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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, Severn Trent Services. The Nitrogen Cycle via Biological Processes. ORGANIC NITROGEN (Proteins, Urea, etc.). Bacterial - PowerPoint PPT Presentation
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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, Severn Trent Services
ORGANIC NITROGEN(Proteins, Urea, etc.)
ORGANIC NITROGEN(Proteins, Urea, etc.)
AMMONIA NITROGENAMMONIA NITROGEN
NITRITE (NO2-)NITRITE (NO2
-)
NITRATE (NO3-)NITRATE (NO3
-)
ORGANIC NITROGEN(Bacteria Cells)
ORGANIC NITROGEN(Bacteria Cells)
ORGANIC NITROGEN(Net Growth)
ORGANIC NITROGEN(Net Growth)
NITROGEN GAS (N2)NITROGEN GAS (N2)
Denitrification
Organic Carbon
Lysis & Auto Oxidation
BacterialDecomposition& Hydrolysis
O2
O2
The Nitrogen Cyclevia Biological Processes
Deep Bed Denitrification Filter General Overview
Deep Bed Denitrification Filter General Overview
• Dissolved nitrate (NO3) is converted to nitrogen gas (N2)
• Heterotrophic bacteria- Use the O in NO3
- as final e- acceptor when free dissolved O2 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 8.2
- Need nutrients such as P, often already available in wastewater
- Reaction rate affected by temperature, carbon source & potential toxins
Deep Bed DenitrificationDeep Bed Denitrification
Severn Trent Services 4
Deep Bed Denitrification Filter - Profile of Components
Sump
Sump Cover Plate
BW Air Lateral
BW Air Header
Underdrain
Support Gravel
Media
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
Deep Bed Denitrification Filter- Air & Water Flow through underdrain
Downflow Operating Mode Upflow Backwash Mode
Deep Bed Denitrification Filter - Air & Water Distribution System
• Stainless Steel Box Header
• Air Laterals, Stainless Steel
– Protected from Gravel & Media
– Located Under Snap T BlockTM Arch
– Located under every other row
• Water Slot in Sump Cover
– Located under every other row, where there is no air lateral
Deep Bed Denitrification Filter- Methanol (carbon) System
• Tank Volume Standard 21-30 Day Supply @ Average Flow
• Tank Continuous Level Measurement• Tank Low and High Level
• Methanol Pumps• Diaphragm• Peristaltic
Supplemental Carbon Control
DenitrificationFilters
FE
Controller(MMI)
NitrateAnalyzer
Influent
Sample
Effluent
Sample
Influent Flow Meter
CarbonFeed Pump
Effluent
Deep Bed Denitrification Filter - Backwash (Solids Removal)
3 Basic Cycles
Backwash Air Only:- 1 to 3 min- Backwash Air Rate of 5 CFM/ft2
Backwash Air/Water Scour:- 10 to 15 min (trough overflow time)- Backwash Air Rate of 5 CFM/ft2
- Backwash Water Rate of 6 GPM/ft2
Backwash Water Only Rinse:- 5 min- Backwash Water Rate of 6 GPM/ft2
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Deep Bed Denitrification Operation- Filtration
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Deep Bed Denitrification Operation - Clearwell
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Deep Bed Denitrification Operation – Air Backwash
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Deep Bed Denitrification Operation – Water Backwash
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Deep Bed Denitrification Operation – Air/Water Backwash
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Deep Bed Denitrification Operation - Mudwell
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: 6-8.2 Preferred
7.0-7.5 Optimum • Presence of Nutrients and/or Toxins• Temperature• Reaction Time: Empty Bed Detention Time (EBDT)
Scituate, MassachusettsCommissioned in 2000
Scituate, Massachusetts
Denitrification Filter Design CriteriaDesign Value
Average flow: 1.60 mgdMax day flow: 2.36 mgdPeak hour flow: 4.34 mgdAverage TSS: 15 mg/L
Average NO3-N: 13 mg/LTemperature: 8 deg Celsius
Plant EffluentTSS: 5 mg/L
NO3-N: 0.5 mg/LTN: 4 mg/L
Denitrification FiltersAverage hydraulic loading 1.22 gpm/sfPeak hydraulic loading 3.30 gpm/sf
12 month rolling average
Filter System
Methanol SystemScituate WWTP
Average Operating DataApril 2001Through November 2006
Flow RateAverage: 1.22 mgdMax day: 3.54 mgdPeak hour: 4.20 mgd
Plant Effluent (Average)CBOD: 3.1 mg/LTSS: 4.5 mg/LTN: 2.9 mg/L
Denitrification FiltersAverage hydraulic loading: 0.70 gpm/sfPeak hydraulic loading: 2.40 gpm/sf
12 month rolling average
Flow(mgd)
WW Temp(deg C)
CBOD(mg/L)
TSS(mg/L)
TN(mg/L)
Dec 1.45 13 2.5 5.2 2.40
Jan 1.40 11 2.1 3.5 3.11
Feb 1.26 10 2.4 3.8 2.47
Mar 1.34 10 3.7 3.3 2.50
Apr 1.60 11 3.1 4.5 2.76
May 1.47 13 3.0 4.1 3.20
Average 1.42 11.3 2.8 4.1 2.74
Cold Temperature Operating DataScituate WWTP
April 2001 Through November 2006
Flow(mgd)
WW Temp(deg C)
InfluentNO3-N(mg/L)
EffluentNO3-N(mg/L)
Dec 06 1.18 11.3 10.1 0.33
Jan 07 1.23 9.2 11.2 0.30
Feb 07 0.94 7.6 12.2 0.18
Mar 07 1.57 8.7 8.8 0.38
Apr 07 2.12 9.4 6.9 0.49
May 07 1.43 12.7 8.0 0.48
Average 1.41 13.0 9.5 0.36
Cold Temperature Operating DataScituate WWTP
Dec 2006 Through May 2007
Allegany County, MarylandCelanese WWTPCommissioned in 2005
Allegany County, MDCelanese WWTP
HeadWorks
2.86 MGD Design
Single StageActivatedSludge
Clarifiers DenitrificationFilters
Denitrification Filter Design CriteriaDesign Value
Average flow: 1.66 mgdMax Month flow: 2.86 mgdPeak hour flow: 6.6 mgdAverage TSS: 30 mg/L
Average NO3-N: 26 mg/LTemperature: 11 deg Celsius
Plant EffluentTSS: 5 mg/L
NO3-N: 2 mg/LTN: 3 mg/L
Denitrification FiltersAverage hydraulic loading 2.6 gpm/sfPeak hydraulic loading 6.0 gpm/sf
Annual Average
Cold Temperature Operating DataCelanese WWTP
Dec 2009 Through May 2012
FlowADF
(mgd)
WW Temp
(deg C)
CBOD(mg/L)
TSS(mg/L)
NOx-N(mg/L)
TN(mg/L)
Dec 1.70 12.5 2.0 3.3 1.7 3.7
Jan 1.68 11.5 1.7 3.0 1.6 3.0
Feb 1.78 10.9 3.7 2.3 1.1 3.7
Mar 2.11 10.6 2.7 3.0 0.7 2.3
Apr 1.71 11.9 4.3 3.0 0.4 1.8
May 1.64 12.9 4.0 3.0 0.7 1.4
Average 1.77 11.7 3.1 2.9 1.0 2.7
Additional Cold Weather Deep Bed Denitrification filters
• New York – 2• Pennsylvania – 2• Maryland – 5• Virginia – 8• Massachusetts – 4• Colorado – 1• California – 2 (High
Elevations)
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 (NO3) is converted to nitrogen gas (N2) 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
Cold Weather Deep Bed Denitrification Filters
Questions??????CONTACT:
Gary M. Lohse, P.E.Regional Sales ManagerSevern Trent Services3000 Advance LaneColmar, Pa 18915Cell: (215) 859 - 3814Direct: (215) 997-4052Fax: (215) 997-4062Email: [email protected]
