CELEX: 51980PC0040
Language: en
Date: 1980-02-08
Title: PROPOSAL FOR A COUNCIL DIRECTIVE ON THE APPROXIMATION OF THE LAWS OF THE MEMBER STATES RELATING TO METHODS OF TESTING THE BIODEGRADABILITY OF NON-IONIC SURFACTANTS AND AMENDING DIRECTIVE 73/404/EEC (presented by the Commission to the Council)

ARCHIVES HISTORIQUES
DE LA COMMISSION
COLLECTION RELIEE DES
DOCUMENTS "COM"
COM (80) 40
Vol. 1980/0016
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 ---pagebreak--- COMMISSION OF THE EUROPEAN COMMUNITIES
                                                           COM(80)40 final
                                                           Brussels / 8th February 1980
                     PROPOSAL       FOR A COUNCIL DIRECTIVE
         ON THE APPROXIMATION OF THE LAWS OF THE MEMBER STATES
          RELATING TO METHODS OF TESTING THE BIODEGRADABILITY
                  OF  NON-IONIC SURFACTANTS AND AMENDING
                                        DIRECTIVE 73 / 404 / EEC
               ( presented by the Commission to the Council )
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C0MC80 ) 40 final
 ---pagebreak---      1 . This proposal for a Council Directive comes under the General Frogra ;'.5Tie
         for the removal of technical barriers to trade , which the Council
         approved on 28 May 1969 , in line with which two Directives relating to
          die same sector have already been adopted . These are the Council
         Directive of 22 November 1973 relating to detergents and the Council
         Directive of the same date relating to methods of testing the
         biodegradability of anionic surfactants ( 1 ).
     2 . The measurement of the level of biodegradability by different methods
       . can cause distortion of the Community market and have a direct effect
         on its operation . A Community solution proposing a single method is
         therefore necessary .
     3 . The biodegradability of detergents is one aspect of the much more wide-
         ranging and very topical problem of environmental pollution in general
         and water pollution in particular .
         For these reasons industry , in agreement with public authorities , has
         progressively shifted its production to detergents containing
         biodegradable surfactants . Nevertheless ,' for certain applications in
         the food industry , the metallurgical industries and in dishwasher
         detergents , small amounts of certain non-ionic surfactants of low
         biodegradability must be used for technical reasons : machines used in
         these industries work at high speed and have to use low-foaming and/or
         highly alkali-resistant surfactants of high detergency . For the time
         being there is no surfactant which is 80% biodegradable and has these
         properties .
         The amounts used in this way are small and the total EEC consumption is
         estimated at some 5 500 - 8 500 tonnes per year , i.e. , less than 1 %
         of all the surfactants used .in cleaning products .
         It should also be pointed out that these surfactants , al though of low
         biodegradability , are not as far as it is known responsible for
         ecological problems in the 'Community and that , even if they were , such
         problems would be strictly local..
         Research is in progress in several Member States with a view to
         developing satisfactory substitute products which are sufficiently
         biodegradable to comply with the Directive .
( 1 ) OJ No L 347 , 17 December 1973 , pp . 51 and 53
     t
                                                                           •/.
 ---pagebreak---       4 . Technical progress necessitates a prompt adaptation of the technical
           standards' in the methods for testing the biodegradability of
           surfactants . Tnat is the reason why this Directive provides for the
           institution of a procedure of close collaboration between the Member
           States and the Commission within the framework of the Committee for the
          •adaptation to technical progress of the directives relating to the .
           removal of technical barriers to trade in detergents . This procedure
           is the one provided for by the Resolution of 28 Kay 1969 and subsequently
           adopted by the Council in different directives .
      5 . In accordance with the Opinions which the European Parliament and the
           Economic and Social Committee delivered on the basic "Detergents "
          Directive , the solution of " total " harmonization has been chosen .
 II . COMMENTS ON SPECIFIC ARTICLES
      Article 1
      This Article establishes the scope of the Directive .
      Article 2
      Article 2 stipulates that a detergent must not be placed on the market if
      it is determined that the level of biodegradability of the non-ionic
      surfactants it contains is less than 80 % , and provides that the methods
      used for this determination ■     -i 1 be those of the OECD, the Federal
      Republic of Germany , France and the United Kingdom .
      Article 3
      This Article lays down the procedure to be followed in the event of a
      dispute .
      Article 4
      This gives a temporary exemption for certain uses of non-ionic surfactants
      with a biodegradability of less than 80% .
      Article 5                                                                  '
      This Article provides for a procedure for the adaptation to technical
      progress of the directive concerning detergents .
      Articles -6 and 7
      These Articles are common to all directives .-                                  '
III . CONSULTATION OF THE SECTORS CONCERNED
      When preparing this Directive , the • Commission took note of the comments made
      by the representatives of the industries concerned .,
 IV * CONSULTATION ' OF THE EUROPEAN PARLIAMENT AND TME ECONOMIC AND SOCIAL
      COMMITTEE
      In accordance with the second paragraph of Article 100 , the opinion of these
      two institutions is necessary .        '                                 .
 ---pagebreak---                     on the approximation of the iaws-of the Member Stated-
                    relating to methods of testing the biodegradability
            of non-ionic surfactants and amending Directive 73 / 404 / EEC ' '
  THE COUNCIL OF THE EUROPEAN COMMUNITIES ,
  Having regard to the Treaty establishing the European Economic Community, and
  in. particular Article 100 thereof ;        .              -
  Having regard to. the proposal.. from the Commission ;
                                                 «
  Having regard to the opinion of the European Parliament ;
  Having regard to the 0/pinio.n of the Economic and Social Committee ; -
  Whereas the methods , of testing in force in the Member States , while pursuing
  the same objective , differ in certain respects and are thus detrimental to
  the functioning of the common market ;              ...
                                           1       .
  Whereas Council Directive 73/404/EEC       relating to
                            *
  detergents provides in .        Article 4 for the adoption of directives
  specifying * methods of testing in order to ascertain that the requirements
  of that Directive are being observed ; whereas Council Directive 73/4 05/EEC of
                     2
  22 November 1973 relating to methods of testing the biodegradability of
  anionic surfactants         specified such methods and tolerances for anionic
  surfactants ;                                                                '
  Whereas , to enable - Member States to determine the level of biodegradability
  of non-ionic surfactants , the methods of testing , already in use for this
  purpose in certain Member States may be used ; whereas , however , in the
  event of di sputes , biodegradabi lity should be tested- by a common
  reference method ;
 OJ No L 347 ,
        ^ •
                   17.12.1973 , p. 51
2OJ No L 347 ,"    17.12.1973 , u. 53
 ---pagebreak---  Whereas in regard to the a^pro^ir.at ion of the lav:s of      Memer States
 relating to detergents , suitable tolerances for meas'arinj biodegr adabil ity
 should be determined , as provided for in -Article 4 of Council Directive
  73/404/EEC                         in order to take account of the
  unreliability of test methods which could lead to rejection decisions with
onsirerable cccno -i c consequences ; whereas a rejection decision must betaken
    only if the results obtained by an analytical method mentioned in
 Article 2 show a level of biodegradabiiity lover than 80% ;
 T. vhereas for the time being small quantities of certain non-ionic surfactants
 of low biodegradabiiity must be used for some purposes because of technical
 problems and in order to prevent other undesirable effects on health and
 the environment ; Whereas it will nevertheless be necessary to review the use
 of these surfactants of low biodegradabiiity in the light of technical
 progress ;
 Whereas technical progress necessitates a rapid adaptation of the technical
 requirements specified by the Directives on detergents ; whereas , to
 facilitate the introduction of the necessary measures , a system should be
 set up providing for close collaboration between the Member States and the
 Commission by means of a Committee for the adaptation , in the light of
 technical progress , of the Directives on the removal of technical barriers
 to trade in detergents ,
 HAS ADOPTED THIS DIRECTIVE :
                                     Article 1
 This Directive concerns the methods of testing tine biodegradabil ity of
 non-ionic surfactants used in detergents .
 ---pagebreak---  . r, accordance with the provisions of Article 4 of             Directive
  '3 /404/EEC ,                      due account being taken of the unrei' l - iit ■
  >•: testing methods , the Member States shall prohibit the placing on the
 market and use on their territory of a detergent if the level of
b lodegr adabil ity of the non-ionic surfactants contained in such
detergent is less than 80% determined in accordance with one of the
 Coilowing methods :
- The OECD method , published in the OECD technical report of 11 June 1976 or»
    the " Proposed Method for the Determination of the Biodegradabi lity of
    Surfactants used in Synthetic Detergents ";
- The method in use in the Federal Republic of Germany , established by the
    " Verordnung uber die Abbaubarkeit anionischer und nichtanionischer grenz-
    f1 achenaktiver Stoffe in Wasch- und Reinigungsmitteln-" of 30 January 1977 ,
    published in the Bundesgesetzblatt , Part I , page 244 ;
- The method in use in France , approved by decree of 28 December 1977
    published in the "Journal Officiel de la Republique Frangaise " of 18 Januar
    1978 , and experimental standard T 73-270 March 1974 , published by the
    " Association frangaise de normalisation " ( AFNOR ) ;
- The method in use in the United Kingdom called the " Porous Pot Test " and
    described in        Technical Report 78 ( 1977 ) by the Water Research Centre .
                                     Article 3
Under the procedure laid down in Article 5 ( 2 ) of
 Directive 73 / 404 / EEC ,          the laboratory opinion on . non-ionic
surfactants shall be based on the " Confirmatory test procedure " described
in the Annex .
                                                                      .   •/.
 ---pagebreak---                                        - 6 ~
                                   Article 4
    Th ? following Articles shall be inserted in Directive 73 / 404 / EEC :
                                   Article 2a
1.    Until 31 December 1984 , Article 2 shall not be applicable to the
    following non-ionic   surfactants :
    a ) low foaming polyalkene oxide addition products used in industrial
        cleaning agents and mechanical dish-washing products ;
    b ) alkali-resistant terminally-blocked alkyl and alkyl-aryl polyglycol
        ethers used in industrial cleaning agents for the food , beverage and
        metal working industries .
2 . During that period of exemption , the exemption shall be re-examined and
    where appropriate adapted in the light of technical progress in accordance
    with the procedure laid down in Article 7 b .
3 . In the event of industrial use of the surfactants referred to inparagrah 1 ,
    the user shall employ the best techniques available in order to limit the
    emission of these surfactants into the aquatic environment .
                                   " Article 7a
1 . A Committee shall be established for the adaptation to technical progress
    of Directives for removing technical barriers to trade in the detergents
    sector , hereinafter called 'the Committee' , which shall consist of
    representatives of the Member States under the chairmanship of a
    representative of the Commission .
2 . The Committee shall establish its rules of procedure .
                                                                            •/.
 ---pagebreak---                     ι
                      • •
                                     "   Article 7b
1 . Where - recourse is had to the procedure defined in thi s iftrti c le , the
                                                                                   r
     matter shall be referred to the Committee by its chairman , on his .
     own initiative or at the request of the representative of a Member State . .
2 . The Commission representative shall submit to the Committee a draft
     of the measures to be taken .      The Committee . - shal I deliver its opinion
     on the draft within a period which may be fixed by the chairman
     according to the urgency of the matter..       A majority of twelve votes
     shall be required before it can deliver its opinion , the votes of the
     Member States being weighted as laid down in Article 148(2 ) of the ■
     Treaty .
     The chairman shall not vote .
3 .. ( a ) The Commission shall adopt the proposed measures where they are
           in accordance with the opinion of the Committee .
     ( b ) Where the proposed measures are not in accordance witji the opinion
           of the Committee , or if no opinion is delivered , the Commission
           shall submit to the Council without delay a proposal on the
           measures to be adopted .                         ~~          ,  . '
   , ( c)  If . the Council has not acted within three months of the date on
           which the proposal was submitted , the proposed measures shall be
           adopted by the Commission .
                                       Article 7c
     The appropriate methods of testing and tolerances , defined either
     directly or by reference to standards laid down outside the institutional
     framework of the Community , in the . Di recti ves referred to in Article 4
     shall be modified , in particular in order to adapt them to technical
     progress in accordance with the procedure laid down in Article 7b ."
 ---pagebreak---                                     „ 8 _
                                  Article 5
1 . The Member States shall bring into force the provisions necessary to
    comply with this Directive within a period of twelve months following its
    notification .  They shall forthwith inform the Commission thereof .
2 . Member States shall communicate to the Commission the text of the provision
    of national law which they adopt in the field covered by this Directive .
                                  Article 6
This Directive is addressed to the Member States .
 ---pagebreak---                                      ANNEX
'DETERMINATION OF THE BIODEGRADABILITY OF NON-IONIC SURFACTANTS
                                  REFERENCE METHOD
                               ( CONFIRMATORY TEST )
                                      CHAPTER 1
1.1 .   Definition
        Non-ionic surface active agents in the sense of this directive
        are those surface active agents , which after passage through
        cationic and anionic ion exchangers are determined as bismuth
       active subs tance ' ( BiAS ) according to the analytical procedure
       described in chapter 3 . '
1.2 .  Equipment needed for measurement
       The method of measurement employs the small activated sludge plant
       shown in figure 1 , and in greater detail in figure 2 . '
       The equipment consists of a storage vessel A for synthetic sewage ,
       dosing pump B , aeration' vessel C , settling vessel D , air lift pump E
       to recycle the activated sludge , and vessel F for collecting the
       treated effluent .
       Vessels A and F must be of glass vor suitable plastic and hold at
       least 24 litres .        Pump B must provide a constant flow of synthetic
       sewage to the aeration vessel ;          this vessel , during normal operation
       contains 3 litres of mixed liquor .           A sintered aeration cube G
       is suspended in the vessel C at the apex of the cone .            The quantity ,
       of air blown through the aerator should be monitored by means of a
       flowmeter H.
1.3 .  Synthetic sewage
       A synthetic sewage is employed for the test .           Dissolve, in each litre
       of tap water :                                                       . .
                •S                       '
           160 mg peptone
           110 mg meat extract                        -             .
             30 mg urea
              7 mg sodium chloride
              A mg calcium chloride , 2 ^0
              2 mg magne sium sulphate , 7 HO ,
             28 mg of dipotassium phosphate (K_HP0, )
       and 10 + 1 mg BiAS .                     -
                 •           ,                                        _         * -
       The ;     BiAS is extracted from the product 'to be tested by the method
       given in Chapter 2 .         The synthetic sewage is freshly prepared daily .
 ---pagebreak---                                       η· 2 ^
. 1.4 ,   Preparation of samples
          1.4.1 .  Uncompounded surfactants may be examined in the original
                   state .    The BiAS content must be determined in order
                   to prepare the synthetic sewage ( 1.3 .).
          1.4.2 .  Formulated products are analysed for BiAS , MBAS and
                   soap content .    They must be subjected to an alcoholic
                   extraction and to . a separation of the BiAS ( see        '
                   Chapter 2 ) .
          The BiAS content of the extract must be known in order to prepare
        . the synthetic sewage .
 1.5 .    Operation of equipment
          Initially ,, fill aeration vessel C and settling vessel D with
          synthetic sewage .     The height of the vessel D should be so
          fixed that the volume contained in the aeration vessel C is
          3 litres .    Inoculation is made by introducing 3 ml of a
          secondary effluent of good quality, freshly collected from a
          treatment plant dealing with a predominantly domestic sewage .
          The effluent must be kept under aerobic conditions in the period
          between sampling and application .     Then set the aerator G ,
          air lift E and dosing device B in operation .      The synthetic
          sewage must pass through the aeration vessel C at a rate of one
          litre per hour ;     this gives a mean retention time of 3 hours .
          The rate of aeration should be so regulated that the contents of
          vessel C are kept constantly in suspension and the dissolved
          oxygen content is at least 2 hig / 1 .  Foaming must be prevented
          by appropriate means .     Antifoaming agents which inhibit the
          activated sludge or contain BiAS must not be used .      The air­
          lift pump E- must be set so that the activated sludge from the
          settling vessel is continually and regularly recycled to
          aeration vessel C.      Sludge which has accumulated around the top
          of the aeration vessel C , in the base of the settling vessel D ,
          or in the circulation circuit must be returned to the circulation
          at least once each day by brushing or some other appropriate
          means .    When the sludge fails to settle , its density may be
          increased by the addition of 2 ml portions of a 5 per cent solution
          of ferric chloride , repeated as necessary .
          The efflent from the settling vessel D is accumulated in vessel F
          for 24 hours , following which a sample is taken after thorough
          mixing .    Vessel F must be carefully cleaned ,,
 ---pagebreak---  1.6 .       Checking measuring equipment
        , The BiAS content ( in mg /1 ) of the synthetic sewage is detenn.ned
            immediately before use .
            The ? iAS content ( in mg / 1 ) of the effluent collected over 24
            hours in vessel F should be determined analytically by the same
            method , immediately after collection : otherwise the samples must,
            be preserved , preferably by freezing .      The concentrations must
            be determined to the nearest 0.1 mg BiAS/1 . -
           As a check on the efficiency of the process , the chemical oxygen
            demand ( COD) or the dissolved organic carbon (DOC) of the
            filtered effluent accumulated in vessel F and of the filtered
           synthetic sewage in vessel A is measured at least twice per week .
        r The reduction in COD or DOC should level off when a roughly
       . regular daily BiAS degradation is obtained i.e. at the end of the
           running-in period shown " in Figure 3 . .
           The loss, on ignition of the dry matter in the activated sludge
           in the aeration tank should be determined twice a week in g /1 .
         • If it is more than 2.5 g /1 , the excess activated sludge must be
           discarded .                                                             ;
           The degradation test is performed at room temperature which should
          be steady and kept between 291 and 298 K C18-25°C).
1*7 .      Calculation of biodegradability
          The percentage degradation t>f BiAS must be calculated every day
          on the basis of the BiAS content? in mg/ 1 of the synthetic sewage
           and of the corresponding effluent accumulated in vessel F.
          The* degradability figures thus obtained should be presented , .
          graphically as in Figure 3 .                                         "       .
          Degradability of the BiAS should be calculated as the arithmetic
          mean of the figures obtained over the 21 days which follow the
          running in period , during which degradation has been regular
          and operation of the plant trouble–free .                                  -
           In any case the duration of the running-in period should not
          exceed six weeks .
          The daily degradation values are calculated to the nearest
          0.1 per cent biit the final result is . given to the nearest whole
          number .
          In some cases it may be permissible to reduce the frequency of
          sampling but at least 14 results collected over the 21 days
          which follow the running-in period should be used in calculating
          the average .                       .           .
                                                                              .7 .
 ---pagebreak---                                     ^ L  -
                                CHAPTER 2
                      PRELIMINARY TREATMENT OF PRODUCTS
                                TO BE TESTED
2-.1 . Preliminary notes
       2.1.1 . Treatment of samples
               The treatment of non-ionic surface active agents and formulated
               detergents prior to the determination of biodegradatility
               in the confirmatory test is : '
               PRODUCTS                        TREATMENT
               Non-ionic surfactants           None
               Formulated detergents           alcoholic extraction
                                               followed by separation of the
                                               non-ionic surfactants by ion
                                               exchange
               The purpose of the alcoholic extraction is to eliminate the
               insoluble and inorganic ingredients of the commercial
               product , which in some circumstances might upset the
               degradation test .
       2»1#2 . Ion Exchange procédure
               Isolation and separation of non-ionic surface active agents
               from soap , anionic and cationic surfactants is required
               for correct biodegradation tests .
               This is achieved by an ion exchange technique using a macro­
               porous exchange resin and suitable elutants for' fractional
               elution .   Thus soap , anionic and non-ionic surfactants may
               be isolated in one procedure .
 ---pagebreak---                                       - 5 "
'      2.1.3 .   Analytical control
                 After homogenizing , the concentration of anionic and non-ionic
                 surfactants in the synthetic detergent is determined according
                 to the MBAS and BiAS analytical procedure .    The soap content
                 is determined by a suitable , analytical method .
                 This analysis of the product is necessary to calculate the
               . quantities required to prepare fractions for the biodegradability
                 tests .
                 Quantitative extraction is not necessary ;    however at least
                 80 per cent of the surfactants nim-Toni'c    should be extracted .
                 Usually , 90 per cent and more is obtained .
2.2 . Principle
      From an homogeneous sample (powders , pastes , and dried liquids ) an
      ethanol extract is obtained which contains the surfactants , soap and
      other alcohol-soluble constituents of the synthetic detergent sample .
      The ethanol extract is evaporated to dryness , dissolved in an isopropanol /
      water mixture and the solution obtained is passed through a strongly
      acidic cation exchange /macro-porous anion exchange combination heated
      to 323 K ( 50 C ) .     This temperature is necessary to prevent precipitation
      of fatty acids in acidic media .
      The non-ionic surfactants are obtained from the effluent by evaporation .
      Cationic surfactants , which might upset the degradation test and the
      analytical procedure are eliminated* by the cation exchanger placed
      on top of the anion exchanger .
2.3 . Chemicals and equipment       ,                              '
      2.3.1 .    Deionised water .                                   ^ -
      2.3.2 . Ethanol , 95 vol . % C^H^-OH
                 (permissible dénaturant : methyl ethyl ketone or
                  methanol ).
 ---pagebreak---                              - 6 τ
£.3.3 ,    Isopropanol /water -mixture ( 50 / 50 v /v ) ;
           50 parts by volume isopropanol (CH^CHOH . CH^) and
           50 parts by volume water ( 2.3.1 )
2,3.4 .    Armonium bicarbonate solution ( 60 / 40 ) :
           0,3 M NH^HC0 o in 1 000 ml of an isopropanol /water
           mixture consisting of 60 parts by volume isopropanol and
           40 parts by volume water ( 2.3.1 )
2.3.5*.    Cation exchanger ( KAT ) , strongly acidic , resistant to
           alcohol ( 50 - 100 mesh ).
2.3.6 .    Anion exchanger ( AAT ) , macro-porous , Merck Lewatit
           MP 7080 ( 70 - 150 mesh ) or equivalent .
2.3.7 .    Hydrochloric acid , 10% HC1 w /w .
2.3.Q      % 000 ml round-bottomed flask with ground glass stopper
           and reflux condenser .
2.3 . 9*   90 mm dia . suction filter (heatable ) for paper filters .
2.3.10 . 2 000 ml filter flask .
2.3.11 . Exchange columns with heating jacket and cock :
           Inner tube 60 mm in diameter and 450 mm in height
           ( Fig . 4 ).
2.3.12 » Water-bath .
2.3.13 . Vacuum drying oven .
2.3.1 /t . Thermostat .
2.3.15 . Rotary evaporator .
                   1
 ---pagebreak--- 2. 4.     Preparation of extract and separation of rion-ionic active agents
          2.4.1 .  Preparation of extract                                x
                   The quantity of surface active agents necessary for the degradation
                   test is about 25 g BiAS .
                   In preparing extracts for the degradation tests , the quantity of
    ' „ .          product to be u^ed should be limited to a max . 1 000 g .       Therefore ,
                   it may be necessary to carry out the operation twice in order
                   to obtain sufficient quantity for the degradation tests .
                   Experience has shown that there are advantages in using a
                  number of small extractions rather than' one large extraction ..
        2.4.2 .    Isolation of alcohol-soluble constituents
                  Add     250 .g of the synthetic detergent to be analyzed to ■% .
                  1250 ml e.thanol and heat the mixture to boiling point and reflux
                  for 1 hour with stirring .       Pass the hot alcoholic solution
                  through a coarse-pored suction filter heated to 323 K (50°C)
                  and suck off sharply ,.     Wash the flask and suction filter with
                  approx . 200 ml hot e.thanol .     Collect the filtrate and filter
                  washings in a filter flask .
                  In the case of pastes or liquid products to be analysed , make
                  sure that not more than 25 g 'anionic surfactants and 35 g soap are
                  contained in the sample .       Evaporate this weighed sample to dryness .
                  Dissolve the residue in 5*00 ml ethanol and proceed as described
                  above .
                  In case " of powders of low apparent density (      300 g/l ) it i6 re- ■
                   commended to increase the ethanol ratio in the relation 20.1 .
                  Evaporate the ethanolic filtrate to complete dryness,' preferably
                  "by means of rotary evaporator . Repeat the operation, if a greater
                  quantity of extract is      required . Dissolve all the residue in 5*000 ml
                   isopropajiol wat er/mijtture .                        ,  ,            .
 ---pagebreak---                                    τ  8 ·
 2.4.3 .     Preparation of ion exchange columns
             Cation exchange column
             Place 600 ml cation exchange resin in a 3 000 ml beaker
             and cover by adding 2 000 ml hydrochloric acid .         Allow
             to stand "for at least 2 hours stirring occasionally .
             Decant the acid and transfer the resin into the column
             ( 2.3.11 .) by means of deionised water .       The column
             should contain a glass wool plug .         Wash the column with
             deionised water at a rate of 10 - 30 ml /min until the
             eluate is free of chloride .     Displace the water with
             2 000 ml isopropanol / water mixture ( 2.3.3 .) at a rate of
             10-30 ml /min .   The exchange column is now ready for
             operation .
             Anion exchange column
             Place 600 ml anion exchange resin in a beaker and cover
             by adding 2 000 ml deionised water .        Allow the exchanger
             to swell for at least 2 hours .      Transfer the resin into the
             column by means of deionised water .         The column should
             contain a glass wool plug .
             Wash the column with 0.3 M ammonium bicarbonate solution ( 2.3.4 )
             until free of chloride .      This requires about 5 000 ml
             solution .    Wash again with 2 000 ml deionised water .
             Displace the water with 2 000 ml isopropanol /water mixture
             ( 2.3.3 ) at a rate of 10 - 30 ml /min .      The exchange column
             is now in the OH form and ready for operation .
                                       V
2' . 4 . 4 . Ion exchange procédure'
             Connect the exchange columns so that the cation exchange
             column is placed on top of the anion exchange column .
             Heat the exchange columns to 323 K (50 C) using a thermostat .
             Heat 5 000 ml of the solution obtained in item 2.4.2 to 333 K
             ( 60 c) and pass the solution through the exchanger combination
             at a rate of 20 -ml /min .   Wash the columns with 1 000 ml
             hot isopropanol /water mixture / i.3.'i ).
 ---pagebreak---                              ~" s **
         To obtain the non-ionic surface active agents , collect
         the filtrate and filter vashings and evaporate to dryness ,
        preferably by means of a rotary evaporator .        The residue  - .
         contains the BiAS .     Add deionised water until a defined
        volume is obtained and determine the BiAS content as in item
         3.3 in an aliquot .     The solution is used as a standard solution
        of non-ionic surf actantfi - for the - degradation test .  The solution
        should be kept at a temperature below 278 K (5 C) .                    »
£.4.5 . Regeneration of exchange resins v                   _
        The cation exchanger is rejected after use .
        The anion exchange resin is regenerated by passing about
        5 000 - 6 000 ml of ammonium bicarbonate solution ( 2.3.4 )
        down the column at a flow rate of approximately 10 ml /min .
        until the eluate is free from anionics (methylene blue test ).
        Then pass 2 000 ml isopropanol /water mixture ( 2.3.3 ) down
        the anion exchanger to wash .      The anion exchanger is again
        ready for operation .                                            ,•
 ---pagebreak---                           - -10 -
                        CHAPTER 3
              •DETERMINATION OF NON-IONIC SURFACE
         ACTIVE AGENTS IN B IODE GRADAT ION TEST LIQUORS
Introduction
Surface active agents are concentrated and isolated by gas
stripping .    In the sample used , the quantity of non-ionic
surfactant should be in the range 250-800 /Jg .
The stripped surfactant is dissolved in ethyl acetate .
After phase separation and evaporation of the solvent , the
non-ionic surfactant is precipitated in aqueous solution with
modified Dragendorff reagent (KBil , + Bad - + glacial afcetic
acid ) .
The precipitate is filtered , washed with glacial acetic acid
and dissolved in ammonium tartrate solution .      The bismuth
in the solution is titrated potentiometrically with pyrrolidinedi-
thiocarbamate solution at pHv4-5 using a bright platinum indicator
electrode and a calomel or silver / silver chloride reference
electrode .
The method is applicable to non-ionic surfactants containing
6-30 alkylene oxide groups .
The titration result is multiplied by the empirical factor
of 54 for conversion to the reference substance - nonylphenol
condensed with 10 mols ethylene oxide (NPlO ).
 ---pagebreak--- Reagents and equipment
All reagents are to be made up in deionised water .
 3.2.1 .     Pure ethyl acetate , freshly distilled .
3.2.2 .      Sodium bicarbonate NaHCO . A.R.
3.2.3 .      Dilute HC1 ( 20 ml hydrochloric acid A.R. conc . per 1 000 ml water )
3.2.4 .     Methanol A. R. , freshly distilled , kept in a glass bottle .
3.2.5 .     Bromocresol purple , 0,1 g in 100 ml methanol .
3.2.6 .     Precipitating agent " : the precipitating agent is a mixture •
         . of 2 volumes of solution A and 1 volume of solution B.                ^
            The mixture is stored in a brown bottle and can be used up to
            one week after mixing .
            3.2.6.1 .  Solution A
                       Dissolve 1.7 g bismuth ( III) nitrate A. R. , ( BiO.NO^.H^O)
                       in 20 ml glacial acetic acid , and make up to 100 ml
                       with water .    Then dissolve 65 g potassium iodide A.R. ,
                       in 200 ml water .    Mix these two solutions in a 1 000 ml
           -           measuring flask , add 200 ml glacial acetic acid
                       ( 3.3.7 .) and make up to 1 000 ml with water .
            3.2.6.2 .  Solution B                          -        '
                       Dissolve 290 g BaCl ^. 21^0 A.R. in 1 000 ml of water .
3.2.7 .    Glacial acetic acid 99-100% ( lower concentrations are
           unsuitable ).
3.2.8 .    Ammonium tartrate solution : mix 12.4 g tartaric acid and 12.4 ml
           of ammonia solution A.R. (d = 0.910) and make up to 1 000 ml with
           water (or use the equivalent amount of ammonium tartrate A.R. ).
3.2.9 .    Dilute ammonia solution : 40 ml ammonia solution A.R. (d = 0.910 )
           diluted to 1 000 ml with water .
3.2.10 . Standard acetate buffer : dissolve 40 g solid sodium hydroxide A.R
           in 500 ml vratex in a 1 000 ml volumetric flask and add 120 ml
           glacial acetic acid ( 3.2.7 .).     Mix thoroughly , cool and make
           up to the .mark with water .
 ---pagebreak---                               - 12
3.2.11 .  Pyrrolidinedithiocarbamate solution ( shortened to
          " Carbate solution ") : dissolve 103 mg sodium Pyrrolidin-
          edithiocarbamate ( C,H KNa S , 2H 0 ) in about 500 ml water ,
          add 10 mln-amyl alcohol A.R. and 0.5 g NaHCO ^ A.R. , and
          make up to 1 000 ml with water .
3.2.12 .  Copper sulphate solution ( for standardization of 3.2.11 .).
          Stock solution
          Mix 1,249 g copper sulphate A.R. ( CuSO , . SH^O) with 50 ml
          0.5 M sulphuric acid and make up to 1 000 ml with water .
          Standard solution
          Mix 50 ml stock solution with 10 ml 0.5 M      H„S0 , and make up
          to 1 000 ml with water .
3.2.13 .  Sodium chloride A.R.
3.2.14 .  Gas-stripping apparatus ( see figure 5 ).
          The diameter of the sintered disc must be the same as the
          internal diameter of the cylinder .
3.2.15 .  Separating funnel , 250 ml .
3.2.16 .  Magnetic stirrer with magnet 25-30 mm .
3.2.17 .  Gooch crucible , diameter of the perforated base ■»
          25 mm , Type G 4 .
3.2.18 .  Circular glass-fibre filter papers , 27 mm diameter with
          fibre diameter 0.5 - 1.5 ^im .
3.2.19 . .Two filter flasks with adaptors and rubber collars ,
          500 ml and 250 ml respectively .
3.2.20 .  Recording potentiometer fitted with a bright platinum
          indicator electrode and a calomel or silver / silver
          chloride reference electrode with a 250 mV range , with
          automatic burette of 20-25ml capacity , or alternative manual
          equipment .
 ---pagebreak---                                           - 13 ->
J3.3  Method                                        -
       3.3.1 .    Concentration and separation of the surfactant
                  Filter the aqueous sample through a qualitative filter paper .
                  Discard the first 100 ml of the filtrate .
                  Into the stripping apparatus , previously rinsed with ethyl
                  acetate , place a measured quantity of the sample , such that
                  it contains between 250 - 800 pg non-ionic surfactant .
                 To improve the separation add 100 g sodium chloride and 5 g
                 sodium bicarbonate .                    '            *
                 If the volume of the sample exceeds 500 ml add these salts to the
                 stripping apparatus in solid form , and dissolve by passing
                 nitrogen or air through info ffoe. ajDf>aca.tu.s . '
     *           If a smaller-sized sample is used , dissolve the salts in 400 ml
                 water and then add to the stripping apparatus .
                 Add water to bring the level to the upper stopcock .
                 Cautiously add 100 ml * ethyl acetate on top . of the water .
                 Fill the wash-bottle in the gas-line (nitrogen or air ) two-
               v thirds full with ethyl acetate .
                 Pass a gas stream of 30 - 60 1 /h through the apparatus ;        the
                 inclusion of a rotameter is recommended .          The rate of aeration
                 must be increased gradually at the beginning .          The gas rate
                 must be so adjusted that the phases remain noticeably separate
                 to minimise the mixing of the phases and the solution of the            ;
                 ethyl acetate in the water .     Stop the gas flow after 5 minutes .
                 If there is a reduction of more than 20% in the voluma of the
                 organic phase through solution in water , the sublation must
                 be repeated paying special attention to the rate of gas flow .
                 Run off the organic phase into a separating funnel .          Return any
                 water in the ^ separating funnel from the aqueous phase - it
                 should only be a few ml - to the stripping apparatus .          Filter
                 the ethyl acetate phase through a dry qualitative filter paper
                 into a 250 ml beaker .
 ---pagebreak---                            n 14 ^
Put a further 100 ml ethyl acetate into the stripping
apparatus and again pass nitrogen or air through for
5 minutes .       Draw off the organic phase into the separating
 funnel used for the first separation , reject the aqueous
phase and run the organic phase through the same filter
as the first ethyl acetate portion .        Rinse both the
 separating funnel and the filter with about 20 ml ethyl
 acetate .
Evaporate the ethyl acetate extract to dryness oil a water-
bath ( fume cupboard ).       Direct a gentle stream of air
over the surface of the solution to accelerate the
evaporation .
Precipitation and filtration
Dissolve the dry residue from 3.3.1 . in 5 ml methanol , add
40 ml water and 0.5 ml diluted HC1 ( 3.2.3 .) and stir the
mixture with a magnetic stirrer .
To this solution add 30 ml of precipitating agent ( 3.2.6 .)
 from a measuring cylinder . . The precipitate forms after
repeated stirring .       After stirring for 10 min . leave the
mixture     to stand for at least '5 min .
Filter the mixture through a Gooch crucible , the base of
which is covered with a glass-fibre filter paper .         First
wash the filter under suction with" about 2 ml glacial
acetic acid .        Then thoroughly wash the beaker , magnet ,
and crucible with glacial acetic acid , of which about
40 - 50 ml is necessary .        It is not necessary to quant­
 itatively transfer the precipitate adhering to the sides of
 the beaker, to the filter , because the solution of the
precipitate for the titration is returned to the precipitating
beaker , and the remaining precipitate will then be dissolved .
 Solution of the precipitate
Dissolve the precipitate in the filter crucible by the
addition of hot ammonium^Vartrate solution ( 3.2.8 .) in
 three portions of 10 ml each .       Allow each portion to stand
 in the crucible for some minutes before being sucked through
 the filter into the flask . •
Put the contents of the filter flask into the beaker used         - ■
for the precipitation .        Rinse the sides of the beaker with a
further 20 ml of tartrate solution to dissolve the rest of the
precipitate .
                            #                    •            ,+
 Carefully wash the crucible , adaptoy and filter flask with
 150 - 200 ml water , and return the rinsing water to the beaker
used for the precipitation .
*) faLo * f 8ù c C
 ---pagebreak---  3 . 3 . A.  The tri «ration
             Stir-the solution with a magnetic stirrer ( 3.2.16 .), add
             a few drops of bromocresol purple ( 3.2.5 .) and add the diluted
            ammonia solution ( 3.2.9 .) until the colour turns violet ( the
             solution is weakly'acid from the residue of acetic acid used
             for rinsing).                                             .
            Then add 10 ml standard acetate buffer ( 3.2 . 10 ) , immerse
            the electrodes in the solution , and titrate potentiometrically
            with standard " carbate solution " ( 3.2.11 .), the burette tip
            being immersed .in the solution .         ,
                         " The titration rate should not exceed 2 ml /min .
                                                                              £
            The endpoint'is the" intersection of the tangents to the            .
            two branches of the potential curve .       It will be observed
            occasionally that the inflection in the potential curve
            becomes flattened ; this can be eliminated by carefully
            cleaning the platinum electrode (by polishing with emery paper ).
3.3.5 .     Blank determinations
            At the same time run a blank determination through the whole
            procedure with 5 ml methanol and 40 ml water , according to the
            instructions in 3.3.2 .      The blank titration should be below
            1 ml . otherwise the purity of the reagents ( 3.2.3 . - 3.2.7 . -
            3.2.8 . - 3.2.9 . - 3.2.10 ) is suspect , especially their content
            of heavy metals^and they must be replaced .       The blank must
            be taken into account in tije calculation of the results .
3.3.6 .     Control of the factor of the " carbate solution "
            Determine the factor for the carbate solution daily .        To do this
            titrate 10 ml of the copper sulphate solution ( 3.2.12 .) with
            carbate solution after the addition of 100 ml water and 10 ml
            standard acetate buffer ( 3.2.10 ).-    If the amount used is J , a"
            ml , the factor f is ;
                                             a
            and all the results of the titrations 'are multiplied by this
            factor .
 ---pagebreak---                            •• là
 Calculation of results
        Every non-ionic surfactant has its own factor , depending
 on the length of the ethylene oxide chain . The concentration of
 non-ionic surfactant expressed in relation to a standard, substance
 - a nonyl phenol with 10 ethylene oxide units ( NP 10)- for which the
 conversion factor is 0,054 «      Using this factor the amount of
 surfactant present in the sample is found expressed as mg
 of NP 10 equivalent , as follows
       (b-c ) . f . 0.054 ■ mg non-ionic surfactant
      where b » volume of " carbate solution " used by the
                      sample (ml )
              c ■» volume of " carbate solution " used by the
                      blank ( ml )
              f = factor of the    carbate solution "
Expression of results
Express the results as mg BiAS / 1 to the nearest 0.1 .
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                                 CALCULATION OF BIODEGRADABILITY - DYNAMIC SIMULATION TEST
oo *>
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                                               Figure 5
                                 GAS - STRIPPING APPARATUS
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