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A Battle to Be the Best:A Comparison of Two Powerful
Sidestream Treatment Technologies:Post Aerobic Digestion and Anammox
A Battle to Be the Best:A Comparison of Two Powerful
Sidestream Treatment Technologies:Post Aerobic Digestion and Anammox
David Oerke/CH2M
Tom Johnson/CH2M
Bruce Johnson/CH2M
Heidi Bauer/CH2M
Steve Graziano/CH2M
2016 Vail Operator Training Seminar
What are PAD & Anammox?
• SidestreamTreatment Technologies
• Reduction of nitrogen
• No supplemental carbon or alkalinity
WEF Webcast 12/9/2009: Sidestream Treatment for Nutrient Removal and Recovery
What is Post Aerobic Digestion?
Aerobic digestion after anaerobic digestion
• Advantages:– Reduction of N
without chems.
– VSS reduction
– Odor reduction
– Struvite stabilization
• Challenges:– Biological heat
– Foam
Example Full-Scale PAD Facilities
Centrifuge
Solids Reduction & Nitrogen Removal
Centrate
AnaerobicDigesters
AerobicDigester
Waste Solids
Raw
Chemically Enhanced Primary Treatment
Step Feed Bioreactor
Membranes
• Spokane County Regional WRF
• Denver Metro WRD NTP – 11/16
• Boulder 75th Street WWTP -10/16
What is Anammox
Anaerobic Ammonium Oxidation • Advantages:
– Reduction of N without chems.
– Lower energy
• Challenges:– Slow growth
– Competition with nitrite oxidizing bacteria
Example Full-Scale AnammoxFacility
Alexandria Renew Enterprises (AlexRenew) Water Resources Recovery Facility (WRRF)
Wett, B., Murthy, S., Takacs, I., Hell, M., Bowden, G., Deur, A., Shaughnessy, M. (2007). Key Parameters for Control of DEMON
Deammonification Process. Wat. Practice
Comparison of Technologies
Post Aerobic Digestion Anammox
Target Flow Stream Entire anaerobic digestion effluent
Dewatering liquors
Nitrogen Removal Method
Nitrification/ Denitrification
Partial Nitritation/ Deammonification
- Carbon Input Degradable material from anaerobic digestion
Not needed
- Aeration Intermittent Intermittent
Biomass Used Conventional Specialized
MethodologyPro2D2 whole plant simulator:
CPES cost estimating system
Assumptions:
– 75.7 ML/d (20 mgd)
– Aeration Basins:
• 5-stage Bardenpho
• 8.5 day SRT
– Biosolids facilities:• 24/7 operation
• Disposal via land application
– Baseline – PAD – Anammox
mg/L Influent Effluent Limitation
BOD 250 10
TSS 240 10
VSS 192
TKN 39
NH3 30 1
TN 39 5.0
TP 6 1.0
Baseline PFD-No Sidestream Treatment
Thickened WAS
SECONDARY CLARIFIERS
AERATION BASINS
RAS
ANAEROBIC DIGESTION
PLANT EFFLUENT
BELT FILTER PRESS
Thickened Primary Solids
FILTRATION
BIOSOLIDS
SCREENING AND GRIT REMOVAL
GB
T
FIL
TR
AT
E Backw
ash
Filt
rate
GRAVITY BELT THICKENER
RAW INFLUENT PUMP STATION
PRIMARY CLARIFIERS
An-aerobic
Anoxic Aerobic Anoxic Aerobic
Recycle
GRAVITY THICKENER
Gravity Thickener Supernatant
WA
S
Post Aerobic Digestion PFD
Thickened WAS
SECONDARY CLARIFIERS
AERATION BASINS
RAS
ANAEROBIC DIGESTION
PLANT EFFLUENT
BELT FILTER PRESS
Thickened Primary Solids
FILTRATION
BIOSOLIDS
SCREENING AND GRIT REMOVAL
GB
T
FIL
TR
AT
E Backw
ash
Filt
rate
GRAVITY BELT THICKENER
RAW INFLUENT PUMP STATION
PRIMARY CLARIFIERS
An-aerobic
Anoxic Aerobic Anoxic Aerobic
Recycle
GRAVITY THICKENER
Gravity Thickener Supernatant
WA
S
POST AEROBIC DIGESTION
Anammox PFD
Thickened WAS
SECONDARY CLARIFIERS
AERATION BASINS
RAS
ANAEROBIC DIGESTION
PLANT EFFLUENT
BELT FILTER PRESS
Thickened Primary Solids
FILTRATION
BIOSOLIDS
SCREENING AND GRIT REMOVAL
GB
T
FIL
TR
AT
E Ba
ckw
ash
Filt
rate
GRAVITY BELT THICKENER
RAW INFLUENT PUMP STATION
PRIMARY CLARIFIERS
An-aerobic
Anoxic Aerobic Anoxic Aerobic
Recycle
GRAVITY THICKENER
Gravity Thickener Supernatant
WA
S
ANAMMOXTreated Filtrate
WA
S
Design Criteria• Baseline:
– Average of 778 kg/d (1,715 lb/d) of carbon
– 3.66 m (12 ft) dia. tank for 30-day max month storage
• PAD:
– Aerobic digester volume of 4,656 m3 (1.23 MG)
• Anammox:
– Based on DEMON® process with an estimated total reactor volume of 1,079 m3 (0.285 MG)
– Two SBR basins with an equally sized basin for Equalization
Life Cycle Assumptions:
Life of Study 20 years
Discount Rate 5.0 %
Inflation Rate 3.0 %
Capital Cost Assumptions:
Start of Construction 2015
Construction Duration 2 years
Markup Factor 2.38
Annual Cost Assumptions:
Electricity Cost $0.0768/kWh
Maintenance and Repair Cost 3.0%/year of equipment cost
Biosolids Hauling Cost $20.58/wet metric ton ($18.67/wet U.S. ton)
Biosolids Disposal Cost $33.07/wet metric ton ($30.00/wet U.S. ton)
Trash Hauling and Disposal Cost $78.33/m3 ($59.89/yd3)
Revenue $0/year
Contingency 20% of annual costs
Cost Assumptions
Results
• Mass Balance:
– Sidestream Treatment
– Filtrate Quality
– Plant Effluent
– Biosolids
• Costs:
– Annual
– Capital
– Life Cycle
Results-Mass Balance-Mass Removed from Sidestream
Results-Mass Balance-Filtrate Quality
Baseline (No SidestreamTreatment)
Sidestream Treatment with PAD
Sidestream Treatment with Anammox
mg/L (kg/d) mg/L (kg/d)% Change
from Baseline
mg/L (kg/d)% Change
from Baseline
NH3 440 (390) 4.5 (4.0) 99% 43 (37) 90%
TKN 490 (430) 45 (40) 91% 59 (51) 88%
TIN 440 (390) 25 (23) 94% 93 (80) 79%
TN 490 (430) 66 (59) 86% 110 (94) 78%
Both sidestream treatment technologies remove significant amounts of nitrogen from the filtrate compared to the baseline.
Results-Mass Balance-Plant Effluent
Baseline (No SidestreamTreatment)
SidestreamTreatment with
PAD
SidestreamTreatment with
AnammoxFlow, m3/d (mgd) 76,000 (20.0) 76,000 (20.0) 76,000 (20.0)BOD, mg/L (kg/d) 1.7 (130) 1.7 (130) 1.7 (130)TSS, mg/L (kg/d) 3.1 (240) 3.1 (240) 3.1 (240)VSS, mg/L (kg/d) 2.1 (160) 2.0 (150) 2.0 (160)NH3, mg-N/L (kg-N/d) 0.4 (30) 0.4 (31) 0.3 (19)TKN, mg-N/L (kg-N/d) 1.8 (140) 1.8 (140) 1.7 (130)NO3, mg-N/L (kg-N/d) 2.6 (200) 2.1 (160) 2.2 (170)TP, mg/L (kg/d) 0.4 (34) 0.5 (37) 0.5 (34)
No significant differences between the two sidestream treatment technologies compared to each other or to the baseline.
Results-Mass Balance-Biosolids
Results-Annual Costs-Energy Use
Baseline (No
SidestreamTreatment)
SidestreamTreatment with PAD
SidestreamTreatment
with Anammox
Sidestream Treatment, kW - 83 42Methanol Feed, kW 5 - -Aeration Basins, kW 594 551 552Anaerobic Digestion, kW 182 182 182Anaerobic Digestion Energy Generation, kW (462) (452) (457)Net Energy, kW 320 365 318Annual Energy Consumption, kWh/yr 2,800,000 3,190,000 2,790,000Annual Energy Cost, $/yr $215,000 $245,000 $214,000
Energy Cost Compared to Baseline, $/yr $30,000 -$1,000Energy Cost Compared to Baseline, % 14.0% -0.5%
Results-Annual Costs-Chemical Use
Baseline (No
SidestreamTreatment)
SidestreamTreatment with PAD
SidestreamTreatment
with Anammox
Methanol Consumption, kg/d (lb/d) 778 (1,715) - -Methanol Consumption, MG/yr (dry tons/yr) 284 (313) - -Annual Methanol Cost, $/yr $139,000 - -
Results-Annual Costs-Biosolids Production
Baseline (No SidestreamTreatment)
SidestreamTreatment with PAD
SidestreamTreatment
with Anammox
Biosolids Production, kg/d (lb/d) 7,982 (17,598)
6,965 (15,354)
7,878 (17,368)
Biosolids Production, dry metric tons/day 8.0 7.0 7.9Biosolids Production, wet metric tons/day 33.3 29.0 32.8Biosolids Production, wet metric tons/yr 12,100 10,600 12,000Annual Disposal Cost, $/yr $651,000 $568,000 $643,000
Disposal Cost Compared to Baseline, $/yr -$83,000 -$8,000Disposal Cost Compared to Baseline, % -12.7% -1.2%
Results-Annual Costs-Total Energy, Chemical, & Biosolids
Baseline (No SidestreamTreatment)
SidestreamTreatment with PAD
SidestreamTreatment
with Anammox
Energy Use, $/yr $215,000 $245,000 $214,000Chemical Use, $/yr $139,000 - -Biosolids Production, $/yr $651,000 $568,000 $643,000Total Annual Costs for Energy, Methanol, & Biosolids Disposal, $/yr $1,005,000 $813,000 $857,000
Total Cost Compared to Baseline, $/yr -$192,000 -$148,000Total Cost Compared to Baseline, % -19.1% -14.7%
Results-Capital CostsCosts in Million Dollars
Baseline (No SidestreamTreatment)
SidestreamTreatment with PAD
SidestreamTreatment
with Anammox
Aeration Basins $19.4 $19.1 $19.1Aeration Basin Blowers $4.4 $4.2 $4.3Carbon Feed and Storage Facility $1.5 - -Anammox Facility - - $3.8Post Aerobic Digestion - $5.3 -Other 11 Facilities $81.6 $81.6 $81.6Additional Project Costs $15.6 $16.1 $15.9
Total Construction Cost $122.5 $126.3 $124.7
Percent Increase from Lowest Construction Cost
- 3.1% 1.8%
Results-Total Annual CostsCosts in Million Dollars Baseline (No
SidestreamTreatment)
SidestreamTreatment with PAD
SidestreamTreatment w/
AnammoxAeration Basins $0.24 $0.23 $0.23Aeration Basin Blowers $0.39 $0.35 $0.36Carbon Feed and Storage Facility $0.24 - -Anammox Facility - - $0.05Post Aerobic Digestion - $0.10 -Biosolids Hauling and Disposal $1.40 $1.20 $1.40
Other 11 Facilities $1.96 $1.96 $1.96
Misc. Annual Costs & Contingency $0.20 $0.20 $0.20
Total Annual Cost $4.43 $4.04 $4.20
NPV of Annual Costs $55.1 $50.7 $52.2
Percent Increase from Lowest Annual Cost
9.7% - 4.0%
Results-Life Cycle CostsCosts in Million dollars
Baseline (No SidestreamTreatment)
SidestreamTreatment with PAD
SidestreamTreatment
with Anammox
Aeration Basins $22.3 $22.1 $22.1Aeration Basin Blowers $9.3 $8.6 $8.7Carbon Feed and Storage Facility $4.5 - -Anammox Facility - - $4.5Post Aerobic Digestion - $6.5 -Biosolids Hauling and Disposal $17.7 $15.4 $17.4
Other 11 Facilities $105.8 $105.8 $105.8
Standard Items $18.0 $18.6 $18.4
Total Net Present Value $177.6 $177.0 $176.9
Percent Increase from Lowest Life Cycle Cost
0.40% 0.06% -
Conclusions-1
• Post Aerobic Digestion and AnammoxSimilarities:
– Excellent option for reduction of nitrogen recycled back to the liquid stream
– Supplemental chemicals not typically required
– Similar effluent quality achieved
– Significant removal of constituents in filtrate
– Less energy required for nutrient removal in aeration basins
Conclusions-2
• Post Aerobic Digestion and AnammoxDifferences:
– Different sidestream flow streams targeted
– PAD removes more BOD, VSS, and Nitrogen
– Greater net annual cost savings for PAD
– Greater net energy savings for Anammox
Conclusions-3• Costs:
– Baseline (No Sidestream Treatment) offers lowest capital cost
– Sidestream Treatment with PAD offers the lowest annual cost
– Equivalent life cycle costs for Baseline, PAD, and Anammox:
• Consider PAD when N removal without chems. desired in addition to additional VSR.
• Consider Anammox when N removal without chems. desired in addition to energy minimization, or if future phosphorus recovery is desired.
A Battle to Be the Best: A Comparison of Two Powerful
Sidestream Treatment Technologies: Post Aerobic Digestion and Anammox
QUESTIONS?David Oerke/CH2M ([email protected])
Tom Johnson/CH2M
Bruce Johnson/CH2M
Heidi Bauer/CH2M
Steve Graziano/CH2M