ISO 20468-8:2022

INTERNATIONAL ISO
STANDARD 20468-8
First edition
2022-07
Guidelines for performance evaluation
of treatment technologies for water
reuse systems —
Part 8:
Evaluation of treatment systems based
on life cycle cost
Lignes directrices pour l’évaluation des performances des techniques
de traitement des systèmes de réutilisation de l’eau —
Partie 8: Évaluation des systèmes de traitement fondée sur le coût
global
Reference number
© ISO 2022
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Published in Switzerland
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions, symbols and abbreviated terms . 1
3.1 Terms and definitions . 1
3.2 Symbols and abbreviated terms . 2
4 Concept of economic evaluation .2
4.1 General . 2
4.2 Timing of the evaluation . 3
4.3 Consideration of water quality. 3
5 Economic evaluation procedure . 3
5.1 Boundary definition . 3
5.2 Cost elements definition . 5
5.3 Calculation . 5
5 .4 E v a lu at ion . 6
6 Evaluation of environmental benefits . 7
6.1 General . 7
6.2 Water recovery ratio and heat output recovery ratio . 7
Annex A (informative) Example of evaluation of treatment systems for municipal water
reuse . 9
Annex B (informative) Example of evaluation of treatment systems for industrial water
reuse .12
Annex C (informative) Evaluation of environmental benefits .15
Bibliography .16
iii
Foreword
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www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 282, Water reuse, Subcommittee SC 3,
Risk and performance evaluation of water reuse systems.
A list of all parts in the ISO 20468 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
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iv
Introduction
The purpose of this document is to more specifically define a methodology for evaluating the economic
performance of treatment systems, which is covered in ISO 20468-1:2018, Clause 7. The background
to this document is the need to promote water reuse projects with cost-effective treatment systems
in communities and industrial facilities in order to achieve sustainable water supply. A variety of
stakeholders, including managers of water reuse projects and owners of water infrastructure and
facilities, can select appropriate treatment systems through comprehensive performance evaluations
using this document and the ISO 20468 series.
The concept of the economic performance evaluation methodology has already been established based
on life-cycle cost (LCC), comprising capital, operation and maintenance (O&M), and disposal costs in
IEC 60300-3-3. The economic performance evaluation methodologies of the petroleum and natural gas
industries and building and constructed assets are defined in ISO 15663 and ISO 15686-5, respectively,
based on the general standard of IEC 60300-3-3. The importance of the economic evaluation, based on
LCC considering the environmental impact, is also described in guidelines for selecting high-quality
[14]
water infrastructure and facilities. With reference to these existing standards, this document
provides a customized evaluation methodology for treatment systems in water reuse projects based
on LCC, taking environmental impact into consideration. In this document there are no restrictions on
applicable treatment systems, such as biological, physical or membrane separation.
v
INTERNATIONAL STANDARD ISO 20468-8:2022(E)
Guidelines for performance evaluation of treatment
technologies for water reuse systems —
Part 8:
Evaluation of treatment systems based on life cycle cost
1 Scope
This document provides life-cycle cost (LCC) methodology for treatment systems for water reuse for
initial planning as well as later performance evaluation. LCC analysis provides valid information to
determine whether the objectives have actually been accomplished and how operations are improved
and optimized. Environmental impact is also taken into account in the LCC evaluation.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 20670, Water reuse — Vocabulary
3 Terms, definitions, symbols and abbreviated terms
For the purposes of this document, the terms and definitions given in ISO 20670 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1 Terms and definitions
3.1.1
capital cost
money used to purchase, install and commission a capital asset
3.1.2
disposal cost
money used to demolish and rehabilitate a capital asset at the end of its life
3.1.3
operation and maintenance cost
cost incurred in running and managing the facility, labour, material and other related costs incurred to
retain a building or its part in a state in which it can perform its required functions
3.1.4
life-cycle cost
total cost incurred during the life cycle
[SOURCE: IEC 60300-3-3:2017, 3.1.13]
3.1.5
life-cycle costing
process of evaluating the difference between the life-cycle costs of two or more alternative options
[SOURCE: ISO 15663:2021, 3.1.27, modified — Note to entry removed.]
3.2 Symbols and abbreviated terms
For the purposes of this document, the following symbols and abbreviated terms apply:
C LCC, LCY/year
C LCC of alternative system, LCY/year
a
C LCC of baseline system, LCY/year
b
C
disposal cost, LCY/year
d
C
capital cost, LCY/year
i
C
operation and maintenance cost, LCY/year
o
C cost for water input or water output in O&M, LCY/year
ow
()
∆C cost reduction in water use, LCY/year
η
heat output recovery ratio
h
η
water recovery ratio
w
LCC life-cycle cost
LCY local currency
O&M operation and maintenance
Q
heat output in alternative system, J/year
outa
Q
heat output in baseline system, J/year
outb
u unit cost, LCY/m
w water consumed, m /year
W
water input in alternative system, m /year
ina
W
water input in baseline system, m /year
inb
W
water output in alternative system, m /year
outa
W
water output in baseline system, m /year
outb
4 Concept of economic evaluation
4.1 General
The concept of life-cycle costing is applied to evaluate the economic performance of treatment systems
in a water reuse project. An economic evaluation procedure using the total cost of the treatment system
throughout a project’s life can be applied to estimate the cost difference between each alternative system
to select an appropriate water reclamation technology, while satisfying the project’s requirements.
This document describes the economic evaluation methodology for treatment systems based on the
following concepts according to existing standards:
— The LCC of an alternative treatment system with water reclamation process (in both cases of new
[3],[15]
installation and renewal or modification) is compared with that of a baseline system.
— The economic evaluation procedure includes definitions of the boundary of a treatment system,
cost elements, calculation and evaluation.
The following characteristics should be especially considered:
— The boundary of an economic evaluation can include an entire treatment system consisting of water
supply process and wastewater treatment process, as well as water reclamation process, when a
[16]
reduction in the total amount of required water is expected by the reclamation process.
— Heat recovery and recovery of valuable materials can be included in the evaluation.
— Env
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