CITY OF SUMNER: CENTRAL WELL DEVELOPMENT

Transcription

1 April 27, :45 PM PNWS-AWWA Section Conference Room 317 CITY OF SUMNER: CENTRAL WELL DEVELOPMENT Case Study for Manganese and Polysulfide Removal Barney Santiago, PE RH2 Engineering, Inc.

2 AGENDA 1. Background and Overview 2. Manganese Treatment 3. Polysulfide Treatment 4. Engineering Considerations 5. Summary

3 1. BACKGROUND AND OVERVIEW City Goals: Develop Central Well Improve Operational Flexibility Meet Projected Water Demands Water Quantity: 1,050 gpm now (2,100 gpm future) Water Quality: Manganese (0.12 ppm) Ammonia (0.2 ppm) Hydrogen Sulfide odor

4 2. MANGANESE TREATMENT Sodium Hypochlorite 3.8 mg/l Dose 60 minutes of Breakpoint Chlorination Reaction Time 8 gpm/sf Manganese Filter Loading Rate ~40 hour run times Informal Taste and Odor Test

5 CHLORINATION OF HYDROGEN SULFIDE Typical Chlorination of Hydrogen Sulfide H 2 S + Cl 2 2HCl + S mg/l chlorine for each mg/l H 2 S to produce elemental sulfur H 2 S + 4Cl 2 + 4H 2 O 8HCl + H 2 SO mg/l chlorine for each mg/l H 2 S to produce sulfuric acid Polysulfides can also form as elemental sulfur combines with residual sulfide H 2 S + Cl 2 2HCl + S 0 ns + H 2 S H 2 S n

6 3. POLYSULFIDE TREATMENT Chemical Feed Sodium meta-bisulfite, sodium bisulfite or sulfur dioxide Initial reaction create sulfite ion which then dissolves polysulfide compounds into thiosulfate Na 2 S 2 O 5 + H 2 O 2Na + +2HSO 3 HSO 3 H + +S03 2- S S S S H 2 S n S H 2 S n 1 Catalytic Granulated Activated Carbon Adsorption Adsorbs sulfite compounds Required elevated dissolved oxygen upstream (aeration)

7 TASTE AND ODOR PILOT STUDY Venturi Injector for Air Addition Catalytic Activated Carbon EBCT: 10 minutes Sodium Hypochlorite Dose: mg/l TREATMENT PROCESS 1: Upstream Catalytic Carbon Filtration 8 gpm/sf Manganese Filter Loading Rate ~40 hour filter run times 60 minutes of Breakpoint Chlorination Reaction Time 8 gpm/sf Manganese Filter Loading Rate ~40 hour filter run times Post-Sodium Hypochlorite Dose: mg/l Pre-Sodium Hypochlorite Dose: 1-2 mg/l Venturi Injector for Air Addition Catalytic Activated Carbon EBCT: 10 minutes TREATMENT PROCESS 2: Downstream GAC Filtration Sodium Meta- Bisulfite Dose: mg/l seconds Sodium Hypochlorite Dose: 2.7 mg/l TREATMENT PROCESS 3: Bench Scale Sodium Meta-Bisulfite Feed 60 Minutes Contact Time Taste and Odor Test Effluent Samples Selected for Informal Taste & Odor Panel

8 INFORMAL TASTE AND ODOR PANEL Sample Comparison Pilot Process 2 Effluent (Catalytic GAC) Pilot Process 3 Effluent (Meta-Bisulfite) City Hall tap Bottled water Neighboring residential tap Treatment Process 2 (Manganese GAC) most accepted ratings except bottled water Catalytic GAC was selected for design Higher capital and O&M costs Produced the most acceptable water

9 4. ENGINEERING CONSIDERATIONS Flow Meter Static Mixer Manganese Removal Filter Air Scour Blower Pre-Filtration Chlorine Injection Sanitary Sewer Central Well Aeration System Air Gap Manhole Process Waste Pump System GAC CONTACTOR GAC CONTACTOR Post-Filtration Chlorine Injection Static Mixer Breakpoint Chlorination Reaction Time Pipeline Flow Meter Backwash Supply Distribution System

10 FACILITY LAYOUT

11 WELL HEAD Vertical Turbine Pump 1,050 gpm Variable Frequency Drive Expandable to 2,100 gpm thru bowl and electrical modifications

12 DISINFECTION SYSTEM 48-pound per day OSEC On-site Sodium Hypochlorite Generation System ProMinent Metering Pumps

13 DISINFECTION SYSTEM 2 Pre-Filtration Injection (0.15 ppm) Minimize Cl 2 Residual in IMAX Filter Effluent Post-Filtration Injection (1.7 ppm) 60-minute Breakpoint Chlorination Reaction Time Pipeline (700 feet of 48 Diameter Pipe)

14 MANGANESE FILTRATION Tonka Water (2 cells; 8-foot diameter x 18-foot long HPF) IMAX Media (Proprietary Pyrolusite & Silica Sand Blend) 8 gpm/square foot loading rate ppm Mn effluent 40 hour filter runtimes expected Simultaneous air & water backwash, no media restratification required

15 CATALYTIC GAC CONTACTOR Loprest Catalytic GAC Contactors (2 vessels, 12-feet diameter, 10-feet sideshell, 78 inches media depth) Jacobi AquaSorb CX-MCA catalytic granular coconut shell based activated carbon media 4.6 gpm/square foot loading rate; 10 minute EBCT Pre-Aeration for hydrogen sulfide removal (Mazzei)

16 PROCESS WASTE SYSTEM Minimal waste via IMAX Air-gap Manhole Lift Station Submersible Pumps w/ VFD Single Pump: 680 gpm Both Pumps: 900 gpm

17 DESIGN FLEXIBILITY: FUTURE EXPANSION

18 DESIGN FLEXIBILITY: FILTER SWAP Strategic Piping and Valves Provide Process Flexibility

19 NORMAL TREATMENT PROCESS Flow Meter Static Mixer Manganese Removal Filter Air Scour Blower Pre-Filtration Chlorine Injection Sanitary Sewer Central Well Aeration System Air Gap Manhole Process Waste Pump System GAC CONTACTOR GAC CONTACTOR Post-Filtration Chlorine Injection Static Mixer Breakpoint Chlorination Reaction Time Pipeline Flow Meter Backwash Supply Distribution System

20 FILTER SWAPPED TREATMENT PROCESS Flow Meter Static Mixer Manganese Removal Filter Air Scour Blower Pre-Filtration Chlorine Injection Sanitary Sewer Central Well Aeration System Air Gap Manhole Process Waste Pump System GAC CONTACTOR GAC CONTACTOR Post-Filtration Chlorine Injection Static Mixer Breakpoint Chlorination Reaction Time Pipeline Flow Meter Backwash Supply Distribution System

21 5. SUMMARY City of Sumner: Central Well Development Polysulfides Threw a Wrench into Manganese Treatment What worked: Initial pre-chlorination dose Manganese removal detectable chlorine trace in effluent to keep media charged Catalytic GAC Contactor (upstream aeration) Post-chlorinate and 60 minute breakpoint reaction time Current [Limited] Plant Operations

22 QUESTIONS? Barney Santiago, PE RH2 Engineering Direct:

23 PHOTOS

24 PHOTOS

25 PHOTOS

26 DESIGN P&ID