Oxygenation System Design. Paul Gantzer, Ph.D., P.E.

Transcription

1 Oxygenation System Design Paul Gantzer, Ph.D., P.E.

2 Oxygenation System Design Outline Review oxygenation and oxygenation strategies Common denominator - Oxygen Data collection Contributors Calculations Calculating oxygen demand Water column profiles using the regression method Remote sensors In-situ SOD chambers Secchi Disk / TSI Design Considerations and tools Induced oxygen demand Plume model

3 Elevation (m) Water Quality Deterioration Julian Day (2001)

4 Before Oxygenation Algae (Taste and Odor) Detritus (Settling organic matter) TOC s Anoxic (Dissolved metals [Iron & Manganese]) Pre-oxidant demands (Fe & Mn) / Coagulant demands (PO 4 & soluble metals)

5 After Oxygenation Less Algae (Reduced internal phosphorous loading) Less Detritus (Less algae biomass) Increased Oxygen Levels (Metals settle to bottom & better fish habitat)

6 Hypolimnetic Oxygenation Oxygenation devices Airlift aerator / layer aeration (air) Bubble plume (air or oxygen) Saturation Technology (i.e. Speece Cone (oxygen) Hybrid water quality management

7 Airlift Aerator

8 Layer Aeration Integrated Hypolimnetic Layer Aeration, Artificial Circulation, and Epilimnetic Expansion System in an off-line storage reservoir in NJ; in operation since 2004 (left). Courtesy of Bob Kortman

9 Bubble Plume (circular) Lake Hallwil, Switzerland Recreation and fisheries 47 m maximum depth 285M m 3 total volume Circular diffusers (6) 30 N km 10

10 Bubble Plume (linear) Courtesy of Mark Mobley

11 Saturation Technology (Speece Cone)

12 Hybrid Water Quality Management Destrat (Air supply) Saturation chamber Pump controller PSA (O 2 supply)

13 Common Denominator Oxygen deficiency / oxygen demand requirements

14 Data Collection (manually collected profiles) Seabird Electronics SBE 19Plus High Resolution Profiler (CTD) Transect Sample Location x x x x x Diffusers x x Sample Locations (X)

15 Remote (DO) Sensors

16 In-situ Sediment Oxygen Demand (SOD)

17 Secchi Disk / Trophic State Index (TSI)

18 Oxygen Demand Contributors Background (HOD) SOD / WOD Redox Production Induced Calculations Discrete depth profiles Remote sensors SOD TSI

19 Elevation (m) Hypolimnetic Oxygen Demand (HOD) f(sod & WOD) Julian Day (2001)

20 DO (g/m 3 ) HOD and time 9 7 End of Year Depletion Rate 0.02 g/m 3 day 5 3 Initial Depletion Rate 0.04 g/m 3 day 1 5-May 5-Apr 6-Mar 5-Feb 6-Jan 4-Jun 4-Jul 1-Dec 1-Nov 2-Oct 2-Sep 3-Aug Time (Days)

21 Chemical Oxygen Demand (Redox) kg O 2 / kg Fe kg O 2 / kg Mn

22 Production

23 Induced Oxygen Demand Observed

24 Dissolved Oxygen (g/m 3 ) Induced Oxygen Demand Baseline O 2 demand (initial) (-0.05 g/m 3 day) 3 days O 2 accumulation (0.40 g/m 3 day) Diffuser Induced O 2 Demand 0.27 and 0.09 g/m 3 day Baseline O 2 demand (final) (-0.05 g/m 3 day) Remainder O 2 accumulation (0.13 g/m 3 day) 1 week following oxygenation (-0.14 g/m 3 day) Jul 12-Aug 11-Sep 11-Oct 10-Nov Time (Days)

25 Dissolved Oxygen Concentration (mg/l) Induced Oxygen Demand (Continued) Averaged Hypolimnion Concentration mg l -1 d mg l -1 d mg l -1 d mg l -1 d mg l -1 d mg l -1 d Jun 28-Jun 18-Jul 7-Aug 27-Aug 16-Sep 6-Oct 26-Oct 15-Nov Date Aeration (Observed) Post Aeration Oxygenation (Observed) Post Oxygenation Air Added Oxygen Added

26 IOD/ Applied Gas Flow Rate HODmass (kg day -1 ) _ CCR y = 22x R 2 = 0.9 SHR y = 6x + 50 R 2 = SHR CCR Oxygen Flow Rate (NCMH)

27 Calculating Oxygen Demand using Water Column Data Demonstrate the regression method of oxygen demand

28 Thermocline (Hypolimnion Boundary)

29 Elevation (ft msl) _ Relative Thermal Resistance to Mixing RTRM = ρ upper layer ρ lower layer ρ 5 ρ RTRM RTRM Temp_C DO mg/l Temp_C hypolimnion boundary hypolimnion line epilimnion line epilimnion boundary DO (mg/l) & Temp (Deg C) epilimnion line epilimnion boundary hypolimnion line hypolimnion boundary RTRM

30 Volume Curve Vol 1 2 A 1 2 A 2 Z 2 Z 1 A 2 Z 2 Z 1 A 1

31 Data Analysis DO mass = V 1 V 2 V n DOi i 1 Vol i Date Elevation hyp_vol Temperature DO_mass DO_Conc 29-Jun Jul Jul Jul Jul average

32 DO (kg) DO (mg/l) Hypolimnion Volume (10 6 Gallons) Data Analysis Date Elevation hyp_vol Temperature DO_mass DO_Conc 29-Jun Jul Jul Jul Jul average Hypolimnion Volume Dissolved Oxygen Concentration y = x R 2 = Jun 28-Jun 3-Jul 8-Jul 13-Jul 18-Jul 23-Jul 28-Jul 2-Aug Date 1400 y = x R 2 = Jun 28-Jun 3-Jul 8-Jul 13-Jul 18-Jul 23-Jul 28-Jul 2-Aug Date Dissolved Oxygen Mass DO conc Rate DO mass Rate Volume Rate Average Volume Average DO 0.06 mg l -1 d kg d gal d gal 2.6 mg l y = x + 2E+07 R 2 = Jun 28-Jun 3-Jul 8-Jul 13-Jul 18-Jul 23-Jul 28-Jul 2-Aug Date

33 Oxygen Depletion Calculation DO conc Rate DO mass Rate Volume Rate Average Volume Average DO DO Concentration Depletion rate:.06 mg l -1 day -1 Average Hypolimnion volume: 1506 x 10 6 gallons DO mass depletion based on average concentration: 340 kg day -1 [.06 mg l -1 day -1 x 1506 MG x ] Uncorrected Mass Depletion Rate: 480 kg day -1 Hypolimnetic Volume Rate of Change: 16.4 x 10 6 gallons day -1 Average DO concentration: 2.6 mg l -1 Corrected DO mass depletion: 320 kg day -1 [480 kg day mg l -1 x 16.4 MG x ] 0.06 mg l -1 d kg d gal d gal 2.6 mg l -1

34 DO Demand Matrix Elevation Volume % Total DO Demand (ft msl) (MG) Capacity (kg/d) Observed Range of Epilimnion and Hypolimnion Boundaries Location HOD rate HOD avg mg l -1 d -1 kg d -1 Site Site Site Site Site Site Site Average 0.34 Total 532.5

35 DO Demand Matrix Hypolimnion Hyp Vol DO Demand Air added Air applied Air Flow Volume Volume Elevation MG kg O2/d lb air/d tons air/d tons air/d SCFM Hp to EL 110 ft to EL ft m msl ft msl MG MG * , , , , , , , , , , , , , , , ,366 Matrix of oxygen demand and corresponding air requirements for a range of hypolimnion volumes, assuming 20% OTE. Arrows represent withdrawal elevations, red out line (EL 90 ft) represents the maximum volume the current compressor capacity can handle, and bold row (EL 97 ft) represents the required design specifications.

36 Calculating Oxygen Demand using Remote Sensor Data Demonstrate the DO demand using remote sensor data

37 Remote (DO) Sensors

38 Dissolved Oxygen, DO (mg/l) _ Dissolved Oxygen, DO (mg/l) _ Remote Sensor DO Depletion Calculation (1) 10 9 y = x R 2 = y = x R 2 = y = x R 2 = y = x R 2 = Nov 18-Dec 17-Jan 16-Feb 18-Mar Date Bottom + 20 Bottom + 15 Bottom + 10 Bottom y = x R 2 = y = x y = x R 2 = R 2 = y = x R 2 = Nov 18-Dec 17-Jan 16-Feb 18-Mar 17-Apr Date Probe Elevation North Twin Corresponding Volume (m 3 ) Depletion Rate Corresponding Depletion Rate Probe Elevation (mg/l day) (kg/day) Volume (m 3 ) (mg/l day) (kg/day) ,067, ,267, ,475, ,944, ,285, ,071, ,019, ,419, (Average Hypolimnion Elevation) 2540 (Average Hypolimnion Elevation) Average Hypolimnion DO demand Baseline Oxygen Addition Rate (SCFM) Estimated Oxygen Addition Rate (SCFM) Average Hypolimnion DO demand Baseline Oxygen Addition Rate (SCFM) 30.3 Diffuser Induced Oxygen Demand (DIOD) mulitplier 2.5 Soth Twin ~40 Estimated Oxygen Addition Rate (SCFM) ~80 Bottom + 20 Bottom + 15 Bottom + 10 Bottom + 5

39 Remote Sensor DO Depletion Calculation (2)

40 Distance Winter (under ice) Late Spring (pre pump/alum) above sediment (mg/l) Date (mg/l) Date (m) SOD Bottom Dec 30 - Jan Apr 15 - Apr Dec 30 - Jan Apr 15 - Apr Jan 7 - Jan Apr 15 - Apr 21 Winter (14-15) A + Be^(-kd) B ka A 0.524

41 Remote Sensor DO Depletion Calculation (2) Distance Winter (under ice) Late Spring (pre pump/alum) above sediment (mg/l) Date (mg/l) Date (m) SOD Bottom Dec 30 - Jan Apr 15 - Apr Dec 30 - Jan Apr 15 - Apr Jan 7 - Jan Apr 15 - Apr 21 Winter (14-15) A + Be^(-kd) B ka A DO mass = n DO i i 1 Vol i DO mass n i=1 A + Be kd i Vol i

42 Calculating Oxygen Demand In-situ SOD Data Demonstrate DO demand using In-situ SOD data

43 In-situ Sediment Oxygen Demand (SOD)

44 Calculating SOD (AHOD) SOD = b V A Where: SOD is the sediment oxygen demand in g/m 2 day, b is the slope of the SOD curve in mg/l hr, V is the volume of the chamber in l (64.85 liters), A is the total surface area of the chamber in m 2 (0.27 m 2 ), and is a constant converting mg/l hr to g/m 2 day.

45 Calculating DO Demand from SOD SOD = b V A = AHOD (Walker (1979)) predicting oxygen status: T DO = O iz h AHOD Where: T DO is effective number of days of oxygen supply in the hypolimnion (days), O i initial oxygen concentration (g m -3 ), and Z h is the mean hypolimnion depth (m). Z h = Z 1 Z T Z M Z = vol S. A. Z T = 1.6Z 0.57 Where: Z is mean depth, Z T is thermocline depth (m), and Z M is maximum depth (m). DO demand kg d = hypolimnion volume O i T DO

46 Calculating Oxygen Demand Secchi Disk / TSI Data Demonstrate DO demand using TSI index

47 Secchi Disk / Trophic State Index (TSI) Total phosphorus (mg/l) TSI (TSIP) = 14.42*[ln(TP average)] Chlorophyll-a TSI (mg/l) (TSIC) = 9.81*[ln(Chlorophyll-a average)] Secchi disk TSI (m) (TSIS) = 60 - (14.41*[ln(Secchi average)])

48 DO Demand and Secchi Disk Lasenby (1975) studied14 southern Ontario Lakes and developed a relationship between areal hypolimnetic oxygen deficits and Secchi depth. log AHOD = 1.37 log SD 0.65 Where: AHOD is areal hypolimnetic oxygen demand (mg cm -2 day -1 ), SD is Secchi depth (m). TSI SD = 10 6 ln SD ln2 Rearranging ln2 6 TSI SD = e 10 Additionally, other formulas were used that relate TP to SD: Dillon and Rigler (1974) Carlson approximation: ln SD = ln TP SD = 48 TP

49 DO Demand and TSI Carlson TSI index: TSI P = 10 6 ln 48 TP ln2 Carlson: TSI Chl a = ln Chl a ln2 Walker (1979) developed a relationship between DHOD (areal hypolimnetic oxygen demand) and TSI in which DHOD could be predicted based on TSI and mean depth (Z). log HOD = a 1 + a 2 TSI + a 3 log Z + a 4 log Z 2 Where: a 1 = a 2 = ± a 3 = 4.55 ± 0.52 a 4 = ± 0.25

50 Oxygenation Design Tools and Considerations Factor of Safety (IOD) Bubble Plume Model

51 IOD/ Applied Gas Flow Rate HODmass (kg day -1 ) _ CCR y = 22x R 2 = 0.9 SHR y = 6x + 50 R 2 = SHR CCR Oxygen Flow Rate (NCMH)

52 Speece Cone

53 Temperature (C) Super Saturation System (SSS) DO demand (kg/d) Design applied gas flow rate (O 2 ) (1 SCFM = 54 kg/d) Determine System Pressure Depth Piping head loss Max DO sat at pressure (Henry s Law) Min flow to achieve DO sat at pressure Flow [vol/time] = DO Demand [mass/time] / DO sat [mass/vol] Pump Curves / Pump selection Csat in Oxygen Pressure (psi)

54 Line Diffuser DMPR ED

55 Plume Characteristics October 23,

56 Plume Model Elevation (m) Distance (m)

57 Diffuser Length / O 2 flux Rate Spring Hollow Reservoir Diffuser Length 2000 ft Design Flow Rate 5 SCFM O 2 flux rate SCFM/LFT Carvins Cove Reservoir Diffuser Length 4000 ft Design Flow Rate 40 SCFM O 2 flux rate 0.01 SCFM/LFT North Twin Lake Diffuser Length 2500 ft Design Flow Rate 80 SCFM O 2 flux rate SCFM/LFT

58 Bathymetry Carvins Cove Reservoir Lake Vadnais Twin Lakes Pleasant Lake Reservoir

59 Diffuser Layouts

60 Oxygenation System Design Thank You