Separator systems for light liquids (e.g. oil and petrol) - Part 2: Selection of nominal size, installation, operation and maintenance

This standard specifies definitions, principles of sizing, installation, operation and maintenance of separator systems for light liquids in accordance with prEN 858-1:1997 as well as requirements and test methods for cleansing agents discharged with the waste water into the separator system. When pollution control requires the treatment of pollutants other than light liquids, additional measures shall be necessary.

Abscheideranlagen für Leichtflüssigkeiten (z.B. Öl und Benzin) - Teil 2: Wahl der Nenngröße, Einbau, Betrieb und Wartung

Diese Norm enthält Begriffe, Bemessungs-, Einbau-, Betriebs-, und Wartungsgrundsätze von Abscheideranlagen für Leichtflüssigkeiten nach prEN  858-1:1997 sowie Anforderungen und Prüfverfahren für Reinigungsmittel, die mit dem Abwasser in die Abscheideranlage eingeleitet werden. Wenn der Umweltschutz die Behandlung von weiteren Schmutzstoffen über die Leichtflüssigkeiten hinaus verlangt, sind zusätzliche Maßnahmen erforderlich.

Installations de séparation de liquides légers (p.e. hydrocarbures) - Partie 2: Choix des tailles nominales, installation, service et entretien

La présente Norme européenne s'applique aux installations de séparation utilisées pour séparer les hydrocarbures d'origine minérale des eaux résiduaires. Elle ne s'applique pas aux graisses et aux huiles d'origine végétale ou animale ni a la séparation d'émulsions ou de solutions.
La présente Norme européenne donne des indications générales sur le choix des tailles nominales, ainsi que sur l'installation, le service et l'entretien des séparateurs de liquides légers fabriqués conformément a l'EN 858-1. Elle donne aussi des recommandations quant aux agents nettoyants appropriés lorsque ceux-ci sont déversés dans un séparateur.

Izločevalniki lahkih tekočin (npr. olja, bencina) - 2. del: Izbira najmanjše velikosti, vgraditev, obratovanje in vzdrževanje

General Information

Status
Published
Publication Date
30-Sep-2003
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
01-Oct-2003
Due Date
01-Oct-2003
Completion Date
01-Oct-2003

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SLOVENSKI STANDARD
SIST EN 858-2:2003
01-oktober-2003

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Separator systems for light liquids (e.g. oil and petrol) - Part 2: Selection of nominal size,

installation, operation and maintenance

Abscheideranlagen für Leichtflüssigkeiten (z.B. Öl und Benzin) - Teil 2: Wahl der

Nenngröße, Einbau, Betrieb und Wartung

Installations de séparation de liquides légers (p.e. hydrocarbures) - Partie 2: Choix des

tailles nominales, installation, service et entretien
Ta slovenski standard je istoveten z: EN 858-2:2003
ICS:
13.060.99 Drugi standardi v zvezi s Other standards related to
kakovostjo vode water quality
SIST EN 858-2:2003 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
EUROPEAN STANDARD
EN 858-2
NORME EUROPÉENNE
EUROPÄISCHE NORM
January 2003
ICS 13.060.30
English version
Separator systems for light liquids (e.g. oil and petrol) - Part 2:
Selection of nominal size, installation, operation and
maintenance

Installations de séparation de liquides légers (par exemple Abscheideranlagen für Leichtflüssigkeiten (z.B. Öl und

hydrocarbures) - Partie 2: Choix des tailles nominales, Benzin) - Teil 2: Wahl der Nenngröße, Einbau, Betrieb und

installation, service et entretien Wartung
This European Standard was approved by CEN on 29 September 2001.

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 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 Management Centre has the same status as the official

versions.

CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,

Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and United

Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36 B-1050 Brussels

© 2003 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 858-2:2003 E

worldwide for CEN national Members.
---------------------- Page: 2 ----------------------
EN 858-2:2003 (E)
Contents
page

Foreword......................................................................................................................................................................3

1 Scope ..............................................................................................................................................................3

2 Normative references ....................................................................................................................................3

3 Terms and definitions....................................................................................................................................4

4 Determination of type and size of separator systems ...............................................................................4

4.1 General............................................................................................................................................................4

4.2 Components of separator systems, their combination and application..................................................4

4.2.1 General............................................................................................................................................................4

4.2.2 Bypass separators.........................................................................................................................................4

4.2.3 Classes of separators....................................................................................................................................5

4.3 Sizing of separators.......................................................................................................................................5

4.3.1 General............................................................................................................................................................5

4.3.2 Factors ............................................................................................................................................................5

4.3.3 Combined drainage of rainwater and wastewater......................................................................................6

4.3.4 Wastewater .....................................................................................................................................................6

4.3.5 Rainwater flow rate ........................................................................................................................................8

4.3.6 Spillages .........................................................................................................................................................8

4.3.7 Quantity of light liquid...................................................................................................................................8

4.3.8 Special cases..................................................................................................................................................9

4.4 Sludge traps ...................................................................................................................................................9

5 Installation ......................................................................................................................................................9

5.1 Limitations......................................................................................................................................................9

5.2 Retention of light liquid...............................................................................................................................10

5.3 Automatic warning devices and electrical devices..................................................................................10

5.4 Drainage to and from separator systems..................................................................................................10

5.5 Place of installation .....................................................................................................................................10

5.6 Protection against escape of light liquids.................................................................................................10

5.7 Connection to the drainage system...........................................................................................................12

6 Operation, inspection and maintenance ...................................................................................................12

Annex A (informative) Density factor f for particular light liquids and combination of components............14

Annex B (informative) Configuration and application of separator systems......................................................17

Bibliography ..............................................................................................................................................................20

---------------------- Page: 3 ----------------------
EN 858-2:2003 (E)
Foreword

This European Standard (EN 858-2:2003) has been prepared by Technical Committee CEN/TC 165 "Wastewater

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 July 2003, and conflicting national standards shall be withdrawn at the latest by

July 2003.

It is the second part of a two part standard for separator systems for light liquids. Part 1 gives principles of design,

performance and testing, marking and quality control of separator systems for light liquids.

When pollution control requires the treatment of pollutants other than light liquids, additional measures can be

necessary.
The annexes A and B are informative.

According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following

countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland,

France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal,

Slovakia, Spain, Sweden, Switzerland and the United Kingdom.
1 Scope

This European Standard applies to separator systems used to separate hydrocarbons of mineral origin from

wastewater. It does not apply to grease and oils of vegetable or animal origin nor to separation of emulsions or

solutions.

This European Standard provides guidance on the selection of nominal sizes, as well as the installation operation

and maintenance of light liquid separators manufactured in accordance with EN 858-1. It also gives advice on the

suitability of cleansing agents if they are discharged to a separator.
2 Normative references

This European Standard incorporates by dated or undated reference, provisions from other publications. These

normative references are cited at the appropriate places in the text, and the publications are listed hereafter. For

dated references, subsequent amendments to or revisions of any of these publications apply to this European

Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the

publication referred to applies (including amendments).

EN 752-2, Drain and sewer systems outside buildings — Part 2: Performance requirements.

EN 752-4, Drain and sewer systems outside buildings — Part 4: Hydraulic design and environmental consideration.

EN 858-1:2002, Separator systems for light liquids (e.g. oil and petrol) — Part 1: Principles of design, performance

and testing, marking and quality control.
---------------------- Page: 4 ----------------------
EN 858-2:2003 (E)
3 Terms and definitions

For the purposes of this European Standard, the terms and definitions given in EN 858-1 as well as the following

term and definition apply.
3.1
cleansing agent

chemical substance which, when combined with light liquids, initially forms an emulsion during cleaning process

that rapidly breaks down in the separator
4 Determination of type and size of separator systems
4.1 General

Separator systems are used in a wide variety of situations to fulfil a number of different requirements. It is important

to establish why a separator system is needed and what specific function it is expected to fulfil before selecting the

appropriate size and type of installation.

Generally, separator systems are installed for one or more of the following reasons:

a) to treat waste water (trade effluent) from industrial processes, vehicle washing, cleansing of oil covered parts

or other sources, e.g. petrol station forecourts;

b) to treat oil contaminated rainwater (run-off) from impervious areas, e.g. car parks, roads, factory yard areas;

c) to retain any spillage of light liquid and to protect the surrounding area.

Where there is no specific sizing method given by a regulatory authority the following guidance on sizing of the

separator system shall be used:
4.2 Components of separator systems, their combination and application
4.2.1 General

The component parts of separator systems complying with EN 858-1 are listed in Table 1.

Table 1 — Components of separator systems
Components Code letter
Sludge trap S
Separator Class II II, II b (for bypass separators)
Separator Class I I, I b (for bypass separators)
Sampling shaft P

Annex B gives guidance on the selection of components to suit particular applications.

4.2.2 Bypass separators

Bypass separators include a device to allow a flow in excess of the maximum permissible flow to bypass the

separator.
---------------------- Page: 5 ----------------------
EN 858-2:2003 (E)

Bypass separators are not suitable for category a) uses (see 4.1). They shall be used only in locations where it is

unlikely that there will be significant hydrocarbon contamination during times of heavy rainfall.

Separator systems shall not surcharge or cause surcharging upstream when subject to their maximum design flow.

4.2.3 Classes of separators
Classes of separators (class I and II) are defined in EN 858-1:2002, clause 4.

Class I separators provide a higher degree of separation than class II separators (see Table B.2 for applications).

4.3 Sizing of separators
4.3.1 General

The sizing of light liquid separators shall be based on the nature and flow rate of the liquids to be treated and will

need to take account of:
 maximum flow rate of rain water;
 maximum flow rate of waste water (trade effluent);
 density of the light liquid;
 presence of substances that may impede separation (e.g. detergents).

The sizing does not take into account special operational conditions (see 4.3.8).

The size of the separator shall be calculated from the following formula:
NS = (Q + f ⋅ Q ) f (1)
r x s d
where
NS is the nominal size of the separator;
is the maximum flow rate of rainwater, in l/s;
Q is the maximum flow rate of wastewater, in l/s;
f is the density factor for the relevant light liquid;
f is the impediment factor depending on the nature of the discharge.
4.3.2 Factors
4.3.2.1 Impediment factor f

The impediment factor f allows for unfavourable separating conditions, e.g. where detergents are present in the

wastewater. The minimum recommended impediment factors are listed in Table 2.
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EN 858-2:2003 (E)
Table 2 — Minimum impediment factors f
Discharge type in accordance with 4.1
a) 2
not relevant as Q = 0 (only rainwater)
c) 1
4.3.2.2 Density factor f

The density factor f allows for differing densities of light liquids when using different combinations of system

components. Additional information is given in annex A.
Table 3 — Density factors f
Density up to 0,85 over 0,85 up to 0,90 over 0,90 up to 0,95
g/cm³
Density factor f
Combination
S-II-P 1 2 3
a a a
S-I-P
1 1,5 2
b b b
S-II-I-P
1 1 1
For class I separators operating by gravity only, use f for class II separator.
For class I and class II separators.
4.3.2.3 Cleansing agents

Cleansing agent manufacturers shall submit a declaration stating that the product is free from organically combined

halogen compounds or BTX aromas. Only cleansing agents which form temporary stable emulsions with light

liquids and then de-emulsify after the cleaning process should be used. Instructions for use shall also be provided,

together with the effects of mixing with other cleansing agents, particularly regarding the separation process.

4.3.3 Combined drainage of rainwater and wastewater

If a separator is receiving rainwater and wastewater, e.g. from vehicle washing, and the two maximum flows are not

expected to occur simultaneously, then the separator can be sized for the higher flow rate.

4.3.4 Wastewater

The wastewater inflow in accordance with 4.1, case a), shall be calculated as the sum of the contributing flows from

the following formula:
Q = Q + Q + Q +... (2)
s s1 s2 s3
where
Q is the flow from draw-off points, in l/s;
Q is the flow from car washes, in l/s;
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EN 858-2:2003 (E)
Q is the flow from high pressure cleaning units, in l/s.
Any other contributing flow shall be added.
4.3.4.1 Draw-off points

Where it is not possible to determine the maximum flow from draw-off points by measurement, it may be estimated

by using Table 4. Table 4 takes account the probability of the likelihood of all draw-off points, irrespective of size,

being used at the same time. Calculations should be based on the flow rates from the largest draw-off points first.

Table 4 — Flow rates from draw-off points
Draw-off points
Nominal diameter
Flows from draw-off point Q in l/s
1st point 2nd point 3rd point 4th point 5th point and subsequent
DN 15 0,5 0,5 0,35 0,25 0,1
DN 20 1,0 1,0 0,70 0,50 0,2
DN 25 1,7 1,7 1,20 0,85 0,3

Values given for supply pressure of about 4 bar to 5 bar; other supply pressures may cause different

Q -values.
Example for calculation of Q for 1 DN 15, 1 DN 20 and 2 DN 25 points:
1st point DN 25 = 1,7 l/s;
2nd point DN 25 = 1,7 l/s;
3rd point DN 20 = 0,7 l/s;

4th point DN 15 = 0,25 l/s; Q = 4,35 l/s

In case of supply pressure differing from that stated in footnote 1 of Table 4, the flow from draw-off point shall be

calculated from the following formula:
s1(4bar)
Q = (3)
s1(xbar)
4bar
xbar
where
Q is the flow from draw-off point at a supply pressure of x bar, in l/s;
s1(x bar)
Q is the flow from draw-off point as given in Table 4, in l/s.
s1(4 bar)
4.3.4.2 Automatic car washes (roll-over, drive-through)

Wastewater from low pressure car washes (with a back pressure up to 20 bar) where only carriage bodies and

chassis are cleaned does not usually contain any significant amount of light liquid.

Should there be wastewater from high pressure car washes (with a back pressure higher than 20 bar) and/or any

additional washing procedures which will result in wastewater containing light liquids, then for every car wash place

or drive through a wastewater value Q of 2 l/s plus a wastewater value Q for each high pressure unit in

s2 s3

accordance with 4.3.4.3 shall be included. When the car wash place is multiple used, e. g. for maintenance, for

plants with higher quantities of waste water i. e. without mechanical cleaning devices, the actual quantity of waste

water has to be considered.
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EN 858-2:2003 (E)

A reduction of the wastewater flow rate Q for plants with water recirculation and overflow into a sewer is not

admissible.
4.3.4.3 High pressure units

Irrespective of the effective use of water from a high pressure unit, a wastewater value Q of 2 l/s shall be

considered. If there is more than one high pressure unit an additional 1 l/s shall be included

...

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