EN 12255-16:2005

SLOVENSKI STANDARD
01-december-2005
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Wastewater treatment plants - Part 16: Physical (mechanical) filtration
Kläranlagen - Teil 16: Abwasserfiltration
Stations d'épuration - Partie 16: Filtration physique (mécanique)
Ta slovenski standard je istoveten z: EN 12255-16:2005
ICS:
13.060.30 Odpadna voda Sewage water
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 12255-16
NORME EUROPÉENNE
EUROPÄISCHE NORM
September 2005
ICS 13.060.30
English Version
Wastewater treatment plants - Part 16: Physical (mechanical)
filtration
Stations d'épuration - Partie 16: Filtration physique Kläranlagen - Teil 16: Abwasserfiltration
(mécanique)
This European Standard was approved by CEN on 28 July 2005.
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 Central Secretariat 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 Central Secretariat has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,
Slovenia, Spain, Sweden, Switzerland and United Kingdom.
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EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2005 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 12255-16:2005: E
worldwide for CEN national Members.

Contents Page
Foreword .3
1 Scope .5
2 Normative references .5
3 Terms and definitions.5
4 Requirements .5
4.1 General .5
4.2 Process types.6
4.2.1 Granular media filters .6
4.2.2 Microstrainers and drum filters .6
5 Planning.6
6 Process design .7
6.1 Design parameters.7
6.2 Selection of filter media.7
6.2.1 General .7
6.2.2 Granular media filters .8
6.2.3 Microstrainers and drum filters .8
6.3 Cleaning systems.8
6.3.1 General .8
6.3.2 Granular media filters .9
6.3.3 Microstrainers and drum filters .9
6.4 Dimensions.9
6.4.1 General .9
6.4.2 Granular media filters .10
6.4.3 Microstrainers and drum filters .10
6.5 Flow distribution .10
6.5.1 General .10
6.5.2 Granular media filters .10

6.5.3 Microstrainers and drum filters .11
6.6 Construction principles.11
6.6.1 General .11
6.6.2 Granular media filters .11
6.6.3 Microstrainers and drum filters .11
6.7 Mechanical and electrical equipment.12
6.7.1 General .12
6.7.2 Granular media filters .12
6.7.3 Microstrainers and drum filters .12
6.8 Performance monitoring .12
6.9 Additional considerations .13

6.9.1 Maintenance .13
6.9.2 Protection of the equipment.13
6.10 Hazard protection.13
Bibliography.14

Foreword
This European Standard (EN 12255-16:2005) 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 March 2006, and conflicting national standards shall be withdrawn at
the latest by March 2006.
It is the sixteenth part prepared by the Working Groups CEN/TC 165/WG 42 and 43 relating to the general
requirements and processes for treatment plants for a total number of inhabitants and population equivalents
(PT) over 50. EN 12255 with the generic title "Wastewater treatment plants" consists of the following Parts:
 Part 1: General construction principles
 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 For requirements on pumping installations at wastewater treatment plants, provided initially as Part 2
"Pumping installations for wastewater treatment plants", see EN 752-6 "Drain and sewer systems outside buildings —
Part 6: Pumping installations.
The parts EN 12255-1, EN 12255-3 to EN 12255-8 and EN 12255-10 and EN 12255-11 were implemented
together as a European package (Resolution BT 152/1998).
Differences in wastewater treatment throughout Europe have led to a variety of systems being developed.
This European Standard gives fundamental information about the systems; this European Standard has not
attempted to specify all available systems.
Detailed information additional to that contained in this European Standard may be obtained by referring to the
bibliography.
The primary application is for wastewater treatment plants designed for the treatment of domestic and
municipal wastewater.
Physical filtration plant include gravity filters (static-bed or moving-bed types) and sieves (microstrainers and
drum filters).
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland
and United Kingdom.
1 Scope
This European Standard specifies design principles and performance requirements for tertiary clarification
(receiving effluent from secondary treatment) by physical filtration plant at wastewater treatment plants serving
more than 50 PT.
2 Normative references
The following referenced documents are indispensable for the application of this European Standard. For
dated references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
EN 1085:1997, Wastewater treatment — Vocabulary
EN 12255–1, Wastewater treatment plants — Part 1: General construction principles
EN 12255–10, Wastewater treatment plants — Part 10: Safety principles
3 Terms and definitions
For the purposes of this European Standard, the terms and definitions given in EN 1085:1997 and the
following apply.
3.1
granular media filter
bed of filter media which is submerged in either an upflow or downflow of effluent to remove solids within the
bed
3.2
drum filter or microstrainer
cylindrical sieve or cloth filter which rotates about a horizontal axis and is partially-immersed in a horizontal
flow of effluent to remove solids
4 Requirements
4.1 General
Physical filtration processes can include the following:
 granular media filters;
 sieves such as microstrainers and drum filters.
Filter processes are used to remove fine suspended solids from treated wastewater by mechanical filtration.
Where aeration is involved, it is normally limited to air scouring to remove solids accumulation trapped by
filtration. Physical filters may also be designed to remove phosphate.
4.2 Process types
4.2.1 Granular media filters
4.2.1.1 Static bed filter
An upflow or downflow of effluent percolates rapidly through a bed of filter media trapping solids within the bed.
For shallow bed and downflow filters, solids are predominantly captured at the surface. The rate of filtration is
high causing a rapid accumulation of solids in the bed and a high rate of increase in headloss. At regular
intervals a bed shall be taken out of service and washed using filtered effluent with or without air scour to
remove accumulated solids. Washing can be affected by either a pumped or siphonic upflow of filtered effluent
across the entire bed or by a travelling bridge washing individual compartments.
4.2.1.2 Moving-bed filter (continuous operation)
In this style of filter, an upflow or downflow of effluent passes continuously through a bed of mineral media to
remove solids. An air lift raises mineral media from the bottom of the bed for washing and returns cleaned
media to the top of the bed, enabling continuous filtration.
4.2.2 Microstrainers and drum filters
Microstrainers and drum filters are based on a sieve or cloth covered cyli
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