Lecture: The world over we create a lot of bio degradable waste. Many of our traditional methods of dumping these wastes into seas of hole in the ground are closing. We need better and we need to take care of the environment. Life Cycle Assessment (LCA) is a 'systems theory' method that accounts for the environment by taking a cradle to grave view of changed products and processes and accounting for all inputs and outputs across the system boundary. I present case studies and some of the ideas and insights in modelling them and what has been learned about the systems

1. Organic-Waste LCA
Case Studies
11th December 2014
Daniel Sandars,
daniel.sandars@cranfield.ac.uk
IHREF, School of Applied Sciences
Evaluating Sustainability:
Waste management
case studies in LCA

2. Waste in Europe
Population 500 million
Municipal solid waste 3 billion tonnes (10-25% organic)
Sewage sludge 9 million dry tonnes
Livestock population 136 million livestock units
136 million dry tonnes slurry/manure

3. Organic waste
disposal?

4. EU waste priorities
1. Waste Prevention
2. Recycling and Reuse
3. Improved Final Disposal & Monitoring

5. global
warming
Best environmental
options?
ozone depletion
N2O, CH4
acidification
drainage
deposition
Nutrient
Overload
pathogens
Metals NO3
-
BOD, PO4
3+
ammonia

6. The System
Environment
The Functional Unit
Natural resource
consumption
Inputs to
farming
Synthetic inputs
to farming
Losses to the
environment
Production System
Nutrients
recycled
The slurry and solid manure
handling chain
Animal
1 tonne lean pig meat
Fertilisers
Feed
Bedding
Waste
to land
Land Cropping
Waste
management
Emissions
to water
Emissions
to air
Land
degradation
Consumable
resources
Energy

7. The System
Environment
The Functional Unit
Natural resource
consumption
Inputs to
farming
Synthetic inputs
to farming
Losses to the
environment
Production System
Nutrients
recycled
The slurry and solid manure
handling chain
Animal
1 tonne lean pig meat
Fertilisers
Feed
Bedding
Waste
to land
Land Cropping
Waste
management
Emissions
to water
Emissions
to air
Land
degradation
Consumable
resources
Energy

8. Slurry tankers
Standard
splash-plate
spreader
Over-the-fence
broadcast spreader
Low trajectory
splash-plate
spreader
Trailing
pipe/shoe
Sub-soil shallow
injection spreader

9. Slurry stores

10. Carbon long time
scales

12. Reference system
• Start with a typical system as a reference
– Pigs on slatted floor
– Uncovered storage
– Splash plate spreading on arable
• Functional Unit(s)
– 1 tonne of pigmeat
– 1 dry tonne organic waste? 100,000 population
equivalent? 1 ha?

15. Weighting Factors
Impact Unit UK 1998
Global Warming Potential 100yr, kg CO2 Equ 7.48E+11
Eutrophication, kg PO4 Equ 4.60E+7
Acidification, kg SO2 Equ 3.89E+9
Photo Chemical Oxide Formation, kg Ethyl Equ 2.11E+9
Source: Department of the Environment Transport and Regions (1988)

16. Results
Weighted Environmnetal Impacts
GWP 100
3.00E-08
2.50E-08
2.00E-08
1.50E-08
1.00E-08
5.00E-09
0.00E+00
-5.00E-09
Smog
Eutrophication
Acidification
Splash Plate (30%)
Trailing Pipe (30%)
Injector (30%)
Trailing Pipe (50%)
Injector (50%)

17. Uncertainty
• What does slurry injection can result in up
to 85% ammonia abatement mean in
practice, most of the time? Why say it?
• Heterogeneity (variability)
• Climatic and environmental uncertainty
• Measurement error and incomplete
knowledge

18. Uncertainty
• What does a claim of up to 85% reduction in
ammonia emissions mean?
• Uncertainty can be due to measurement
difficulties or chance conditions
• The LCA requires well rounded management
averages. It is the uncertainty of this mean rather
than the population that we use.
• To be worthwhile, the benefits of a technique need
to be due to more than random chance.

19. 10% coefficient of variation of ammonia emissions

20. Farm scale AD

21. Farm scale AD

22. Holsworthy Centralised
Anaerobic Digester

23. Holsworthy CAD
• 12,100 t CO2 eqv reduction of global warming (100
years)
• 48 t NO3 eqv eutrophication reduction
• 310 t SO2 eqv acidification increase
• 59 t PO4 eqv habitat nutrification increase
Unfortunately the later two are the more sensitive
impacts where agriculture’s contribution is
proportionally greater

24. Controlling the N
0.020
0.015
0.010
0.005
0.000
-0.005
-0.010
-0.015
-0.020
0% 10% 20% 30% 40% 50% 60% 70% 80% 90%
Abatement of digestate NH3 landspreading losses
t/kt Western European Impacts
Global Warming Normal
Acidification Normal
Eutrophication Normal
Fig. 6.6 LCA predictions of the overall effects abating ammonia losses from land spreading of
digestate on Global Warming, Acidification and Eutrophication, each normalised with respect to
current Western European environmental emissions inventory (Anon, 2005)

25. • 1. Reduce the volume of sewage sludge
produced
• 2. Improve sewage sludge treatment
• 3. Develop a high quality sewage sludge based
fertiliser product
• 4. Improve the energy efficiency of waste water
treatment

27. • Three median…representative systems are defined
• A On-site sludge treatment c. 5k person
equivalents
• B Small scale centralised with 50% of sludge
imported c. 75 k person equivalents
• C Large scale centralised with 50% of sludge
imported c. 200 k person equivalents
• When multiplied/scaled up these will be
representative of approximately 80% of the European
Union (Geographical scope)

29. Conclusions