carbon is best used for biological nutrient removal at the … · 2019-05-15 · carbon is best...

5/13/2019

VWEA Education Seminar 2019 1

Carbon is Best Used for Biological Nutrient Removal at the Nansemond Treatment Plant

Beverley StinsonWendell Khunjar

Opening Argument

(Appetizer)

1. Carbon for BNR is more cost effective

2. Enhanced Biological Phosphorus Removal (EBPR) facilitates P recovery, a limited, high value resource, so better for the environment and food supply

3. Reduced GHG emissions by

• Offset chemical fertilizer production• Reduced ferric & methanol chemical• Reduced trucking

4. EBPR sets us up for high value carbon recovery and reuse

5. We are on the verge of having it all

• Energy Neutrality• Nutrient Removal / Recovery • High Value Carbon Recovery• Reduced GHG emissions

5/13/2019


Effective carbon management is central to WRRFs of the future

Anaerobic

digester

Effluent

~50%

Biogas

100% ~50%~5%

~25%

~20%

~37%

Biosolids

Do we attempt to recover

as much energy in the

influent carbon through

biogas production?

Do we use the carbon

for nutrient removal

and recovery?

What is the role of high

value carbon recovery in

WRRFs?

The industry trend is towards maximizing beneficial recovery of the carbon as biogas…

Anaerobic

digester

Effluent

~50%

Biogas

100% ~50%~5%

~25%

~20%

~37%

Biosolids

Maximize energy

recovery from biogas

Minimize carbon use

for nutrient control

Energy purchased

Energy produced

5/13/2019


The new resource management paradigm is upon us

Source

water

Drinking

Water

Treatment

Wastewater

Generation

Water

Biosolids

Energy

Nutrient Products

Water

Resource

Recovery

Facility

High Value Carbon Products

e.g., bioplastics, cellulose

Industry Trend Assumes…

These assumptions are not valid at all WRRFs

Offsetting energy purchases is highest

priority at utility

Harvesting chemical energy is best means for

achieving purchased energy neutrality

5/13/2019


A Tale of Two ENR Plants

A-B Plant for maximum carbon capture and digestion

• Digestion + CHP

• Methanol to drive denitrification

• Alum to precipitate P

5-stage Bardenpho Plant

• No chemical addition

• No Digestion

Influent Q = 1 MGD

Effluent TN = 3.0 mg/L

Effluent TP = 0.3 mg/L

A-B Plant – Focused on Maximizing Energy Recovery

Digestion + CHP

Item (Unit) Carbon for Power

Total Pumping Power (hp) 28

Total Blower Power (hp) 24

Total Misc. Power (hp) 11

Total Power Demand (hp) 63

Energy/Volume Treated (kWh/MG) 1,126

Methanol Usage (gpd) 15

Secondary Alum Usage (gpd) 123

Tertiary Alum Usage (gpd) 68

Digester Biogas (ft3/d) 16,760

Digester Heating Power Requirement (hp) 48

CHP Heat Power Generated (hp) 61

CHP Electricity Generated (hp) 54

Net Power Purchased from Grid (hp) 9

Net Total Power Emissions (TCO2eq/y) 1,210

Sludge Disposal (DT/d) 0.75

Sludge Disposal (WT/d) 4.1

5/13/2019


5-Stage Bardenpho Plant

NO Digestion + CHP

Item (Unit)Carbon to Drive

ENR

Total Pumping Power (hp) 22

Total Blower Power (hp) 29

Total Misc. Power (hp) 19

Total Power Demand (hp) 70

Energy/Volume Treated (kWh/MG) 1,248

Methanol Usage (gpd) 0

Secondary Alum Usage (gpd) 0

Tertiary Alum Usage (gpd) 0

Digester Biogas (ft3/d) 0

Digester Heating Power Requirement (hp) 0

CHP Heat Power Generated (hp) 0

CHP Electricity Generated (hp) 0

Net Power Purchased from Grid (hp) 70

Net Total Power Emissions (TCO2eq/y) 1,940

Sludge Disposal (DT/d) 0.68

Sludge Disposal (WT/d) 3.8

Breakdown of Annual Costs

Carbon for power only is not always the best value solution

Important to consider ALL priorities

ItemCarbon for

CHPCarbon to Drive ENR

Net Power Cost (@$0.10/kWh) $ 5,849 $ 45,569

Methanol Cost (@ $1.13/gal) $ 6,187 $ -

Alum Cost (@ $1.12/gal) $ 78,196 $ -

Sludge Disposal Cost (@ $50/WT) $ 75,548 $ 69,072

Total Annual Costs $ 165,780 $ 114,642

5/13/2019


eutrophication

Today, we will demonstrate that carbon for BNR provides the best value for Nansemond Treatment Plant

Offsets need for supplemental

carbon

Reduces aeration and

alkalinity addition

Supports Bio-P and struvite

recovery

Best leverages existing

infrastructure

Evidence Presentation

(Main Course)

5/13/2019


Nansemond WWTP is a 30 MGD facility that employs a 5-stage BNR for N and P removal

Quick Facts About Current Operation at NTP

Future Effluent TN target ~ 4.0 mg/L

Future Effluent TP target ~ 1.0 mg/L

Current Flow

~ 18 mgd

PC %TSS removal

~ 50%

Effluent NutrientTN ~ 6.5 mg/L (average)

TP < 0.9 mg/L (average)

Struvite produced

~ 850 lb/day

Methanol demand

~ 820 gal/day

Energy demand

~ 2,500 kW/MG

Biogas production

~ 14 ft3/lb VSR

Cake production

~ 1,300 lb TS/MG

Digester HRT

~ 17 day

5/13/2019


Biological treatment is the biggest energy sink at the NTP

• Similar profile to most ENR WRRFs

• Tempting to use this to assign priority to carbon use

• But we need the whole picture

Approximate based on flows/concentration

Implementing BNR optimization can reduce energy needs onsite

1,334

1,697

1,876

1,947

5,676

870

1,075

1,133

1,198

2,815

0 1,000 2,000 3,000 4,000 5,000 6,000

BOD-removal only

Nitrification

BNR

ENR

MBR

B1

F1

G1

M1

N1

Electric Intensity (kWh/MG)

Typical

40% average reduction by implementing best practices

(35% reduction)

(37% red.)

(40% red.)

(38% red.)

(50% red.)

5/13/2019


Offsetting supplemental carbon should be the first priority at NTP at current market prices

Highest value to offset supplemental carbon first

followed by electricity

Significant amount of energy embedded in biosolids that not currently extracted

$0.06/kWh$1.30/gal MicroC3000

Heat already generated onsite offsets

electricity purchases

What is the break even point for energy vs. BNR?

Electricity @ $0.06/kWh

$0.075/kWh

Supplemental Carbon @ $1.30/gal

Under current market conditions, NTP should continue to

utilize influent carbon to offset BNR needs as a #1 priority

Continue to use biogas to offset heating requirements

Consider processes that extract value from biosolids

5/13/2019


Key Evidence


2. Enhanced Biological Phosphorus Removal (EBPR) facilitates P recovery, a limited high value resource, so better for the environment and food supply


• Offset chemical fertilizer production• Reduced chemical production • Reduced trucking




The new resource management paradigm is upon us

Source

water

Drinking

Water

Treatment

Wastewater

Generation

Water

Biosolids

Energy

Nutrient Products

Water

Resource

Recovery

Facility

High Value Carbon Products

e.g., bioplastics, cellulose

5/13/2019


We are at the Nexus of the Water-Food-Energy Paradigm

Source: US Census Bureau, International Data Base, 2006 UN Global Forecast, 2004

10

8

6

4

2

0

1950 1970 1990 2010 2030 2050

9.45 Billion

70% UrbanGlobalPopulation

Urban Population

Year

Po

pu

lati

on

in

Bil

lio

ns

• 50% increase in population by 2050

– 9 Billion

• Water demand growing at twice the

rate of population growth

• By 2030, the 8 billion people living

on earth will need

• 30% more water

• 40% more energy

• 50% more food

• Until recently believed that there was less than 100 years of phosphorus reserves

• China recently doubled tariffs on phosphorus exports

• Price of Phosphate rock has soared over past couple of years

• Phosphorus is key to Food Security – Water / Food / Energy Nexus

Enhanced Nutrient Recovery – Food Security

Phosphorus production – 90% in 5 regions. Source IFDC.

5/13/2019


Haber Bosch Process for Ammonia Fertilizer Production

• 1-2% of Global Energy Demand

• 3% Global Natural Gas demand

• 5% CO2 Emissions

Ammonia Fertilizer Production1945 to 2010

Key Evidence








5/13/2019


25

25

Biofuels

Engineering Microbial Processes to Recover High Value Carbon Products

Biogrout, SmartSoils®Commercial Chemicals,

Solvents, Lipids, BioisopreneBioplastics

BioFertilizers®Electricity

Looking into the future…

* Assumes 100% acetic acid; **Assumes polyhydroxybutyrate

Fermentation

Unprocessed

Carbon

Bioplastic pre-

cursors

Volatile Fatty Acids

$56 to 180/MMBTU

$390 to 490/MMBTU

Biogas (methane)

$5 to 50/MMBTU

5/13/2019


How would we facilitate recovery of VFA and PHA at WRRFs?

PS

Raw Influent To disinfection

Secondary

treatment

WAS

Anaerobic

digestion DewateringSidestream

Biosolids

disposalFermentation

PHA

Production

PHA Rich

Biomass

High Strength

Waste

HSW Character

Sludge Character

Process Stoichiometry

Energy/Commodity Data

Energy Product

Carbon Product

Biosolids Impacts

BNR Impacts

Capital and O&M Req’s

Descriptive life cycle economics

How do the economics of recovery impact implementation of VFA or PHA recovery?

5/13/2019


-1,000,000

-500,000

0

500,000

1,000,000

1,500,000

2,000,000

2,500,000

3,000,000

3,500,000

2017 2022 2027 2032 2037

Ne

t P

rese

nt

Co

st

($)

Years

VFA (supplemental)

VFA (purified)

PHA (purified)

Economics of VFA and PHA Recovery at 5 Stage ENR

VFA yield = 0.20 lb VFA/lbpCOD

PHA yield = 0.15 lb VFA/lb VFA

VFA pays back within 15 year

PHA does not payback

Economics of VFA and PHA Recovery at 5 Stage ENR

VFA yield = 0.25 lb VFA/lb pCOD

PHA yield = 0.15 lb VFA/lb VFA

VFA pays back within 10 to 12 year

PHA can pay back within 20 year period-1,000,000

-500,000

0

500,000

1,000,000

1,500,000

2,000,000

2,500,000

3,000,000

3,500,000

2017 2022 2027 2032 2037

Ne

t P

rese

nt

Co

st

($)

Years

VFA (supplemental)

VFA (purified)

PHA (purified)

5/13/2019


Key Evidence








32

32

WERF Electrical NeutralityPower for TreatmentPower ProducedNeutrality = 26%

BNR w/CHP – Typical

5760kWh/d

12996 kWh/d

584kWh/d

3195 kWh/d

5/13/2019


33

33

Pioneering modules: ●CEPT●FOG and Food Processing Waste Co-digestion (market-limited) ●Thermal Hydrolysis Pretreatment (THP) ●Wastewater Heat Recovery (Adsorption Chiller) ●ADD – FERMENTATION TO GRAVITY THICKENER

WERF Electrical NeutralityPower for TreatmentPower ProducedNeutrality = 61%

4149 kWh/d

584 kWh/d

7404 kWh/d

BNR w/CHP & Best Practices +++ Pioneering Module

5/13/2019


Can we achieve both goals?

Reduce energy and carbon demand with innovative technologies

Membrane aerated biofilm

reactors (MABR)Mainstream

Deammonification

Anaerobic ammonia

oxidation

1 lb Ammonia (NH3-N)

1/2 lb Nitrite (NO2--N)

1/2 lb Nitrogen gas (N2)

&

Small amount of Nitrate

37.5% O2nitritation

Carbon for BNR provides the best value for Nansemond Treatment Plant


carbon


alkalinity addition


recovery


infrastructure

Positions for future carbon

economy

Under current market conditions, NTP should

continue to utilize influent carbon to offset BNR

needs as a #1 priority

Optimize and reduce energy demand



5/13/2019


Closing Argument

(Dessert)

Evidence has proven that:

Carbon for BNR is more cost effective

Enhanced Biological Phosphorus Removal (EBPR) facilitates P recovery, a limited high value resource, so better for the environment and food supply

Reduced GHG emissions by


EBPR sets us up for high value carbon recovery and reuse

We are on the verge of having it all


Carbon for BNR provides the best value for Nansemond Treatment Plant


carbon


alkalinity addition


recovery


infrastructure

Positions for future carbon

economy

Under current market conditions, NTP should

continue to utilize influent carbon to offset BNR

needs as a #1 priority

Optimize and reduce energy demand



5/13/2019


39

39

Biofuels

Engineering Microbial Processes to Synthesize High Value Carbon Products

Biogrout, SmartSoils®Commercial Chemicals,

Solvents, Lipids, BioisopreneBioplastics

BioFertilizers®Electricity

We foresee that we can have it all -Energy Neutrality & Nutrient Removal

Reduce energy and carbon demand with innovative technologies

Membrane aerated biofilm

reactors (MABR)Mainstream

Deammonification

Anaerobic ammonia

oxidation

1 lb Ammonia (NH3-N)

1/2 lb Nitrite (NO2--N)

1/2 lb Nitrogen gas (N2)

&

Small amount of Nitrate

37.5% O2nitritation

5/13/2019


We Rest Our Case

Your Honour

carbon is best used for biological nutrient removal at the … · 2019-05-15 · carbon is best...

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