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
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
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
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
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
complete listing of these bodies can be found at www.iso.org/members.html.
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.
— Environmental impacts can also be included in the evaluation, along with an economic evaluation.
4.2 Timing of the evaluation
A water reuse project requires a careful evaluation of goals, including an assessment of technology
feasibility and relative costs to achieve the objectives. The evaluation can be conducted at the planning
stage, O&M stage and disposal stage. The assumed data at the planning stage can be replaced with
actual and more accurate data at the other stages. This can provide stakeholders with a greater
opportunity of understanding the project status.
4.3 Consideration of water quality
Generally, the construction cost and the operation cost of a water reclamation facility differ greatly
depending on the water quality of the wastewater supplied and the reclaimed water quality required.
When a water reclamation facility is adopted, it is important to evaluate and select appropriate
technologies to satisfy the requirements of water quality and quantity that are specified by users (see
ISO 20468-1:2018, Clause 6).
5 Economic evaluation procedure
5.1 Boundary definition
For the economic evaluation of treatment systems, it is necessary to accurately define the boundary in
accordance with the characteristics of an individual water reuse project. In particular, relevant facilities
that will be affected by the project should be included in the boundary. For example, if heat recovered
by the water reclamation process is utilized for a heating system, the facilities for heat recovery, such as
a heat pump, should be within the boundary. In general, heat pump and heat exchanger equipment are
widely applied for the heat recovery facilities in municipal sewage plants. Direct reuse of hot water is
often applied in industrial facilities.
In the definition of the boundary, it is important to properly define the alternative system and the
baseline system. For example, if the alternative system is defined with the installation of a new water
reclamation process, the baseline system does not need the reclamation process. The boundary can be
defined for each of several systems with different water reclamation technologies as candidates and
compared with a baseline system.
An example of the boundary of an alternative system and a baseline system in a water reuse project
utilizing treated municipal wastewater is shown in Figure 1. Treated water with its quality improved
by a reclamation process in the alternative system can be used for building and landscapes. Heat
recovered by the facility with the water reclamation process can be used for air conditioning systems
and other purposes. As a result, an alternative system can achieve cost reduction for water and energy
supplies compared with the baseline system. An example of facilities and items in the defined boundary
in a case study on a water reuse project using treated municipal wastewater is shown in Annex A.
Figure 1 — Example of boundary of treatment system in a municipal water reuse project
Another example of the boundary of an alternative system with a water reclamation process and
that of a baseline system are shown in Figure 2. The boundary in the baseline system consists of the
water supply process, including water treatment and wastewater treatment processes. In addition, the
boundary in the alternative system includes the water reclamation process. The water reclamation
process improves treated water quality to meet the needs of domestic use and heat supply facilities, thus
enabling heat recovery and recovery of valuable materials, along with water recovery. Consequently, the
benefits of cost-effectiveness are estimated from the reduction in the amount of the water supply and
water treatment in the alternative system. An examp
...