Carbon footprint and biosolids treatment

Dr Bill Barber

process generated

vs. supply chain

fossil fuel use vs.

process emissions

manufacture construction

vs. operating

Carbon footprint

Embodied

Operating

+

Indirect

Direct

+

Owned

Influenced

+

Power (kWhr) Fuel

N2O, CH4

CO2e / kWhr

Emissions

Processing

Indirect Carbon Footprint

Depends on power source

Wind 0.05 Solar 0.02 – 0.04 Nuclear 0.05 Biomass 0.02 – 0.08 Gas 0.20 Coal 0.80 – 1.20

4

0

0.2

0.4

0.6

0.8

1

1.2

1960 1970 1980 1990 2000 2010 2020 2030

UK

Po

we

r G

HG

em

issi

on

fac

tor

[kgC

O2

e/k

Wh

r]

Power Emission Factors depend on energy mix

Power Emission Factors depend on energy mix

0

0.2

0.4

0.6

0.8

1

1.2

1.4

NSW + ACT VIC QLD SA WA TAS NT UK

Car

bo

n f

oo

tpri

nt

[kg

CO

2/k

Wh

r]

Coal

Gas

Manufacture Transport

N2O, CH4

Fuel

CO2e CO2e CO2e

Emissions Power

Quantity

Design

Embodied Carbon Footprint

Aggre

gate

Sand

Soil

Asp

halt

Sto

ne

Pla

ster

Concre

te

Road

Soil-

cem

ent

Hig

h s

trength

Pre

-cast

Bricks

Cla

y

Mort

ar

Pla

sterb

oard

Cla

y p

ipe

Cla

y ti

le

Tim

ber

Bitum

en

Cem

ent

Gla

ss

Hard

board

Port

land …

Paper

Carb

on S

teel

Insu

latio

n

Pla

stic

s

Copper

Pain

t

Sta

inle

ss S

teel

Alu

min

ium

Em

bo

die

d C

arb

on

Fo

otp

rin

t

Embodied Carbon Footprint

Metals complex materials fertilizers

Natural materials

Processed Natural Materials

Sustainability – Carbon Footprint

Electricity, 77%

Process Emissions,

17%

Transport, 5%

Other, 1%

Pumping +

Aeration

• Biosolids influences all of these parameters

• UK Water industry > 5 million tonnes CO2e

• Only the power industry emits more carbon footprint

WwTW Transport

N2O, CH4

Biogas

-CO2e

Fuel

CO2e CO2e CO2e CO2e

Emissions Chemicals Power

Carbon Impacts in Biosolids Carbon Footprint of Biosolids

Land Application

Emissions

N2O, CH4

CO2e

Fertilizer Disp

-CO2e

(Sequestration)

-CO2e

Landfill

Emissions

CH4

CO2e

Biogas

-CO2e

+16 CO2e -532 kg CO2e

157 kg CH4

1000 kg

39

1 k

g

609 kg 589 kg

CHP

+168 kg CO2e

+380 kg CO2e

8 kg CH4

138.9

kg C

H4

18.1

kg C

H4

20

kg

8 k

g C

H4

Primary Digestion Open secondary Digestion

Dir

ect a

tmo

sp

he

ric

em

issio

n

Dir

ect a

tmo

sp

he

ric

em

issio

n 649 kWhr

-704 CO2e -893 kg CO2e

202 kg CH4

1000 kg

50

4 k

g

496 kg

CHP

+189 kg CO2e

193 k

g C

H4

9 k

g C

H4

Primary Digestion Secondary Digestion

Dir

ect a

tmo

sp

he

ric

em

issio

n 1089 kWhr

Pre-treatment

Para

sitic

Dem

and

Carb

on

Fo

otp

rin

t

Cla

ss A

lim

ing

Raw

Dry

ing

Lim

e +

su

pp

he

at

Ra

w I

ncin

era

tion

No digestion

Th

erm

al h

yd

roly

sis

+ M

AD

Se

rie

s a

cid

ph

ase

+ M

AD

TA

D-M

AD

ATA

D

Pre

-MA

D p

aste

uri

sa

tio

n

Dig

este

d D

ryin

g

Dig

este

d In

cin

era

tio

n

Ad

va

nce

d D

ige

ste

d In

c

With digestion

Carbon Footprint of Class A Biosolids treatment

Carbon footprint breakdown

Liming Composting TH + MAD

BH + MAD TAD + MAD ATAD

Key: ( Biosolids Transport); ( Land Emissions); ( Chemicals); ( Dewatering); ( Transport Other); ( Power); ( Gas); ( Process Emissions); ( Down Time)

Carbon footprint breakdown

Liq Past + MAD Raw Drying MAD + Drying

Lime + S H Raw Incineration

MAD + Incineration

Key: ( Biosolids Transport); ( Land Emissions); ( Chemicals); ( Dewatering); ( Transport Other); ( Power); ( Gas); ( Process Emissions); ( Down Time)

- Australian government reduction target of 5% of 2000 levels by 2020

• 357 million t/CO2 e year

- Currently being measured and reported

- Carbon tax will come in force 1 July 2012

• Will cover 500 worst polluters (approx 60% of the emissions)

• This will include all large water companies

• $ 23 AUD/t carbon dioxide

Rising 2.5% per year

- Will become trade scheme 1 July 2015

Australia

http://www.nocarbontax.com.au/shop/components/com_virtuemart/shop_image/product/No_Carbon_Tax_Ca_4d6dbff466ff4.jpg

0

100,000

200,000

300,000

400,000

500,000

600,000

700,000

Hunter Water

Melbourne Water

SA Water SunWater Sydney Water

Water Corp.

Car

bo

n f

oo

tpri

nt

[t C

O2

/yr]

SCOPE 2

SCOPE 1

Carbon Footprint of Australian Water Industry

Data plot using Australian Government NGER 2009/10 data

0

100,000

200,000

300,000

400,000

500,000

600,000

700,000

Hunter Water

Melbourne Water

SA Water SunWater Sydney Water

Water Corp.

Car

bo

n f

oo

tpri

nt

[t C

O2

/yr]

SCOPE 2

SCOPE 1

Carbon Footprint of Australian Water Industry

Data plot using Australian Government NGER 2009/10 data

Carbon Footprint of Australian Water Industry

Normalised (to UK) Carbon Footprint of Australian

Water Industry

Tightening Legislation

Tightening Legislation

Tightening Legislation

Case Study – New advanced digestion facility

Option 1 – New raw sludge incineration plant

Main Inputs/Outputs impacting Carbon

Contributing

Sites Dewatering Conveying

Sludge Transport

Power Chemicals

Power Chemicals Start-up Gas Combustion Air

Pre-drying Air provision Waste Heat Recovery Dust Removal Acid gas clean-up Scrubber Effluent Treatment

Power Generation

Waste Sludge Flue gas Ash Transport

Incinerator Plant

Option 2 – Advanced Digestion with existing incineration

Contributing Sites

Digestion Centre

Dewatering Conveying

Sludge Transport

Power Chemicals

Re-liquification Thickening Thermal Hydrolysis Anaerobic Digestion Liquor Treatment Dewatering Conveying CHP Plant

Power Chemicals Natural Gas

Renewable Energy Generation

Liquid Sludge Pumping

Power Chemicals Start-up Gas Combustion Air

Pre-drying Air provision Waste Heat Recovery Dust Removal Acid gas clean-up Scrubber Effluent Treatment

Power Generation

Waste Sludge

Sludge cake Export

Flue gas Ash Transport

Existing Incinerator Plant

Weight of Construction Materials

Raw Incinerator Advanced

Digestion

Weig

ht of

Co

nstr

uction

mate

rial

Steel

Concrete

Embodied Carbon

Raw Incinerator Advanced

Digestion

Em

bo

die

d C

arb

on

(C

O2e

)

Total Concrete (CO2e)

Total Steel (CO2e)

Factors Contributing to Increasing Operating Carbon

Raw

Incinerator

Advanced

Digestion

Bre

akdow

n o

f carb

on f

ootp

rint

Dewatering at DH

Land Application

Additional pumping to SG

Incinerator chemicals

Incinerator power demand

Ash transport

Downtime

Incinerator emissions

Sludge transport

Dewatering (inc liquor treatment)

Impacts and benefits on operating carbon

Raw Incinerator Advanced

Digestion

Opera

ting C

arb

on f

ootp

rint

Total

Total Benefits

Biogas production

Energy generation at

incinerator

Fertilizer displacement

Carbon sequestration

Whole Life Carbon Impact

0 10 20 30 40 50

Cu

mu

lative C

arb

on

Fo

otp

rint

Years in operation

Liming

Raw Incineration

AD

AD delay 5

AD Delay 10

Summary

- Everything we do has a carbon impact and that also includes biosolids production and processing

- Carbon footprint is made up of:

• embodied and operating

• Indirect and Direct

• Owned and influenced emissions

- Choice of technology has large impact on carbon footprint of biosolids options

- Anaerobic digestion is very influential

• Renewable energy generation

• Reduces biosolids for further processing

• Can improve dewatering so reducing transport

Thank You

bill.barber@aecom.com

44,8

70 (

Raw

Incin

era

tion)

52,230

Transport

8,640

Fuel

CO2e

Incineration

37,370

CO2e

Pow

er

Chem

icals

M

anufa

ctu

re

Em

issio

ns

N2O

Dow

ntim

e

CH

4 +

N2O

Ash

T

ransport

Gas

Dewatering

CO2e

Poly

mer

Pow

er

Manufa

ctu

re

6,220

Power Generation

CO2e

Avoided Power

7,360

29,3

00 (

Option 1

– E

xis

ting)

Dewatering

CO2e

Poly

mer

Po

we

r

Manufa

ctu

re

6,500

Lime Addition

Lime Manufacture

CO2e

CO

2

Pow

er

5,600

Transport

Fuel

CO2e

11,300

Field Application

GHG Emissions

CO2e

N2O

CH

4

16,800

Fertiliser Manufacture

CO2e

Avoided Power

10,850

40,200 29,3

00 (

Option 1

– E

xis

ting)

Advanced Digestion Carbon Footprint

1. Impact on existing digestion plant

2. Impact at existing incineration facility processing additional sludge

3. Recycling of additional Class A biosolids

4. Additional transport (double-handling)

652 (Existing Digestion)

–26,282 (New Digestion) –

26,934 (Reduction at Existing Digestion) =

SBAP – Impact at Davyhulme Impact on existing digestion plant

10,778 (Contributory land application)

1,969 (Beneficial land application) –

8,809 (Additional land application) =

Additional land application emissions

10,778 (Contributory incineration)

1,969 (Beneficial incineration) –

8,809 (Additional Incineration) =

Impact on existing incineration plant

-26,934 (Reduction at existing digestion)

3,829 (Additional land application) +

8,809 (Additional Incineration) +

–2,888 (Advanced Digestion Total) =

11,408 (Additional Transport) +

Total for Advanced Digestion Option