IWA 28:2018

INTERNATIONAL IWA
WORKSHOP 28
AGREEMENT
First edition
2018-04
Faecal sludge treatment units —
Energy independent, prefabricated,
community-scale resource-recovery
units — Safety and performance
Unités de traitement de matières de vidange — Unités de
récupération préfabriquées et autonomes en énergie pour des
ressources à l'échelle locale — Sécurité et performances
Reference number
©
ISO 2018
© ISO 2018
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ii © ISO 2018 – All rights reserved

Contents Page
Foreword .vii
Introduction .viii
1 Scope . 1
2 Normative references . 1
3 Terms, definitions and abbreviated terms . 2
4 General requirements . 8
4.1 Industrial design and manufacture . 8
4.2 Hazard and operability study and risk assessment . 8
4.3 Ambient operation conditions . 8
4.4 Expected technical lifetime . 9
4.5 Treatment unit input . 9
4.5.1 Input types . 9
4.5.2 Specification of input parameters and ranges . 9
4.5.3 Input specification templates . 9
4.5.4 Additional input specifications for thermal and biological processes . 9
4.6 Requirements for handling of faecal sludge as a fuel .10
4.6.1 Delivery and reception of faecal sludge .10
4.6.2 Storage of faecal sludge .10
4.6.3 Feeding system .10
4.6.4 Additional requirements for thermal treatment units .10
5 Energy balance and resource recovery .10
5.1 General .10
5.2 Energy balance .10
5.2.1 Energy independence .10
5.2.2 Energy positive .11
5.3 Resource recovery .11
6 Performance requirements .11
6.1 Technical process availability .11
6.1.1 Mean time between failure (MTBF) .11
6.1.2 Mean time to repair (MTTR) .12
6.1.3 Preventive maintenance time (T ) .12
pm
6.2 Process reliability .12
6.2.1 Process stability .12
6.2.2 Start reliability and start time .12
6.2.3 Shut-off reliability and shut-off time .12
7 Safety and functional requirements .12
7.1 Applicability .12
7.2 Process control.13
7.2.1 General.13
7.2.2 Degree of automation .13
7.2.3 Intentional starting of operation .13
7.2.4 Intentional stopping of operation .13
7.2.5 Emergency stop .13
7.2.6 Continuous monitoring .13
7.2.7 Feedback of process failures .13
7.2.8 Safety-related functions of the control system .14
7.2.9 Input overload protection monitoring .14
7.2.10 Overpressure protection .14
7.2.11 Fire and overheating prevention .14
7.2.12 Explosion prevention .15
7.3 Process redundancy .15
7.4 Material fire resistance .15
7.5 Security and safety of electrical energy supply .15
7.5.1 Security of electrical energy supply .15
7.5.2 Safety requirements for electrical energy supply .16
7.6 Structures and supporting elements .16
7.6.1 Structural integrity .16
7.6.2 Integrity against external impacts .17
7.7 Sanitary requirements .17
7.7.1 Hygienic design .17
7.7.2 Materials .17
7.7.3 System tightness .17
7.7.4 Leakage protection.17
7.8 Mechanical requirements .17
7.8.1 Pressurized equipment .17
7.8.2 Pipes, hoses and fittings .18
7.8.3 Tanks and vessels .18
7.8.4 Moving and rotating parts .18
7.8.5 Vibration .19
7.9 Radiation .19
7.9.1 High temperatures of parts and surfaces .19
7.9.2 Low temperatures of parts and surfaces .19
7.9.3 Electromagnetic compatibility.19
7.9.4 Other sources of radiation .19
7.10 Electric and electrical components .19
8 Operability .20
8.1 Safe loading .20
8.2 Anthropometric design .20
8.2.1 General.20
8.2.2 Forces to be applied .20
8.2.3 Accesses and stairs .20
8.2.4 Aisles and platforms .20
8.2.5 Enclosed spaces .20
8.3 Lighting .20
8.4 System ergonomic design .20
9 Maintainability .21
9.1 Adjustability and maintainability .21
9.1.1 Identification of adjustment and maintenance needs .21
9.1.2 Ease of maintenance of devices, components and subassemblies .21
9.2 Access to adjustment and maintenance points .21
9.3 Requirements for adjustment and maintenance activities .21
9.3.1 Discharge and cleaning, testability, adjustment and maintenance on the
running system .21
9.3.2 Safe handling of electrical equipment .21
9.4 Spare parts .21
9.5 Tools and devices .22
10 Outputs .22
10.1 Solid .22
10.1.1 General.22
10.1.2 Pathogens .22
10.1.3 Heavy metals .22
10.1.4 Additional requirements of solids for disposal .23
10.2 Effluent .23
10.2.1 Pathogens .23
10.2.2 Environmental parameters .23
10.2.3 Requirements for effluent .24
10.3 Air emissions from thermal treatment units .24
10.4 Odour .25
10.5 Noise .25
iv © ISO 2018 – All rights reserved

11 Testing .25
11.1 Certification bodies .25
11.2 Input characterization .26
11.3 Solid and effluent .26
11.3.1 Pathogens in solid outputs and effluent .26
11.3.2 Heavy metals in solid outputs .26
11.3.3 Environmental parameters for effluent .27
11.4 Air emissions .27
11.4.1 Loss on ignition and total organic carbon .27
11.4.2 Temperature and residence time .28
11.4.3 Air pollution emissions .28
11.5 Odour .31
11.5.1 Test methods for odour output .31
11.5.2 Measurement planning .32
11.5.3 Measurement principles .32
11.5.4 Sampling location requirements .32
11.5.5 Measurement process .32
11.5.6 Sampling train .32
11.5.7 Materials selection .32
11.5.8 Additional equipment considerations .33
11.5.9 Sample collection on a solid or liquid surface .33
11.5.10 Selection of panellists .33
11.6 Noise .33
11.6.1 Test methods for noise output .33
11.6.2 Measurement planning .34
11.6.3 Measurement objective/scope .34
11.6.4 Requirements for the sampling location .34
11.6.5 Measurement equipment .34
11.6.6 Calibration .35
11.6.7 Operation of treatment unit during test .35
11.6.8 Sound level meter setting .35
11.6.9 Microphone orientation .35
11.6.10 Correction for background noise and reflecting surfaces in test environment .35
11.6.11 N , Number of uncertain measurements due to background noise .35
K1
11.6.12 Representative A-weighted sound pressure level .35
12 Product literature .36
12.1 General .36
12.2 Input .36
12.3 Performance claims .37
12.4 Unit boundaries .37
12.5 Energy independence assessment .37
12.6 Environmental sustainability .38
12.6.1 Consumable consumption .39
12.6.2 Greenhouse gas emissions (GHG) .39
12.6.3 Characteristics of resource recovered products .39
12.7 Maintenance and operator documentation .39
12.7.1 Language requirements .39
12.7.2 Provision of manual .39
12.7.3 Number of documents.39
12.7.4 Recurring operation and maintenance .41
12.7.5 Complexity of configuration, adjustment and maintenance activities .41
Annex A (informative) Input specification templates .42
Annex B (informative) Additional input specifications .44
Annex C (informative) Sustainability .46
Annex D (informative) Workshop resolutions .50
Annex E (informative) Workshop contributors .51
Bibliography .56
vi © ISO 2018 – All rights reserved

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 on 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 the following
URL: www .iso .org/iso/foreword .html.
International Workshop Agreement IWA 28 was developed and approved over a series of three
workshops hosted by the American National Standards Institute (ANSI) in Durban, South Africa, in June
2017, in Singapore in September 2017 and in Dakar, Senegal, in January 2018.
Introduction
Hygienic sanitation facilities are crucial for public health, yet 61 % of the global population do not
use safely managed sanitation services, i.e. excreta safely disposed of in situ or treated off-site (see
Reference [186]).
Improved environmental sanitation has a multitude of socio-economic benefits. Functional sanitation
systems improve health and welfare and are fundamental to human development. Integrated business
models throughout the sanitation value chain can ensure the economic viability of processes that turn
waste into valuable resources, such as biofuels or agriculture products. Sanitation systems can also
conserve water, thus leading to even broader livelihood improvements. According to the World Health
Organization, the estimated economic benefit of the return on a US$1 investment in sanitation is in the
range of US$5 to US$28 (see Reference [185]).
NOTE The focus of this document is treatment (as depicted in the red box).
Figure 1 — Sanitation value chain
The focus of this technical document on non-sewered faecal sludge treatment units is represented by
the red box along the sanitation value chain in Figure 1, indicating the treatment components of faecal
sludge management. The purpose of this document is to specify performance and safety requirements
of community-scaled resource-oriented faecal sludge treatment units serving approximately 1 000
to 100 000 people, ensuring technical robustness and safety in terms of human health and the
environment. This document aims to facilitate the commercialization and transfer of these treatment
units into the market.
1)
This document complements ISO 30500 on-site user-interface non-sewered sanitation systems
(depicted at left in Figure 1).
This document aims to specify technical requirements and recommendations for community-scale
resource-oriented faecal sludge treatment units in terms of performance, reliability, availability,
maintainability and safety. This document further aims to promote trust among the different
stakeholders involved in faecal sludge management, such as investors, technology developers,
regulatory bodies, local service providers and users, increasing their willingness to implement
innovative new technologies. Manufacturers and technology developers can use this document to
gain consumer confidence in the reliability and safety of treatment units. Stakeholders can use this
document as a benchmark to compare performance capabilities of different treatment unit options and
identify which option is most suitable for their needs.
1) Under preparation. Stage at the time of publication: ISO/DIS 30500:2018.
viii © ISO 2018 – All rights reserved

This document specifies minimum requirements of all types of outputs from the treatment unit to
ensure safety for human health and the environment. It does not specify or mandate the quality of
resources recovered as these are highly dependent on the local (e.g. economic, social) context.
This document is intended to ensure the general performance, safety and sustainability of such units.
This document also includes requirements for operability and maintainability to ensure safety and
performance of the treatment unit. Figure 2 illustrates the scope of this document with respect to
treatment unit inputs and outputs.
Figure 2 — Scope of this document
The dashed line in Figure 2 shows the boundary of the scope of this document. Inputs are primarily
faecal sludge derived from human excreta (likely contaminated with domestic waste) and can include
additional inputs at the discretion of the manufacturer. This document does not specify which forms
of excreta and additional inputs are treated within the unit (e.g. urine, faeces, greywater); these inputs
are defined by the manufacturer.
Inputs are illustrated as partially within and partially outside the document’s scope to illustrate
that the manufacturer defines the input characteristics which meet the requirements set forth in
this document. The performance, safety, operability and maintainability of the treatment unit are
addressed in this document, as are human health and safety aspects of the treatment unit’s solid, liquid
and gaseous outputs. Noise and odour outputs of the treatment unit are also addressed within this
document. However, the quality and value of any resource recovery and reuse products derived from
treatment unit outputs are outside the scope of this document. Apart from the requirement for energy
independence during steady-state operation, this document does not set performance targets with
respect to the amount or type of energy or resources that needs to be recovered and/or locally used.
This document excludes transportation and any intermediary processes required to supply the
treatment unit with the defined inputs.
Provisions of this document apply to the treatment unit according to its unit boundaries, i.e. within the
process chain beginning with its specified inputs and ending with its outputs.
Annex C on sustainability highlights some of these considerations.
International Workshop Agreement IWA 28:2018(E)
Faecal sludge treatment units — Energy independent,
prefabricated, community-scale resource-recovery units —
Safety and performance
1 Scope
This document specifies requirements and test methods to ensure safety, performance and sustainability
of community-scale resource-oriented faecal sludge treatment units that serve approximately 1 000 to
100 000 people. This document applies to treatment units that:
a) primarily treat faecal sludge;
b) are able to operate in non-sewered and off-grid environments;
c) are prefabricated.
This document does not apply to sanitation treatment units requiring sewer infrastructure, or to those
requiring electric grid access during steady state operation.
Treatment units to which this document applies exhibit resource recovery capability (e.g. recovering
energy, reusable water, soil amendment) and are capable of being energy neutral or energy net positive.
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 7250 (all parts), Basic human body measurements for technological design
ISO/IEC 17065:2012, Conformity assessment — Requirements for bodies certifying products, processes
and services
ISO 20816-1, Mechanical vibration — Measurement and evaluation of machine vibration — Part 1: General
guidelines
ISO 55000, Asset management — Overview, principles and terminology
IEC 60050, International electrotechnical vocabulary
IEC 60204-1, Safety of machinery — Electrical equipment of machines — Part 1: General requirements
IEC 60942, Electroacoustics — Sound calibrators
IEC 61260-1, Octave-band and fractional-octave-band filters — Part 1: Specifications
IEC 61672-1, Electroacoustics — Sound level meters — Part 1: Specifications
IEC 82079-1, Preparation of instructions for use — Structuring, content and presentation — Part 1: General
principles and detailed requirements
API 650, Welded steel tanks for oil storage
ASTM D7348-13, Standard test methods for loss on ignition (LOI) of solid combustion residues
AWWA D-100, Welded carbon steel tanks for water storage
DIN 4109-1, Sound insulation in buildings
EN 13137, Characterization of waste — Determination of total organic carbon (TOC) in waste, sludges and
sediments
EN 13725, Air quality — Determination of odour concentration by dynamic olfactometry
EN 15259, Air quality — Measurement of stationary source emissions — Requirements for measurement
sections and sites and for the measurement objective, plan and report
EN 15936, Sludge, treated biowaste, soil and waste — Determination of total organic carbon (TOC) by dry
combustion
FDBR-RL7, Acceptance testing of waste incineration plants with grate firing systems
NFPA 30:2018, Flammable and Combustible Liquids Code
UL 58, Standard for steel underground tanks for flammable and combustible liquids
UL 142, Standard for steel aboveground tanks for flammable and combustible liquids
Directive 2010/75/EU of the European Parliament and of the Council of 24 November 2010 on industrial
emissions (integrated pollution prevention and control)
3 Terms, definitions and abbreviated terms
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
3.1 General
3.1.1
human excreta
waste products of human metabolism, in solid or liquid form, generally urine and/or faeces
[SOURCE: ISO 24521:2016, 3.3]
3.1.2
faecal sludge
untreated sludge generated from the storage of human excreta (3.1.1) that can be mixed with flush
water, solid domestic waste (3.2.1) and other liquids
3.1.3
input
substances fed to the treatment unit for the purpose of treating those substances
Note 1 to entry: Input to treatment units covered by this document is required to be derived primarily from faecal
sludge (3.1.2), which can be contaminated by liquid and solid domestic waste (3.2.1) and can include different
forms of biomass (3.2.2).
3.1.4
prefabricated
factory produced, either as a fully assembled unit or as a set of components that assemble to form the unit
2 © ISO 2018 – All rights reserved

3.1.5
design requirement
requirement that specifies or constrains the design of a system or system componentcf. functional
requirement, implementation requirement, interface requirement, performance requirement, physical
requirement
[SOURCE: ISO/IEC/IEEE 24765:2017, 3.1146]
3.1.6
risk assessment
overall process comprising a risk analysis and a risk evaluation
[SOURCE: ISO 14971:2007, 2.18]
3.1.7
safety assessment
review of the aspects of design and operation of the treatment unit, which are relevant to the protection
of persons or the safety of the treatment unit, including the analysis of the safety and protection
provision established in the design and operation of the treatment unit and the analysis of risks
associated with normal conditions and accident situations
3.1.8
design process
process of converting the requirements of the functional specification into the technical specification
[SOURCE: ISO 13880:1999, 3.3]
3.1.9
functioning as intended
conforming to all expectations in terms of performance, capacity and safety as specified by the
manufacturer
EXAMPLE The treatment process is functioning as intended when the process is stable and the output
criteria are met.
3.1.10
reasonably foreseeable misuse
use of a machine in a way not intended by the designer, but which can result from readily predictable
human behaviour
[SOURCE: ISO 12100:2010, 3.30]
3.2 Input, energy balance and resource recovery
3.2.1
domestic waste
waste that arises from domestic use of a private dwelling
3.2.2
biomass
material of biological origin excluding material embedded in geological and/or fossilized formations
[SOURCE: ISO 16620-1:2015, 3.1.2]
3.2.3
steady state
condition in which all relevant operational parameters are not significantly changing with time
...