Pres reinnova nick cawthorne v2

Los retos en la gestión de residuos urbanos en una economía globalizadaEls reptes en la gestió de residus urbans en una economia globalitzada

Challenges in waste management in a globalized economy

ORGANIZADO POR: CON LA COLABORACIÓN DE:

Comparing the Life Cycle Assessment (LCA) Performance of Residual Waste Treatment Solutions

Nick CawthorneGolder Associates (UK) Ltd



Background

• EU Landfill Directive (Article 5 Landfill Diversion Targets)• Objective to reduce environmental impact of landfill (particularly

global warming) and increase recycling and recovery;• Mechanisms: landfill bans, separate collection, recycling targets

and landfill tax;• These mechanisms encourage residual waste diversion but don't

optimise alternative solution;• Alternative waste solution will have very different impacts

associated with waste treatment and very different benefits associated with energy and materials recovery;

• Life Cycle Assessment (LCA) considers overall environmental performance of waste solution options.



Objective of this LCA Study

Compare Life Cycle environmental performance of different residual waste treatment solutions.

In consideration of:

• Treatment and Transport impacts;• Residues disposal;• Materials recovery benefit;• Energy recovery benefit.



Life Cycle Assessment Model

• Waste Resource Assessment Tool for the Environment (WRATE) is the LCA tool used in UK for waste management applications;

• Background database contains standard LCI data from ecoinvent centre Switzerland and detailed process data for many waste treatment options;

• Results available for different impact assessments including global warming potential and resource depletion;

• Developed by Golder Associates and ERM for Environment Agency in UK.



WRATE Modelling• Seven scenarios for the management of residual waste.

• Assumptions and Limitations– Waste composition data - Typical UK Residual Waste;– 250,000 tonnes waste;– Vehicles are ‘waste collection vehicles’ or ‘Intermodal Road

Transport’ travelling 25 km, road type split is 80% urban/20% rural;

– The electricity mix selected is year 2011, UK;– All landfills - HDPE composite liner and HDPE cap;– Waste treatment uses existing processes in WRATE for each

treatment type.



Scenarios Modelled• Scenario 1 - Waste to Energy (Power);• Scenario 2 - Mechanical Biological Treatment (RDF); • Scenario 3 - Materials Recycling Facility, MRF

(Recycling and RDF);• Scenario 4 - Mechanical Biological Treatment

(Stabilisation);• Scenario 5 - Mechanical Biological Treatment

(Recycling and Anerobic Digestion);• Scenario 6 - Waste to Energy

(Combined Heat and Power, CHP); and• Scenario 7 - Landfill.

Note: Scenarios 2, 3 RDF to cement kiln;Scenarios 2, 3, 5 waste residues to off site WtE;Scenario 5 AD Digestate landfilled as stabilite.



Materials Recycling Facility (MRF)



Mechanical Biological Treatment Plant

http://en.wikipedia.org/wiki/File:Haase_Lubeck_MBT.JPG



Waste to Energy plant (WtE)



Refuse Derived Fuel (RDF)

Cement kiln



Scenario 1: Waste to Energy (Power)Waste to Resources ConferenceWaste to Energy (power)

Residual Waste Commercialvehicles

IncineratorsPower

Ferrous Ferrous

OTHEROTHER



Scenario 5 - MBT (Anerobic Digestion)Waste to Resources ConferenceMBT (AD)

Residual Waste To MBT

IncineratorsPower

Ferrous

OTHEROTHER



Material Recovery RatesScenario Number

and Treatment Solution

Paper & Card

(tonnes)

Plastic Film

(tonnes)

Dense Plastic

(tonnes)

Glass (tonnes)

Ferrous (tonnes)

Non Ferrous (tonnes)

RDF (tonnes)

IBA (tonnes)

1 WtE (Power) 7,566 1,150 54,956

2 MBT (RDF) 6,734 1,769 110,277 28,552

3MRF

(Recycling, RDF)

5,497 11,269 8,384 2,243 17,964 39,303

4MBT

(Stabilisation)3,723 7,258 1,986 18,988

5 MBT (AD) 41,324 1,984 2,977 5,580 8,339 2,070 4,925

6 WtE (CHP) 7,566 1,150 54,956

7 Landfill



Results – Global Warming Potential: Multiple Impact AssessmentsCollection

Transportation LandfillRecycling

Intermediate Facilities Treatment and Recovery

Euro

pean

Per

son

Equi

vale

nt

Scenario: 1 2 3 4 5 6 7



Results – Global Warming Potential (Combined)

Scenario: 1 2 3 4 5 6 7

Kg

CO

2 E

q.



Best Performing Solutions - Global Warming Potential

1. Scenario 3 – Materials Recycling Facility, MRF (Recycling and RDF);2. Scenario 6 – Waste to Energy (Combined Heat and Power, CHP)3. Scenario 1 – Waste to Energy (Power)4. Scenario 2 – Mechanical Biological Treatment (RDF)5. Scenario 5 – Mechanical Biological Treatment (Anerobic Digestion)6. Scenario 4 – Mechanical Biological Treatment (Stabilisation)7. Scenario 7 – Landfill.

Note: Results very different if MBT/MRF residues to landfill not WtE



Explanation of Results

Scenario 3 – Materials Recycling Facility, MRF (Recycling and RDF)• Recycling of dense plastic, ferrous metal and glass;• Non recycled waste to energy recovery, RDF to cement kiln and

residues WtE;• No waste to landfill.

More carbon benefit is achieved by recycling a given amount of plastic or paper than can be achieved by combusting for energy recovery in a WtE plant or in a cement kiln as RDF.

Scenario 6 WtE (CHP), Scenario 1 – WtE (Power) and Scenario 2 – MBT (RDF)

• Less Recycling (metal recycling only);• Non recycled waste to energy recovery, RDF and WtE;• No waste to landfill.



Scenario 5 – MBT (AD) and Scenario 4 – MBT (Stabilisation)

• Recycling plastic, paper/card, metals and glass;• Low energy recovery (AD only) net of energy

consumption for treatment;• Significant landfill disposal.

Scenario 7 (landfill)• All waste landfilled;• No material or energy recovery, other than via landfill

gas utilisation.

Explanation of Results



Observations• Best performing solutions include a high degree of

recycling and energy recovery of all other waste; • Plastic, paper/card and glass can only be recycled before

combustion;• Recovery rates of metals, particularly non ferrous metal, is

likely to be higher prior to combustion than recovery from bottom ash;

• Carbon benefit is particularly sensitive to non ferrous metal recovery;

• Any solution which includes significant landfilling of stabilised waste will perform less well;

• Any solution which includes landfilling of residue fractions will perform less well.



Conclusions• The carbon (global warming potential) performance of

residual waste treatment solutions is enhanced where the maximum amount of materials are recycled followed by combustion of all residues for energy recovery (RDF or WtE);

• More carbon is recovered by material recycling than by energy recovery of the same waste;

• Comment: Financial incentives typically focused more on energy recovery than material recycling;

• Landfilling of stabilised waste or residues greatly reduces the performance of the solution.



• MBT/MRF and WtE typically seen as two fundamentally separate approaches;

• Optimisation of MBT/MRF requires WtE of residues (possibly at separate facility);

• Optimisation of WtE requires recycling of materials in advance (MRF before WtE);

• Optimisation converges the two approaches towards a single solution;

• Maximum material recycling followed by Energy recovery and zero landfill;

• Energy recovery by RDF or WtE.

Conclusions



Muchas Gracias

Nick [email protected]

Pres reinnova nick cawthorne v2

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