.48E-049.75E-012.45E-02-1.60E+01-8.26E+00-5.01E+00-6.61E+00-10-4

111.00E-117.99E-144.49E-057.99E-012.01E-01-1.81E+01-9.35E+00-5.10E+00-5.70E+00-11-3

121.00E-122.85E-161.60E-062.85E-017.15E-01-2.05E+01-1.08E+01-5.55E+00-5.15E+00-12-2

131.00E-133.83E-192.15E-083.83E-029.62E-01-2.34E+01-1.27E+01-6.42E+00-5.02E+00-13-1

141.00E-143.97E-222.23E-103.97E-039.96E-01-2.64E+01-1.47E+01-7.40E+00-5.00E+00-140

log Ct =-5

log K1 =-2.250.0056234133

log K2 =-6.750.0000001778

log K3 =-11.60

As(V)

H3AsO4

H2AsO4-

HAsO42-

AsO43-

log[H3As]

log[H2As-]

log[HAs2-]

log[As3-]

log[H+]

log[OH-]

pH

log Concentration

As(III)

H3AsO4

H2AsO4-

HAsO42-

AsO43-

H3AsO4

H2AsO4-

HAsO42-

AsO43-

pH

Fraction

As(III) Solubility


01.00E+001.00E+006.03E-104.68E-221.82E-35-5.00E+00-1.42E+01-2.63E+01-3.97E+010-14

11.00E-011.00E+006.03E-094.68E-201.82E-32-5.00E+00-1.32E+01-2.43E+01-3.67E+01-1-13

21.00E-021.00E+006.03E-084.68E-181.82E-29-5.00E+00-1.22E+01-2.23E+01-3.37E+01-2-12

31.00E-031.00E+006.03E-074.68E-161.82E-26-5.00E+00-1.12E+01-2.03E+01-3.07E+01-3-11

41.00E-041.00E+006.03E-064.68E-141.82E-23-5.00E+00-1.02E+01-1.83E+01-2.77E+01-4-10

51.00E-051.00E+006.03E-054.68E-121.82E-20-5.00E+00-9.22E+00-1.63E+01-2.47E+01-5-9

61.00E-069.99E-016.02E-044.67E-101.82E-17-5.00E+00-8.22E+00-1.43E+01-2.17E+01-6-8

71.00E-079.94E-015.99E-034.65E-081.81E-14-5.00E+00-7.22E+00-1.23E+01-1.87E+01-7-7

81.00E-089.43E-015.68E-024.41E-061.72E-11-5.03E+00-6.25E+00-1.04E+01-1.58E+01-8-6

91.00E-096.24E-013.76E-012.92E-041.14E-08-5.20E+00-5.42E+00-8.53E+00-1.29E+01-9-5

101.00E-101.41E-018.52E-016.61E-032.57E-06-5.85E+00-5.07E+00-7.18E+00-1.06E+01-10-4

111.00E-111.52E-029.14E-017.09E-022.76E-04-6.82E+00-5.04E+00-6.15E+00-8.56E+00-11-3

121.00E-129.18E-045.53E-014.29E-011.67E-02-8.04E+00-5.26E+00-5.37E+00-6.78E+00-12-2

131.00E-131.41E-058.49E-026.59E-012.56E-01-9.85E+00-6.07E+00-5.18E+00-5.59E+00-13-1

141.00E-144.36E-082.63E-032.04E-017.93E-01-1.24E+01-7.58E+00-5.69E+00-5.10E+00-140

log Ct =-5

log K1 =-9.220.0000000006

log K2 =-12.110

log K3 =-13.410

As(III) Solubility

H3AsO4

H2AsO4-

HAsO42-

AsO43-

H3AsO3

H2AsO3-

HAsO32-

AsO33-

log[H3As]

log[H2As-]

log[HAs2-]

log[As3-]

log[H+]

log[OH-]

pH

log Concentration

As(V) Solubility

H3AsO3

H2AsO3-

HAsO32-

AsO33-

alpha-o

H2AsO4-

HAsO42-

AsO43-

pH

Fraction

As vs S


01.00E+001.00E+002.02E-01-0.692.19E-01-0.667.94E-088.92E-09-8.05

11.00E-011.00E+002.02E-01-0.692.19E-01-0.667.94E-078.92E-09-8.05

21.00E-021.00E+002.02E-01-0.692.19E-01-0.667.94E-068.92E-09-8.05

31.00E-031.00E+002.02E-01-0.692.19E-01-0.667.94E-058.92E-09-8.05

41.00E-041.00E+002.02E-01-0.692.19E-01-0.667.94E-048.92E-09-8.05

51.00E-051.00E+002.02E-01-0.692.19E-01-0.667.88E-038.96E-09-8.05

61.00E-069.99E-012.02E-01-0.692.19E-01-0.667.36E-029.34E-09-8.03

71.00E-079.94E-012.03E-01-0.692.20E-01-0.664.43E-011.27E-08-7.90

81.00E-089.43E-012.14E-01-0.672.32E-01-0.638.88E-013.40E-08-7.47

91.00E-096.24E-013.24E-01-0.493.51E-01-0.469.88E-011.50E-07-6.82

101.00E-101.41E-011.43E+000.151.55E+000.199.99E-011.07E-06-5.97

111.00E-111.52E-021.33E+011.121.44E+011.161.00E+001.04E-05-4.98

121.00E-129.18E-042.20E+022.342.38E+022.381.00E+001.27E-04-3.89

131.00E-131.41E-051.43E+044.161.55E+044.191.00E+002.70E-03-2.57

141.00E-144.36E-084.63E+066.675.02E+066.709.99E-011.08E-01-0.97

logKsp

log K1 =-9.220.0000000006-1.39-1.32logK1 =-7.17.94E-08-61.02

log K2 =-12.1104.07E-024.79E-02logK2 =-171.00E-179.55E-62

log K3 =-13.410

Reactions:



Orpiment:

As2S3 + 6H2O = 3HS- + 2H3AsO3 + 3H+

As vs S

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

Arsenolite (As2O3)

Claudetite (As2O3)

Orpiment (As2S3)

pH

log Concentration

U(VI)

pHH+Alpha3AlAsO4AlAsO4Ca3(AsO4)2Ca3(AsO4)2CrAsO4CrAsO4Cu3(AsO4)2Cu3(AsO4)2Fe3(AsO4)2Fe3(AsO4)2FeAsO4FeAsO4Mn3(AsO4)2Mn3(AsO4)2LaAsO4LaAsO4

01.00E+002.50E-212.52E+022.402.99E+088.481.76E+000.251.72E+055.243.98E+066.601.59E+000.203.28E+066.526.55E-01-0.18

11.00E-012.38E-188.16E+000.914.88E+066.695.71E-02-1.242.81E+033.456.50E+044.815.15E-02-1.295.35E+044.732.12E-02-1.67

21.00E-021.61E-153.14E-01-0.509.79E+044.992.20E-03-2.665.63E+011.751.30E+033.111.98E-03-2.701.07E+033.038.16E-04-3.09

31.00E-033.79E-132.04E-02-1.693.69E+033.571.43E-04-3.842.12E+000.334.91E+011.691.29E-04-3.894.05E+011.615.32E-05-4.27

41.00E-044.38E-111.90E-03-2.722.13E+022.331.33E-05-4.881.23E-01-0.912.84E+000.451.20E-05-4.922.34E+000.374.95E-06-5.31

51.00E-054.38E-091.90E-04-3.721.35E+011.131.33E-06-5.887.75E-03-2.111.79E-01-0.751.20E-06-5.921.48E-01-0.834.95E-07-6.31

61.00E-063.79E-072.04E-05-4.699.27E-01-0.031.43E-07-6.845.33E-04-3.271.23E-02-1.911.29E-07-6.891.02E-02-1.995.32E-08-7.27

71.00E-071.61E-053.14E-06-5.509.79E-02-1.012.20E-08-7.665.63E-05-4.251.30E-03-2.891.98E-08-7.701.07E-03-2.978.16E-09-8.09

81.00E-082.38E-048.16E-07-6.091.94E-02-1.715.71E-09-8.241.12E-05-4.952.59E-04-3.595.15E-09-8.292.13E-04-3.672.12E-09-8.67

91.00E-092.49E-032.52E-07-6.604.75E-03-2.321.77E-09-8.752.73E-06-5.566.32E-05-4.201.59E-09-8.805.21E-05-4.286.56E-10-9.18

101.00E-102.45E-028.04E-08-7.091.20E-03-2.925.63E-10-9.256.93E-07-6.161.60E-05-4.805.08E-10-9.291.32E-05-4.882.09E-10-9.68

111.00E-112.01E-012.81E-08-7.553.41E-04-3.471.97E-10-9.711.96E-07-6.714.54E-06-5.341.77E-10-9.753.74E-06-5.437.31E-11-10.14

121.00E-127.15E-011.49E-08-7.831.59E-04-3.801.04E-10-9.989.16E-08-7.042.12E-06-5.679.39E-11-10.031.74E-06-5.763.87E-11-10.41

131.00E-139.62E-011.28E-08-7.891.33E-04-3.888.98E-11-10.057.67E-08-7.121.77E-06-5.758.10E-11-10.091.46E-06-5.843.34E-11-10.48

141.00E-149.96E-011.26E-08-7.901.30E-04-3.888.83E-11-10.057.51E-08-7.121.74E-06-5.767.96E-11-10.101.43E-06-5.843.28E-11-10.48

logKsp

log K1 =-2.250.0056234133-15.8-18.9-20.11-35.1-28.28-20.2-28.7-20.97

log K2 =-6.750.00000017780000002.00E-290

log K3 =-11.60


U(VI)

00000000

00000000

00000000

00000000

00000000

00000000

00000000

00000000

00000000

00000000

00000000

00000000

00000000

00000000

00000000

CrAsO4

FeAsO4

Ca3(AsO4)2

Fe3(AsO4)2

Mn3(AsO4)2

Cu3(AsO4)2

AlAsO4

LaAsO4

AlAsO4

Ca3(AsO4)2

CrAsO4

Cu3(AsO4)2

Fe3(AsO4)2

FeAsO4

Mn3(AsO4)2

LaAsO4

pH

log Concentration


Rx: As2O3 + 4H+ + 2HS- + 2e- = As2S2 + 3H2O

log K =50.45

logSt4710

014.1210.875.22

-104.120.87-4.78


pK1 =7.10.00079369780.44268836620.9987425577

pK2 =17

000

000

pH = 4

pH = 7

pH = 10

As2O3

As2S2

log [Total S(-II)]

pe


01.00E+009.90E-01-5.00E+00-7.00E+00-1.40E+01-2.60E+01

11.00E-019.09E-01-5.04E+00-6.04E+00-1.20E+01-2.30E+01

21.00E-025.00E-01-5.30E+00-5.30E+00-1.03E+01-2.03E+01

31.00E-039.09E-02-6.04E+00-5.04E+00-9.04E+00-1.80E+01

41.00E-049.89E-03-7.00E+00-5.00E+00-8.00E+00-1.60E+01

51.00E-059.89E-04-8.00E+00-5.00E+00-7.00E+00-1.40E+01

61.00E-069.09E-05-9.04E+00-5.04E+00-6.04E+00-1.20E+01

71.00E-075.00E-06-1.03E+01-5.30E+00-5.30E+00-1.03E+01

81.00E-089.09E-08-1.20E+01-6.04E+00-5.04E+00-9.04E+00

91.00E-099.89E-10-1.40E+01-7.00E+00-5.00E+00-8.00E+00

101.00E-109.89E-12-1.60E+01-8.00E+00-5.00E+00-7.00E+00

111.00E-119.09E-14-1.80E+01-9.04E+00-5.04E+00-6.04E+00

121.00E-125.00E-16-2.03E+01-1.03E+01-5.30E+00-5.30E+00

131.00E-139.09E-19-2.30E+01-1.20E+01-6.04E+00-5.04E+00

141.00E-149.90E-22-2.60E+01-1.40E+01-7.00E+00-5.00E+00

log Ct =-5

log K1 =-20.01

log K2 =-70.0000001

log K3 =-120

-5.0024353766-7.2524353766-14.0024353766-25.6024353766

-5.0237602389-6.2737602389-12.0237602389-22.6237602389

-5.1937787001-5.4437787001-10.1937787001-19.7937787001

-5.8211474173-5.0711474173-8.8211474173-17.4211474173

-6.7584132459-5.0084132459-7.7584132459-15.3584132459

-7.7584132478-5.0084132478-6.7584132478-13.3584132478

-8.821147582-5.071147582-5.821147582-11.421147582

-10.1937856825-5.4437856825-5.1937856825-9.7937856825

-12.0238635084-6.2738635084-5.0238635084-8.6238635084

-14.0035188222-7.2535188222-5.0035188222-7.6035188222

-16.0110123977-8.2610123977-5.0110123977-6.6110123977

-18.0973423124-9.3473423124-5.0973423124-5.6973423124

-20.5455411585-10.7955411585-5.5455411585-5.1455411585

-23.4169542986-12.6669542986-6.4169542986-5.0169542986

-26.4017255251-14.6517255251-7.4017255251-5.0017255251

H3AsO4

H2AsO4-

HAsO42-

AsO43-

log[H3As]

log[H2As-]

log[HAs2-]

log[As3-]

pH

log Concentration

Coagulation-Filtration - Chwirka & Thomson*Redox Chemistry of As


Coagulation-Filtration - Chwirka & Thomson*Solubility of As(III) Compounds


Chart6

-0.6949999997-0.6599999997-8.0496547346

-0.6949999974-0.6599999974-8.0496545474

-0.6949999738-0.6599999738-8.0496526751

-0.6949997383-0.6599997383-8.0496339532

-0.6949973831-0.6599973831-8.0494468074

-0.694973832-0.659973832-8.0475826314

-0.6947383903-0.6597383903-8.0296327396

-0.6923909494-0.6573909494-7.8962700006

-0.6695873622-0.6345873622-7.4685915349

-0.4900590707-0.4550590707-6.8244183926

0.15456605230.1895660523-5.9695004682

1.12422472391.1592247239-4.9819318027

2.34222394042.3772239404-3.8947592931

4.15624072324.1912407232-2.5691320818

6.66549149126.7004914912-0.9651976797

Arsenolite (As2O3)

Claudetite (As2O3)

Orpiment (As2S3)

pH

log Concentration

As(V)


01.00E+009.94E-015.59E-039.94E-102.50E-21-5.00E+00-7.25E+00-1.40E+01-2.56E+010-14

11.00E-019.47E-015.32E-029.47E-082.38E-18-5.02E+00-6.27E+00-1.20E+01-2.26E+01-1-13

21.00E-026.40E-013.60E-016.40E-061.61E-15-5.19E+00-5.44E+00-1.02E+01-1.98E+01-2-12

31.00E-031.51E-018.49E-011.51E-043.79E-13-5.82E+00-5.07E+00-8.82E+00-1.74E+01-3-11

41.00E-041.74E-029.81E-011.74E-034.38E-11-6.76E+00-5.01E+00-7.76E+00-1.54E+01-4-10

51.00E-051.74E-039.81E-011.74E-024.38E-09-7.76E+00-5.01E+00-6.76E+00-1.34E+01-5-9

61.00E-061.51E-048.49E-011.51E-013.79E-07-8.82E+00-5.07E+00-5.82E+00-1.14E+01-6-8

71.00E-076.40E-063.60E-016.40E-011.61E-05-1.02E+01-5.44E+00-5.19E+00-9.79E+00-7-7

81.00E-089.47E-085.32E-029.47E-012.38E-04-1.20E+01-6.27E+00-5.02E+00-8.62E+00-8-6

91.00E-099.92E-105.58E-039.92E-012.49E-03-1.40E+01-7.25E+00-5.00E+00-7.60E+00-9-5

101.00E-109.75E-125.48E-049.75E-012.45E-02-1.60E+01-8.26E+00-5.01E+00-6.61E+00-10-4

111.00E-117.99E-144.49E-057.99E-012.01E-01-1.81E+01-9.35E+00-5.10E+00-5.70E+00-11-3

121.00E-122.85E-161.60E-062.85E-017.15E-01-2.05E+01-1.08E+01-5.55E+00-5.15E+00-12-2

131.00E-133.83E-192.15E-083.83E-029.62E-01-2.34E+01-1.27E+01-6.42E+00-5.02E+00-13-1

141.00E-143.97E-222.23E-103.97E-039.96E-01-2.64E+01-1.47E+01-7.40E+00-5.00E+00-140

log Ct =-5

log K1 =-2.250.0056234133

log K2 =-6.750.0000001778

log K3 =-11.60

As(V)

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

H3AsO4

H2AsO4-

HAsO42-

AsO43-

log[H3As]

log[H2As-]

log[HAs2-]

log[As3-]

log[H+]

log[OH-]

pH

log Concentration

As(III)

0000

0000

0000

0000

0000

0000

0000

0000

0000

0000

0000

0000

0000

0000

0000

H3AsO4

H2AsO4-

HAsO42-

AsO43-

H3AsO4

H2AsO4-

HAsO42-

AsO43-

pH

Fraction

As(III) Solubility


01.00E+001.00E+006.03E-104.68E-221.82E-35-5.00E+00-1.42E+01-2.63E+01-3.97E+010-14

11.00E-011.00E+006.03E-094.68E-201.82E-32-5.00E+00-1.32E+01-2.43E+01-3.67E+01-1-13

21.00E-021.00E+006.03E-084.68E-181.82E-29-5.00E+00-1.22E+01-2.23E+01-3.37E+01-2-12

31.00E-031.00E+006.03E-074.68E-161.82E-26-5.00E+00-1.12E+01-2.03E+01-3.07E+01-3-11

41.00E-041.00E+006.03E-064.68E-141.82E-23-5.00E+00-1.02E+01-1.83E+01-2.77E+01-4-10

51.00E-051.00E+006.03E-054.68E-121.82E-20-5.00E+00-9.22E+00-1.63E+01-2.47E+01-5-9

61.00E-069.99E-016.02E-044.67E-101.82E-17-5.00E+00-8.22E+00-1.43E+01-2.17E+01-6-8

71.00E-079.94E-015.99E-034.65E-081.81E-14-5.00E+00-7.22E+00-1.23E+01-1.87E+01-7-7

81.00E-089.43E-015.68E-024.41E-061.72E-11-5.03E+00-6.25E+00-1.04E+01-1.58E+01-8-6

91.00E-096.24E-013.76E-012.92E-041.14E-08-5.20E+00-5.42E+00-8.53E+00-1.29E+01-9-5

101.00E-101.41E-018.52E-016.61E-032.57E-06-5.85E+00-5.07E+00-7.18E+00-1.06E+01-10-4

111.00E-111.52E-029.14E-017.09E-022.76E-04-6.82E+00-5.04E+00-6.15E+00-8.56E+00-11-3

121.00E-129.18E-045.53E-014.29E-011.67E-02-8.04E+00-5.26E+00-5.37E+00-6.78E+00-12-2

131.00E-131.41E-058.49E-026.59E-012.56E-01-9.85E+00-6.07E+00-5.18E+00-5.59E+00-13-1

141.00E-144.36E-082.63E-032.04E-017.93E-01-1.24E+01-7.58E+00-5.69E+00-5.10E+00-140

log Ct =-5

log K1 =-9.220.0000000006

log K2 =-12.110

log K3 =-13.410

As(III) Solubility

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

H3AsO4

H2AsO4-

HAsO42-

AsO43-

H3AsO3

H2AsO3-

HAsO32-

AsO33-

log[H3As]

log[H2As-]

log[HAs2-]

log[As3-]

log[H+]

log[OH-]

pH

log Concentration

As(V) Solubility

0000

0000

0000

0000

0000

0000

0000

0000

0000

0000

0000

0000

0000

0000

0000

H3AsO3

H2AsO3-

HAsO32-

AsO33-

alpha-o

H2AsO4-

HAsO42-

AsO43-

pH

Fraction

As vs S


01.00E+001.00E+002.02E-01-0.692.19E-01-0.667.94E-088.92E-09-8.05

11.00E-011.00E+002.02E-01-0.692.19E-01-0.667.94E-078.92E-09-8.05

21.00E-021.00E+002.02E-01-0.692.19E-01-0.667.94E-068.92E-09-8.05

31.00E-031.00E+002.02E-01-0.692.19E-01-0.667.94E-058.92E-09-8.05

41.00E-041.00E+002.02E-01-0.692.19E-01-0.667.94E-048.92E-09-8.05

51.00E-051.00E+002.02E-01-0.692.19E-01-0.667.88E-038.96E-09-8.05

61.00E-069.99E-012.02E-01-0.692.19E-01-0.667.36E-029.34E-09-8.03

71.00E-079.94E-012.03E-01-0.692.20E-01-0.664.43E-011.27E-08-7.90

81.00E-089.43E-012.14E-01-0.672.32E-01-0.638.88E-013.40E-08-7.47

91.00E-096.24E-013.24E-01-0.493.51E-01-0.469.88E-011.50E-07-6.82

101.00E-101.41E-011.43E+000.151.55E+000.199.99E-011.07E-06-5.97

111.00E-111.52E-021.33E+011.121.44E+011.161.00E+001.04E-05-4.98

121.00E-129.18E-042.20E+022.342.38E+022.381.00E+001.27E-04-3.89

131.00E-131.41E-051.43E+044.161.55E+044.191.00E+002.70E-03-2.57

141.00E-144.36E-084.63E+066.675.02E+066.709.99E-011.08E-01-0.97

logKsp

log K1 =-9.220.0000000006-1.39-1.32logK1 =-7.17.94E-08-61.02

log K2 =-12.1104.07E-024.79E-02logK2 =-171.00E-179.55E-62

log K3 =-13.410

Reactions:



Orpiment:

As2S3 + 6H2O = 3HS- + 2H3AsO3 + 3H+

As vs S

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

Arsenolite (As2O3)

Claudetite (As2O3)

Orpiment (As2S3)

pH

log Concentration

U(VI)

pHH+Alpha3AlAsO4AlAsO4Ca3(AsO4)2Ca3(AsO4)2CrAsO4CrAsO4Cu3(AsO4)2Cu3(AsO4)2Fe3(AsO4)2Fe3(AsO4)2FeAsO4FeAsO4Mn3(AsO4)2Mn3(AsO4)2

01.00E+002.50E-212.52E+022.402.99E+088.481.76E+000.251.72E+055.243.98E+066.601.59E+000.203.28E+066.52

11.00E-012.38E-188.16E+000.914.88E+066.695.71E-02-1.242.81E+033.456.50E+044.815.15E-02-1.295.35E+044.73

21.00E-021.61E-153.14E-01-0.509.79E+044.992.20E-03-2.665.63E+011.751.30E+033.111.98E-03-2.701.07E+033.03

31.00E-033.79E-132.04E-02-1.693.69E+033.571.43E-04-3.842.12E+000.334.91E+011.691.29E-04-3.894.05E+011.61

41.00E-044.38E-111.90E-03-2.722.13E+022.331.33E-05-4.881.23E-01-0.912.84E+000.451.20E-05-4.922.34E+000.37

51.00E-054.38E-091.90E-04-3.721.35E+011.131.33E-06-5.887.75E-03-2.111.79E-01-0.751.20E-06-5.921.48E-01-0.83

61.00E-063.79E-072.04E-05-4.699.27E-01-0.031.43E-07-6.845.33E-04-3.271.23E-02-1.911.29E-07-6.891.02E-02-1.99

71.00E-071.61E-053.14E-06-5.509.79E-02-1.012.20E-08-7.665.63E-05-4.251.30E-03-2.891.98E-08-7.701.07E-03-2.97

81.00E-082.38E-048.16E-07-6.091.94E-02-1.715.71E-09-8.241.12E-05-4.952.59E-04-3.595.15E-09-8.292.13E-04-3.67

91.00E-092.49E-032.52E-07-6.604.75E-03-2.321.77E-09-8.752.73E-06-5.566.32E-05-4.201.59E-09-8.805.21E-05-4.28

101.00E-102.45E-028.04E-08-7.091.20E-03-2.925.63E-10-9.256.93E-07-6.161.60E-05-4.805.08E-10-9.291.32E-05-4.88

111.00E-112.01E-012.81E-08-7.553.41E-04-3.471.97E-10-9.711.96E-07-6.714.54E-06-5.341.77E-10-9.753.74E-06-5.43

121.00E-127.15E-011.49E-08-7.831.59E-04-3.801.04E-10-9.989.16E-08-7.042.12E-06-5.679.39E-11-10.031.74E-06-5.76

131.00E-139.62E-011.28E-08-7.891.33E-04-3.888.98E-11-10.057.67E-08-7.121.77E-06-5.758.10E-11-10.091.46E-06-5.84

141.00E-149.96E-011.26E-08-7.901.30E-04-3.888.83E-11-10.057.51E-08-7.121.74E-06-5.767.96E-11-10.101.43E-06-5.84

logKsp

log K1 =-2.250.0056234133-15.8-18.9-20.11-35.1-28.28-20.2-28.7

log K2 =-6.750.00000017780000000

log K3 =-11.60


U(VI)

0000000

0000000

0000000

0000000

0000000

0000000

0000000

0000000

0000000

0000000

0000000

0000000

0000000

0000000

0000000

AlAsO4

Ca3(AsO4)2

CrAsO4

Cu3(AsO4)2

Fe3(AsO4)2

FeAsO4

Mn3(AsO4)2

pH

log Concentration


Rx: As2O3 + 4H+ + 2HS- + 2e- = As2S2 + 3H2O

log K =50.45

logSt4710

014.1210.875.22

-104.120.87-4.78


pK1 =7.10.00079369780.44268836620.9987425577

pK2 =17

000

000

pH = 4

pH = 7

pH = 10

As2O3

As2S2

log [Total S(-II)]

pe


01.00E+009.90E-01-5.00E+00-7.00E+00-1.40E+01-2.60E+01

11.00E-019.09E-01-5.04E+00-6.04E+00-1.20E+01-2.30E+01

21.00E-025.00E-01-5.30E+00-5.30E+00-1.03E+01-2.03E+01

31.00E-039.09E-02-6.04E+00-5.04E+00-9.04E+00-1.80E+01

41.00E-049.89E-03-7.00E+00-5.00E+00-8.00E+00-1.60E+01

51.00E-059.89E-04-8.00E+00-5.00E+00-7.00E+00-1.40E+01

61.00E-069.09E-05-9.04E+00-5.04E+00-6.04E+00-1.20E+01

71.00E-075.00E-06-1.03E+01-5.30E+00-5.30E+00-1.03E+01

81.00E-089.09E-08-1.20E+01-6.04E+00-5.04E+00-9.04E+00

91.00E-099.89E-10-1.40E+01-7.00E+00-5.00E+00-8.00E+00

101.00E-109.89E-12-1.60E+01-8.00E+00-5.00E+00-7.00E+00

111.00E-119.09E-14-1.80E+01-9.04E+00-5.04E+00-6.04E+00

121.00E-125.00E-16-2.03E+01-1.03E+01-5.30E+00-5.30E+00

131.00E-139.09E-19-2.30E+01-1.20E+01-6.04E+00-5.04E+00

141.00E-149.90E-22-2.60E+01-1.40E+01-7.00E+00-5.00E+00

log Ct =-5

log K1 =-20.01

log K2 =-70.0000001

log K3 =-120

-5.0024353766-7.2524353766-14.0024353766-25.6024353766

-5.0237602389-6.2737602389-12.0237602389-22.6237602389

-5.1937787001-5.4437787001-10.1937787001-19.7937787001

-5.8211474173-5.0711474173-8.8211474173-17.4211474173

-6.7584132459-5.0084132459-7.7584132459-15.3584132459

-7.7584132478-5.0084132478-6.7584132478-13.3584132478

-8.821147582-5.071147582-5.821147582-11.421147582

-10.1937856825-5.4437856825-5.1937856825-9.7937856825

-12.0238635084-6.2738635084-5.0238635084-8.6238635084

-14.0035188222-7.2535188222-5.0035188222-7.6035188222

-16.0110123977-8.2610123977-5.0110123977-6.6110123977

-18.0973423124-9.3473423124-5.0973423124-5.6973423124

-20.5455411585-10.7955411585-5.5455411585-5.1455411585

-23.4169542986-12.6669542986-6.4169542986-5.0169542986

-26.4017255251-14.6517255251-7.4017255251-5.0017255251

H3AsO4

H2AsO4-

HAsO42-

AsO43-

log[H3As]

log[H2As-]

log[HAs2-]

log[As3-]

pH

log Concentration

Coagulation-Filtration - Chwirka & Thomson*Solubility of As(V) Species


Coagulation-Filtration - Chwirka & Thomson*Important PointsAs has two oxidation states - As(III) & As(V)As(III)Non-ionic (H3AsO3) at neutral pHHigh solubilityMore toxic to many organismsAs(V)Ionic (H2AsO4-/HAsO42-) at neutral pHSome phases are less solubleMore reactive in solution:MembranesIXAdsorption


Coagulation-Filtration - Chwirka & Thomson*CoprecipitationCoprecipitation involves removal of two or more constituents by a precipitation reaction. Coprecipitation of As with Fe(OH)3 is an effective treatment process:

FeCl3 + 3H2O = Fe(OH)3(s) + 3H+ + 3Cl-Points:Produces HCl which will lower pHTypical Fe dose ~10-4 M, whereas As conc. ~10-7 M, hence As is minor component within precipitateAs likely removed by adsorption onto Fe(OH)3 surface with subsequent enmeshment as floc particle growsAl(OH)3 also effective


Coagulation-Filtration - Chwirka & Thomson*Solubility of Fe(OH)3


Coagulation-Filtration - Chwirka & Thomson*Effect of pH on Surface Charge of Fe(OH)3


Chart2

0.00000005130.99999994870

0.00000051290.99999948710

0.00000512860.99999487140

0.00005128350.99994871640.0000000001

0.00051259850.99948739550.000000006

0.00510244230.99489695820.0000005995

0.04878138990.95116129690.0000573131

0.33765605390.65837683330.0039671127

0.76191973010.14856250710.0895177628

0.45570626250.00888556390.5354081736

0.07842568040.00015291790.9214214017

0.00843953430.00000164560.9915588201

0.00085041420.00000001660.9991495692

0.00008510660.00000000020.9999148933

0.000008511300.9999914887

FeOH2+

FeOHo

FeO-

FeOH

FeOH2+

FeO-

pH

Fraction

Sheet1

pH[H+]FeOHFeOH2+FeO-

01.00E+005.13E-081.00E+006.03E-17

11.00E-015.13E-071.00E+006.03E-15

21.00E-025.13E-061.00E+006.03E-13

31.00E-035.13E-051.00E+006.03E-11

41.00E-045.13E-049.99E-016.02E-09

51.00E-055.10E-039.95E-015.99E-07

61.00E-064.88E-029.51E-015.73E-05

71.00E-073.38E-016.58E-013.97E-03

81.00E-087.62E-011.49E-018.95E-02

91.00E-094.56E-018.89E-035.35E-01

101.00E-107.84E-021.53E-049.21E-01

111.00E-118.44E-031.65E-069.92E-01

121.00E-128.50E-041.66E-089.99E-01

131.00E-138.51E-051.66E-101.00E+00

141.00E-148.51E-061.66E-121.00E+00

log K1 =7.291.95E+07

log K2 =-8.931.17E-09

&A

Page &P

Sheet1

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

&A

Page &P

FeOH2+

FeOHo

FeO-

FeOH

FeOH2+

FeO-

pH

Fraction

Coagulation-Filtration - Chwirka & Thomson*Covalent Bond Formation(Grossl et al., 1997)


Coagulation-Filtration - Chwirka & Thomson*pH of Zero Point of ChargeElectrostatic attraction is important first step in adsorptionpHzpc = pH at which net surface charge = 0Surface is positive at pH < pHzpcMost clay minerals have pHzpc < 6Hence poor adsorptionClays dominate surface chemistry of soilsFe(OH)3 and Al2O3 have relatively high pHzpcGood adsorbents of As(V)


Coagulation-Filtration - Chwirka & Thomson*As Removal by Conventional Treatment (McNeill & Edwards 1997)Survey of conventional coagulation-flocculation water treatment plantsCorrelate As removal to removal of Fe, Mn, & Al

[Fe] = Iron Precip. Formed (mM)


Coagulation-Filtration - Chwirka & Thomson*As Removal by Conventional Trt. - 2


Chart1

00

4540

6560

8075

8782

9085

[Fe]

[Fe]+[Al]

Precipitate Formed (mM)

As Removal (%)

Sheet1

Precip. Formed (mM)[Fe][Fe]+[Al]

000

0.014540

0.026560

0.048075

0.068782

0.089085

Sheet1

[Fe]

[Fe]+[Al]

Precipitate Formed (mM)

As Removal (%)

Sheet2

Sheet3

Coagulation-Filtration - Chwirka & Thomson*As Removal by Conventional Trt. - 3Strong correlation to removal of Fe & use of FeCl3 as coagulantWeaker correlation to removal of Al & use of AlumPossible sorption onto colloidal Al(OH)3 which passes through granular media filtersImproved As removal achieved by minimizing effluent total Al concentrationNote the importance of particulate As


Coagulation-Filtration - Chwirka & Thomson*Arsenic Removal vs FeCl3 Dose, Albuquerque NM


Chart4

408.46

19.237.99

3.37.36

1.187.2

1.517.05

1.186.83

0.756.56

&A

Page &P

Residual Arsenic

Filtrate pH

FeCl3 Dose, mg Fe/L

Residual As, ug/L

Filtrate pH

Fe(OH)3 Vs FeCl3

Arsenic Data Transcribed from Ganesh's Graphs

Preformemed Fe(OH)3 Dose as Fe, mg/LResidual Arsenic from Preformed Fe(OH)3 Addition, ug/LFerric Chloride Dose as Fe, mg/LResidual Arsenic from Ferric Addition, ug/L

040040

1.7631.462.519.23

411.425.53.3

6.383.337.31.18

7.572.559.341.51

9.552.13121.18

11.881.0518.10.75

15.480.89

17.290.87

18.80.74

&A

Page &P

Fe(OH)3 Vs FeCl3

00

00

00

00

00

00

00

0

0

0

&A

Page &P

Residual Arsenic from Preformed Fe(OH)3 Addition, ug/L

Residual Arsenic from Ferric Addition, ug/L

Ferric Dose as Fe, mg/L

Residual Arsenic, ug/L

FeCl3

Ferric Chloride Dose as Fe, mg/LResidual Arsenic from Ferric Addition, ug/LFiltate pH

0408.46

2.519.237.99

5.53.37.36

7.31.187.2

9.341.517.05

121.186.83

18.10.756.56

&A

Page &P

FeCl3

00

00

00

00

00

00

00

&A

Page &P

Residual Arsenic

Filtrate pH

FeCl3 Dose, mg Fe/L

Residual As, ug/L

Filtrate pH

As Removal with FeCl3 and Rapid Mixing

Fe(OH)3

Preformemed Fe(OH)3 Dose as Fe, mg/LResidual Arsenic from Preformed Fe(OH)3 Addition, ug/LFiltrate pH

0408.43

1.7631.468.18

411.427.69

6.383.337.11

7.572.557.08

9.552.136.86

11.881.056.72

15.480.896.48

17.290.876.43

18.80.746.33

&A

Page &P

Fe(OH)3

00

00

00

00

00

00

00

00

00

00

&A

Page &P

Residual Arsenic from Preformed Fe(OH)3 Addition, ug/L

Filtrate pH

Fe(OH)3 Dose, mg Fe/L

Residual As, ug/L

Filtrate pH

Phase 1 Fe(OH)3 Addition Pump Mixing

Sheet4

&A

Page &P

Sheet5

&A

Page &P

Sheet6

&A

Page &P

Sheet7

&A

Page &P

Sheet8

&A

Page &P

Sheet9

&A

Page &P

Sheet10

&A

Page &P

Sheet11

&A

Page &P

Sheet12

&A

Page &P

Sheet13

&A

Page &P

Sheet14

&A

Page &P

Sheet15

&A

Page &P

Sheet16

&A

Page &P

Coagulation-Filtration - Chwirka & Thomson*Ambient pH: FeCl3 vs As Leakage, NAS Fallon


Coagulation-Filtration - Chwirka & Thomson*El Paso Jar Testing


Coagulation-Filtration - Chwirka & Thomson*pH Adjustment with CO2, NAS Fallon, NV


Coagulation-Filtration - Chwirka & Thomson*Silica Impacts Arsenic Removal at pH 7.0 and AbovepH 8.5pH 7.5pH 6.5FeCl3 Dose: 4 mg/LAfter Clifford and Ghurye


Coagulation-Filtration - Chwirka & Thomson*Silica Speciation with pH


Coagulation-Filtration - Chwirka & Thomson*Silica in US Water Supplies (NAOS)After Davis and Edwards


Coagulation-Filtration - Chwirka & Thomson*Polymeric SilicaAfter Davis and Edwards50 mg/L17 mg/L5 mg/L


Coagulation-Filtration - Chwirka & Thomson*Coagulation/ FiltrationUse pressure filtersDirect Filtration frequently used for iron and manganese removal.Limited to low ferric dose applications. High coagulant dose will result in frequent backwash requirementsIncreased residuals production & handling costsIncreased production of wastewater


Coagulation-Filtration - Chwirka & Thomson*Schematic of Coagulation/ FiltrationAerationFeCl3Rapid MixSolids to DewateringTreated WaterPressure FilterSolids to LandfillRaw WaterCO2CO2


Coagulation-Filtration - Chwirka & Thomson*Calculation of Filter Loading LimitationRule of Thumb, no more than 10 mg/L of FeCl3Limit Solids Loading to 0.1 lbs/SFMay need to add sedimentation


Coagulation-Filtration - Chwirka & Thomson*Vertical Pressure Filter


Coagulation-Filtration - Chwirka & Thomson*Direct Filtration Performance(Based on 0.1 lbs Solids/sf)


Coagulation-Filtration - Chwirka & Thomson*Backwash Water as Percent of Production(Based on 250 gal/sf)


Coagulation-Filtration - Chwirka & Thomson*C/F O&M IssuesLarge backwash volume (20 gpm/sf for 10 minutes) Tanks may need internal painting, 10 yr intervals. Use 316 SST.Standby filters, typically provided, but need to evaluate.Pneumatic or electric valve operators.


Coagulation-Filtration - Chwirka & Thomson*Coagulation/ Pressure FiltrationParticle sizeParticle breakthroughbackwash requirementsfilter ripeningBackup Filters


Coagulation-Filtration - Chwirka & Thomson*Coagulation/ MicrofiltrationPilot tested in Albuquerque, 1998Pilot tested in NAS Fallon, NV, 2001Pilot tested in El Paso, TX, 2001/2002Fallon Paiute Shoshone Tribe: 0.5 mgdCity of Albuquerque: 2.3 mgd


Coagulation-Filtration - Chwirka & Thomson*Microfiltration General ConceptsLow Operating Pressure, 5 - 30 psi0.1 to 0.2 micron pore sizeWater flow from Outside to the InsideAir-Water BackwashBackwash Every 25 to 30 minutes (95% recovery)Flux rate defined as Gallons/SF/Day (GFD)Chemical Cleaning Frequency > 30 days


Coagulation-Filtration - Chwirka & Thomson*What is C/MF?


Coagulation-Filtration - Chwirka & Thomson*Pressure Driven Membranes


Coagulation-Filtration - Chwirka & Thomson*MF Process Operates in Direct Filtration Mode


Coagulation-Filtration - Chwirka & Thomson*Solids are Removed from Module by an Air-Water Backwash


Coagulation-Filtration - Chwirka & Thomson*Coagulation/ MicrofiltrationPilot tested in Albuquerque, 1998Pilot tested in NAS Fallon, NV, 2001Pilot tested in El Paso, TX, 2001/2002Fallon Paiute Shoshone Tribe: 0.5 mgdCity of Albuquerque: 2.3 mgd


Coagulation-Filtration - Chwirka & Thomson*Microfiltration General ConceptsLow Operating Pressure, 5 - 30 psi0.1 to 0.2 micron pore sizeWater flow from Outside to the InsideAir-Water BackwashBackwash Every 25 to 30 minutes (95% recovery)Flux rate defined as Gallons/SF/Day (GFD)Chemical Cleaning Frequency > 30 days


Coagulation-Filtration - Chwirka & Thomson*What is C/MF?


Coagulation-Filtration - Chwirka & Thomson*Pressure Driven Membranes


Coagulation-Filtration - Chwirka & Thomson*MF Process Operates in Direct Filtration Mode


Coagulation-Filtration - Chwirka & Thomson*Solids are Removed from Module by an Air-Water Backwash


Coagulation-Filtration - Chwirka & Thomson*Pall Microfilter


Coagulation-Filtration - Chwirka & Thomson*Memcor PerformanceNAS Fallon, 15 mg/L FeCl325 GFD (No FeCl3)27 GFD38 GFD(No FeCl3)32 GFD27 GFD


Coagulation-Filtration - Chwirka & Thomson*Memcor Cleaning EfficiencyNAS Fallon, Citric Acid


Coagulation-Filtration - Chwirka & Thomson*Pall PerformanceNAS Fallon, FeCl3 45 mg/L


Coagulation-Filtration - Chwirka & Thomson*El Paso C/MF Pilot Studies


Coagulation-Filtration - Chwirka & Thomson*El Paso Pilot StudiesOnly Pall MF testedFerric dose 10 mg/LpH lowered to 6.8 with CO2


Coagulation-Filtration - Chwirka & Thomson*El Paso Pall Performance


Coagulation-Filtration - Chwirka & Thomson*Fallon Paiute Shoshone Tribe C/MF PFD


Coagulation-Filtration - Chwirka & Thomson*Fallon Paiute Shoshone Tribe C/MF


Coagulation-Filtration - Chwirka & Thomson*Fallon Paiute Shoshone Tribe As Treatment Faciliy


Coagulation-Filtration - Chwirka & Thomson*Fallon Paiute Shoshone Tribe Start-upDecember 2004


Chart2

202939

4156

3123

311

11

4

pH = 6.8

pH = 7.4

pH = 8.0

Ferric Chloride Dose

Finished Water Arsenic

Sheet1

Fallon Paiute-Shoshone Tribe Arsenic WTP Optimization Testing


pH = 6.8pH = 7.4pH = 8.0

fieldlabfieldlabfieldlab

Bottle No.FeCl3 Dosearsenic (ug/L)arsenic (ug/L)Bottle No.FeCl3 Dosearsenic (ug/L)arsenic (ug/L)Bottle No.FeCl3 Dosearsenic (ug/L)arsenic (ug/L)

20453020205102429211157039

21487420615151521235106

20215632072012122134563

2012063208251211

203*10370209301011

* this data point looks to be a sampling error and2104084

has been removed from the

Sheet1

pH = 6.8

pH = 7.4

pH = 8.0



Arsenic Removal Using C/MF (Field Arsenic Testing)

Sheet2

pH = 6.8

pH = 7.4

pH = 8.0



Sheet3

Coagulation-Filtration - Chwirka & Thomson*C/MF SummaryEmerging Technology for Arsenic TreatmentCan be designed for high flux rates with Low TOC groundwaterOptimize solids loading by pH pre-treatmentCost competitive with other technologies


Coagulation-Filtration - Chwirka & Thomson*Recent Studies on Particle Size Filtration and Arsenic Removal


Coagulation-Filtration - Chwirka & Thomson*C/MF O&M IssuesMembrane Replacement: Pall warrantees membranes for 10 years, prorated.Chemical cleaning with citric acid, can not be recycled, must be disposed of.Provide sufficient replacement parts, not system redundancy.


Coagulation-Filtration - Chwirka & Thomson*Comparison of C/MF to Pressure Filters at the Fallon Paiute Shoshone Tribe


Coagulation-Filtration - Chwirka & Thomson*Residuals Characteristics for C/MF and C/FC/MF around 4% to 5 % Backwash.C/F around 5% to 10% Backwash.Recycle the backwash water to minimize wastewater.Ferric residuals will pass TCLP, however, may not pass the Cal WET.


Coagulation-Filtration - Chwirka & Thomson*Residuals HandlingMechanical dewatering will be complicated: Ferric sludge is difficult to dewaterNeed body additives, Diatomaceous EarthFilter Bottom Dumpsters and polymer for small applications.Solids drying ponds:Ponds need to be lined.Anaerobic conditions may release the As.Provide access for sludge removal equipment.


Coagulation-Filtration - Chwirka & Thomson*Concurrent Iron, Manganese, and ArsenicDrinking Water StandardsFe: Secondary Standard of 0.30 mg/LMn: Secondary Standard of 0.05 mg/L


Coagulation-Filtration - Chwirka & Thomson*Iron and Arsenic RemovalOxidize Fe with Cl2 or O3Adsorb As onto Fe(OH)3 precipitatepH needs to be around 7.3


Coagulation-Filtration - Chwirka & Thomson*Manganese and Arsenic RemovalAs requires low pH for adsorptionMn requires high pH (>10) for oxidation with Cl2Mn oxidation by ClO2 is rapid & appears to be independent of pHClO2 reported to be ineffective for As(III) oxidation.May need to add Cl2 in addition


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