EN 12255-11:2023

SLOVENSKI STANDARD
01-maj-2023
Nadomešča:
SIST EN 12255-11:2001
Čistilne naprave za odpadno vodo - 11. del: Zahtevani splošni podatki
Wastewater treatment plants - Part 11: General data required
Kläranlagen - Teil 11: Erforderliche allgemeine Angaben
Stations d’épuration - Partie 11 : Informations générales exigées
Ta slovenski standard je istoveten z: EN 12255-11:2023
ICS:
13.060.30 Odpadna voda Sewage water
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN 12255-11
EUROPEAN STANDARD
NORME EUROPÉENNE
February 2023
EUROPÄISCHE NORM
ICS 13.060.30 Supersedes EN 12255-11:2001
English Version
Wastewater treatment plants - Part 11: General data
required
Stations d'épuration - Partie 11 : Informations Kläranlagen - Teil 11: Erforderliche allgemeine
générales exigées Angaben
This European Standard was approved by CEN on 2 January 2023.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

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, Türkiye 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
© 2023 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 12255-11:2023 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
Introduction . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Symbols and abbreviations . 7
5 Requirements . 7
5.1 Contract strategy . 7
5.2 Provision of loading data. 8
5.2.1 General . 8
5.2.2 Sewerage system . 8
5.2.3 Population served . 8
5.2.4 Significant trades and industries . 8
5.2.5 Data from existing wastewater treatment plants . 9
5.2.6 Design flows and loads . 10
5.3 Effluent quality, requirements for the disposal of residues and sludge . 10
5.3.1 Effluent quality . 10
5.3.2 Requirements for storm water overflow discharge . 10
5.3.3 Requirements for the residues from preliminary treatment . 11
5.3.4 Requirements for sludge disposal . 11
5.4 Site description . 11
5.4.1 General . 11
5.4.2 Plans (maps) of the site . 11
5.4.3 Existing wastewater treatment plants . 11
5.4.4 Ground geology, groundwater and climate . 12
5.4.5 Special site constraints . 12
5.5 Additional data required . 12
5.6 Time schedule . 13
5.7 Start-up and guarantee testing . 13
5.7.1 Start-up . 13
5.7.2 Guarantee testing . 14
5.8 Operational cost information . 14
5.9 Documents to be provided by a turn-key contractor or the consulting engineer . 14
5.9.1 Complete documents . 14
5.9.2 Design options . 14
5.9.3 Proposed solution . 14
5.10 Calculation and presentation of costs . 15
5.10.1 Construction costs . 15
5.10.2 Operational costs . 15
5.10.3 Presentation of costs . 17
Bibliography . 18

European foreword
This document (EN 12255-11:2023) has been prepared by Technical Committee CEN/TC 165 “Waste
water engineering”, the secretariat of which is held by DIN.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by August 2023, and conflicting national standards shall
be withdrawn at the latest by August 2023.
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.
This document supersedes EN 12255-11:2001.
This is the eleventh part of the EN 12255 series prepared by Working Group CEN/TC 165/WG 40,
relating to the general requirements and processes for treatment plants for a total number of
inhabitants and population equivalents (PT) over 50.
The EN 12255 series with the generic title “Wastewater treatment plants” consists of the following
parts:
— Part 1: General construction principles
— Part 2: Storm management systems
— Part 3: Preliminary treatment
— Part 4: Primary settlement
— Part 5: Lagooning processes
— Part 6: Activated sludge process
— Part 7: Biological fixed-film reactors
— Part 8: Sludge treatment and storage
— Part 9: Odour control and ventilation
— Part 10: Safety principles
— Part 11: General data required
— Part 12: Control and automation
— Part 13: Chemical treatment - Treatment of wastewater by precipitation/flocculation
— Part 14: Disinfection
— Part 15: Measurement of the oxygen transfer in clean water in aeration tanks of activated sludge
plants
— Part 16: Physical (mechanical) filtration
NOTE Part 2 is under preparation.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organisations of the
following countries are bound to implement this European Standard: 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, Türkiye and the
United Kingdom.
Introduction
Differences in wastewater treatment throughout Europe have led to a variety of systems being
developed. This document gives fundamental information about the systems; this document has not
attempted to specify all available systems. A generic arrangement of wastewater treatment plants is
illustrated below in Figure 1.

Key
1 preliminary treatment
2 primary treatment
3 secondary treatment
4 tertiary treatment
5 additional treatment (e.g. disinfection or removal of micropollutants)
6 sludge treatment
7 lagoons (as an alternative)
A raw wastewater
B effluent for re-use (e.g. irrigation)
C discharged effluent
D screenings and grit
E primary sludge
F secondary sludge
G tertiary sludge
H stabilised sludge
I digester gas
J returned water from dewatering
Figure 1 — Schematic diagram of wastewater treatment plants
The primary application is for wastewater treatment plants designed for the treatment of domestic and
municipal wastewater.
NOTE For requirements on pumping installations at wastewater treatment plants, see EN 752, Drain and
sewer systems outside buildings — Sewer system management and the EN 16932 series, Drain and sewer systems
outside buildings — Pumping systems:
— Part 1: General requirements;
— Part 2: Positive pressure systems;
— Part 3: Vacuum systems.
1 Scope
This document specifies data which is necessary for the planning, design, bidding, performance
guarantees, construction, start-up and compliance testing of a wastewater treatment plant or parts of it.
This document gives fundamental information about the practices; this document has not attempted to
specify all available practices.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— IEC Electropedia: available at https://www.electropedia.org/
— ISO Online browsing platform: available at https://www.iso.org/obp
3.1
relevant plant
new wastewater treatment plant; rebuild, upgrade or extension of an existing wastewater treatment
plant or a part of a new or extended wastewater treatment plant (e.g. sludge handling facilities)
3.2
client
municipality, city or other organization which intends to build a wastewater treatment plant or parts
thereof, or its representative
[SOURCE: EN 12255-1:2002, 3.6]
3.3
functional tender
tender document that contains the design flows and loads, a description of the site where the relevant
plant is to be erected, the relevant discharge limits and any additional requirements
3.4
sectional tender
separate tender documents prepared for different sections of work that may be constructed by different
entities
Note 1 to entry: Examples of sections of work can include: earth work, concrete work, mechanical equipment,
electrical installations, buildi
...