A life cycle assessment based procedure for development of environmental sustainability indicators f

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A life cycle assessment based procedure for
development of environmental sustainability
indicators for urban water systems

• Sandra Oisalu
• Tallinna Tehnikaülikool
• 2005

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Content

• Introduction
• Environmental sustainability indicators
• Methods for selection of indicators
• LCA
• The iterative procedure
• System boundaries
• Case studies
• Results
• Conclusions

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Introduction

• Environmental sustainability is often vaguely
  defined and clear measurement procedures are
  lacking so sustainability indicators to reflect
  the endvironmental sustainability of urban water
  systems is needed.
• Analytical basis LCA
• Case studies developed and developing region

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Environmetnal sustainability indicators

• Environmetnal sustainability indicators
• Proposed for use at city, region or country
  levels
• To assess the environmental performance of
  infrastructure, agriculture and production
• Often developed in an ad hoc fashion without a
  structured framework for identifying indicatiors

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Methods for selection of indicators

• PICABUE method- theoretical approach, Bellagio
  principles as guidlines for the sustainability
  assessment process
• Life cycle assessment- designed to evaluate and
  where possible reduce environmental impact for
  the entire life cycle of a product, process or
  service

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LCA

• Advantages
• Well-established and standardised method,
  includes LCIA
• Has been used for estimating environmental loads
  from urban water systems, usually wastewater
  systems
• LCA studies have revealed the importance of
  nutrient recycling and energy recovery
• Disadvantages
• Complex
• Time-consuming
• Here we present an iterative procedure for
  ESI selection using a framework based on LCA
  results and methodology, with Case Studies being
  an integrated part of ESI development

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The iterative procedure
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System boundaries
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Case studies (1)

• Two Case Studies were performed
• The aim was
• to investigate how the urban water systems had
  changed over time and to assess the current
  situation
• to test the indicators in a developed and
  developing region

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Case studies (2)

• Framework-
• the urban water system was divided into 4
  environemtal and technical systems following the
  life cycle of urban water management
• Withdrawal of freshwater
• Production, distribution and use of drinking
  water
• Collection and treatment of wastewater
• Handling of by-products such as sludge, biogas
  and heat
• For each system ESI were formulated for
  environmental performance and pressure on the
  environment

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Case studies (3)

• Case study 1 Göteborg, Sweden
• Second largest municipality in Sweden
• Population 450 000
• Area 450 km2
• Responsible for water management-
• Göteborg Water and Sewage Works
• Göteborg Regional Sewage Works (the Rya WWTP)
• Time perspective 20-25 years
• Information collection from the early 1970s to
  the late 1990s

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Case studies (4)

• Case study 2 King Williams Town, South Africa
• Population 35 500
• Population has low income and is expected to grow
  approx. 3 per year
• 2 freshwater reservoirs supply the area with
  drinking water after treatment at the KWT water
  purification works
• The wastewater is led to one of two treatments
  plants
• The system boundaries are the same as for
  Göteborg
• Information available for the last 3-5 years

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Results

• Recommended ESI for assessing the environmental
  sustainability of urban water systems is
  presented on next slide
• The table discribes the most important indicators
  based on results from different LCA studies and
  similar studies
• The results depend on several choises such as
  selection of system boundaries and impact
  categories but is useful as a first set of ESI

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Conclusions

• The iterative procedure combines empirical
  results with a theorethical framework based on
  LCA
• Case Studies results which empirically defined
  the most important indicators for the system
• Case studies also helped to reveal information
  gaps and problems conserning availability and
  quality of information
• LCA helped to determine priorities and ESI which
  were not so obvious i.e. Recycling of nutrients