Evaluation of the Multi-Port Diffuser Systemfor the Lebanon WWTP

Kwabena Adu-Sarkodie, P.E.

Sept. 15, 2009

Presentation Outline

Brief Regulatory Overview

Existing Outfall/Detailed Design

Protocol for Performance Evaluation

Preliminary Results of Evaluation andNext Steps

Presentation Outline

Brief Regulatory Overview

Existing Outfall/Detailed DesignExisting Outfall/Detailed DesignExisting Outfall/Detailed Design

Protocol for Performance EvaluationProtocol for Performance EvaluationProtocol for Performance Evaluation

Preliminary Results of Evaluation andPreliminary Results of Evaluation andPreliminary Results of Evaluation andNext StepsNext StepsNext Steps

Mixing Zone Overview

The dilution credit is a numerical value

associated with the mixing zone that is used

in the calculation of effluent limitations

Regulatory Requirements/Dilution Ratios in OR

In Calculating Dilution Ratio for:

Use The Critical Receiving Water Flow of:

Use Critical Plant Flow of:

Acute Aquatic Life Criterion

1Q10

Average Dry Weather Flow

Chronic Aquatic Life Criterion

7Q10

Human Health Criterion

Harmonic Mean (Carcinogens)

30Q5 (Non-Carcinogens)

1Q10 - Lowest flow that occurs for one day with a statistical frequency of once every 10 years. 7Q10 - Average low flow that occurs for seven consecutive days with a statistical frequency of once every 10 years.

30Q5 - Lowest average low flow that occurs for 30 consecutive days with a statistical frequency of once every 5 years.

Overall Site View

Lebanon WWTP

New Outfall DiffuserNew Outfall Diffuser

Existing OutfallRegulatory

Mixing Zone

South Santiam River

Existing Outfall Pipeline to the South Santiam River

Comparison Between Plant Data and Allowable Limits

0.25

0.3

0.35

0.4

6

7

8

9

NPDES

Plant Data Plant Data

8.20.37

0

0.05

0.1

0.15

0.2mg/L

Chlorine Residual

NPDES - Monthly Average

NPDES - Daily Maximum

Plant Data - Monthly Average (Sept. 2002-2004)

Plant Data - Daily Maximum (Sept. 2002-2004)

0

1

2

3

4

5mg/L

Ammonia

NPDES - Monthly Average

NPDES - Daily Maximum

Plant Data - Monthly Average (Sept. 2002-2004)

Plant Data - Daily Maximum (Sept. 2002-2004)

NPDES NPDES

0.941.89

5.6

0.01 0.02

0.18

Mixing Zone at South Santiam RiverZID = Zone of Initial Dilution (Acute Mixing Zone)

CMZ = Chronic Mixing Zone

10 ft100 ft

Objective: Design discharge for appropriate mixing at the boundary zone

Flow Direction

Strategy for Improving MixingStatistical Analysis1Q10 , 7Q10 , 30Q5,

Harmonic Mean, Plant Flow

Statistical Analysis1Q10 , 7Q10 , 30Q5,

Harmonic Mean, Plant Flow

Modeling Verification

Detailed DesignDetailed Design

CORMIX ModelingCORMIX Modeling

Plant Data

Parameter2024(mgd)

Build-Out(mgd)

Average Dry Weather Flow (ADWF) 3 5

Average Wet Weather Flow (AWWF) 8 14

Max. Month Dry Weather Flow (MMDWF) 7 12Max. Month Dry Weather Flow (MMDWF) 7 12

Max. Month Wet Weather Flow (MMWWF) 12 21

Peak Day Flow (PDF) 20 26

Peak Wet Weather Flow (PWWF) 26 36

River Data

Parameter Value, cfs Value, mgd

1Q10 / 7Q10 450 291

Harmonic Mean 1380 892Harmonic Mean 1380 892

30Q5 540 349

CORMIX Model

• General Features§ Uses N.S. Equations to Predict Mixing Conditions after Plume is Discharged

§ Dimensions Parameters Used to Define Different Portions of Flow

§ Steady State Conditions§ Single Port Diffusers, Multi-Port Diffusers, Surface Discharge Conditions

Graphical Representation

Presentation Outline

Brief Regulatory OverviewBrief Regulatory OverviewBrief Regulatory Overview

Existing Outfall/Detailed Design

Protocol for Performance EvaluationProtocol for Performance EvaluationProtocol for Performance Evaluation

Preliminary Results of Evaluation andPreliminary Results of Evaluation andPreliminary Results of Evaluation andNext StepsNext StepsNext Steps

Detailed Design

Duck-billed Check Valve, Typical of 11

Presentation Outline

Brief Regulatory OverviewBrief Regulatory OverviewBrief Regulatory Overview

Existing Outfall/Detailed DesignExisting Outfall/Detailed DesignExisting Outfall/Detailed Design

Protocol for Performance Evaluation

Preliminary Results of Evaluation andPreliminary Results of Evaluation andPreliminary Results of Evaluation andNext StepsNext StepsNext Steps

Model VerificationDye Used Yellow Green Xanthene

Dye

Supplier Kingscote Chemicals

Approved National Science Approved National Science Foundation

Reported Minimum Dilution

10ppb (10 µg/L)

Actual Visual Limit(Based on River Water)

10 mg/L

Testing Protocol

Water Tank

Weir River

Model Verification

Buoy

~ 4 mins

Green Dye Exiting at the Ports Closest to the West Bank

Plume is fully developed and Green Dye Exits all 11 Ports

~ 12 mins

Model VerificationIndividual Effluent Streams

Plume is Distinctly Demarcated at 11 Ports

Plume is Homogeneous 100 Feet Downstream of the Discharge Port Buoys

Homogeneous Plume

~ 9 mins

~ 9 mins

Model Verification

Mixing Zone: Plume is Rectangular in Shape, as Predicted by CORMIX Model

100-Foot Mark

80-Foot Mark

60-Foot Mark

~9.5 -10 mins

Comparison of PredictionsScenario

Bulk Average Plume Dilution

at CMZ(a)

River Flow = 450 cfs (292 mgd) (1Q10/7Q10)Plant Flow = 3 mgd (Design/Year 2024)

26.6

River Flow(b) = 450 cfs (292 mgd) (1Q10/7Q10)Plant Flow(b) = 5 mgd (Build-Out ADWF)

17

River Flow = 540 cfs (349 mgd) (30Q5)Plant Flow = 3 mgd (Design/Year 2024 ADWF)

30.6

River Flow = 540 cfs (349 mgd) (30Q5)Plant Flow = 5 mgd (Build-Out ADWF)

19.3

River Flow = 1,380 cfs (892 mgd) (Harmonic Mean)62.1

(a) ZID was modeled at 10 feet downstream from the multi-port diffuser; CMZ was modeled as being 100 feet from the multi-port diffuser.

(b) The conditions indicated are the worst case scenario, and is therefore the minimum dilution expected.River Flow = 1,380 cfs (892 mgd) (Harmonic Mean)

Plant Flow = 3 mgd (Design/Year 2024 ADWF)62.1

River Flow = 1,380 cfs (892 mgd) (Harmonic Mean)Plant Flow = 5 mgd (Build-Out ADWF)

37.9

River Flow = 1,380 cfs (892 mgd) (Harmonic Mean)Plant Flow = 7 mgd (Design/Year 2024 MMDWF)

27.9

River Flow = 1,380 cfs (892 mgd) (Harmonic Mean)Plant Flow = 12 mgd (Design/Year 2024 MMWWF)

17.3

River Flow = 6,000 cfs (3,878 mgd) (MMWWF)Plant Flow = 12 mgd (Design/Year 2024 MMWWF)

55.6

River Flow = 6,000 cfs (3,878 mgd) (MMWWF)Plant Flow = 21 mgd (Build-Out MMWWF)

32.7

River Flow(c) = 1,670 cfs (1,079 mgd)Plant Flow(c) = 1.05 mgd (Plant Operating Condition)(d)

minimum dilution expected.

(c) The conditions indicated here are the actual conditions that the preliminary experiment was conducted.

(d) Plant flows from 08/22/08-10/08/08 were from 1.0-2.2 mgd.

ADWF = Average Dry Weather FlowAWWF = Average Wet Weather FlowMMDWF = Maximum Month Dry Weather Flow MMWWF = Maximum Month Wet Weather Flow

Presentation Outline

Brief Regulatory OverviewBrief Regulatory OverviewBrief Regulatory Overview

Existing Outfall/Detailed DesignExisting Outfall/Detailed DesignExisting Outfall/Detailed Design

Protocol for Performance EvaluationProtocol for Performance EvaluationProtocol for Performance Evaluation

Preliminary Results of Evaluation andNext Steps

Next Steps

• Develop Final Test Protocol• Conduct Final Test• Prepare Report for DEQ on behalf of City • Prepare Report for DEQ on behalf of City of Lebanon

Acknowledgements

• City of Lebanon• Department of Environmental Quality• Mark Zinniker, P.E. – Project Manager• Mark Zinniker, P.E. – Project Manager• Laura Farthing, P.E. – Project Engineer• Corie Peterson, P.E. – Project Manager/Engineer

Questions