Evaluation of the Multi-Port Diffuser System for the Lebanon WWTP. Kwabena Adu-Sarkodie, P.E.

Transcription

1 Evaluation of the Multi-Port Diffuser System for the Lebanon WWTP Kwabena Adu-Sarkodie, P.E. Sept. 15, 2009

2 Presentation Outline Brief Regulatory Overview Existing Outfall/Detailed Design Protocol for Performance Evaluation Preliminary Results of Evaluation and Next Steps

3 Presentation Outline Brief Regulatory Overview Existing Outfall/Detailed Design Protocol for Performance Evaluation Preliminary Results of Evaluation and Next Steps

4 Mixing Zone Overview The dilution credit is a numerical value associated with the mixing zone that is used in the calculation of effluent limitations

5 Regulatory Requirements/ Dilution Ratios in OR In Calculating Dilution Ratio for: Acute Aquatic Life Criterion Chronic Aquatic Life Criterion Human Health Criterion Use The Critical Receiving Water Flow of: 1Q10 7Q10 Harmonic Mean (Carcinogens) 30Q5 (Non-Carcinogens) Use Critical Plant Flow of: Average Dry Weather Flow 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.

6 Overall Site View Lebanon WWTP New Outfall Diffuser Existing Outfall Regulatory Mixing Zone South Santiam River

7 Existing Outfall Pipeline to the South Santiam River

8 Comparison Between Plant Data and Allowable Limits Plant Data Plant Data mg/l NPDES Ammonia mg/l NPDES Chlorine Residual NPDES - Monthly Average NPDES - Daily Maximum Plant Data - Monthly Average (Sept ) Plant Data - Daily Maximum (Sept ) NPDES - Monthly Average NPDES - Daily Maximum Plant Data - Monthly Average (Sept ) Plant Data - Daily Maximum (Sept )

9 Mixing Zone at South Santiam River ZID = Zone of Initial Dilution (Acute Mixing Zone) CMZ = Chronic Mixing Zone 10 ft 100 ft Flow Direction Objective: Design discharge for appropriate mixing at the boundary zone

10 Strategy for Improving Mixing Statistical Analysis 1Q10, 7Q10, 30Q5, Harmonic Mean, Plant Flow CORMIX Modeling Detailed Design Modeling Verification

11 Parameter Plant Data 2024 (mgd) Average Dry Weather Flow (ADWF) 3 5 Average Wet Weather Flow (AWWF) 8 14 Max. Month Dry Weather Flow (MMDWF) 7 12 Max. Month Wet Weather Flow (MMWWF) Peak Day Flow (PDF) Peak Wet Weather Flow (PWWF) Build-Out (mgd)

12 River Data Parameter Value, cfs Value, mgd 1Q10 / 7Q Harmonic Mean Q

13 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

14 Graphical Representation

15 Presentation Outline Brief Regulatory Overview Existing Outfall/Detailed Design Protocol for Performance Evaluation Preliminary Results of Evaluation and Next Steps

16 Detailed Design Duck-billed Check Valve, Typical of 11

17 Presentation Outline Brief Regulatory Overview Existing Outfall/Detailed Design Protocol for Performance Evaluation Preliminary Results of Evaluation and Next Steps

18 Model Verification Dye Used Supplier Approved Reported Minimum Dilution Actual Visual Limit (Based on River Water) Yellow Green Xanthene Dye Kingscote Chemicals National Science Foundation 10ppb (10 µg/l) 10 mg/l

19 Testing Protocol Water Tank Weir River

20 Model Verification ~ 4 mins Buoy Green Dye Exiting at the Ports Closest to the West Bank ~ 12 mins Plume is fully developed and Green Dye Exits all 11 Ports

21 Model Verification Individual Effluent Streams ~ 9 mins Plume is Distinctly Demarcated at 11 Ports Homogeneous Plume Plume is Homogeneous 100 Feet Downstream of the Discharge Port Buoys ~ 9 mins

22 Model Verification ~ mins Mixing Zone: Plume is Rectangular in Shape, as Predicted by CORMIX Model 100-Foot Mark 80-Foot Mark 60-Foot Mark

23 Scenario River Flow = 450 cfs (292 mgd) (1Q10/7Q10) Plant Flow = 3 mgd (Design/Year 2024) River Flow (b) = 450 cfs (292 mgd) (1Q10/7Q10) Plant Flow (b) = 5 mgd (Build-Out ADWF) River Flow = 540 cfs (349 mgd) (30Q5) Plant Flow = 3 mgd (Design/Year 2024 ADWF) River Flow = 540 cfs (349 mgd) (30Q5) Plant Flow = 5 mgd (Build-Out ADWF) River Flow = 1,380 cfs (892 mgd) (Harmonic Mean) Plant Flow = 3 mgd (Design/Year 2024 ADWF) River Flow = 1,380 cfs (892 mgd) (Harmonic Mean) Plant Flow = 5 mgd (Build-Out ADWF) River Flow = 1,380 cfs (892 mgd) (Harmonic Mean) Plant Flow = 7 mgd (Design/Year 2024 MMDWF) River Flow = 1,380 cfs (892 mgd) (Harmonic Mean) Plant Flow = 12 mgd (Design/Year 2024 MMWWF) River Flow = 6,000 cfs (3,878 mgd) (MMWWF) Plant Flow = 12 mgd (Design/Year 2024 MMWWF) River Flow = 6,000 cfs (3,878 mgd) (MMWWF) Plant Flow = 21 mgd (Build-Out MMWWF) River Flow (c) = 1,670 cfs (1,079 mgd) Plant Flow (c) = 1.05 mgd (Plant Operating Condition) (d) Bulk Average Plume Dilution at CMZ (a) Comparison of Predictions (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. (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 mgd. ADWF = Average Dry Weather Flow AWWF = Average Wet Weather Flow MMDWF = Maximum Month Dry Weather Flow MMWWF = Maximum Month Wet Weather Flow

24 Presentation Outline Brief Regulatory Overview Existing Outfall/Detailed Design Protocol for Performance Evaluation Preliminary Results of Evaluation and Next Steps

25 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

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

27 Questions