Texas Association of Clean Water Agencies

Transcription

1 Texas Association of Clean Water Agencies Odor & Corrosion Control Economics of PRI-SC Process Paris Neofotistos U.S. Peroxide September 25, 2009

2 About US Peroxide, LLC Who we are Industry leaders in cost effective peroxygen (H2O2) based technology and full service programs Focus on resolving environmental problems in the municipal and industrial marketplace What we do best Provide turn-key solutions that integrate our application expertise and full-service capabilities Provide performance driven programs that satisfy the long term technical, operational and economic needs of the customer

3 Company Profile Leader in advanced UV water treatment Designs, manufactures, and markets pressurized & open-channel ultraviolet disinfection systems Over 4,000 municipal UV disinfection facilities in over 50 countries Headquarters London, ONT Associates Diversified technology leader Designs, manufactures, and markets innovative products and services with strong brand names and significant market positions Headquarters Washington, DC 2008 Revenues ~$12.4B Associates 40,000

4 Chemical Selection Short List Force mains Nitrate (Bioxide formulations) Iron salts H2O2 (< 1-2 hours) Caustic shocking Oxygen Mg / Ca hydroxide Interceptors PRI-SC Iron salts Nitrate (Bioxide formulations) Mg / Ca hydroxide Pump Stations Bleach H2O2 Vapor treatment There is no magic bullet! Many technologies have a fit depending on the details of the application. Most collection systems are best suited by using multiple technologies.

5 Chemical Treatment Alternatives Hydrogen Peroxide

6 H2O2 - Sulfide Reactions Curative mode - Direct Oxidation H2O2 + H2S Sº + 2H2O Molecular wt Weight ratio Curative dose ratio: 1lb H2O2 per lb Sulfide Preventative mode D.O. Supply 4H2O2 2O2 + 4H2O Molecular wt. 4(34) 2(32) Weight ratio Sulfide re-dox 2O2 + S= SO4= Preventative dose ratio: 4lbs H2O2 per lb of Sulfide

7 Chemical Treatment Alternative Iron Salts

8 Conventional Iron Salts Ferrous (Fe +2 ) or ferric (Fe +3 ) salts FeCl2, FeCl3, FeSO4 most common Corrosive / acidic Equilibrium precipitation chemistry Ferric oxidizes and precipitates Not affected by oxygen uptake rates Catalytic oxidation afforded by re-aeration Durational Control Gravity mains Forcemains Digesters (anaerobic) Solids transfer lines

9 Conventional Iron Salts Ferrous Reaction FeCl2 + H2S FeS + 2HCl (ph dependent) Theoretical Dose: Practical Dose: 1.75 lbs Fe per lb Sulfide 2 to 6 lbs Fe per lb Sulfide Ferric Reaction 2FeCl3 + 3H2S S o + 2FeS + 6HCl Theoretical Dose: Practical Dose 1.2 lbs Fe per lb of Sulfide 1.5 to 4 lbs Fe per lb Sulfide

10 Iron Salts / Impact Low levels (<0.2 mg/l DS) can be hard to achieve High doses can deplete wastewater alkalinity Increases solids loading / processing costs High doses can deposit in pipes and on equipment Fe residuals can both enhance and hinder plant operations

11 Chemical Treatment Alternatives Peroxide Regenerated Iron Technologies PRI-TECH

12 PRI Ferrous Chemistry Iron Sulfide reaction: H2S + FeCl2 FeS + 2 HCl Regeneration by peroxide: FeS + H2O2 S 0 + Fe(OH)2 Subsequent Iron Sulfide reactions: Fe(OH)2 + H2S FeS + 2 H2O Net reaction: 2 H2S + FeCl2 + H2O2 S 0 + FeS + 2 HCl + 2H2O Peroxide Regenerated Iron technology utilizes the advantages of both iron and hydrogen peroxide while minimizing their drawbacks.

13 PRI Ferric Chemistry Iron Sulfide reaction: 2 H2S + 2FeCl2 2 FeS + 4 HCl Regeneration by peroxide: 2 FeS + 3 H2O2 2 S Fe(OH)3 Subsequent Iron Sulfide reactions: 2 Fe(OH)3 + 3 H2S S FeS + 6 H2O Net reaction: 5 H2S + 2 FeCl2 + 3 H2O2 3 S FeS + 4 HCl + 6H2O

14 Simplified PRI-SC Iron sponge analogy 1. Iron sponge 2. soaks up H 2 S H 2 S FeS 4. H 2 O 2 rinse cleans sponge Fe (ll/lll) Fe (ll/lll) 3. the sponge becomes spent 6. Iron sponge can be re-used as if new. 5. sulfide is converted to inert sulfur

15 Rapid Oxidation/Regeneration PRI-SC - Catalyzed Sulfide Oxidation

16 Plant PRI-TECH Concept IPIM Intraplant Iron Management Operations Strategy PRI intervention (PRI-TECH ) Outcome driven Fe transformations (Fe +2 /Fe +3 ) Increasing H2O2 Dose

17 Use of Regenerated Iron As Fe (ll) Collection System Durational H2S control in interceptors As Fe (ll/lll) Treatment Plant Reduced scrubber loading Catalysis of H2O2 H2S in primaries CEPT Phosphorus control Biosolids processing

18 PRI-Chem Examples Chem-P Removal (Fe +3 transformation) PRI-SC PRI-Chem Springfield, Raleigh & Lexington Similar applications PRI-SC follow-on benefit Chem-P removal cost benefit Reduced or eliminated alum/aluminate costs Performance maintained Springfield: $200k/yr savings in Alum (pays for Fe in collections) Raleigh: $150k/yr savings in Fe and Alum Operations savings on lamp cleaning Lexington: $27k savings during 6 mo odor season

19 Springfield, MO - Alum Usage Alum usage before Odor Control Program before FeCl 2 Baseline Average Alum usage was 2437 gpd from April 05 to March 06. Alum Cost was $1219 per day or $444,753 per year. In 2007 Average Alum usage was 1290 gpd The alum savings was $574/day or $209,328 per year The total odor control program cost was $233,802 In 2008 Average Alum usage was 1173 gpd The alum savings was $632/day or $230,680 per year The total odor control program cost was $210,030

20 San Diego Point Loma PRI Program CEPT Enhancement Goals: Cost Savings via FeCl3 reduction Equal or better performance Effluent quality Originally dosing 24 mg/l FeCl3 Outcomes: Currently saving about $7k/day Equal to slightly improved performance Significant improvement in effluent quality Bleach savings

21 PRI-DE 1. FeS + H2O2 S0 + Fe(OH) FeS + 3 H2O2 2 S0 + 2 Fe(OH)3 Applications: Sulfide control Struvite control Digester performance Biogas Outcome drivers: H2S reduction (gas quality) Sludge odor control (pre/post) Fe cost savings O&M cost savings Methane increase Examples: SAWS, Manatee, San Diego demo, PHX demo (Ph2)

22 San Antonio Experience Began as primarily odor control at DAF Thickeners using H2O2 addition ended up providing Biosolids processing enhancements Dios Rios WWTP processes sludge from Leon Creek Mixed primary and WAS - 300,000 to 400,000 gpd Sludge is iron laden (collection system) H2S treatment was effective immediately Dose of about 150 to 200 mg/l Sludge benefits measured later Methane gas production increased 20% to 25% over baseline (e.g. before H2O2 addition began) Most likely due to improved sludge quality and role of regenerated ferric in digestion Paper at WEF Odor Conference 2006 and WEFTEC 2006 H2O2 started

23 Cost Comparison to Iron Salts Fe regeneration (sulfide oxidation) H 2 O 2 + FeS S o + Fe OH - MW 1 x 34 1 x 56.5 Wt. ratio $ per lb $ 0.77 a $ 0.46 Fe purchase Difference Typical TX FeSO4 Price = a. Full-Service Turnkey Price b. Commodity Price $ 1.08 b $ 0.62 per lb-fe 57% savings

24 PRI-TECH Partial Customer List Orange County Sanitation District City of San Francisco SROG Southern Avenue Interceptor, City of Phoenix City of Albuquerque San Diego MWD MGD Point Loma System Springfield, MO Manatee County, FL Tarpon Springs, FL Palm Beach County, FL Henrico County, VA Trinity River Authority, Texas Cedar Rapids, IA Yuma, AZ City of Raleigh, NC

25 North Texas Municipal Water District Program Objectives: Improve Sulfide Control without increasing cost Program Summary: Replace Lower Rowlett Creek Bioxide with Ferrous Chloride Regenerate the Iron at Dublin Road LS Control/Monitor Points: Dublin Road LS Allen Junction

26 North Texas Municipal Water District FeCl2 and H2O2 Storage and Dosing Systems

27 NTMWD - System Schematic

28 NTMWD - PRI-SC TM Start Up

29 NTMWD - PRI-SC TM Gaseous H 2 S

30 NTMWD - PRI-SC TM Gaseous H 2 S

31 NTMWD - Chemical Dosages Warm Weather PRI-SC Dosage: FeCl 330 gpd H 2 O 60 gpd Bioxide Dosage: 300 gpd Cold Weather PRI-SC Dosage: FeCl 230 gpd H 2 O 35 gpd Bioxide Dosage: 250 gpd

32 Results Summary Warm Weather

33 Results Summary Cold Weather In this segment of the NTMWD collection system, PRI-SC is the better fit providing improved H2S reductions at equal budget.

34 Questions?