CEN/TR 17614:2021

SLOVENSKI STANDARD
01-marec-2021
Standardna metoda za ocenjevanje in izboljšanje energijske učinkovitosti čistilnih
naprav za odpadno vodo
Standard method for assessing and improving the energy efficiency of waste water
treatment plants
Standardmethode zur Bewertung und Verbesserung der Energieeffizienz von
Kläranlagen
Méthode standard d’évaluation et d’amélioration de l’efficacité énergétique des stations
d'épuration
Ta slovenski standard je istoveten z: CEN/TR 17614:2021
ICS:
13.060.30 Odpadna voda Sewage water
27.015 Energijska učinkovitost. Energy efficiency. Energy
Ohranjanje energije na conservation in general
splošno
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

CEN/TR 17614
TECHNICAL REPORT
RAPPORT TECHNIQUE
January 2021
TECHNISCHER BERICHT
ICS 13.060.30; 27.015
English Version
Standard method for assessing and improving the energy
efficiency of waste water treatment plants
Méthode standard d'évaluation et d'amélioration de Standardmethode zur Bewertung und Verbesserung
l'efficacité énergétique des stations d'épuration der Energieeffizienz von Kläranlagen

This Technical Report was approved by CEN on 4 January 2021. It has been drawn up by the Technical Committee CEN/TC 165.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TR 17614:2021 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
Introduction . 4
1 Scope . 5
2 Normative References . 5
3 Terms and definitions . 5
4 General considerations of methodologies . 5
5 Methodology for Rapid Audit (RA). 6
5.1 General . 6
5.2 Identification of the WWTP typology . 6
5.3 Energy consumption data collection . 7
5.3.1 Energy consumption data . 7
5.3.2 Energy producing WWTPs and sludge imports . 9
5.3.3 Chemical energy consumption . 9
5.3.4 Total energy consumption estimation . 10
5.4 Identification of the WWTP boundaries and calculation of Key Performance
Indicators (KPIs) . 11
5.5 Calculation of the Water Treatment Energy INDEX (WTEI) as a single indicator. 15
6 Methodology for Decision Support (DS) . 18
6.1 General . 18
6.2 Identification of the WWTP typology . 18
6.3 WWTP boundaries . 19
6.4 Request required approvals and keep communication (operators, site managers,
process engineers, budget holders and other possible end users) and health safety
considerations . 22
6.5 Create database describing all equipment on site . 22
6.6 Select equipment for online monitoring and install online monitors according to
manual . 24
6.7 Energy consumption data collection . 24
6.7.1 Energy consumption data . 24
6.7.2 Chemical energy consumption . 26
6.7.3 Energy producing WWTPs and sludge imports . 27
6.7.4 Gross and net energy consumption at stage estimation . 28
6.8 Key Performance Indicators (KPIs) . 28
6.9 Monitor site for KPIs (how often to monitor, methods used for monitoring). 40
6.10 Water Treatment Energy Index (WTEI) as a composite indicator . 40
Annex A (informative) Rapid Audit methodology applied to a case study . 44
Annex B (informative) Decision Support methodology applied to a case study . 48
Annex C (informative) Overview of training of auditors . 58
Bibliography . 62

European foreword
This document (CEN/TR 17614:2021) has been prepared by Technical Committee CEN/TC 165 “Waste
water engineering”, the secretariat of which is held by DIN.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.

Introduction
Wastewater Treatment Plants (WWTPs) are one of the most expensive public industries in terms of
energy requirements, accounting for more than 1 % of consumption of electricity in Europe. Thus, there
is a need to stop the current unsustainable energy consumption of the sector in line with the objectives
of Europe 2020 and the EU Sustainable Development Strategy (SDS).
The energy consumption must be related with the performance of a WWTP and parameters such as
effluent flow, nutrient removal, biochemical oxygen demand (BOD), chemical oxygen demand (COD),
suspended solids, orthophosphate (PO ), ammonia (NH ) and nitrate (NO ) need to be estimated or
4 4 3
determined at various stages of the WWTP for an effective estimation and assessment of energy
efficiency in WWTP.
This document presents a methodology to guide water experts and auditors on how to evaluate the
energy performance of a WWTP reaching a final energy diagnosis and the calculation of a Water
Treatment Energy Index (WTEI).
The methodology intends to be a very simple and easy to follow document that can be effortlessly
understood and put in practice by operators, site managers, process engineers as well as energy
auditors. It includes: planning the estimation of energy consumption at a WWTP; requesting approvals
and keeping communication (operators, site managers, process engineers, budget holders and other
possible end users) and health safety considerations; compilation of a database describing all
equipment on site; selection of equipment for online monitoring and install online monitors according
to manual; monitoring site for KPIs; training of people on the online tool and audits; audit, data
collection and validation; calculation of the WTEI and classification of WWTPs. Furthermore the
application of the methodology was completed to 3 case studies as practical examples.
The methodology included in this document considers two approaches for the determination of energy
consumption in WWTPs, namely Rapid Audit and Decision Support.
Rapid Audit is aimed at a rapid estimation of the WTEI of a particular WWTP using existing information.
This method uses existing information including historical data on energy consumption as well as the
wastewater influent and effluent. A trained auditor can calculate the WTEI and the obtained values can
be compared against a large database.
Decision Support is aimed at establishing the WTEI of a particular WWTP and providing information
that can be used as decision support of an energy efficiency diagnosis. It requires online energy data
obtained over extended periods of time as well as intensive wastewater sampling campaigns to
establish KPIs for each individual treatment stage. The combined information from the online meters
and wastewater sampling can then be used to calculate the WTEI using carefully selected statistical
tools and energy performance indicators. The methodology described includes guidelines on how to
select equipment/processes to place energy monitors, how to monitor the WWTP and how data should
be processed and reported. The Decision Support methodology can be used to provide an WWTP energy
benchmark but also understand impact of seasonal variations, storm events, changes in maintenance
routines, implementation of new equipment (e.g.: screens, pumps, blowers, etc.) as well as retrofitting
of existing processes as well as implementation of new processes. This methodology can also be used as
a tool to identify energy efficiencies and inefficiencies so further actions can be planed and the impact
can be measured and verified online. The Decision Support methodology can also be used as training
tool as well as help water utilities to clearly communicate to operators, engineers and the general public
how changes in operation and behaviour that can lead to energy efficiency and reduce energy
consumption.
This document is based on the outcomes of the ENERWATER project, a coordination and support action
funded by European Commission under Programme H2020 (www.enerwater.eu).
1 Scope
This document defines a methodology for determining and assessing the energy efficiency of Waste
Water Treatment Plants (WWTP). The methodology aims at describing, in a systematic way, the various
steps required to establish the Water Treatment Energy Index (WTEI) of a particular WWTP.
The methodology includes the classification of WWTPs in different types, identification of different
stages of treatment, identification of key performance indicators (KPIs), overview of existing energy
monitoring standards and the detailed description of the methodology, including a step by step
guideline of how to apply and implement it.
The methodology is divided in 2 sub-methods that should be selected and followed according to the
following goals:
— The Rapid Audit (RA) method allows for a quick estimation of the water treatment energy index
(WTEI) based on existing information such as historical data pertaining to energy use records along
with influent and effluent quality values. The aim of this methodology is to provide a WWTP energy
benchmark, a rapid tool to identify energy efficiencies and inefficiencies so further actions can be
planned, as well as to evaluate the impact of WWTP retrofitting.
The Rapid Audit methodology is detailed step by step in Clause 4 of this TR and can be used as a
standalone document. The application of the Rapid Audit methodology to one real WWTP is shown
in Annex A.
— The Decision Support (DS) method requires intensive monitoring across a WWTP of energy usage
and water quality parameters that provides an accurate and detailed calculation of WTEI for each
stage as well as its overall value for the plant. The goal of this assessment is to serve as a diagnosis
of the functions/equipment in a plant that may lead to poor energy efficiency performance.
The Decision Support methodology is detailed step by step in Clause 5 of this TR and can be used as
a standalone document. The application of the Decision Support methodology to one real WWTP is
shown in Annex B.
2 Normative References
There are no normative references in this document.
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following addres
...