SIST EN ISO 9887:1998

SLOVENSKI STANDARD
SIST EN ISO 9887:1998
01-januar-1998
Kakovost vode - Vrednotenje aerobne biološke razgradljivosti organskih snovi v
vodnem okolju - Semi kontinuirna metoda aktivnega blata (SCAS) (ISO 9887:1992)
Water quality - Evaluation of the aerobic biodegradability of organic compounds in an
aqueous medium - Semi-continuous activated sludge method (SCAS) (ISO 9887:1992)
Wasserbeschaffenheit - Bestimmung der aeroben biologischen Abbaubarkeit
organischer Stoffe im wäsrigen Medium - Halbkontinuierlicher Belebtschlammtest
(SCAS) (ISO 9887:1992)
Qualité de l'eau - Evaluation, en milieu aqueux, de la biodégradabilité aérobie des
composés organiques - Méthode semi-continue par boues activées (Méthode SCAS)
(ISO 9887:1992)
Ta slovenski standard je istoveten z: EN ISO 9887:1994
ICS:
13.060.70 Preiskava bioloških lastnosti Examination of biological
vode properties of water
SIST EN ISO 9887:1998 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 9887:1998

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SIST EN ISO 9887:1998

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SIST EN ISO 9887:1998

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SIST EN ISO 9887:1998

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SIST EN ISO 9887:1998

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SIST EN ISO 9887:1998
INTERNATIONAL
STANDARD 9887
First edition
1992-l O-01
Water quality - Evaluation of the aerobic
biodegradability of organic compounds in an
- Semi-continuous activated
aqueous medium
sludge method (SCAS)
Qua/it@ de I’eau - haluafion, en milieu aqueux, de la biod&gradabilit6
- Methode semi-continue par boues
akrobie des compos& organiques
actkkes (Methode SCAS)
Reference number
IS0 9887: 1992(E)

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SIST EN ISO 9887:1998
IS0 9887:1992(E)
Foreword
IS0 (the International Organization for Standardization) is a worldwide
federation of national standards bodies (IS0 member bodies). The work
of preparing International Standards is normally carried out through IS0
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, govern-
mental and non-governmental, in liaison with ISO, also take part in the
work. IS0 collaborates closely with the International Electrotechnical
Commission (IEC) on all matters of electrotechnical standardization.
Drat? International Standards adopted by the technical committees are
circulated to the member bodies for voting. Publication as an lnter-
national Standard requires approval by at least 75 % of the member
bodies casting a vote.
International Standard IS0 9887 was prepared by Technical Committee
ISO/TC 147, Water qualify, Sub-Committee SC 5, Biological methods.
Annexes A and B of this International Standard are for information only.
0 IS0 1992
All rights reserved. No part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without
permission in writing from the publisher.
International Organization for Standardization
Case Postale 56 l CH-1211 Geneve 20 l Switzerland
Printed in Switzerland
ii

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SIST EN ISO 9887:1998
INTERNATIONAL STANDARD IS0 9887:1992(E)
Evaluation of the aerobic biodegradability of
Water quality -
organic compounds in an aqueous medium -
Semi-continuous activated sludge method (SCAS)
WARNING - SAFETY PRECAUTIONS - Activated sludge and sewage may contain potentially
pathogenic organisms. Therefore appropriate precautions should be taken when handling them. Toxic
test compounds and those whose properties are unknown should be handled with care.
1 Scope 2 Normative references
This International Standard specifies a method for
the evaluation of the biodegradability (“ultimate” or
The following standards contain provisions which,
“primary”) of organic compounds. The conditions
through reference in this text, constitute provisions
described in this International Standard are much
of this International Standard. At the time of publi-
more favorable for biodegradation than those spec-
cation, the editions indicated were valid. All stan-
ified in the methods for biodegradability described
dards are subject to revision, and parties to
in IS0 7827, IS0 9408 and IS0 9439.
agreements based on this International Standard
are encouraged to investigate the possibility of ap-
The method applies to organic compounds which
plying the most recent editions of the standards in-
are
dicated below. Members of IEC and IS0 maintain
registers of currently valid International Standards.
a) soluble at the concentration used under the test
conditions;
IS0 78273984, Water quality - Evaluation in an
aqueous medium of the “ultimate” aerobic
b) non-volatile, or which have a negligible vapour
biodegradability of organic compounds - Method by
pressure under the test conditions;
analysis of dissolved organic carbon (DOC).
c) not lost by foaming from the test solution;
IS0 8192:1986, Water quality - Test for inhibition of
oxygen consumption by activated sludge.
d) not significantly adsorbable on glass and acti-
vated sludge;
IS0 8245:1987, Water quality - Guidelines for the
determination of total organic carbon (TOC).
e) not inhibitory to the test micro-organisms at the
concentration chosen for the test, Inhibitory ef-
IS0 9408:1991, Water quality -- Evaluation in an
fects can be determined by using a suitable test
aqueous medium of the “ultimate”
aerobic
method (e.g. see IS0 8192). If the test compound
biodegradability of organic compounds - Method by
is toxic, the test concentration has to be lower
determining
the oxygen demand in a closed
or a pre-exposed inoculum can be used.
respirometer.
the semi-
NOTE 1 Additionally, or alternatively,
IS0 9439:1990, Water quality - Evaluation in an
continuous activated sludge (SCAS) units may be used to
aqueous medium
of the “ultimate” aerobic
provide sludge exposed to the test compound, in order to
biodegradability of organic compounds - Method by
see whether the sludge becomes adapted, to be used as
analysis of released carbon dioxide.
inocula in other biodegradation tests.
1

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SIST EN ISO 9887:1998
IS0 9887:1992(E)
metabolized). These features, combined with daily
3 Definitions
re-inoculation when domestic sewage is used as the
medium, provide highly favourable conditions for
Fo r the urposes of this International Standard, the
P
both adaptation and extensive biodegradation.
fol lowin definitio ns apply.
9
3.1 ultimate biodegradation: The level of degra-
dation achieved when the test compound is totally
5 Test environment
utilized by micro-organisms resulting in the pro-
duction of carbon dioxide, water, mineral salts and
Incubation shall take place in the dark or in diffused
new microbial cellular constituents (biomass).
light, in an enclosure which is maintained between
20 “C and 25 ‘C and which is free from vapours
which are toxic to micro-organisms.
3.2 primary biodegradation: The level of degra-
dation achieved when the test compound undergoes
structural other than complete
change,
any
mineralization, as the result of microbial action. 6 Reagents
6.1 Tap water, containing less than 2 mg/l of DOC.
3.3 suspended solids (of an activated sludge): The
amount of solids obtained by filtration or
6.2 Distilled or de-ionized water, containing less
centrifuging of a known volume of sludge under
than 2 mg/l of DOC.
specified conditions and drying to 105 OC at constant
mass.
6.3 Sewage
6.3.4 Synthetic sewage
Dissolve in 1 Iitre of tap water (6.1).
4 Principle
Peptone 160 mg
The concentration of dissolved organic carbon
(DOC) in the effluent from a semi-continuous acti-
Meat extract
vated sludge unit, which is being dosed at daily in-
(or 270 mg of commercial peptone-meat
tervals on a fill-and-draw basis with sewage and a
extract preparation) 110 mg
known concentration of test compound, is compared
Urea 30 mg
with the concentration of DOC in the effluent from a
control unit dosed with sewage alone. Any differ-
Sodium chloride (NaCI) 7 mg
ence between the concentration of DOC in the
effluents is assumed to be due to the residual test Calcium chloride dihydrate (CaC1,.2H,O) 4 mg
substance, and the percentage degra-
Magnesium sulfate heptahydrate
dation/elimination is calculated from this difference
(MgSO,.-/H,O)
2 mg
and the concentration of test substance (as DOC)
added to the sewage.
Dipotassium hydrogen phosphate
28 mg
(K*HPO,) -
analysis may give additional information on
Specific
biodegradation. For convenience, a 100 times more concentrated
primary
solution may be prepared in distilled water (6.2),
which can be stored at 4 OC for up to 1 week, and the
The length of the test is indeterminate, but experi-
synthetic sewage made daily from this by appropri-
ence suggests that this is from 12 weeks to
ate dilution with tap water (6.1). After dilution, this
26 weeks.
synthetic sewage contains approximately: 105 mg/l
of C, 46 mg/l of N, 5 mg/l of P and the pH is between
A high concentration of aerobic micro-organisms is
7,0 and 7,5.
used (initially 1 g/l to 4 g/l of suspended solids) and
the effective detention period of sewage is 36 h.
Since no sludge is deliberately wasted, the retention
6.3.2 Domestic sewage
time of the sludge is high. The carbonaceous mate-
Collect settled sewage, if possible, freshly each day
rial in the sewage feed is norrnally almost com-
from the outlet of the primary settlement tank of a
pletely oxidized within 8 h after the start of each
treatment plant dealing with predominantly domes-
aeration cycle. Thereafter, the sludge respires
tic sewage. For weekends, sewage may be stored
endogenously for the remainder of the aeration pe-
riod, during which time the only available substrate at 4 T. Sewage for the daily feeding of the test units
can be taken from this stored material.
is the test compound (unless this is also readily

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SIST EN ISO 9887:1998
IS0 9887:1992(E)
300 ml. However, if more exposed sludge is required as
7 Apparatus
inocula to follow the course of adaptation by separate
die-away tests, larger SCAS units (e.g. 1,5 litres) may be
Ordinary laboratory equipment and
required.
7.1 Semi-continuous activated sludge (SCAS) units
7.2 Wash bottles or similar vessels, containing wa-
ter for saturating air with water.
The aeration units can simply be, for example,
measuring cylinders fitted with an aeration tube and
glass sinter for supplying compressed air, which
7.3 Measuring equipment, of sufficient sensitivity
shall be free from organic carbon and toxic vapours
for the measurement of dissolved organic carbon
and shall be presaturated with water vapour to re-
(see IS0 8245).
duce losses by evaporation. Alternatively, the aer-
ation vessel can be, for example, a tube (see
7.4 Device for filtration, with membrane filters of
figure 1) suitably supported and fitted with an air in-
suitable porosity (nominal aperture diameter of
let tube and a tap so that one-third of the total vol-
0,2 pm to 0,45 pm) ‘which neither adsorb organic
ume of mixed liquor remains in the vessel after
compounds nor release organic carbon significantly.
draining off settled supernatant. One such apparatus
is required for each test substance and one for each
control.
7.5 Centrifuge.
NOTE 2 A suitable volume of mixed liquor has been
found to
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