1、BRITISH STANDARD BS EN ISO 9887:1995 BS 6068-5.14: 1995 Water quality Evaluation of the aerobic biodegradability of organic compounds in an aqueous medium Semi-continuous activated sludge method (SCAS) The European Standard EN ISO 9887:1994 has the status of a British StandardBSENISO9887:1995 This B
2、ritish Standard, having been prepared under the directionof the Environment andPollution Standards PolicyCommittee, was publishedunder the authorityofthe Standards Boardand comes into effect on 15 February 1995 BSI 10-1999 The following BSI references relate to the work on this standard: Committee r
3、eference EPC/44 Special announcement in BSINews March 1992 ISBN 0 580 23170 4 Cooperating organizations The European Committee for Standardization (CEN), under whose supervision this European Standard was prepared, comprises the national standards organizations of the following countries: Austria Oe
4、sterreichisches Normungsinstitut Belgium Institut belge de normalisation Denmark Dansk Standard Finland Suomen Standardisoimisliito, r.y. France Association franaise de normalisation Germany Deutsches Institut fr Normung e.V. Greece Hellenic Organization for Standardization Iceland Technological Ins
5、titute of Iceland Ireland National Standards Authority of Ireland Italy Ente Nazionale Italiano di Unificazione Luxembourg Inspection du Travail et des Mines Netherlands Nederlands Normalisatie-instituut Norway Norges Standardiseringsforbund Portugal Instituto Portugus da Qualidade Spain Asociacin E
6、spaola de Normalizacin y Certificacin Sweden Standardiseringskommissionen i Sverige Switzerland Association suisse de normalisation United Kingdom British Standards Institution Amendments issued since publication Amd. No. Date CommentsBSENISO9887:1995 BSI 10-1999 i Contents Page Cooperating organiza
7、tions Inside front cover National foreword ii Foreword 2 1 Scope 3 2 Normative references 3 3 Definitions 3 4 Principle 3 5 Test environment 4 6 Reagents 4 7 Apparatus 4 8 Procedure 5 9 Calculation and expression of results 7 10 Test report 7 Annex A (informative) Examples of results of SCAS test on
8、 various compounds 9 Annex B (informative) Typical control values 9 Annex ZA (normative) 9 Figure 1 Example of test apparatus 5 Figure 2 Graph of removal of compounds (DOC) in SCAS test 8 National annex NA (informative) Committees responsible 10 National annex NB (informative) Cross-references Insid
9、e back coverBSENISO9887:1995 ii BSI 10-1999 National foreword This British Standard has been prepared under the direction of the Environment and Pollution Standards Policy Committee and is the English language version of ENISO9887:1994 Water quality Evaluation of the aerobic biodegradability of orga
10、nic compounds in an aqueous medium Semi-continous activated sludge method (SCAS), published by the European Committee for Standardization (CEN), which endorses ISO9887:1992, published by the International Organization for Standardization (ISO). A British Standard does not purport to include all the
11、necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, t
12、heEN ISO title page, pages 2 to 10, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 98
13、87 October 1994 ICS 13.060.40 Descriptors: Water, quality, organic compounds, tests, determination, biodegradability, aerobic bacteria English version Water quality Evaluation of the aerobic biodegradabilityof organic compounds in an aqeous medium Semi-continuous activated sludge method (SCAS) (ISO
14、9887:1992) Qualit de leau Evaluation, en milieu aqueux, de la biodgradabilit arobie des composs organiques Mthode semi-continue par boues actives (MthodeSCAS) (ISO 9887:1992) Wasserbeschaffenhiet Bestimmung der aeroben biologischen Abbaubarkeit organischer Stoffe im warigen Medium Halbkontinuierlich
15、er Belebtschlammtest (SCAS) (ISO 9887:1992) This European Standard was approved by CEN on1994-10-14. 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
16、-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 und
17、er 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, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherl
18、ands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CEN European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels 1994 Copyright reserved to CEN members Ref. No. EN ISO 9887:1994 EE
19、NISO9887:1994 BSI 10-1999 2 Foreword This European Standard has been taken over by Technical Committee CEN/TC230, Water analysis, from the work of ISO TC147, Water quality, of the International Organization for Standardization (ISO). This European Standard shall be given the status of a national sta
20、ndard, either by publication of an identical text or by endorsement, at the latest by April1995, and conflicting national standards shall be withdrawn at the latest by April1995. According to the CEN/CENELEC Internal Regulations, the following countries are bound to implement this European Standard:
21、 Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland, United Kingdom. NOTENormative references to international publications are listed in Annex ZA (normative).ENISO9887:1994 BSI 10-1999 3 WARNING
22、 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 This International Standard specifies a
23、 method for the evaluation of the biodegradability (“ultimate” or “primary”) of organic compounds. The conditions described in this International Standard are much more favorable for biodegradation than those specified in the methods for biodegradability described in ISO7827, ISO9408 and ISO9439. Th
24、e method applies to organic compounds which are a) soluble at the concentration used under the test conditions; b) non-volatile, or which have a negligible vapour pressure under the test conditions; c) not lost by foaming from the test solution; d) not significantly adsorbable on glass and activated
25、 sludge; e) not inhibitory to the test micro-organisms at the concentration chosen for the test. Inhibitory effects can be determined by using a suitable test method (e.g.seeISO8192). If the test compound is toxic, the test concentration has to be lower or a pre-exposed inoculum can be used. NOTE 1A
26、dditionally, or alternatively, the semicontinuous activated sludge (SCAS) units may be used to provide sludge exposed to the test compound, in order to see whether the sludge becomes adapted, to be used as inocula in other biodegradation tests. 2 Normative references The following standards contain
27、provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate t
28、he possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 7827:1984, Water quality Evaluation in an aqueous medium of the “ultimate” aerobic biodegradability of organic compounds Met
29、hod by analysis of dissolved organic carbon (DOC). ISO 8192:1986, Water quality Test for inhibition of oxygen consumption by activated sludge. ISO 8245:1987, Water quality Guidelines for the determination of total organic carbon (TOC). ISO 9408:1991, Water quality Evaluation in an aqueous medium of
30、the “ultimate” aerobic biodegradability of organic compounds Method by determining the oxygen demand in a closed respirometer. ISO 9439:1990, Water quality Evaluation in an aqueous medium of the “ultimate” aerobic biodegradability of organic compounds Method by analysis of released carbon dioxide. 3
31、 Definitions For the purposes of this International Standard, the following definitions apply. 3.1 ultimate biodegradation the level of degradation achieved when the test compound is totally utilized by micro-organisms resulting in the production of carbon dioxide, water, mineral salts and new micro
32、bial cellular constituents (biomass) 3.2 primary biodegradation the level of degradation achieved when the test compound undergoes any structural change, other than complete mineralization, as the result of microbial action 3.3 suspended solids (of an activated sludge) the amount of solids obtained
33、by filtration or centrifuging of a known volume of sludge under specified conditions and drying to105 C at constant mass 4 Principle The concentration of dissolved organic carbon (DOC) in the effluent from a semi-continuous activated sludge unit, which is being dosed at daily intervals on a fill-and
34、-draw basis with sewage and a known concentration of test compound, is compared with the concentration of DOC in the effluent from a control unit dosed with sewage alone. Any difference between the concentration of DOC in the effluents is assumed to be due to the residual test substance, and the per
35、centage degradation/elimination is calculated from this difference and the concentration of test substance (as DOC) added to the sewage. Specific analysis may give additional information on primary biodegradation. The length of the test is indeterminate, but experience suggests that this is from12we
36、eks to26weeks.ENISO9887:1994 4 BSI 10-1999 A high concentration of aerobic micro-organisms is used (initially1g/l to4g/l of suspended solids) and the effective detention period of sewage is36h. Since no sludge is deliberately wasted, the retention time of the sludge is high. The carbonaceous materia
37、l in the sewage feed is normally almost completely oxidized within8h after the start of each aeration cycle. Thereafter, the sludge respires endogenously for the remainder of the aeration period, during which time the only available substrate is the test compound (unless this is also readily metabol
38、ized). These features, combined with daily re-inoculation when domestic sewage is used as the medium, provide highly favourable conditions for both adaptation and extensive biodegradation. 5 Test environment Incubation shall take place in the dark or in diffused light, in an enclosure which is maint
39、ained between20 C and25 C and which is free from vapours which are toxic to micro-organisms. 6 Reagents 6.1 Tap water, containing less than2mg/l of DOC. 6.2 Distilled or de-ionized water, containing less than2mg/l of DOC. 6.3 Sewage 6.3.1 Synthetic sewage Dissolve in1litre of tap water (6.1). For co
40、nvenience, a100times more concentrated solution may be prepared in distilled water (6.2), which can be stored at4 C for up to1week, and the synthetic sewage made daily from this by appropriate dilution with tap water (6.1). After dilution, this synthetic sewage contains approximately:105mg/l of C, 4
41、6mg/l of N, 5mg/l of P and the pH is between7,0 and7,5. 6.3.2 Domestic sewage Collect settled sewage, if possible, freshly each day from the outlet of the primary settlement tank of a treatment plant dealing with predominantly domestic sewage. For weekends, sewage may be stored at4 C. Sewage for the
42、 daily feeding of the test units can be taken from this stored material. 7 Apparatus Ordinary laboratory equipment and 7.1 Semi-continuous activated sludge (SCAS) units The aeration units can simply be, for example, measuring cylinders fitted with an aeration tube and glass sinter for supplying comp
43、ressed air, which shall be free from organic carbon and toxic vapours and shall be presaturated with water vapour to reduce losses by evaporation. Alternatively, the aeration vessel can be, for example, a tube (seeFigure 1) suitably supported and fitted with an air inlet tube and a tap so that one-t
44、hird of the total volume of mixed liquor remains in the vessel after draining off settled supernatant. One such apparatus is required for each test substance and one for each control. NOTE 2A suitable volume of mixed liquor has been found to be150ml contained in a unit of250ml to300ml. However, if m
45、ore exposed sludge is required as inocula to follow the course of adaptation by separate die-away tests, larger SCAS units (e.g.1,5litres) may be required. 7.2 Wash bottles or similar vessels, containing water for saturating air with water. 7.3 Measuring equipment, of sufficient sensitivity for the
46、measurement of dissolved organic carbon (see ISO8245). 7.4 Device for filtration, with membrane filters of suitable porosity (nominal aperture diameter of0,24m to0,454m) which neither adsorb organic compounds nor release organic carbon significantly. 7.5 Centrifuge 7.6 pH-meter Peptone 160 mg Meat e
47、xtract (or 270 mg of commercial peptone-meat extract preparation) 110 mg Urea 30 mg Sodium chloride (NaCl) 7 mg Calcium chloride dihydrate (CaCl 2 .2H 2 O) 4 mg Magnesium sulfate heptahydrate (MgSO 4 .7H 2 O) 2 mg Dipotassium hydrogen phosphate (K 2 HPO 4 ) 28 mgENISO9887:1994 BSI 10-1999 5 8 Proced
48、ure 8.1 Preparation of the test solutions Prepare a solution of the test compound (and reference compound if required, see note3) in the water (6.2) containing not less than400mg/l of DOC. Under the conditions of the test (see8.3.2), this test solution will give an initial concentration of20mg/l of
49、DOC in the SCAS units. If the test compound is not toxic, higher concentrations (e.g.50mg/l of DOC) may be used. Ensure that the pH of the mixture of test solution and sewage is not significantly different from that of the sewage alone. If necessary, adjust the pH with an inorganic acid or alkaline solution. NOTE 3No reference compounds are recommended, but in investigating a new substance it may be useful to test simultaneously one of the compounds (listed in Annex A) which have already been evaluated. 8.2
