Energy-Efficient Mixing Using “Large Bubble” Method · Energy-Efficient Mixing Using “Large...

Energy-Efficient Mixing Using “Large Bubble” Method Presented by: Stuart Humphries, EnviroMix

180 East Bay Street Charleston SC 29401 843.573.7510 www.enviro-mix.com

Need for Energy Conservation

• Energy prices expected to rise

• Decreased tax revenues/reduction in water sales

• Stringent nutrient effluent limits driving treatment complexity and

energy consumption

• Current infrastructure is inadequate

Source: Annual Energy Review 2009, U.S. Energy Information Administration, Report No. DOE/EIA-0384(2009), August 19, 2010

Need for Energy Conservation

2

WWTP Energy Usage

Aeration/Mixing

WWTP Energy Usage

• Energy Efficient Aeration Systems • Flexible Blowers • Energy Efficient Mixers

3

mixers

mixers

AEROBIC ANOXIC

RETURN SLUDGE

NITRATE RECYCLE

POST-ANOXIC

AEROBIC TN < 3 mg/L

TP = < 0.3 mg/L ANAEROBIC

mixers INFLUENT

Optional Methanol Addition

Five-Stage Modified Bardenpho Configuration

Optional Chemical Addition

Modified Bardenpho Diagram

Configured to Obtain Low Concentrations of Both N & P

Continuous mixing is a major cause of energy consumption 4

• Conventional point source solution

• Functional but costly…

• 2x power costs of distributed energy model

• Maintenance is a key challenge

• Low flexibility/integration potential

• Short life span: 5-7 years

New Mixing Paradigm

• Distributed mixing & energy solution

• Effective & efficient; 60%+ energy savings

• Variable operator settings

• Highly scalable

• Design flexibility

• Smart systems integration/process automation

Point-Source Mixing Technology

Distributed Energy Model

“Large Bubble” Mixing

5

• Incorporated May 2004 • Patented process • Excellent professional team • Provide hardware-only or turn-key

solutions • New infrastructure or retrofit • Attractive ROI/payout • Proven & reliable system components

Video

6

BioMix Oxygen Transfer

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Oxygen Transfer

• The large compressed gas volumes have rapid upward velocity

• Controlled turbulence and currents provide mixing

• Insignificant amount of oxygen

• Anoxic (even anaerobic) mixing system

Technology Components

Touch Screen Input

Multiple Parameter Variables

SCADA Integration Ready

Mobile communications

Fault detection w/ mobile notification

Solenoid Operated Air Control Valves •15 year rated •Replacement with 2 bolts

Fault Detection and Notification

Firing parameter control

Optimization of power efficiency and TSS uniformity

Master Control Panel/User Interface

Valve Control Panel(s) Automation Power Source & Nozzle

Patented air distribution technology Rotary Screw Compressor Nozzle design/layout flexibility

• Cyclic Aeration/Mixing

• DO Control

• SNdN

• Influent Demand Response

• TSS Load Balancing

Process Controls “Large Bubble” Mixing

8

Stainless Steel BioMix Nozzle with Large Bubble-Sized Softball

• Anchored to Tank Floor • Self-Cleaning • No Maintenance of In-Tank Components

Nozzle

9

Installation

10

Installation

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Installation

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Clifford W. Randall, PhD, Dis.M.ASCE The C. P. Lunsford Professor Emeritus Civil and Environmental Engineering Room 418, Durham Hall Virginia Tech Blacksburg, VA 24061-0246 T 540 231 6018 and William O. Randall, P.E., BCEE

Comparative Analysis Authors

Randall Comparative Analysis

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A1 A2


BioMix

14


Comparative Analysis

• F. Wayne Hill Water Resources Center, Gwinnett County, GA

• Performed from April 2009 – February 2010

• Large Bubble Mixing system installed in five cells in Train 10

• Existing 15-HP submersible mechanical mixers with controls

•Large Bubble Mixing system consisted of an 15-HP rotary screw compressor,

floor-mounted nozzles, piping, and controls

A1 A2

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TSS Mixing Study

F. Wayne Hill WRC TSS Mixing Study

Train 10, Tank A2

Large Bubble Mixer

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Randall Comparative Analysis - Energy Comparison

Energy Comparison

• Demonstrated that Large Bubble mixing uses significantly less power

• 45 – 60%+ savings

• Maximum efficiency through multiple basin application

A1

A2 B1

B2

17

Energy Comparison

Amps 66.00 15.14

Volts 467.65 483.00

Power Factor 0.55 0.93

Horsepower 39.42 15.79

HP/1000 ft3 0.243 0.097

Kilowatts 29.40 11.78

$/Yr @ $0.06/kW-Hr $15,453 $6,192

$/Yr @ $0.10/kW-Hr $25,754 $10,319

$/Yr @ $0.15/kW-Hr $38,632 $15,479

Energy Comparison Large Bubble vs. (3) 15-HP Submersible Mixers

60% Savings

Maximum efficiency through multiple basin application

Submersible Mixer (x3)

Large Bubble

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F. Wayne Hill WRC ORP Study

Randall Comparative Analysis ORP Study

A1 A2

mV

Oxi

c An

oxic

An

aero

bic

A1 – Primary Influent Selector Tank A2 – Anaerobic/Anoxic with RAS (nitrates)

A2

A1

ORP data indicate anaerobic conditions while using compressed air -based Large Bubble Mixing system

L / B

L / B

Large Bubble

Large Bubble

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Ortho-P Study

A2

0.0

5.0

10.0

15.0

20.0

25.0

30.0

10/06/10 10/07/10 10/08/10 10/09/10 10/10/10 10/11/10 10/12/10 10/13/10 10/14/10 10/15/10

mg/

L O

rtho

-P (a

s P)

Date

Ortho-P (as P) for Respective Anaerobic Selector Cells Parallel Process Trains, Cells A2 F. Wayne Hill WRC, Gwinnett County GA

BR#5-A2

BR#7-A2

BR#10-A2 (BioMx) Large Bubble

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Ortho-P Study

C6

BDL BDL 0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

0.18

10/06/10 10/07/10 10/08/10 10/09/10 10/10/10 10/11/10 10/12/10 10/13/10 10/14/10 10/15/10

mg/

L O

rtho

-P (a

s P)

Date

Ortho-P (as P) for Respective Final Oxic Modified Bardenpho Cells Parallel Process Trains, Cells C6 F. Wayne Hill WRC, Gwinnett County GA

BR#5-C6

BR#7-C6

BR#10-C6 BioMx

Effluent Permit (Total P)

Large Bubble

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Anoxic Mixing

Project Profile:

Application- Anoxic Mixing Process- A2/O Facility- ReWa Mauldin Rd WWTP, Greenville SC

Management Goals:

• Reduce electrical power consumption: Target-66%

Utilize 5-hp compressor in lieu of 15-hp mechanical mixer

• Reduce future maintenance requirements

Process Objectives:

• Maintain low D.O. levels

• ORP < 100 mV

• Denitrification rates analogous to mechanical mixing

Extensive maintenance history with costly mechanical mixers

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Large Bubble vs. Mechanical Anoxic Mixing

ReWa Mauldin Road WWTP (Greenville SC) Results

Effluent Nitrate (NO3-N)

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(Large Bubble)

Anaerobic Digester Mixing

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Mechanical Mixing Video

Surface Air-Water Oxygen Entrainment



Dissolved Oxygen

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(Large Bubble)

ORP



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(Large Bubble)



Effluent Ortho-Phosphate (PO4)

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(Large Bubble)

AVG = 11.14 AVG = 10.29

Mechanical Mixer Geometric Challenges

x

x x

x

x

Mechanical Mixer Access?

Large Bubble System

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Mechanical Mixing Geometric Challenges

Geometry Is Not Critical Example: Sloped Bottom Circular Tank

“Rings” of Nozzles, Center Ring in Cone Bottom, Nozzles Installed up Side Slope

Geometry Advantage

Thickener Rehab Project (GA) Inner Ring: Primary sludge (3.5%), Outer Ring: Waste activated sludge (2%)

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High, localized mixing energies in numerous locations Greater mixing equals greater methane…...more power generation Customizable firing parameters Energy-efficient, low maintenance

Anaerobic Digester Gas Mixing


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Anaerobic Digester Gas Mixing Video

Anaerobic Digester, AR

33 11/01/12

Anaerobic Digester, AR

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Municipal Wastewater Applications

Anoxic

BNR System

Channel

Sludge Storage

EQ

Sludge

Digester

Aeration

Pump

Station

Anaerobic

Swing Zone

Chlorine Contact

Chamber

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• Gentle, no-shear floc formation • No mechanical or electrical components in the water • Non-clogging, self-cleaning 316SS in-tank components • Adjustable firing parameters for varying mixing requirements • One compressor may be used to efficiently mix over 40 tanks

WTP Flocculation Tank “Large Bubble” Mixing System

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Corroded Mechanical Flocculator

Municipal Water Applications

Water Storage Tank “Large Bubble” Mixing System

Municipal Water Applications

Case Study – Power Consumption

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Mixed Liquor Channel, TN

Mixed Liquor Channel, TN

Mixed Liquor Channels

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O&M Comparison

O&M Comparison Large Bubble vs. Coarse Bubble Diffused Air Mixing

Mixed Liquor Channels

CENTRIFUGAL BLOWERElectrical

Blower Quantity

Blower Operating

HP Blower CFM Capacity

SST Channel CFM Reqmt

Reqmt % Reqmt % as HP Operating Kilowatts

Annual Cost @ $0.07/kW-Hr



1 1 2400 36000 3600 10.0% 240.00 179.04 $109,787.33 $125,471.23 $141,155.14

MaintenanceBlower

QuantityBlowers in

UseMaintenance Cost/Blower

% Blowers In Use

Annual Maint Cost

Annual Maint Cost

Annual Maint Cost

1 1 $5,000.00 100.0% $5,000.00 $5,000.00 $5,000.00

$114,787.33 $130,471.23 $146,155.14

ChannelMx Electrical

Total Tanks Tanks In Service

Estimated Operating HP

Operating Kilowatts




3 3 38.50 28.72 $17,611.72 $20,127.68 $22,643.64

MaintenanceCompressor

QuantityCompressors

In UseMaintenance

Cost/Compressor% Compr In

UseAnnual Maint

CostAnnual Maint

CostAnnual Maint

Cost1 1 $4,000.00 100.0% $4,000.00 $4,000.00 $4,000.00

$21,611.72 $24,127.68 $26,643.64

At $0.07/kW-Hr At $0.08/kW-Hr At $0.09/kW-Hr

$93,175.61 $106,343.56 $119,511.50

TOTAL ANNUAL COST

TOTAL ANNUAL COST

BioMx YEARLY O&M SAVINGS

LARGE BUBBLE

40

Current Rate: $0.07/kW-Hr $0.08/kW-Hr $0.09/kW-HrCENTRIFUGAL BLOWERInitial Purchase Incl. Local Controls and MCC $0 $0 $0Installation $0 $0 $0Electrical (Power) * $2,339,946 $2,674,225 $3,008,503Maintenance * $88,618 $88,618 $88,618TOTAL $2,428,565 $2,762,843 $3,097,121

BIOMIX Initial Purchase Incl. Local Controls and MCC $299,000 $299,000 $299,000Installation (by others) $60,000 $60,000 $60,000Engineering Design (by others) $10,000 $10,000 $10,000Electrical (Power) * $375,366 $428,990 $482,614Maintenance * $79,756 $79,756 $79,756TOTAL $824,123 $877,747 $931,370*Present Worth Cost: 20 years, 3% loan rate, 4% energy cost increase/year, 2% maintenance cost increase/year

$0.07/kW-Hr $0.08/kW-Hr $0.09/kW-Hr$1,604,442 $1,885,096 $2,165,750

3.98 3.49 3.10BIOMIX PRESENT WORTH SAVINGS

PAYBACK PERIOD† (YEARS)

20-Year Present Worth Analysis Large Bubble vs. Coarse Bubble Diffused Air Mixing

Cost of Ownership Present Worth Analysis

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LARGE BUBBLE

PRESENT WORTH SAVINGS

Case Study – Maintenance

42

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Anaerobic/Anoxic Zones, MD

Anaerobic/Anoxic Zones, MD

O&M Comparison

O&M Comparison Large Bubble vs. (68) Submersible Mixers

Anaerobic/Anoxic Cells

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SUBMERSIBLE MIXERElectrical

Mixer Quantity

HP HP Connected Mixers in Use Operating HP Operating Kilowatts




56 4 224 56 224.00 167.10 $139,063.95 $153,702.26 $168,340.5712 7.5 90 12 90.00 67.14 $55,873.91 $61,755.37 $67,636.84

total $194,937.86 $215,457.63 $235,977.41

MaintenanceMixer

QuantityMixers in Use Maintenance

Cost/Mixer*% Mixers In

UseAnnual Maint

CostAnnual Maint

CostAnnual Maint

Cost68 68 $1,434.00 100.0% $97,512.00 $97,512.00 $97,512.00

$292,449.86 $312,969.63 $333,489.41*$29,497/68 mixers=$434/yr maintenance/repair + 100% replacement every 10 years

BIOMIX Electrical

Total Tanks Tanks In Service

Estimated Operating HP

Operating Kilowatts




20 20 73.00 54.46 $45,319.95 $50,090.47 $54,860.99

MaintenanceCompressor

QuantityCompressors

In UseMaintenance

Cost/Compressor†% Compr In

UseAnnual Maint

CostAnnual Maint

CostAnnual Maint

Cost2 2 $4,700.00 100.0% $9,400.00 $9,400.00 $9,400.00

$54,719.95 $59,490.47 $64,260.99†$2500/yr maintenance/repair + 100% replacement every 10 years

Current Rate: $0.095/kW-Hr $0.105/kW-Hr $0.115/kW-Hr$237,729.91 $253,479.16 $269,228.42

TOTAL ANNUAL COST

TOTAL ANNUAL COST

BIOMIX YEARLY O&M SAVINGS


20-Year Present Worth Analysis Large Bubble vs. (68) Submersible Mixers

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Current Rate: $0.095/kW-Hr $0.105/kW-Hr $0.115/kW-HrSUBMERSIBLE MIXERInitial Purchase Incl. Local Controls and MCC $0 $0 $0Installation $0 $0 $0Electrical (Power) * $3,496,943 $3,865,043 $4,233,142Maintenance * $1,327,287 $1,327,287 $1,327,287TOTAL $4,824,231 $5,192,330 $5,560,429

BIOMIX Initial Purchase Incl. Local Controls and MCC $535,700 $535,700 $535,700Installation (by others) $110,000 $110,000 $110,000Engineering Design (by others) $15,000 $15,000 $15,000Electrical (Power) * $812,984 $898,561 $984,138Maintenance * $127,948 $127,948 $127,948TOTAL $1,601,632 $1,687,209 $1,772,786*Present Worth Cost: 15 years, 3% loan rate, 6% energy cost increase/year, 2% maintenance cost increase/year

$0.095/kW-Hr $0.105/kW-Hr $0.115/kW-Hr$3,222,599 $3,505,121 $3,787,643

2.78 2.61 2.45† Difference of respective initial purchase plus installation and engineering design totals, divided by yearly O&M savings.

PAYBACK PERIOD† (YEARS)BIOMIX PRESENT WORTH SAVINGS

LARGE BUBBLE


Case Study – Payback Period

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Mixed Liquor Channels and Flocculation Tanks, PA

47 (3) 400-hp 25,000-cfm PD blowers

(two operating, one standby) (2) 1750-hp air compressors (one operating, one standby)

O&M Comparison

O&M Comparison Large Bubble vs. Coarse Bubble Diffused Air Mixing

Floc Tanks and Mixed Liquor Channels

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LARGE BUBBLE

20-Year Present Worth Analysis Large Bubble vs. Coarse Bubble Diffused Air Mixing


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LARGE BUBBLE


50

Lease Model

Existing Power

and Maintenance

Required

Anaerobic and Anoxic Zones

Power and

Maintenance BioMix™

Owner Savings $ Per Year

Before Lease During Lease $590,000, 6 years, 1.970%

Quarterly Payments

After Lease

Municipal Lease Option WRF, Georgia

Owner Savings

15

30

45

60

75

90

105

120

0

135 Thousand

$131,731

$20,101

$104,501

$7,129

$20,101

$111,630 Lease Payment

Power and Maintenance

BioMix™

Client Profiles

Hopewell Regional Treatment- 50 MGD

F. Wayne Hill – 60 MGD

ASA – 54 MGD

McBee – Water Storage Tank

Client Examples

Installation/Delivery

Large Bubble Under Design

Large Bubble Selected for Design

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Fourche Creek – 16 MGD

Bucklin Point – 116 MGD

Franklin County General Authority – 4 MGD

Mount Pleasant – 4 MGD

“Large Bubble” Mixing Key Benefits:

• Effective Mixing using Large Bubble

• Energy Reduction – 70%+ versus mechanical mixing

• Reduced Maintenance

• Facilitates Nutrient Removal

• Preserve Potable Water Quality

Key Benefits

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Questions?

Conclusion

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Energy-Efficient Mixing Using “Large Bubble” Method Presented by: Stuart Humphries, EnviroMix

180 East Bay Street Charleston SC 29401 843.573.7510 www.enviro-mix.com

Energy-Efficient Mixing Using “Large Bubble” Method · Energy-Efficient Mixing Using “Large...

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