Technologies and Costs for Removal of Arsenic From Drinking Water

More documents

Recommendations

Info

3.9 SEPARATION PROCESSES3.9.1 MicrofiltrationMicrofiltration is a low-pressure membrane process which has only a marginal ability toremove arsenic due to its relatively large pore size in comparison to other membrane processes. MFremoves contaminants from a feed stream primarily through sieving. Typically, MF does not requirepretreatment beyond approximately 500-mm prefiltration. Because MF is not an effective stand-alonetechnology for removal of arsenic, capital and O&M cost estimates for MF are not provided in thischapter.3.9.2 UltrafiltrationUltrafiltration is a low-pressure membrane process which removes contaminants from a feedstream primarily through sieving. Typically, UF does not require pretreatment beyond approximately200-mm prefiltration. UF has the benefit of being lower in both capital and O&M costs than highpressuremembrane processes. Because UF is not an effective stand-alone technology for removal ofarsenic, capital and O&M cost estimates for UF are not provided in this chapter.3.9.3 NanofiltrationNanofiltration is a high-pressure membrane process capable of significant arsenic removal.NF removes contaminants from a feed stream primarily through a combination of diffusion and sievingmechanisms. Typically, NF requires pretreatment to remove suspended solids and other foulants fromthe feed stream. NF has greater arsenic removal capabilities than low-pressure membrane processes,however, capital and O&M costs for NF are usually greater than equivalent costs for low-pressureprocesses. Due to decreased removal efficiency when operated at higher recoveries, NF is not yetdemonstrated to be a reliable treatment for arsenic. Because NF is not an effective stand-alonetechnology for removal of arsenic, capital and O&M cost estimates for NF are not provided in thischapter.3.9.4 Reverse OsmosisReverse Osmosis is a high-pressure membrane process which removes dissolved contaminantsfrom a feed stream primarily through diffusion rather than physical straining. RO requires a high3-56
quality feed stream and often requires substantial pretreatment to remove suspended solids and otherfoulants. RO also often requires pH adjustment after the membrane process and may require theaddition of an anti-scalant before the membrane process. For the purpose of this analysis, costs werenot provided for a substantial pre-treatment system, other than the anti-scalant system. RO has thebenefit of greater arsenic removal compared to low-pressure membrane processes, but is typicallyassociated with higher capital and O&M costs. Costs are not provided for RO because other optionsare more cost effective and have much smaller waste streams. RO may be cost effective if removalof other contaminants is needed and water quantity is not a concern.Both the VSS Model and the W/W Cost Model included cost estimation for RO. Since theW/W Cost Model was assembled, however, RO spiral-wound membrane module costs havedecreased by approximately 50 percent. For this reason, the membrane module portion of the capitalcosts can be reduced by 50 percent. The membrane replacement portion of the O&M costs can alsobe reduced by 50 percent to account for reductions in membrane costs. The W/W Cost Model for ROwas only valid up to a capacity of 200 mgd. The model also makes an assumption that recovery is 80percent for systems of 1 to 10 mgd, and 85 percent for systems larger than 10 mgd.3.10 GREENSAND FILTRATIONGreensand filtration is an oxidation filtration process that has demonstrated effectiveness forthe removal of arsenic. The greensand filtration medium is produced by treating glauconite sand withKMnO 4 until the granular material (sand) is coated with a layer of manganese oxides, particularlymanganese dioxide. Arsenic compounds displace species from the manganese oxide (presumably OH -and H 2 O), becoming bound to the greensand surface - in effect an exchange of ions. The oxidativenature of the manganese surface converts As(III) to As(V), and As(V) is adsorbed to the surface.The VSS model was used for estimating greensand filtration capital and O&M costs.Greensand filtration costs were not included in either the Water Model or the W/W Model. Thistechnology is considered to be a small systems technology and as a result costs were not estimated forlarger systems. This technology could be effectively operated in larger system sizes, but cost data arenot readily available. The key parameter is the ratio of source water iron and arsenic. If high3-57
Page 1:
United StatesEnvironmental Protecti
Page 5:
ACKNOWLEDGMENTSThis document was pr
Page 8 and 9:
2.5.7 Reverse Osmosis .............
Page 10 and 11:
5.0 POINT-OF-ENTRY/POINT-OF-USE TRE
Page 12 and 13:
LIST OF FIGURES2-1 Pressure Driven
Page 14 and 15:
LIST OF ACRONYMSAAAWWAAWWARFBLSBVC/
Page 16 and 17:
POUpoint-of-useppbparts per billion
Page 18 and 19:
# Alternative treatment processes s
Page 20 and 21:
This page was intentionally left bl
Page 23 and 24:
ends up as ferric hydroxide. In alu
Page 25 and 26:
Optimization Hierarchy for Coagulat
Page 27 and 28:
Substantial arsenic removal has bee
Page 29 and 30:
Vickers et al. (1997) reported that
Page 31 and 32:
was reduced to 0.05 mg/L when the i
Page 33 and 34:
Field StudiesSurveys of lime soften
Page 35 and 36:
Effect of pHpH may have significant
Page 37 and 38:
RegenerationRegeneration of AA beds
Page 39 and 40:
een developed provide important inf
Page 41 and 42:
applicability of IX at a particular
Page 43 and 44:
TABLE 2-1Typical IX Resins for Arse
Page 45 and 46:
solution strength. Arsenic elutes r
Page 47 and 48:
2.4.12 Typical Design ParametersThr
Page 49 and 50:
2.5.2 Important Factors for Membran
Page 51 and 52:
arsenic size distribution to correl
Page 53 and 54:
AWWARF (1998) also performed UF pil
Page 55 and 56:
presumably due to changes in electr
Page 57 and 58:
RO performance is adversely affecte
Page 59 and 60:
TABLE 2-10Arsenic Removal with RO a
Page 61 and 62:
eversal is the decreased potential
Page 63 and 64:
2.6 ALTERNATIVE TECHNOLOGIES2.6.1 I
Page 65 and 66:
20 mg As per gram of iron was remov
Page 67 and 68:
The most significant weakness of th
Page 69 and 70:
3.0 TECHNOLOGY COSTS3.1 INTRODUCTIO
Page 71 and 72:
included in the estimates presented
Page 73 and 74: Table 3-3Water Model Capital Cost B
Page 75 and 76: 3.2.3 Implementing TDP Recommended
Page 77 and 78: sources. The September 1998 index v
Page 79 and 80: Amortization, or capital recovery,
Page 81 and 82: 3.3 ADDITIONAL CAPITAL COSTSThe cos
Page 83 and 84: PilotingThe Technology Design Panel
Page 85 and 86: The 1993 Technology and Cost Docume
Page 87 and 88: cause disinfection by-product (DBP)
Page 89 and 90: Figure 3-1Pre-oxidation - 1.5 mg/L
Page 91 and 92: 3.6 PRECIPITATIVE PROCESSES3.6.1 Co
Page 93 and 94: enhanced coagulation treatment plan
Page 95 and 96: Figure 3-4Enhanced Coagulation/Filt
Page 97 and 98: Small Systems (Less than 1 mgd)The
Page 99 and 100: Figure 3-6Coagulation Assisted Micr
Page 101 and 102: 3.6.6 Enhanced Lime SofteningEnhanc
Page 103 and 104: Figure 3-8Enhanced Lime SofteningO&
Page 105 and 106: 3. Empty Bed Contact Time (EBCT) is
Page 107 and 108: For design flows greater than 1 mgd
Page 109 and 110: Figure 3-9Activated AluminaCapital
Page 111 and 112: Figure 3-11Activated Alumina (pH 8
Page 113 and 114: Figure 3-13Activated Alumina (pH Ad
Page 115 and 116: 3.7.2 Granular Ferric HydroxideGran
Page 117 and 118: 6. The capital costs include a redu
Page 119 and 120: Figure 3-15Bed Volumes to Arsenic B
Page 121 and 122: Figure 3-17Anion Exchange (< 20 mg/
Page 123: Figure 3-19Anion Exchange (20-50 mg
Page 127 and 128: Figure 3-20Greensand FiltrationCapi
Page 129 and 130: 3.11 COMPARISON OF COSTSThe April 1
Page 131 and 132: 4.0 RESIDUALS HANDLING AND DISPOSAL
Page 133 and 134: mechanical dewatering processes. Wh
Page 135 and 136: Storage lagoons are best suited for
Page 137 and 138: the current Industrial Pretreatment
Page 139 and 140: 4.3.3 Dewatered Sludge Land Applica
Page 141 and 142: usually determined by the Paint Fil
Page 143 and 144: for arsenic toxicity by a substanti
Page 145 and 146: The solids content of the backwash
Page 147 and 148: carbonate hardness removal produces
Page 149 and 150: Domestic sewage means untreated san
Page 151 and 152: 4.4.10 Reverse OsmosisReverse osmos
Page 153 and 154: Figure 4-1Anion Exchange (< 20 mg/L
Page 155 and 156: Figure 4-3Anion Exchange (20-50 mg/
Page 161 and 162: Figure 4-9Activated Alumina (pH 7 -
Page 163 and 164: Figure 4-11Activated Alumina (pH Ad
Page 165 and 166: Figure 4-13Greensand FiltrationWast
Page 167 and 168: 5.0 POINT-OF-ENTRY/POINT-OF-USE TRE
Page 169 and 170: chromatographic peaking, which occu
Page 171 and 172: 5.3.1 Case Study 1: Fairbanks, Alas
Page 173 and 174: Manufacturer and laboratory data su
Page 175 and 176:
Figure 5-2POU Reverse OsmosisO&M Co
Page 177 and 178:
# Installation time - 1 hour unskil
Page 179 and 180:
Figure 5-3POU Activated AluminaTota
Page 181 and 182:
6.0 REFERENCESAmy, G.L. and P. Bran
Page 183 and 184:
Cooperative Research Centres for Wa
Page 185 and 186:
Fuller, C.C., J.A. Davis, G.W. Zell
Page 187 and 188:
Le, X.C., and M. Ma (1998). “Dete
Page 189 and 190:
Scott, K., J. Green, H.D. Do and S.
Page 191:
Appendix AVery Small Systems Capita
Page 194 and 195:
Table A4 - VSS Document Capital Cos
Page 197 and 198:
Table B1.1 - Base Costs Obtained fr
Page 199 and 200:
Page 201 and 202:
Page 203 and 204:
Page 205 and 206:
Page 207 and 208:
Table B11.1 - Base Costs Obtained f
Page 209 and 210:
Table B13.1 - Base Costs Obtained f
Page 211:
Appendix CW/W Cost Model Capital Co
Page 214 and 215:
Table C2.1 - Base Costs Obtained fr
Page 216 and 217:
Page 218 and 219:
Page 220 and 221:
Page 222 and 223:
Table C10.1 - Base Costs Obtained f
Page 224 and 225:
Page 226 and 227:
Page 228 and 229:
Page 230 and 231:
Page 232 and 233:
Page 234 and 235:
Page 236 and 237:
Page 238 and 239:
Page 240 and 241:
Page 243 and 244:
APPENDIX D: BASIS FOR REVISED ACTIV
Page 245 and 246:
Company case study is 18 minutes (2
Page 247 and 248:
egressed against their respective v
Page 249 and 250:
costs for small systems is as follo
Page 251 and 252:
were based on $40/sq ft). The proce
Page 253 and 254:
Basis. Capital cost components incl
Page 255 and 256:
The source water at Plant D has the
Page 257 and 258:
equation y = (2*10 -8 )x 2 + 0.0002
Page 259 and 260:
The maximum run length is 18,500 be
Page 261 and 262:
Since the available arsenic capacit
Page 263 and 264:
If the first column can be operated
Page 265 and 266:
which includes lighting, ventilatio
Page 267 and 268:
disposal costs, if needed, are cove
Page 269:
Appendix EBasis for Revised Anion E
Page 272 and 273:
2. The estimated cost of the anion
Page 274 and 275:
9. The capital costs have been esti
Page 276 and 277:
Thus, the cost of a road and fence
Page 278 and 279:
length when sulfate is at or below
Page 280 and 281:
the labor rates for both large and
Page 282 and 283:
2. US EPA. Technologies and Costs f
Page 284:
show all

Technologies and Costs for Removal of Arsenic From Drinking Water

Create successful ePaper yourself

Delete template?

Save as template?