1. SPWSTAC 2006 From POU to Centralized Arsenic Treatment: A Small Water System Case Study 2006 NGWA Naturally Occurring Contaminants Conference J. Mitchell Spear, Charles A. Cole, Yuefeng Xie and Alison Shuler Penn State Harrisburg

2. Objective  Conduct an evaluation of a POU device for removal of arsenic in a small public water system to determine the feasibility and cost effectiveness with respect to a similar centralized treatment technology. SPWSTAC 2006

3. POU vs. Centralized Treatment The advantages of decentralized (POU) treatment in small public water systems. 1) Lower capital cost 2) Treating only water for consumption (approx. 10- 40 percent total water) 3) No highly skilled operators needed 4) Waste disposal not a problem 5) Cost saving in smaller systems SPWSTAC 2006

4. POU vs. Centralized Treatment The advantages of centralized treatment in small public water systems 1) Treats all water 2) Lower annual costs 3) Little customer involvement 4) Cost saving in larger systems SPWSTAC 2006

5. POU vs. Centralized Treatment Cost Comparison Most studies estimated this number is between 100 to 200 connections SPWSTAC 2006

6. Overview  Community Selection  Treatment Technology Selection  POU Installations  Arsenic Removal Results  POU Costs  Centralized Treatment Installation and Costs  Summary SPWSTAC 2006

7. Background System selection  Within US EPA Region III  CWS – primarily residential  Arsenic Concentration (10 µg/L<[As]<50 µg/L )  Population less than 500  Service connections (between 30 - 200)  No plan to meet upcoming MCL SPWSTAC 2006

8. Background System selection  Mohrsville, PA Population size375 Service Connections125 Production (GPD)17000 Storage Capacity (Gallons)125000 Wells1 Disinfectant12.5% sodium hypochlorite SPWSTAC 2006

9. Water Quality Characteristics ParameterUnits pH7.3 Arsenic, total28.6 µg/L Chlorine residual0.2-0.3 mg/L Alkalinity86.0 mg/L Total solids220 mg/L Total dissolved solids216 mg/L Calcium37.5 mg/L Magnesium8.05 mg/L Iron80.0 µg/L Manganese40.0 µg/L SPWSTAC 2006

10. Treatment Selection General Factors to Consider  Water Chemistry  S.S., Iron, pH, organics, bacteria  Infrastructure Constraints  Available space, electricity, sewer  Permitting Constraints  Labor  Availability and skill SPWSTAC 2006

11. Treatment Technology Selection  Ability to treat both As +3 and As +5  NSF 61 approval  NSF 53 approval  Residuals (TCLP and WET)  Ability to scale up (POU to Central treatment) --- Isolux™ - Magnesium Elektron, Inc. (Zirconium hydroxide adsorptivemedia) SPWSTAC 2006

12. Installations POU Treatment Design SPWSTAC 2006

13. Installations SPWSTAC 2006

14. POU Pilot Test Result SPWSTAC 2006

15. Monitoring Results on all POUs by GFAA SPWSTAC 2006

16. Monitoring Results by Flowmeter Flow (gal/min)Gallons Treated Mean0.7376 Median0.8330 Minimum0.390 Maximum0.9781 SPWSTAC 2006

17. POU Piloting Costs (1 st year) ItemDollar amount Installation 90.00 POU system 267.50 T-valve 6.50 Housing 95.00 Pre filter (2X/year) 18.00 Carbon Filter (2X/year) 36.00 Isolux™ 70.00 Flow Meter 42.00 Field testing (2X) 6.00 Compliance testing 15.00 Operation & Maintenance* 0 - 200.00 Total378.50 - 578.50

18. POU Annual Cost Capital Costs $ 2004 Installation90.00 T-Valve6.50 Housing95.00 Flow meter42.00 Total233.50 6% for 10 years317.30 Total (yearly)31.73 Total (monthly)2.64 SPWSTAC 2006 Operating Costs $ 2004 Pre-filter18.00 Carbon filter36.00 Isolux™70.00 Field testing6.00 Compliance15.00 O & M200.00 Total (yearly)345.00 Total (monthly)28.75 Total - $31 / unit / month

19. POU Acceptance?  25 Pa. Code § 109.602 Acceptable design.  (e) Point-of-use devises which are treatment devices applied to a single tap are not an acceptable treatment methods for complying with an MCL or treatment technique requirement. SPWSTAC 2006

20. Centralized Treatment  75 gpm Treatment System w / 100% redundancy  Two 48 x 6 inch towers – 2 inch inlet and outlet  1 Flow meter / totalizer  Particulate prefilter housing  36 – 42 inch Isolux removal cartridges  3 hp booster pump SPWSTAC 2006

22. Centralized Treatment Annual Cost Capital Costs $ 2006 Treatment Modules 47000 Transportation200 Cartridges (36)6480 Start up and Training 2880 Total56560 6% for 10 years76848 Total (yearly)7684 SPWSTAC 2006 Total - $9 / connection / month Operating Costs $ 2006 Cartridges5913 Particulate Filter139 Transportation150 Media Management175 Total (yearly)6377 Total Capital + Operating (yearly) 14061

23. Estimated Monthly Cost Comparison Type of SystemCost/Connection POU $15 - $31 Centralized $9* Treatment * Based on proposal for Isolux media, does not include additional time for operations SPWSTAC 2006

24. POU vs. Centralized Treatment Cost Comparison SPWSTAC 2006

25. User Survey Results  Amount willing to pay for POU (monthly)  Average $5  Minimum $0  Maximum $8  Amount willing to pay for centralized treatment (monthly)  Average $10  Minimum $0  Maximum $32 SPWSTAC 2006

26. Initial “hurdles”  Financial  Water association vs. public water utility  Water association awarded special allowance grant  Permitting  Contracted with licensed engineer for state permitting and overall site plan design  Site Location  No Available space near well house SPWTAC 2006

27. Current Status  Proposal submitting to Pa DEP  Site plan accepted by Association Board  Contractors designated for site work  Targeted start up – March 2006 SPWSTAC 2006

28. Summary  POU effective for removing arsenic  Might be more economical solution in very small water systems  Record keeping, communication, increased sampling  Centralized Treatment chosen for Mohrsville site SPWSTAC 2006

29. Acknowledgements  US EPA Small Public Water Systems Technology Assistance Center Grant for funding the study  Magnesium Elektron, Inc. and Jim Knoll for their technical guidance  Alice Renshaw (President of Mohrsville Water Association) for her cooperation  All participating homeowners SPWSTAC 2006

30. Contact Information US EPA Small Public Water System Technology Assistance Center J. Mitchell Spear Laboratory Supervisor, ETC jms63@psu.edu (717) 948-6357 SPWSTAC 2006