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Deep Bed Denitrification Performance Cold Weather Operation for Two Northeast WWTPs Presented by: Gary M. Lohse, P.E., Severn Trent Services Ken Wineberg,

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Presentation on theme: "Deep Bed Denitrification Performance Cold Weather Operation for Two Northeast WWTPs Presented by: Gary M. Lohse, P.E., Severn Trent Services Ken Wineberg,"— Presentation transcript:

1 Deep Bed Denitrification Performance Cold Weather Operation for Two Northeast WWTPs Presented by: Gary M. Lohse, P.E., Severn Trent Services Ken Wineberg, Severn Trent Services

2 ORGANIC NITROGEN (Proteins, Urea, etc.) ORGANIC NITROGEN (Proteins, Urea, etc.) AMMONIA NITROGEN NITRITE (NO 2 - ) NITRATE (NO 3 - ) ORGANIC NITROGEN (Bacteria Cells) ORGANIC NITROGEN (Bacteria Cells) ORGANIC NITROGEN (Net Growth) ORGANIC NITROGEN (Net Growth) NITROGEN GAS (N 2 ) Denitrification Organic Carbon Lysis & Auto Oxidation Bacterial Decomposition & Hydrolysis O2O2 O2O2 The Nitrogen Cycle via Biological Processes

3 Deep Bed Denitrification Filter General Overview Dissolved nitrate (NO 3 ) is converted to nitrogen gas (N 2 ) Heterotrophic bacteria - Use the O in NO 3 - as final e - acceptor when free dissolved O 2 is not available (anoxic environment) - Need organic carbon source for energy and cell-building - Easy to stop and start - Prefer pH range is neutral – works in range of ~ 6.0 to Need nutrients such as P, often already available in wastewater - Reaction rate affected by temperature, carbon source & potential toxins

4 Deep Bed Denitrification Severn Trent Services 4

5 Deep Bed Denitrification Filter - Profile of Components Sump Sump Cover Plate BW Air Lateral BW Air Header Underdrain Support Gravel Media

6 Deep Bed Denitrification Filter - Underdrain system Support Media and Gravel Handle Hydraulic Shocks – minimize possible damage to filter internals Minimize Potential Pluggage in Applications with High Solids Loading or Biological Activity Collect Filtrate in Normal Operating Mode Helps Evenly Distribute BW Air & Water Across Entire Area of the Filter Bed

7 Deep Bed Denitrification Filter - Air & Water Flow through underdrain Downflow Operating ModeUpflow Backwash Mode

8 Deep Bed Denitrification Filter - Air & Water Distribution System Stainless Steel Box Header Air Laterals, Stainless Steel –Protected from Gravel & Media –Located Under Snap T Block TM Arch –Located under every other row Water Slot in Sump Cover –Located under every other row, where there is no air lateral

9 Deep Bed Denitrification Filter - Methanol (carbon) System Tank Volume Standard Day Average Flow Tank Continuous Level Measurement Tank Low and High Level Methanol Pumps Diaphragm Peristaltic

10 Supplemental Carbon Control Denitrification Filters FE Controller (MMI) Nitrate Analyzer Influent Sample Effluent Sample Influent Flow Meter Carbon Feed Pump Effluent

11 Deep Bed Denitrification Filter - Backwash (Solids Removal) 3 Basic Cycles  Backwash Air Only: - 1 to 3 min - Backwash Air Rate of 5 CFM/ft 2  Backwash Air/Water Scour: - 10 to 15 min (trough overflow time) - Backwash Air Rate of 5 CFM/ft 2 - Backwash Water Rate of 6 GPM/ft 2  Backwash Water Only Rinse: - 5 min - Backwash Water Rate of 6 GPM/ft2

12 Severn Trent Services 12 Deep Bed Denitrification Operation- Filtration

13 Severn Trent Services 13 Deep Bed Denitrification Operation - Clearwell

14 Severn Trent Services 14 Deep Bed Denitrification Operation – Air Backwash

15 Severn Trent Services 15 Deep Bed Denitrification Operation – Water Backwash

16 Severn Trent Services 16 Deep Bed Denitrification Operation – Air/Water Backwash

17 Severn Trent Services 17 Deep Bed Denitrification Operation - Mudwell

18 Factors Affecting Denitrification Filter Design Influent NO3-N Concentration Dissolved Oxygen (DO) Concentration  Low DO Preferred Carbon Source Characteristics & Availability Alkalinity: 50 PPM+ Preferred pH Range: Preferred  Optimum Presence of Nutrients and/or Toxins Temperature Reaction Time: Empty Bed Detention Time (EBDT)

19 Scituate, Massachusetts Commissioned in 2000

20 Scituate, Massachusetts

21 Denitrification Filter Design Criteria Design Value Average flow:1.60 mgd Max day flow:2.36 mgd Peak hour flow:4.34 mgd Average TSS:15 mg/L Average NO 3 -N:13 mg/L Temperature:8 deg Celsius Plant Effluent TSS:5 mg/L NO 3 -N:0.5 mg/L TN:4 mg/L Denitrification Filters Average hydraulic loading1.22 gpm/sf Peak hydraulic loading3.30 gpm/sf 12 month rolling average

22 Filter System Methanol System Scituate WWTP

23 Average Operating Data April 2001Through November 2006 Flow Rate Average:1.22 mgd Max day:3.54 mgd Peak hour:4.20 mgd Plant Effluent (Average) CBOD:3.1 mg/L TSS:4.5 mg/L TN:2.9 mg/L Denitrification Filters Average hydraulic loading:0.70 gpm/sf Peak hydraulic loading:2.40 gpm/sf 12 month rolling average

24 Flow (mgd) WW Temp (deg C) CBOD (mg/L) TSS (mg/L) TN (mg/L) Dec Jan Feb Mar Apr May Average Cold Temperature Operating Data Scituate WWTP April 2001 Through November 2006

25 Flow (mgd) WW Temp (deg C) Influent NO 3 -N (mg/L) Effluent NO 3 -N (mg/L) Dec Jan Feb Mar Apr May Average Cold Temperature Operating Data Scituate WWTP Dec 2006 Through May 2007

26 Allegany County, Maryland Celanese WWTP Commissioned in 2005

27 Allegany County, MD Celanese WWTP Head Works 2.86 MGD Design Single Stage Activated Sludge Clarifiers Denitrification Filters

28 Denitrification Filter Design Criteria Design Value Average flow:1.66 mgd Max Month flow:2.86 mgd Peak hour flow:6.6 mgd Average TSS:30 mg/L Average NO 3 -N:26 mg/L Temperature:11 deg Celsius Plant Effluent TSS:5 mg/L NO 3 -N:2 mg/L TN:3 mg/L Denitrification Filters Average hydraulic loading2.6 gpm/sf Peak hydraulic loading6.0 gpm/sf Annual Average

29 Cold Temperature Operating Data Celanese WWTP Dec 2009 Through May 2012 Flow ADF (mgd) WW Temp (deg C) CBOD (mg/L) TSS (mg/L) NO x -N (mg/L) TN (mg/L) Dec Jan Feb Mar Apr May Average

30 Additional Cold Weather Deep Bed Denitrification filters New York – 2 Pennsylvania – 2 Maryland – 5 Virginia – 8 Massachusetts – 4 Colorado – 1 California – 2 (High Elevations)

31 Conclusion Deep beds allow maximum ability for solids to be captured providing for consistently low TSS and turbidity effluents with a varying load of TSS Filter media becomes attachment site for denitrifying bacteria in which dissolved nitrate (NO 3 ) is converted to nitrogen gas (N 2 ) providing nitrogen removal through a biological process Need organic carbon source for energy and cell-building and nutrients such as P, often already available in wastewater Backwash water is typically only 2 – 4 % of forward flow. Lower backwash consumption and recycle cuts plant operating costs and increases plant capacity. Reaction rate affected by temperature, carbon source & potential toxins Deep Bed Denitrification filters can achieve TSS of below 4 mg/l and TN limits of below 3 mg/l even in cold climates

32 Cold Weather Deep Bed Denitrification Filters Questions?????? CONTACT: Gary M. Lohse, P.E. Regional Sales Manager Severn Trent Services 3000 Advance Lane Colmar, Pa Cell: (215) Direct: (215) Fax: (215)


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