Technologies and Costs for Removal of Arsenic From Drinking Water

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appear to present some competition for arsenic. The addition of 4 mg/L DOC reduced As(V) sorptionby about 50 percent.Effect of Empty Bed Contact TimeThe EBCT can affect the arsenic removal efficiency of IOCS. Benjamin et al. (1998)conducted continuous flow IOCS column tests using arsenic-spiked water from Lake Washington. Alltests were run by adjusting the feed solution to pH 7. Sampling ports at various points in the systemallowed EBCTs ranging from 2.5 to 15 minutes to be tested. Low arsenic concentrations (i.e.
20 mg As per gram of iron was removed at pH 8, and 50 mg As per gram of iron was removed at pH7. Arsenic removal seems to be very dependent on the iron to arsenic ratio.Packed bed column tests demonstrated significant arsenic removal at residence times of 5 to15 minutes. Significant removal of both arsenate and arsenite was measured. The highest adsorptioncapacity measured was 11 mg As removed per gram of iron. Flow distribution problems wereevident, as several columns became partially plugged and better arsenic removal was observed withreduced flow rates.Spent media from the column tests were classified as nonhazardous waste. Projectedoperating costs for SMI, when the process is operated below a pH of 8, are much lower thanalternative arsenic removal technologies such as ferric chloride addition, reverse osmosis, andactivated alumina. Cost savings would increase proportionally with increased flow rates andincreased arsenic concentrations.Possible treatment systems using SMI include continuous stirred tank reactors, packed bedreactors, fluidized bed reactors, and passive in situ reactors. Packed bed and fluidized bed reactorsappear to be the most promising for successful arsenic removal in pilot-scale and full-scale treatmentsystems based on present knowledge of the SMI process.2.6.3 Granular Ferric HydroxideA new removal technique for arsenate, which has recently been developed at the TechnicalUniversity of Berlin (Germany), Department of Water Quality Control, is adsorption on granularferric hydroxide (GFH) in fixed bed reactors. This technique combines the advantages of thecoagulation-filtration process, efficiency and small residual mass, with the fixed bed adsorption onactivated alumina, and simple processing.Driehaus et al. (1998) reported that the application of GFH in test adsorbers showed a hightreatment capacity of 30,000 to 40,000 bed volumes with an effluent arsenate concentration neverexceeding 10 µg/L. The typical residual mass was in the range of 5-25 g/m 3 treated water. Theresidue was a solid with an arsenate content of 1-10 g/kg. Table 2-14 summarizes the data of theadsorption tests.2-45
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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
Page 14 and 15: LIST OF ACRONYMSAAAWWAAWWARFBLSBVC/
Page 16 and 17: POUpoint-of-useppbparts per billion
Page 18 and 19: # Alternative treatment processes s
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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: 2.6 ALTERNATIVE TECHNOLOGIES2.6.1 I
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
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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 4-5Coagulation Assisted Micr
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Figure 4-7Coagulation Assisted Micr
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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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Table B1.1 - Base Costs Obtained fr
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Table B11.1 - Base Costs Obtained f
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Table B13.1 - Base Costs Obtained f
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Appendix CW/W Cost Model Capital Co
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Table C2.1 - Base Costs Obtained fr
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Table C10.1 - Base Costs Obtained f
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APPENDIX D: BASIS FOR REVISED ACTIV
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Company case study is 18 minutes (2
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egressed against their respective v
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costs for small systems is as follo
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were based on $40/sq ft). The proce
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Basis. Capital cost components incl
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The source water at Plant D has the
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equation y = (2*10 -8 )x 2 + 0.0002
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The maximum run length is 18,500 be
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Since the available arsenic capacit
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If the first column can be operated
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which includes lighting, ventilatio
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disposal costs, if needed, are cove
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Appendix EBasis for Revised Anion E
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2. The estimated cost of the anion
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9. The capital costs have been esti
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Thus, the cost of a road and fence
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length when sulfate is at or below
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the labor rates for both large and
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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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