Technologies and Costs for Removal of Arsenic From Drinking Water

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Basis. An old activated alumina design manual for fluoride removal recommends that the beddiameter be equal to or greater than the bed depth to prevent “wall effects” (5). This sourcealso states that good practice dictates that the bed depth be a minimum of three feet and amaximum of six feet. The Water Model assumed a bed depth of 5 feet for all conceptualdesigns (6). Many of the conceptual designs in the cost estimating manual had bed depths thatexceeded the diameter, so the recommendation in the design manual was not strictly appliedto all designs. For design flows less than 50,000 gallons per day, the bed depth is greater thanthe bed diameter. The data from the three case studies where activated alumina is beingoperated without regeneration, the bed depth is greater than the bed diameter (2, 3).7. The vessel cost has been sized based on 50% bed expansion during backwash even thoughbackwashing may not be necessary on a routine basis for smaller systems. The vessel volumewas calculated as (1.5)(media volume).Basis. The old design manual and the Water Model used 50% bed expansion to size the vessel(5, 6). Both of these designs are based on regeneration of the media rather than disposableoperation. The bed expansion for the one case study where it could be calculated was 30%(3). The design approach used as the basis for the case studies in the AwwaRF report used80% expansion (7). However, this design was also based on regeneration of the media ratherthan disposable media operation and was based on designs greater than 1 mgd. Since theexpansion is only necessary for backwashing, 50% expansion was assumed for all sizes.Backwashing is not performed on a routine basis at any of the three small systems operatingactivated alumina without regeneration.8. The vessel cost is based on the following equation:Cost = 63.288 * (Vessel Volume in gallons) ^ 0.679Basis. Quotes were obtained from two manufacturers for glass-lined carbon steel vessels withworking pressure rating between 75 and 150 psi and meeting American Society of MechanicalEngineers (ASME) Code Section VIII requirements. Sizes ranging from 140 gallons to 6764gallons were used to develop the equation. Vessel costs for sixteen different sizes wereD-4
egressed against their respective volumes to derive the equation. Costs from the AwwaRFreport cannot be used for comparison because of an apparent error in the vessel costs. Thevendor quote used for vessel costs is actually a vendor quote for a complete activated aluminasystem. The vendor quote presents budget prices for three design flows and different sizevessels are used for each design flow. The vessel sizes are listed with the budget price andthis is apparently the source of the mistake. The three full-scale systems using activatedalumina on a disposable basis use fiberglass tanks instead of carbon steel tanks because thepressure drop is very small. Fiberglass tanks would be less expensive than the carbon steelvessels, so the vessel costs are conservative for very small systems.9. The capital costs include a redundant column to allow the system to operate while the mediais being replaced in the old roughing column.Basis. A redundant vessel has been included for each set of roughing and polishing columns.While the activated alumina media is being replaced in this column, the other two columns canstill function as a roughing and polishing column. Activated alumina media is not included inthe redundant vessel(s) as a capital cost to make it easier to estimate O&M costs. The Phoenixcase study uses a redundant roughing and polishing column (4). This design did not seem tobe the most efficient because one column would contain partially used activated alumina, butwould not be in operation while the media in the other column was being replaced. The initialAlbuquerque design did not contain a redundant column, but instead relied upon the oldpolishing column to treat all the water while the media was replaced in the old roughingcolumn (7). The two full-scale sites in New Hampshire split the flow into two streams andhad roughing and polishing columns treating half the water (3). Redundant columns were notincluded; however, one set of columns could treat all the water if there was a problem withthe other set.10. The remaining components of the process equipment include concrete, pipe and valves andelectrical and instrumentation. A cost factor of 14.43% of the manufactured equipment andactivated alumina was used for these other construction cost components.D-5
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United StatesEnvironmental Protecti
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ACKNOWLEDGMENTSThis document was pr
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2.5.7 Reverse Osmosis .............
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5.0 POINT-OF-ENTRY/POINT-OF-USE TRE
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LIST OF FIGURES2-1 Pressure Driven
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LIST OF ACRONYMSAAAWWAAWWARFBLSBVC/
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POUpoint-of-useppbparts per billion
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# Alternative treatment processes s
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ends up as ferric hydroxide. In alu
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Optimization Hierarchy for Coagulat
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Substantial arsenic removal has bee
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Vickers et al. (1997) reported that
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was reduced to 0.05 mg/L when the i
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Field StudiesSurveys of lime soften
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Effect of pHpH may have significant
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RegenerationRegeneration of AA beds
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een developed provide important inf
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applicability of IX at a particular
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TABLE 2-1Typical IX Resins for Arse
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solution strength. Arsenic elutes r
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2.4.12 Typical Design ParametersThr
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2.5.2 Important Factors for Membran
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arsenic size distribution to correl
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AWWARF (1998) also performed UF pil
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presumably due to changes in electr
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RO performance is adversely affecte
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TABLE 2-10Arsenic Removal with RO a
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eversal is the decreased potential
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2.6 ALTERNATIVE TECHNOLOGIES2.6.1 I
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20 mg As per gram of iron was remov
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The most significant weakness of th
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3.0 TECHNOLOGY COSTS3.1 INTRODUCTIO
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included in the estimates presented
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Table 3-3Water Model Capital Cost B
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3.2.3 Implementing TDP Recommended
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sources. The September 1998 index v
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Amortization, or capital recovery,
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3.3 ADDITIONAL CAPITAL COSTSThe cos
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PilotingThe Technology Design Panel
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The 1993 Technology and Cost Docume
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cause disinfection by-product (DBP)
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Figure 3-1Pre-oxidation - 1.5 mg/L
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3.6 PRECIPITATIVE PROCESSES3.6.1 Co
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enhanced coagulation treatment plan
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Figure 3-4Enhanced Coagulation/Filt
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Small Systems (Less than 1 mgd)The
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Figure 3-6Coagulation Assisted Micr
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3.6.6 Enhanced Lime SofteningEnhanc
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Figure 3-8Enhanced Lime SofteningO&
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3. Empty Bed Contact Time (EBCT) is
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For design flows greater than 1 mgd
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Figure 3-9Activated AluminaCapital
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Figure 3-11Activated Alumina (pH 8
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Figure 3-13Activated Alumina (pH Ad
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3.7.2 Granular Ferric HydroxideGran
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6. The capital costs include a redu
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Figure 3-15Bed Volumes to Arsenic B
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Figure 3-17Anion Exchange (< 20 mg/
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Figure 3-19Anion Exchange (20-50 mg
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quality feed stream and often requi
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Figure 3-20Greensand FiltrationCapi
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3.11 COMPARISON OF COSTSThe April 1
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4.0 RESIDUALS HANDLING AND DISPOSAL
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mechanical dewatering processes. Wh
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Storage lagoons are best suited for
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the current Industrial Pretreatment
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4.3.3 Dewatered Sludge Land Applica
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usually determined by the Paint Fil
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for arsenic toxicity by a substanti
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The solids content of the backwash
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carbonate hardness removal produces
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Domestic sewage means untreated san
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4.4.10 Reverse OsmosisReverse osmos
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Figure 4-1Anion Exchange (< 20 mg/L
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Figure 4-3Anion Exchange (20-50 mg/
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Figure 4-9Activated Alumina (pH 7 -
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Figure 4-11Activated Alumina (pH Ad
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Figure 4-13Greensand FiltrationWast
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5.0 POINT-OF-ENTRY/POINT-OF-USE TRE
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chromatographic peaking, which occu
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5.3.1 Case Study 1: Fairbanks, Alas
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Manufacturer and laboratory data su
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Figure 5-2POU Reverse OsmosisO&M Co
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# Installation time - 1 hour unskil
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Figure 5-3POU Activated AluminaTota
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6.0 REFERENCESAmy, G.L. and P. Bran
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Cooperative Research Centres for Wa
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Fuller, C.C., J.A. Davis, G.W. Zell
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Le, X.C., and M. Ma (1998). “Dete
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Scott, K., J. Green, H.D. Do and S.
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Appendix AVery Small Systems Capita
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Table A4 - VSS Document Capital Cos
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Page 211: Appendix CW/W Cost Model Capital Co
Page 214 and 215: Table C2.1 - Base Costs Obtained fr
Page 222 and 223: Table C10.1 - Base Costs Obtained f
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Page 243 and 244: APPENDIX D: BASIS FOR REVISED ACTIV
Page 245: Company case study is 18 minutes (2
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
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Technologies and Costs for Removal of Arsenic From Drinking Water

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