Arsenic US EPA Demonstration Program and Latest Research Results

Arsenic: USEPA Demonstration Program and Latest Research Results Tom Sorg USEPA Cincinnati, OH Workshop on Inorganic Contaminant Issues August 21-23, 2007 Cincinnati, OH Topics •Short Summary of USEPA Arsenic Demonstration Program •Latest Research USEPA Arsenic Demonstration Program • $23 million will have been funded on the arsenic demonstration program. ($12M EPA; $11M Congress) • Three sets of projects (50 sites): Round 1 – 12 demonstration projects Round 2 – 28 demonstration projects Round 2a – 10 demonstration projects • Focused on commercially ready technologies or engineering approaches Arsenic Demonstration Projects 50 projects – 26 States States No. of Sites States No. of Sites ME NH VT CT NY DE MD PA OH MI WI IL MN 3 3 1 2 1 1 1 1 2 3 2 2 4 ND SD LA TX NM AZ UT ID NV MT WA OR CA 1 1 1 3 3 3 1 2 1 1 1 2 3 Arsenic Demonstration Sites (50) 26 States * VT WA OR ME * * NH MA * MT ND *** * * NV * CA * ID * * SD WY NE * MN * ** * IA NY * WI CT NJ MD * UT CO KS MO AZ ** * *MI * * * * * * OH IL * * IN * * KY TN PA * * * DE MD WV VA NC SC ** * NM * * * TX OK AR LA MS AL GA * * * * FL Arsenic Removal Technologies – 50 projects (Rd 1& 2) Technologies Adsorption media Adsorptive media w/ Pretreatment (IR) Iron Removal Coagulation/Filtration Ion Exchange (NO3) POU - RO RO System Modification (Iron Removal) To be selected Total 26 2 12 3 2 1 1 1 2 Adsorptive Media Adsorption Media Products (10) E33S & E33P GFH ATS Complex 2000 IsoluxTM ArseneXnp ARM 200 AAFS 50 G2 ADSORBSIA KemIron Arsenic Demonstration Program – 50 Projects Program Round 1 Round 2 Round 2a TOTALS Sites 12 28 10 50 Systems Installed 12 25 0 37 Studies Completed 7 14 0 21 Progress Reports 10 11 0 21 Final Reports 2 2 0 4 Reports provided on EPA web page at: http://www.epa.gov/ORD/NRMRL/wswrd/dw/arsenic/ Latest Research Results •Questions/Responses •Future Common Questions / Responses Question 1 What was basis for equipment selection? Common Questions / Responses Question 1 – Response Major Considerations Water Quality – Iron / Arsenic / Co-contaminants Residuals – Type/Quantity and Disposal Options Available System Operating Cost Arsenic Removal Technologies Major Player Iron “a very effective adsorber of arsenic” Rule of Thumb Removal of 1 mg/L of iron achieves removal of 50 ug/L arsenic (Optimized condidtions) Iron common to many ground waters! Removal of iron leads to removal of arsenic! Arsenic Removal Technology Selection Guide Based Upon the Arsenic and Iron Concentration in the Source Water. 50 Fe SMCL 45 B Modified Iron Removal Process Arsenic Concentration -ug/L 40 35 30 25 20 15 10 5 0 0.0 0.1 0.2 C Media Adsorption Ion Exchange Iron Coag/Filtration Iron Removal (M) Membrane Process Fe tio Ra s /A of / 20 1 A Iron Removal Process Optimized for As Removal As MCL 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 Iron Concentration - mg/L Arsenic Removal Technology Selection Guide Based Upon the Arsenic and Iron Concentration in the Source Water. 50 Fe SMCL 45 B Modified Iron Removal Process Arsenic Concentration -ug/L 40 35 30 25 20 15 10 5 0 0.0 0.1 0.2 C Low Iron Media Adsorption Ion Exchange Iron Coag/Filtration Iron Removal (M) Membrane Process Fe tio Ra s /A of / 20 High Iron A Iron Removal Process Optimized for As Removal 1 As MCL 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 Iron Concentration - mg/L Technologies – Raw Water Arsenic/Iron Concentrations Site 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 As ug/L 25 34 30 17 34 27 25 27 20 16 146 42 14 29 39 14 15 Fe mg/L 3.10 3.00 2.60 2.48 2.10 1.80 1.60 1.55 1.50 1.40 1.33 1.30 0.90 0.81 0.55 0.50 0.33 Tech. IR IR IR AM IR IR IR/AM IR IR IR IR IR/AM IR IR IR IR Site 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 As ug/L 19 25 50 28 52 14 37 19 18 14 30 36 26 56 30 33 33 Fe mg/L 0.27 0.25 0.17 0.16 0.13 0.13 0.13 0.10 0.07 0.06 0.05 0.05 0.40 0.03 0.02 0.02 0.02 POU AM AM AM CF AM CF AM AM AM AM AM AM Tech. AM AM AM Site 35 36 37 37 39 40 41 42 43 44 45 46 47 48 49 50 As ug/L 35 15 56 33 17 37 29 33 41 44 88 21 25 25 24 62 Fe mg/L 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 Tech. AM AM CF AM IE AM AM AM AM IE AM AM AM RO AM AM Technology Selection Verses Raw Water As/Fe Concentrations 100 90 0.3 mg/L Fe SMCL Iron Removal Systems Adsorptive Media Coagulation/Filtration Arsenic Concentration - ug/L 80 70 60 50 40 30 20 10 0 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 Iron Concentration - mg/L Common Questions / Responses Question 1 – Response Major Considerations Water Quality – Iron / Arsenic / Co-contaminants Residuals – Type/Quantity and Disposal Options Available System Operating Cost Residuals Technology Liquids Adsorptive Media Iron Removal Coagulation/Filtration Ion Exchange Reverse Osmosis Backwash Water w/ Solids (Possible) Backwash Water w/ Solids Backwash Water w/ Solids Regeneration Brine Reject Water Residuals Solids Exhausted Media Residuals Disposal Options Backwash Water Sewer Ground - Direct Septic System Recycle Evaporation/Holding Pond IE Brine/ RO Reject Water Sewer Septic System Evaporation/Holding Pond Adsorptive Media (Exhausted) Landfill Regeneration (on /off site) Holding (?)Pond Recycle Tank Residual Disposal Methods Used Residuals Disposal Method Sewer – 8 Ground – 1 Septic System – 1 Recycle / Sewer – 2 No BW – 6 Ground – 5 Sewer – 5 Recycle – 2 Septic System – 1 Sewer – 1 Holding Pond - 1 Iron Removal Backwash Water Coagulation/ Filtration Backwash Water Adsorptive Media Backwash Water Ion Exchange Brine Common Questions / Responses Question 1 – Response Major Considerations Water Quality – Iron / Arsenic / Co-contaminants Residuals – Type/Quantity and Disposal Options Available System Operating Cost Operational Cost Major Factor in Selection of Coagulation/Filtration Systems! Technology Selection Verses Raw Water As/Fe Concentrations 100 90 0.3 mg/L Fe SMCL Iron Removal Systems Adsorptive Media Coagulation/Filtration Arsenic Concentration - ug/L 80 70 60 50 40 30 20 10 0 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 Iron Concentration - mg/L Common Questions / Responses Question 2 Are adsorptive media arsenic removal capacities meeting manufacturers estimates? Common Questions / Responses Question 2 – Response Base upon experience of the arsenic demo program some are, but many are not! Performance Adsorptive Media (As V) Site A B C D E F G H I J K As ug/L pH Units SiO2 mg/L 39 45 31 88 33 33 41 64 23 19 14 8.3 7.8 8.4 7.4 7.9 6.9 7.7 6.9 7.1 7.7 7.3 7.3 11 13 14 69 30 26 19 25 35 14 8 PO4 mg/L <0. 05 <0.05 <0.03 <0.1 <0.03 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 BVs to 10 ug/L 5,500 5,400 6,000 7,500 12,000 20,000 7,000 25,000 40,000 40,000 (1ST) 41,000 (2nd) >62,000 >68,000 Common Questions / Responses Question 3 If adsorptive media process has been selected for the treatment system, how does one select the adsorptive media? Common Questions / Responses Question 2 – Response Major Considerations Performance – BVs (removal capacity) - Time (replacement) Cost – Media & media replacement Residuals – Backwash water disposal options Spring Brook MHP, Wales, ME (ATS Media) SP Oxidation Columns SP Tanks 1 1+2 1+2+3 BV Cu ft 1.5 3.0 4.5 EBCT min 2.2 4.4 6.6 1 1 SP Design flow – 14 gpm Actual flow - 10.4 gpm Backwash water - none As – 38 ug/l (90% As III) pH – 8.5 2 2 SP 3 3 SP SP Spring Brook MHP, Wales, ME Arsenic III Removal by Adsorptive Media (ATS) at Spring Brook MHP, Wales, ME 70 60 Arsenic Concentration - ug/L 50 40 30 5000 BVs 20 10 MCL 0 0 2 4 6 8 10 12 14 16 18 20 22 24 26 Time - Weeks Raw Well Water After Oxidation Tank After AM Tank 1 After AM Tank 2 After System - Tank 3 Replacement Cost $755/Column $915 Labor/travel $2,465 Total Media Cost $5.00 $4.50 $500/cf $400/cf $4.00 $300/cf $200/cf $3.50 $100/cf Cost ($/1,000 gal) $3.00 $2.50 $2.00 $1.50 $1.00 $0.50 $0.00 10 20 30 40 50 60 70 80 90 100 M edia Life (x1,000 Bed Volumes) Arsenic III Removal by Adsorptive Media (E33) at Brown City, MI (May, 2004 to May, 2007) 30 Arsenic concentration - ug/L 25 20 Raw Water 15 10 Cl2 moved to before MCL 5 treatment system Treated Water 0 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 Bed Volumes X 1000 Common Questions / Responses Question 2 – Response Major Considerations Performance – BVs/Time Cost – Media & media replacement Residuals – Disposal of backwash water No disposal option – Consider media/system that does require backwashing or 100% recycle Latest Research Results •Questions/Responses •Future Adsorptive Media Systems Future System designs/equipment (most) allows for the use of a variety of media products. (EBCT major factor) Utilities will be switching to lower cost media products or to lower cost process (Coagulation/Filtration). Adsorptive Media Pressure Tank Freeboard Surface loading rate 5-9 gpm/sq ft Bed expansion 15 -50 % Media EBCT 3 – 10 min Bed depth 3-6 ft Adsorptive Media System Fiberglass Tanks Results AM System Operational Cost - $/1000 gal Category Flow - gpm Media - cf Media Replacement Media Disposal Labor Total Cost Electricity $/1000 gal Labor $/1000 gal Media $1000 gal (est) Total $1000 gal NH 10 5 Lead TK $1,500 $200 $2,345 $4,045 0.001 0.33 6.00 6.33 $1,235 $2,785 0.001 1.80 15.00 16.80 VT 22 3 2 tanks $1,550 NM 320 160 (40K BVs) $24,000 $680 $2,120 $26,800 0.001 0.05 0.60 0.65 MD 320 160 (80K BVs) $24,000 680 $2,120 $26,800 0.05 0.07 0.30 0.43 $12,950 $70,550 0.001 0.18 5.00 5.18 NV 350 240 (7.5K BVs) $57,000 Adsorptive Media (Cost Range - $70 to $500 cf) Adsorption Media Products (10) E33S & E33P GFH ATS Complex 2000 IsoluxTM ArseneXnp ARM 200 AAFS 50 G2 ADSORBSIA KemIron Arsenic III Removal by Adsorptive Media (ATS) at Spring Brook MHP, Wales, ME 70 60 Arsenic Concentration - ug/L 50 40 30 5000 BVs 20 10 MCL 0 0 2 4 6 8 10 12 14 16 18 20 22 24 26 Time - Weeks Raw Well Water After Oxidation Tank After AM Tank 1 After AM Tank 2 After System - Tank 3 Replacement Cost $755/Column $915 Labor/travel $2,465 Total RSSCT Study – Spring Brook NHP Site (As 38 ug/L – pH 8.5) Media KemIron GFH Adsorbia GTO ARM 200 (Old) ARM 200 (New) E33 ArsenXnp AAFS50 A/Complex 2000 RSSCT BVs to 10 ug/L 25,000 23,000 12,500 17,500 13,000 20,000 18,000 6,700 5,000-6,500 Full Scale System BVs to10 ug/L 11,500 8,500 Adsorptive Media System Changes Site Spring Brook MHP Bow, NH STMIGID Original Media ATS G2 GFH ( 3 Tanks) New Media/Process KemIron & GFH AAFS50 GFH (1) KemIron (2) May convert to Coagulation/Filtration ARM 200 (Trial Run) Coagulation/Filtration Shut down because of high cost Shut down because of uranium (disposal) Valley Vista Rollinsford, NH Desert Sands, NM Lake Isabella, CA AAFS50 E33 E33 ArsenXnp Results IR System Operational Cost - $/1000 gal Site MN WI MN MI System IR IR IRw/Fe add IRw/Fe add Flow gpm 20 45 140 150 Chemicals 0.12 (KMnO4) 0.16 (Cl2) 0.03 (FeCl3) ? Electricity 0.04 0.07 0.04 0.07 Labor 0.27 0.11 0.22 0.15 Total 0.43 0.33 0.29 0.22 Note - Disposal of residuals not included Adsorptive Media Systems Future Some adsorptive media products can be regenerated There are other products, particularly the iron based products, that are not currently being regenerated. Research starting on the regeneration of these products. Preliminary tests indicating that up to 85% of arsenic can be stripped off with caustic solution. Regeneration could lead to lower operating cost. Media Regeneration • Spent Media including: • GFH (2) • KemIron (1) • E33 (2) • ARM 200 (1) • Use 4% caustic solution Results – Arsenic Demonstration Program Performance Systems shown ability to reduced arsenic to below MCL Utilities have found most systems easy to operate Many systems have improved the general distribution water quality Change in water quality has not resulted in any Pb/Cu issues Results – Arsenic Demonstration Program Performance All spent throw-away media has passed TCLP tests Utility can switch adsorptive media products with out having to change adsorptive media equipment. Utility can switch adsorptive media system over to coagulation/ filtration system. Acknowledgements • Battelle Memorial Institute – Columbus OH • Water utilities participating in the arsenic demonstration program Tom Sorg 513/ 569-7370 sorg.thomas@epa.gov