lca & drinking water treatment
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03/09/2012
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LCA & drinking water treatment
Desirée Marín CETaqua (Water technology Centre)
XII INTERNATIONAL SUMMER SCHOOL FOR THE ENVIRONMENT
Life Cycle Assessment and Water Issues
04/09/12Universitat de Girona, 3rd-7th September
20121
Contents
1. Introduction
2. Drinking water treatment processes
3. Dealing with LCA and drinking water
4. Conclusions
5. Discussion
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1. Introduction
Aim: Assure safety in water supply + reduce impacts of water discharge to nature
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Avoided impacts vs. Induced impacts?
Outcomes from studies on LCA & drinking water
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Energy consumptionmain cause of env.
impacts(Sombekke et.al., 1997; Mahgoub et.al., 2010)
Transport impactsusually insignificant
(Tarantini and Ferri, 2001; Racoviceanu et.al., 2007)
Construction and decommissioning
negligible impacts(Friedrich, 2001; Raluy et.al., 2005;
Stokes and Horvath, 2006)but important when analysing
water transfers( Raluy et.al. 2005, Peters and
Rouse, 2005)
Alternativetreatment
processes havehigher env. burdens
than conventionaltreatments
(Vince et. al. 2008)
Detailed review on the
Summerschool’s book !
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2. Drinking water treatment processes
Objective of a DWTP:
Reduce or eliminate
undesired components in water (e.g particulate matter, oils and fats, toxic chemicals, viruses, pathogen agents, bacteria, etc.)
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Drinking water regulations
98/83/EC Stablishes thelegal quality requirementsof water for humanconsumption including:
• Microbiological
• Chemical
• Other parameters
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98/83/EC
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Mandatory compliance
98/83/EC
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Mandatory compliance
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98/83/EC
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To be controlled
Drinking water regulations
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75/440/CEE Defines 3 types of surface water intended for drinking water abstraction in terms of quality/treatment needed:
• Type A1: simple physical + disinfection
• Type A2: normal physical + chemical + disinfection
• Type A3: intensive physical + chemical + extendedtreatment + disinfection
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Treatment processes
• Physical treatment
� Clarification
� Filtration
� Membrane treatments
• Chemical Treatment
• Disinfection
• Other treatments
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Extraction
Pre-treatment
Treatment
Advanced treatment
Post-treatment
Disinfection
Clarification
Objective: Eliminate
particulate matter
(diluted compounds mainly organic matter from nature)
Particulate
matter colours
water
Main processes:
� Coagulation
� Flocculation
� Decantation
� Flotation
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Clarification: Coagulation-flocculation
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Coagulants: salts based on Al or Fe (Al3SO4, FeCl3, …) or acid/basic polymers aluminum based (PAC, Wac, Alba 18, etc.)
Flocculants: inorganics (activated silica, clays, sand or calcite) or organics (starch, alginates or polyacrylamides polyDADMAC)
Clarification: Decantation
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Rectangular static vertical clarifier
lamellas
�Static/Dynamic
�Rectangular/Circular
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Clarification: Decantation
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Circular dynamic sludge recirculation clarifier (Accelator®)
� Dynamic: sludge recirculation/ sludge blanket
Clarification: flotation
Dissolved/induced air flotation eliminates light flocs (algae, oils, etc.)
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Filtration
Objective: Remove
particulate matter that cannot be sedimentated by its retention in a bed
of a porous material or in a fixed support
� Structure: Open/closed
� vfiltration: low /high
� Material:
� Sand
� Activated Carbon
� Dual-media (multi- layer)
� Anthracite, etc.
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Membrane treatments
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Membrane treatments
Microfiltration Ultrafiltration
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� Submergible
� Pressurised
(in-out/ out-in)
Nanofiltration
Membrane treatmentsReverse Osmosis
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Membrane treatments
Electrodialysis reversal
Removes ions and other charged species by using electricity
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Chemical treatment
Acidification
Reduces pH by dosing CO2
in order to remineralise water from membranes
or stripping
Stripping
Eliminates dissolved gases (H2S, CO2, etc.) and VOC’s by an aeration (G-L exchange) �
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Stripping /CO2 towers
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Chemical treatment
Softening
Reduce carbonate in remineralised water by:
� Lime addition
� Catallytic process
� Clarification
� Ion exchange resins
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Neutralisation
Post-treatment based on a remineralisation (pH adjustment) by dosing calcite (calcium carbonate), calcium hydroxide, etc. �
Other: Adsorption
Objective: eliminate pesticides, detergents, chlorinated solvents, phenols, PACs, odours, colour, etc.
Regeneration of AC needed!
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GAC
bed filter
Activated Carbons:
� Powdered (PAC)
� Granular (GAC)
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Disinfection
Objective: Remove dissolved
mineral matter, eliminate pathogen agents, eliminate taste and odours, ammonia, etc. by an oxidation process
This is a key step!
Not disinfected =
Main types:
� UV radiation
� Ozonation
� Chlorine andderivatives
� Potassiumpermanganate
� Electro-chlorination
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Disinfection
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UV disinfection lamps Ozone (produced in-situ)
� Oxidation efficiency: O3>ClO2>HClO>OCl->NH2Cl� Permanence: NH2Cl (days) > ….> O3 (30 min)
Potassium permanganate
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3. Dealing with LCA in drinking water
ISO 14040 & 14044 (2006)
Clearly identify in a report important decisions made along the LCA stages
ILCD Handbook http://lct.jrc.ec.europa.eu/assessment/publications
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Goal
Definition of:
� Aim of study
� Limitations
� Target Audience
� Intended application
� Decision context
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LCA Direct applications
(from ISO 14040/44)
• Product development and improvement
• Strategic planning
• Public policy making
• Marketing
• Other
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Goal: Aim of study
State and keep in mind:
� Main reasons for the study
� Commissioners
Study results and report shouldprovide satisfactory answers to commissioner’s objective
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Goal: Limitations
Identify limitations on the usability of the LCA resultsdue to the goal or methodology:
� Limited impact-coverage
� Assumptions made
� Method-related
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Limited impact-coverage Method-relatedAssumptions made on
the system or scenarios
Carbon
footprinting
Primary energy
consumption
LCIA method:
Site-specific
results
LCI method approach:
market-price allocation in eco-efficiency studies
Representativeness:
time, location, use-
pattern, etc.
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Goal: Target audience
Identify to whom the results will be communicated
� Critical review needs
� Form and technical level of the report
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Citizens
Local/
regional
authorities
National/
international
authorities
Water utilitiesScientific
community
Know env. impacts of a DWTP in the
neighborhood
Supportdecision-
making on aninvestmenton a DWTP
Support policy-making on a
chemical used forwater purification
Improve eco-efficiency of a
plant, help decision-makingon a technology
Compare results or take them as
a basis for other studies
Examples of potential target audience in LCA-drinking water studies and intended applications
Goal: Intended applications
Identification of Key Environmental Performance Indicators
(KEPI) of a product group for Ecodesign / Simplified LCA
Weak point analysis of a specific product
Detailed Ecodesign / Design for recycling
Perform simplified KEPI-type LCA / Ecodesign study
Comparison of specific goods and services
Benchmarking of specific products against the product group’s
average
Green Public or Private Procurement (GPP)
Development of life cycle based Type I Ecolabel criteria
Development of Product Category Rules (PCR) or a similar
specific guide for a product group
Development of a life cycle based Type III environmental
declaration for a specific good or service
Development of the “Carbon footprint”, “Primary energy
consumption” or similar indicator for a specific product
Greening the supply chain
Clean Development Mechanism (CDM) and Joint
Implementation
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Providing quantitative life cycle data as annex to an Environmental
Technology Verification (ETV) for comparative use
Policy development: Forecasting and analysis of the
environmental impact of pervasive technologies, raw material
strategies, etc. and related policy development
Policy information: basket-of-products (or product groups) type of
studies
Policy information: identifying product groups with the largest
environmental impact
Policy information: identifying product groups with the largest
environmental improvement potential
Monitoring environmental impacts of a nation, industry sector,
product group, or product
Corporate or site environmental reporting including calculation of
indirect effects in Environmental Management Systems (EMS)
Accounting studies that according to their goal definition do not
include any interaction with other systems
Development of specific, average or generic unit process or LCI
results data sets for use in specified types of LCA applications
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Goal: Decision context
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LCI Modelling framework:
Attributional or consequential
Goal: Attributional LCA
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PROCESS DATA
LCA- IMPACTS ACCOUNTING
ENVIRONMENTAL
PROFILE
HOT-SPOTS IDENTIFICATION
PROCESS IMPROVEMENT
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Goal: Consequential LCA
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≠ POSSIBLE SCENARIOS
PROCESS
LCA MODEL
≠ ENVIRONMENTAL
CONSEQUENCES
SCENARIOS COMPARISON
STRATEGIC PLANNING
POLICY and DECISION-MAKING
Goal: Example
�Project: (CEN-2008-1027)
�Task: Carbon footprint of drinking water treatment processes
�Commissioner: Agbar with funding of CDTI (Spanish Ministry)
�Aim: Compare different drinking treatment processes in terms of CO2 equivalent emissions
�Audience: water utility (Agbar) + CDTI + scientific community
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Goal: Example
�Intended applications:
� Comparison of specific goods and services
� Development of the “Carbon footprint”, “Primary energy consumption” or similar indicator for a specific product
�Decision context: Situation C: accounting
�LCI modelling framework: Attributional LCA
�Limitations: inventory focused on carbon footprint
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Goal: Example
Attributional LCA
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3.2 M inhabitants
250 hm3/year
3 river basins(surface and groundwater) and seawater
High water stress and industrial activity
6 waterworks
12 treatmenttechnologies
Barcelona MetropolitanArea, Spain
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Goal: Example
Attributional LCA
Environmental assessment of all the treatment facilities in the BMA at a process-unit level and focused on carbon footprint
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Pre
-tre
atm
en
t
Pre
-tre
atm
en
t
Goal: Example
Consequential LCA
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BMA Drinking water tre
atment
carbon footprint (T
n CO2 eq)
Scenario analysis
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Scope
Definition of:
� System’s description
� System’s function
� Functional unit / Reference flow
� Boundaries
� Cut-off criteria
� Impact categories to be covered
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Scope: System’s description
Knowing the system is important to:
� Define properly the functional unit
� Interpret results correctly and re-adjust LCI/LCIA if needed
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Scope: Functional unit
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Example of functional unit: 1 m3 produced waterwith legal minimum quality requirements forhuman consumption according to 98/83/ECEuropean Directive
System’sfunction?
E.g. To produce drinkingdrinking water
According to:
� Goal & scope
� Comparisons to be madebetween system’s
Recommendation: look at previoussimilar studies
Scope: Boundary and cut-off criteria example
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� Cut-off criteriabased on literature
� Boundary: cradle to gate
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Scope: Impact categories and method req.
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� Method selection:
e.g. CML 2 baseline
LCA Aim?Quantify GHG
emissions
�Identification of impact categories:
Climate change (kg CO2 eq.)
Calculationmethod
requirements?
Midpointmethod withCC category
IPCC ,Time horizon
100 years
LCI: Data sources
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Drinking watertreatment plant
Energy consumption
Chemicals consumption
Generated waste
Etc.
Databases(i.e Encoinvent )
Production of 1kwh of Electricity in Spain
Production of 1 kg of NaOH
Disposal of 1 kg of inert waste to landfill
Etc.
Literature Production of 1 kg of Granular Activated Carbon
(Muñoz 2006, Bayer et.al. 2005)
Activation of 1 kg of Granular Activated Carbon
(Muñoz 2006, Bayer et.al. 2005)
Own developed Production of 1 kg of aluminium polychloride
Production of 1 kg of antiscalant
Production of 1 kg polyDADMAC
Production of 1 kg polyacrylamide
EXAMPLESDATA SOURCE
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LCI: Data from DWTP
Types:
� Construction
� Operational data� Financial data (for further analysis such as LCC)
Sources:
� Water utility
� Local/regional authorities
Steps:
� Identification of data needed
� Design of a data collectionform
� Know data quality andcollection procedure
� Assess data apropiateness
� Identify data gaps
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LCI: Example of data form
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Comments: � Transport data is missing
but many suppliers arespecified
� Only sludge as a waste is specified (sand, GAC, etc. missing) and transport is missing
� Sludge treatmentchemicals are not linked to a specific treatmentprocess
2006 2007 2008 2009 2010
kg XXXXXX XXXXXX XXXXXX XXXXXX
kg XXXXXX XXXXXX XXXXXX XXXXXX XXXXXX
kg XXXX XXXXX XXXXXX XXXXXX
kg XXXXXX XXXXXX XXXXX XXXXXX
kg
kg XXXXXX XXXXXX XXXXXX XXXXXX XXXXXX
kg XXXXXX XXXXXX XXXXXX XXXXXX
kg XXXXXX XXXXXX XXXXXX XXXXXX
kg XXXXXX
kg XXXXXX
kg XXXXXX XXXXXX XXXXXX XXXXXX XXXXXX
kg XXXXX XXXXXX XXXXXX XXXXXX XXXXXX
kg XXXXXX XXXXXX
kg XXXXXX XXXXX
kg XXXXXX XXXXX
kg XXXXXX XXXXXX
kg XXXXXX XXXXXX
kg XXXX XXX XXX XXXXX
kg XXXXXX XXXXXX XXXXXX XXXXXX XXXXXX
kg XXXX XXXXX XXXX XXXXX XXXX
kg XXXX XXXX XXXX XXXX
kg XXXXXX XXXXXX XXXXXX XXXXXX XXXXXX
kg XXXXXX XXXXXX XXXXXX XXXXXX XXXXX
kg XXXXXX XXXXXX XXXXXX XXXXXX XXXXXkg XXXXXX XXXXXX XXXXXX XXXXXX XXXXXX
NEW kg XXXXXX XXXXX
REGENERATED kg XXXXXX XXXXXX XXXXXX
NEW kg XXXXXX XXXXX
REGENERATED kg XXXXX XXXXXX XXXXXX XXXXXX XXXXXX
kg XXXXX
GAS / KG SPRAY
DRYIED m3 XXXXXX XXXXXX XXXXXX XXXXXX XXXXXX
GAS / KG REGEN. m3 XXXXXX
kWh XXXXXX XXXXXX XXXXXX XXXXXX XXXXXX
kWh XXXXXX XXXXXX XXXXXX XXXXXX XXXXXX
kWh XXXXXX XXXXXX XXXXXX XXXXXX XXXXXX
kWh XXXXXX XXXXXX XXXXXX XXXXXX XXXXXX
kWh XXXXXX XXXXXX
kWh XXXXXX XXXXXX XXXXXX XXXXXX XXXXXX
kWh XXXXXXkWh XXXXXX XXXXXX XXXXXX XXXXXX XXXXXX
kWh XXXXXX XXXXXX XXXXXX XXXXXX XXXXXX
kWh XXXXXX XXXXXX XXXXXX XXXXXX XXXXXX
m3 XXXXXX XXXXXX XXXXXX XXXXXX XXXXXX
m3 XXXXXX XXXXXX XXXXXX XXXXXX XXXXXX
m3 XXXXXX XXXXXX XXXXXX XXXXXX XXXXXX
m3 XXXXXX XXXXXX XXXXXX XXXXXX XXXXXX
m3 XXXXXX XXXXXX
% XXXXXX XXXXXX
Surface
Reverse Osmosis
Ozonation
Pumping (water elevation)
Water extraction (surface and groundwater)
Pre-treatment (Pre-oxidation, Decantation & Sand-
% of total produced water coming from RO
Osmotised water (produced)
Groundwater
Surface
Groundwater
GAC NORIT
GAC CHEMV.
GAC regenerated on-site
GAC REGENERATION on-
SPRAY DRYING
Spray drying
Thickening
Sludge pumpingGAC reactivation on-site
Produced water pumping to storage tanks
PAX
ALBA - 18
PAX - XL60
PAX - 18
SPRAY DRYIED TO CIMENT KILNS SPRAY DRYIED TO LANDFILL
DEWATERED TO LANDFILL
SULPHURIC ACID
ANTISCALANT
IRON CHLORIDE (FeCl3)
SODIUM BISULFITE
NITROGEN OZONE
OXYGEN OZONE
DEFLOCULANT (NaOH)
PROSEDIM ASP-34
POLYELECTROLITE OPTIFLOC A -
CHLORINE CARBUROS METÁLICOS
CHLORINE KEMIRA
CALCITE
CHLORINE KEMIRA
CHLORINE CARBUROS METÁLICOS
SODIUM CHLORITE ARAGONESAS
SODIUM CHLORITE ATOFINA (L)
ALUMINA
ALUMINA H40
Wa
ter
Water intake
Produced water
Osmotised
water
En
erg
y
Natural Gas
Wa
ste
Sludge disposed
Ma
teri
als
Activated
carbon
Electricity
(Water
treatment)
Electricity
(Sludge
treatment)
Drinking Water Treatment plant X
Ch
em
ica
ls
Water
treaatment
Pre-oxidation
Coagulation-
Decantation
Ozonation
Reverse
Osmosis
Disinfection
Sludge
treatment
Sludge
treatment
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LCI: Example of data formTreatment process Flow 2007 2009 Unit Description / Assumptions
Extraction
Electricity xxxxxxx xxxxx kWh Groundwater extraction pumps
Waterxxxxx xxxxxxxx m3 Surface water
xxxxxxx xxxx m3 Groundwater
Pre-treatment
Electricity xxxxxx xxxxxxxx kWh
Chlorinexx xxxxx kg Distance to supplier 170 Kmxx kg Distance to supplier 15 Km
Sodium chloritex kg Distance to supplier 350 Km
xx kg Distance to supplier 650 KmAluminum polichloride x xxx kg Distance to supplier 170 KmAluminum sulphate xxx Kg Distance to supplier 170 Km
Sand waste xx xx kg Distance to landfill 45 km
Pumping (elevation) Electricity xxxxxx xxxxxx kWh
Ozonation
Electricity xxxxxxx xxxxxxx kWh Ozone in-situ production Oxygen xxxx xxxx kg Distance to supplier 25 KmNitrogen xxxx xxxx kg Distance to supplier 25 Km
GAC filtration
GAC newxxxxx kg Distance to supplier 1300 Km
xx kg Distance to supplier 1300 Km
GAC regeneratedxxx kg Distance to supplier 1300 Km
xxxxx Kg Distance to supplier 1300 Km
Reverse Osmosis
Electricity xxxxxxxx kWhOsmotised water xxxxxxx m3
Sulphuric acid xxx KgIron Chloride xx kg CoagulantSodium bisulfite x kgAntiscalant x kg RO Pre-treatmentCalcite xxxx kg Remineralisation
Post-treatmentChlorine
xxxx xxxx kg Distance to supplier 170 Kmxxx xxx kg Distance to supplier 15 Km
Water xxxxxxxx xxxxxxx m3 Produced at plant
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LCI: DatabasesLink DWTP data to DB’s process datasets:
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LCI: Databases
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Flow/Process Database LCI Process dataset
Electricity Ecoinvent 2.0 Electricity, low voltage, at grid/ES S
Chlorine Ecoinvent 2.0 Chlorine, liquid, production mix, at plant/RER S
Chlorine Transport Ecoinvent 2.0 Transport, lorry 3.5-7.5t, EURO3/RER S
Sodium chlorite Ecoinvent 2.0 Chlorine dioxide, at plant/RER S
Coagulant transport Ecoinvent 2.0 Transport, van <3.5t/RER S
Coagulants/flocculants x Own inventory data set
Sand to landfill Ecoinvent 2.0Process-specific burdens, inert material landfill/CH S
Oxygen Ecoinvent 2.0 Oxygen, liquid, at plant/RER S
Nitrogen Ecoinvent 2.0 Nitrogen, liquid, at plant/RER S
Reactivated GAC x Adapted from: (Muñoz, 2006)
GAC production x Adapted from: (Muñoz, 2006)
Sodium Bisulfite Ecoinvent 2.0 Sulphite, at plant/RER S
Sulphuric acid Ecoinvent 2.0 Sulphuric acid, liquid, at plant/RER S
Calcite Ecoinvent 2.0 Limestone, milled, packed, at plant/CH S
Hydrochloric acid Ecoinvent 2.0 Hydrochloric acid, 30% in H2O, at plant/RER S
Iron chloride (III) Ecoinvent 2.0 Iron (III) chloride, 40% in H2O, at plant/CH S
Natural gas Ecoinvent 2.0Natural gas, burned in industrial furnace >100kW/RER S
Sodium hydroxide Ecoinvent 2.0Sodium hydroxide, 50% in H2O, production mix, at plant/RER S
Not found in DB butassumption ismade bysubstitution
Literature
LCI: LiteratureProduction of Granular activated Carbon from «I. Muñoz, PhD. Thesis UAB 2006» :
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LCI: Own developedExample: Anionic copolymer (flocculant)*:
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Info from:
� Supplier’s
� Literature**
� Calculations (mainly stoichiometric and thermodynamic)
Not in DB’s nor
in literature
Sodium hydroxide,
50% in H2O,
production mix, at
plant/RER S
(ECOINVENT)
Acrylic acid, at
plant/RER S
(ECOINVENT)
Water,
deionised, at
plant/CH S
(ECOINVENT)
Acrylonitrile E
(Industry data
2.0 )
*All rights reserved. No part of this information may be used, reproduced or transmitted in any form or by anymeans without previous permission of the authors .
**Chemical Engineer's Handbook - Robert H. PerryEncyclopedia of Industrial Chemistry- ULLMANN’S
LCIA
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Classification
Midpointimpacts
calculation
Endpointsimpacts
calculations Normalisation Weighting
METHOD
Inventory
• Compound 1
• Compound 2
• …
• Compound n-1
• Compound n
Impact categories
•• ClimateClimate changechange• Ozone layer dep.
• Acidification
• Human toxicity
• Photochemicaloxidation
• …
Damage categories
• Human health
• Ecosystems
• Resources
• …
Normalisationfactors
• Default values • Regional factors•…
Weighting factors
• Default values
• 1 for all impacts
• Own criteria
• Etc.
� SimaPro 7.2 Software � CML 2 baseline
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LCIA: impact categories
Impact categories most important in DWTP’s:
� Climate change
� Ozone layer depletion
� Human toxicity
� Water use
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LCIA: method-attached limitations
Human toxicity
Impacts on human health due to waterconsumption cannot be estimated through LCA � Riskassessment
Water use
Further research is needed in order to ‘know’ theregionalised impacts of fresh-water use (consumptiveand degradative)
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Interpretation of results
�Identification of significant issues :
LCI weak point analysis
Key impact categories
�Scenario analysis
�Sensivity and uncertainity analysis
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Int. of results: examples
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Pre-treatment, pumping and EDR are the process-units with higher environmental impacts.
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Int. of results: examples
�energy consumption is the main source of impacts on climate change
�chemicals consumption (e.g. coagulants, oxidants) is the principle cause of impacts on the ozone layer depletion
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Int. of results: examples
�Plants with membrane treatments have higher GHG emissions related to energy consumption
�Transport presents high GHG emissions in the conventional plants assessed mainly due to GAC transport outside Spain.
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Int. of results: examples
�Conventional plants: pre-treatment has high GHG emissions due to chemicals consumption.
�Membrane treatment: pre-treatment is not significant but high GHG emissions associated to the electricity consumption.
EDR: 0.40 kg CO2 eq./produced m3
RO (Brackish): 0.52 kg CO2 eq./produced m3
RO (seawater): 1.67 kg CO2 eq./produced m3
04/09/12Universitat de Girona, 3rd-7th September
2012
Car
bo
nfo
otp
rin
t
Int. of results: examples
During drought (2007) the plant prioritised groundwater extraction:
-High extraction impacts due to pumping
-Low chemicals and energy consumption in pre-treatment and GAC filtration
The impacts of adding a new
process (UF+RO) to meet new THM regulations increased 0.04 kg CO2/m3 the plant’s carbon footprint. However, it also improved its water quality.
04/09/12Universitat de Girona, 3rd-7th September
2012
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Int. of results: examples
�Sludge treatment presented lower impacts (20%) than water treatment (80%).
�Recycling in cement industry can reduce the environmental impact of cement
production and avoid the impacts from sludge landfilling. However, additional
sludge treatment (e.g. drying), may be required.
�Need to use consequential LCA to decide whether to treat sludge previous to its valorisation or not, depending on the amount of sludge and its requirements .
04/09/12Universitat de Girona, 3rd-7th September
2012
Int. of results: examples
04/09/12Universitat de Girona, 3rd-7th September
2012
5 MW installed7 GWh/year produced
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Int. of results: examples
�GAC is produced and reactivated in Italy or The Netherlands (1300 km from Barcelona)
�Impact reductions up to 18% should have been achieved in the BMA if there was a GAC generation and reactivation plant in Spain.
�There are > 260 drinking water treatment plants using GAC in Spain
04/09/12Universitat de Girona, 3rd-7th September
2012
9% impactreduction
18% impactreduction
-2.000 4.000 6.000 8.000
10.000 12.000 14.000 16.000 18.000
BMA Savings (average 2007, 2009)
Tn C
O2
eq
./ye
ar
GHG's emissions savings
Plant located in Madrid (Spain)
Plant located in Catalonia (Spain)
Int. of results: examples
�NaClO2 causes around 30% of the chemicals’ impacts.
�The substitution of NaClO2 by Cl2 in conventional plants:
75% the disinfection carbon footprint
5% the plant’s carbon footprint
40% the disinfection impacts on ozone layer depletion
90% the plant’s impacts on ozone
layer depletion.
04/09/12Universitat de Girona, 3rd-7th September
2012
3%
4%
5%
5%
HCl; 11%
NaClO2; 28%
PAC; 44%
Carbon footprint of chemicals- conventional
plants
PolyDADMAC
Lime
Others
CO2
HCl
NaClO2
PAC
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Int. of results: examples
04/09/12Universitat de Girona, 3rd-7th September
2012
�Carbon footprint of a drinking water treatment plant: 0.1 - 2.2 kg CO2 eq. /m3
�The carbon footprint of the water treatment in the BMA is around 0.4 kg CO2
eq. /m3
Int. of results: examples
Sensivity analysis: how results change when...?
04/09/12Universitat de Girona, 3rd-7th September
2012
Own inventory for polyelectrolyte
Iron Chloride inventory for polyelectrolyte%
Ozo
ne
laye
r d
eple
tio
n
% C
limat
e C
han
ge
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Conclusions
� Centralised or decentralised solutions for environmentalproblems? � Need for a holistic approach (LCA)
� The impact of a DWTP depends on inlet water quality andon its location and design (Carbon Footprint 0.1-2.7 kg CO2/m3)
� Membrane technologies have higher GHG emissions but also produce higher quality water (EDR 0.4 ; RO (Brackish) 0.52; SWRO 1.67 kg CO2 eq./m3) � Include water quality
parameters in order to also quantify the environmental benefits of water treatments
� Need of specific research on inventories of chemicals,
materials and waste disposal in the water sector
04/09/12Universitat de Girona, 3rd-7th September
2012
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