Arsenic Removal with Bayoxide E33 Ferric Oxide Media & SORB 33 As Adsorption Frank Stanish Severn Trent Services, Inc. AWWA New York Conference Saratoga Springs, NY April 15, 2015
Agenda Background on arsenic Arsenic Toxicity Sources of arsenic Arsenic in Water Arsenic Regulations Arsenic Treatment Methods Case Study Problem and Solution: Hilltown Township Arsenic Removal Project Frequently Asked Questions Severn Trent Services 2
Arsenic Background Natural occurring metalloid element Atomic Symbol: As Atomic number: 33 Atomic Weight: 74.92 Severn Trent Services 3
Arsenic Toxicity USEPA Group A Human Carcinogen Short-term (acute) and long-term (chronic) effects Skin, lung and bladder cancer Acute GI damage Cardiac problems Vomiting / Diarrhea Dehydration Partial paralysis / blindness Hemolysis Vertigo Shock / Death Severn Trent Services 4
Arsenic Chemistry Arsenic found in ground waters is normally in an inorganic form as a soluble oxyanion species. It has 2 valence states, As(III) and As(V). Oxidized As(V) Oxyanion Dissociation H 3 AsO 4 H 2 AsO 4- + H + pk s = 2.2 H 2 AsO 4 - HAsO 4 2- + H + pk s = 6.9 HAsO 4 2- AsO 4 3- + H + pk s = 11.5 Reduced As(III) Oxyanion Dissociation H 3 AsO 3 H 2 AsO 3- + H + ph 6-8 In waters within a natural ph range, the following species are present: H 3 AsO 3, H 2 AsO 3-, H 2 AsO 4 - & HAsO 4 2- As(III) occurs mainly under reducing conditions, e.g., in the absence of oxygen. When this water comes in contact with air, As(III) is oxidized to As(V). Severn Trent Services 5
Arsenic Sources in US Drinking Water Severn Trent Services 6
USEPA Arsenic Rule & Severn Trent s Role Timeline - Lower Potable Water Arsenic Levels Current Limit in 1990 s - 50 g/l 1993 WHO Recommends 10 g/l 1994 USEPA Recommends 2-20 g/l 2000 New EC Directive 2003 UK Adopts 10 g/l Standard 2006 USEPA Compliance for 10 g/l MCL Severn Trent Water Severn Trent Services Sister Company in the UK 16 Well Water Sites with As > 10 g/l Total Treatment Capacity - 46.8 MGD (177 ML/Day) since 2003 Severn Trent Services 7
As Removal Treatment Selection Adsorption Simple & non-regenerative in most cases Single step process for most applications Coagulation/Filtration Cost effective for large scale systems (over 4 MGD) Effective for high Fe/Mn waters No chemicals besides disinfection if Fe/As wgt ratio > 25 Reverse Osmosis Effective if other TDS must be removed Won t remove As(III) Ion Exchange Good for waters with high As & ph and low SO 4 & HCO 3 Hybrid resins with impregnated Fe Oxide Selective for As Requires regeneration/postreatment; won t remove As(III) Severn Trent Services 8
SORB 33 Adsorption with Bayoxide E33 Media SORB 33 - Severn Trent s Adsorption Process STS & Lanxess Partnered to Develop Granular Ferric Oxide (GFO) Media for As Removal Lanxess: Large Technical Oxide Producer Specialists in Iron Oxide Technologies Bayoxide E33 (GFO) - Adsorption Media Exclusive Agreement between STS & Lanxess NSF Standard 61 Approved Severn Trent Services 9
Adsorption - SORB 33 Systems Water Flows through a bed of media Pros Easy Operation Little automation Simple Maintenance Not complex Lowest Capital Commonly lowest O&M Cons Complex Waters with multi contaminants Causes low bed volumes Most accepted technology Majority of projects in US have selected adsorption Severn Trent Services 10
Adsorption - SORB 33 Systems Bernallilo, NM Four 4 -Ø Adsorbers 450 gpm Loma Linda, CA Four 14 -Ø Adsorbers 3,000 gpm Severn Trent Services 11
Adsorptive Media Pilot Testing 3 rd Party Breakthrough Curves determine best performance 4 different medias tested at Mesa, AZ by DSWA Bed Volume vs. Arsenic 35 30 25 Arsenic, ppb 20 15 Average Influent WRT Z33 GFH Solmetex AsXnp Bayoxide E33 10 5 0 0 10,000 20,000 30,000 40,000 50,000 60,000 Bed Volumes Severn Trent Services 12
Test Evaluation Breakthrough Curves Breakthrough Curve Measures Media Performance - Longevity Arsenic effluent levels vs volume treated ( BV s or gallons H 2 O/cu ft of media) As Breakthrough Point at which media needs replacement The higher the BV s to breakthrough, the lower the operating cost Typical SORB 33 Arsenic Adsorption Curve 40 Influent As Concentration (μg/l) 30 20 10 As MCL Treated Water As As Breakthrough 0 0 25,000 50,000 75,000 100,000 125,000 150,000 Time (based on 75% Use Factor): 6 Mos 12 Mos 18 Mos Bed Volumes of Water Treated (BV s) Severn Trent Services 13
On-site Pilot Test Program Program Scope PG P-01 Test Protocol S-06 Vent V-11 4 - Clear Column with Media E33 Feed Sample P-04 B wash Discharge S-08 P-01 Manual Valves P-03 B wash Supply Backwash Sample P-04 Simple Instruments Consistent Water Supply Data Collection & Monitor FQI FI PDI P-02 FI/FQI P-03 P-02 Weekly Sampling 2-6 Month Program Pres Reg r Rate Set E33 GFO Media P-09 Effluent/Media Backwash Well Water Media Drain Media Support S-07 Treated Water Or Backwash Effluent Rate Set Treated Water Sample /Drain Severn Trent Services 14
Coagulation / Filtration - Omni-SORB Media Product Composition 5% Manganese Dioxide (MnO 2 ) impregnated quartz (sand) Non-porous blackish gray catalytic filtration media Dense media 88 lb/ft 3 Screen Size 18 x 60 mesh Dustless facilitates backwash Producer Fermavi (Brazil) Mines rich MnO 2 ore, refines into product Media Life 9+ Years; Disposable as nonhazardous waste Service Conditions Filtration rates of 7-10 gpm/ft 2 Backwash rates of 14-16 gpm/ft 2 Severn Trent Services 15
Coagulation / Filtration - Omni-SORB Media Coagulation / Filtration Iron Removal Removes Fe and Mn Removal As/Fe/Mn Needs high Iron level Fe:As - 25:1 or better As/Fe/Mn or Fe/Mn Catalyze the Fe and Mn in an oxidation/precipitation process Coagulation / Filtration of Fe oxide & Mn oxide Ferric chloride addition if needed As adsorbed by Fe oxide Backwash Severn Trent Services 16
Omni-SORB Systems Parallel Flow Filters Automated Valves Process Controls & PLC Rozel, KS 600 gpm Fe & Mn Removal Three 6 -Ø Filters Houghton, NY 700 gpm As Coag Filtration Four 7 -Ø Filters N+1 Redundancy Severn Trent Services 17
Application Inquiry to Full Scale System Step 1 Site Qualification Form Complete & Submit Client & Contact Info Flows, contaminants & concentrations Severn Trent Analysis Conceptualize Design Flexibility Budget Proposal Budget Capital Budget O&M Severn Trent Services 18
Water Quality Characterization Key to Design Site Qualify Form s analytical table highlights key species Key Species Arsenic (As, g/l) Bypass if As <25; Series if As >25 ph (no units) Use CO 2 or Acid to adjust if water ph >8.0 and/or high SiO 2 Phosphate (PO 4 or P mg/l) Consumes media capacity; Use Omni- SORB if PO 4 > 0.8 (0.3 mg/l as P) Silica (SiO 2, mg/l) Coats media above 40; use ph adjust Iron (Fe, mg/l) If Fe >0.2, As is reduced; chlorination required; If Fe >0.35, consider Omni-SORB Manganese (Mn, mg/l) If Mn >0.06, Mn buildup in bed, makes backwash difficult; chlorination required; Omni-SORB pretreat Vanadium (V, g/l) Consumes media capacity; ph adjust helps reduce its effect Severn Trent Services 19
Sizing & Estimate Summary Adsorption Example Process Sizes System Vessel Size Media Volume Performance BV s, etc. Flows Configuration Operating Costs: Includes annualized media replace & chemicals Proposals Estimates Cost ROM or Budget Rough Order of Magnitude Issue to Client Severn Trent Services 20
Media Replacement & Disposal Media Removal STS subcontractors Vacuum removal or vactor truck Fill rolloffs or sacks TCLP analysis verify media is non-hazardous Media Replacement Gravity fill - 52 ft3 sacks Roof Hatch Added Hydraulic fill eductors Aqua Pennsylvania Site Roof Hatch Added for Gravity Fill 30 Minute Fill - 52 ft³ per Vessel Severn Trent Services 21
Case Study Hilltown Township, PA Severn Trent Services 22
Hilltown Township Well No. 2 Hybrid Fe/Mn Filtration & As Adsorption Well No. 3 300 gpm Multiple Contaminants Arsenic 15 µg/l Iron 250 µg/l Manganese 110 µg/l Aside from As removal, needed to remove Fe & Mn Black & red water issue Hybrid design 1 OmniSORB filter & 2 E33 Adsorbers Oxidize & filter all of the water to remove Fe & Mn Treat 50% of filtered water through adsorption Bypass and blend remainder System in service for 9 years Bayoxide E33 lasted 7 years before replacement Severn Trent Services 23
Hilltown Township Hybrid Fe/Mn Filtration & As Adsorption Severn Trent Services 24
Questions? Acknowledgements: Gary Weaver - Principal Castle Valley Consultants, Inc. 10 Beulah Road 215 348 8257 gjweaver@casval.com Severn Trent Water Purification, Inc. Gary M. Lohse, P.E. Regional Sales Manager 3000 Advance Lane Colmar, PA 18915 T: +1 215 859-3814 E: glohse@stservices.com www.severntrentservices.com