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 (David.Oerke@ch2m.com)

Tom Johnson/CH2M

Bruce Johnson/CH2M

Heidi Bauer/CH2M

Steve Graziano/CH2M