Madoni, 1994 (SBI)

download Madoni, 1994 (SBI)

of 9

Transcript of Madoni, 1994 (SBI)

  • 8/18/2019 Madoni, 1994 (SBI)

    1/9

    Wat. Res. Vo l. 28, No . 1, pp. 67-7 5, 1994 0043-1354/94 $6.0 0+0 .00

    Printed in Gre at Britain. All rights reserved Copyright © 1993 Pergamon Press Ltd

    A S L U D G E B IO T IC I N D E X S B I ) F O R T H E E V A L U A T I O N

    O F T H E B IO L O G I C A L P E R F O R M A N C E O F A C T I V A T E D

    S L U D G E P L A N T S B A S E D O N T H E M I C R O F A U N A

    A N A L Y S I S

    PAOLO MADO NI~

    Istituto d i Ecologia, Universit~i di Parma, Viale delle Scienze, 43100 Parm a, Italy

    First received August 1992; accepted in revised for m April 1993)

    Ab stra ct-- An objective index, the Sludge Biotic Index (SBI), based on the microfauna associated w ith

    activated-sludge mixed liquor, has been devised to monitor activated-sludge plant performance. The

    prop osed m ethod makes it possible to define the biological quality of the sludge using numerical values

    (biotic index) of 0-10, and to group SBI values into four quality classes. The method is based on two

    principles. First , the dominance of the microfauna keygroups changes in relation to the environmental

    and operat ional condi t ions of the plant . In par t icular , some protoz oa such as smal l f lagella tes and the

    ciliates

    Vorticella microstoma

    and

    Opercularia

    spp have a negative influence on the index value. Secondly,

    the number of morphological species is reduced as the performance of the plan t gets worse. The ad vanta ge

    of this method over other schemes is that i t provides numerical values which enable the operator to

    monitor the prevalent plant operating conditions on a daily basis.

    Key words- -pro tozoa ,

    activated sludge, Sludge Biotic Index, in dicator species, plant performance

    INTRODUCTION

    N u m e r o u s b i o t i c i n d i c e s h a v e b e e n d e v e l o p e d t o

    a s s e s s t h e d e g r e e o f p o l l u t i o n i n f r e s h w a t e r e c o s y s -

    t e m s . F o r r i v e r s , t h e E x t e n d e d B i o t i c I n d e x ( E B I ) b y

    W o o d i w i s s ( 1 9 8 0 ) , b a s e d o n m a c r o i n v e r t e b r a t e s , i s

    o n e o f t h e m o s t w i d e l y u s e d i n E u r o p e . T h i s m e t h o d

    i s b a s e d o n t w o p h e n o m e n a : t h e c h a n g e i n t h e

    c o m p o s i t i o n o f t h e t a x o c e n o s i s a s t h e p o l l u t i o n l e v e l

    r is e s, a n d t h e r e d u c t i o n i n n u m b e r o f t a x o n o m i c

    g r o u p s a s p o l l u t i o n i n c r e a s e s . O b j e c t iv e i n d i c e s su c h

    a s t h e E x t e n d e d B i o t ic I n d e x a n d t h e S a p r o b i c I n d e x

    ( S l a d e c e k , 1 9 7 3 ) , p r e s e n t m e t h o d s f o r c a l c u l a t i n g

    f i x e d i n d e x v a l u e s f o r a n y g i v e n c o m m u n i t y , i n d e p e n -

    d e n t o f t h e a n a l y s t ' s p e r s o n a l e v a l u a ti o n . B o t h t h e

    r a n d o m f l u c tu a t i o n s fo u n d i n s a m p l e s t a k e n u n d e r

    t h e s a m e c o n d i t i o n s a n d t h e p e r s o n a l s u b j e c t i v it y i n

    s a m p l i n g a n d c o u n t i n g t e c h n i q u e s , r e p r e s e n t tw o

    f a c t o r s p o s s i b l y i n t r o d u c i n g a c e r t a i n d e g r e e o f u n -

    c o n t r o l l e d v a r i a b i l i t y .

    T h e r o u t i n e a n a l y s i s o f t h e m i c r o f a u n a a s a n

    i n d i c a t o r o f a c t i v a te d - s l u d g e p la n t p e r f o r m a n c e i s

    b e c o m i n g m o r e a n d m o r e c o m m o n . T h i s a n a ly s i s

    q u i c k l y g i v e s u s e f u l i n f o r m a t i o n o n t h e b i o l o g i c a l

    a c t i v i t y o f t h e s l u d g e b a s e d o n t h e c o m m u n i t y s t r u c -

    t u r e o f th e m i c r o o r g a n i s m s p r e s e n t . H o w e v e r , t h e

    m i c r o f a u n a i s a l s o u s e d t o i n d i c a t e c h a n g e s i n t h e

    p e r f o r m a n c e o f s p e c if i c a c t i v a t e d - s l u d g e p l a n t s ( A I -

    S h a h w a n i a n d H o r a n , 1 99 1; E s t e b a n

    e t a l . ,

    1991) but

    t h e s e m e t h o d s c a n n o t n e c e s s a r i l y b e a p p l i e d d i r e c t l y

    t o o t h e r s i m i l a r p l a n t s . O n t h e c o n t r a r y , o t h e r

    m e t h o d s , b a s e d o n m i c r o s c o p i c an a l y s is c a n b e a p -

    p l i e d t o a n y p l a n t t o e s t i m a t e b o t h t h e q u a l i t y o f th e

    e f f lu e n t ( C u r d s a n d C o c k b u r n , 1 9 70 b ) a n d t h e p e r -

    f o r m a n c e o f t h e p l a n t ( D r a k i d e s , 1 9 7 8; M a d o n i ,

    1981, 1988) . S om e o f these m e tho ds , how ever , a r e

    s u b j e c t i v e i n d i c e s n o t b e i n g b a s e d o n r i g i d c a l c u -

    l a t i o n s , b u t o n t h e a n a l y s t ' s p e r s o n a l i n t e r p r e t a t i o n o f

    t h e m i c r o f a u n a t h a t c o l o n i z e t h e a c t i v a t e d s l u d g e

    u n d e r i n v e s t i g a t i o n . O b j e c t i v e i n d i c e s h a v e a g r e a t

    a d v a n t a g e o v e r s u b j e c t iv e o n e s in t h a t i n d e x v a l u e s

    a s s e s s e d b y d i f f e r e n t o p e r a t o r s a r e c o m p a r a b l e .

    I n t h i s p a p e r a n o b j e c t i v e i n d e x i s p r o p o s e d t o

    e s t i m a t e t h e b i o l o g i c a l q u a l i t y o f t h e s l u d g e i n a n

    a e r a t i o n t a n k o f a c t i v a t e d - s l u d g e p l a n t s . T h e m e t h o d ,

    t h a t i s i n s p i r e d b y t h e E x t e n d e d B i o t i c I n d e x

    ( W o o d i w i s s , 1 9 8 0) i s a p p l i c a b l e t o a l l t y p e s o f a c t i -

    v a t e d - s l u d g e p l a n t s .

    MICROFAUNA IN ACTIVATEDSLUDGE

    B i o l o g i c a l s e w a g e - t r e a t m e n t p l a n t s m a y b e r e -

    g a r d e d a s m a n - m a d e e c o s y s t e m s s u b je c t e d to e x t r e m e

    c o n d i t i o n s . A s i n e v e r y o t h e r b i o l o g i c a l s y st e m , t h e

    c o m m u n i t y l i v i n g i n t h e a e r a t i o n b a s i n o f a n a c t i -

    v a t e d - s l u d g e p l a n t h a s a p r e c i s e s t r u c t u r e ( c o m -

    p o n e n t s a n d f a c t o r s ) a n d f o l l o w s e x a c t d y n a m i c s ( i n

    t i m e a n d s p a c e ) . I n a c t i v a t e d s l u d g e s , b i o t i c c o m -

    p o n e n t s a r e r e p r e s e n t e d b y d e c o m p o s e r s ( b a c t e r i a ,

    f u n g i ) w h i c h u t i l i z e t h e d i s s o l v e d o r g a n i c m a t t e r i n

    t h e w a s t e w a t e r , a n d b y c o n s u m e r s ( h e t e r o t r o p h i c

    f l a g e ll a t e s, c i l ia t e s , r h i z o p o d s , a n d s m a l l m e t a z o a n s )

    w h i c h f e e d o n d i s p e r s e d b a c t e r i a a n d o t h e r o r g a n -

    i s m s . I t is w e l l - k n o w n t h a t a c t i v a t e d s l u d g e s d e v e l o p

    67

  • 8/18/2019 Madoni, 1994 (SBI)

    2/9

    68

    PA O L O M A D O N I

    Table 1. List of ciliated protozo a com mo nly found in activated sludg es and th eir food h abit

    Bacterivorous

    Carn ivorous Free-swimming Crawl ing At tached

    Holotrichs Colpoda sp Aspidisca cicada Carchesium sp p

    A ci ne ri a i n c u r v a t a C o l p i d i u m olpoda Aspidisca lynceus Episo lis spp

    Amphileptus sp. Colpidium campylum Chi lodone l la unc inata O pe rc ul ar iaoarctato

    Coleps hirtus* Cinetochilum margaritaceum Euplotes affinis Opercularia microdiscus

    Litonotus spp Cyclidium glaucoma Euplotes moebiusi Opercularia minima

    Spathidium

    spp

    Dexiotricha

    sp.

    Euplotes patella Stentor

    spp

    Sucto r ians Glaucoma scintillans Stylonychia spp Vaginicola crystallina

    Acineta spp Loxocephalus sp. Tri thigmostoma cucu Uu lus Vo rt ic e l la om al lar ia

    Metacineta sp. Paramecium spp Trochilia minuta Vortwella microstoma

    Podophrya spp P s e u d o c o h n i l e m b u susillus Vorticella octava

    Tokophrya spp Sathrophilus sp. Zoothamnium spp

    Spirostomum teres

    Tetrahymena pyriformis

    complex

    Uronema nigricans

    Acineria uncinatat

    Drepanomonas revolutat

    Trachelophyllum pusillum t

    *Omnivorous;

    t incertae saedis:

    these species are free-swimming forms but their grazing activity seems to be linked to the

    floc.

    spec if ic com mun i t i e s o f p r o t ozo a w hi ch a r e sus t a i ned

    by l a r ge popu l a t i ons o f bac t e r ia . C i l i a ted p r o t ozo a

    a r e ve r y nu mer o us i n a l l t ypes o f ae r ob i c b i o l og ica l -

    t r e a t m e n t s y s t e m s ; t h e y a r e c o m m o n l y f o u n d i n

    densi t i es of abou t 10,000 cell s /ml of ac t ivated s ludge

    mi xed l i quor , and cons t i t u t e appr ox . 5 % of t he d r y

    w e i gh t o f suspended so l i ds i n mi xed li quor . A l t ho ugh

    abo u t 230 spec ie s o f p r o t o zoa hav e been obse r ved

    i n t he va r i ous t ypes o f ae r ob i c t r ea t men t sys t ems ,

    on l y f ew have been obse r ved f r equen t l y ( C ur ds

    and C ockbur n , 1970a ; Madon i and G he t t i , 1981) .

    Tab le 1 show s the li st of the mo st im po r tan t c i li a tes

    f ound i n ac t i va t ed s l udge . T he ma j o r i t y o f c i l i a t e s

    p r e sen t i n b i o l og i ca l w a t e r t r ea t men t p l an t s f eed

    upo n d i spe r sed popu l a t i ons o f bac t e r i a . T he bac t e r i vo-

    rous c i l i a tes in act ivated s ludge can be subdivided

    i n t o t h r ee g r o ups on t he bas i s o f behav i our : f r ee -

    sw i mmer s , c r aw l e r s , and a t t ached .

    Al l bacter ivorous c i l i a tes re ly upon c i l i ary cur rents

    t o f o r ce suspended bac t e r i a i n t o t he o r a l r eg i on . So ,

    whi le f ree-swimming and a t tached c i l i a tes are in

    com pe t i t i on f o r bac t e r i a d i spe rsed i n t he l i qu i d phase ,

    c r aw l i ng f o r ms , t ha t a r e i n c l ose p r ox i mi t y t o su r f ace

    gr ow t hs , f eed upon pa r t i c l e s t ha t on l y l i gh t l y adhe r e

    t o t he s l udge and t ha t a r e d i s l odged by t he f eed i ng

    currents very eas i ly .

    ~ S l u d g e

    F l a g e l l a t e s b a ct e r i a b a c t e r i a

    Ca r n i v o r o u s

    c i l i a t e s

    I Fi l te r - fe ed ing I

    v I c i l ia tes

    D i sp e r se d

    O r g a n i c m a t t e r ( D O M - P O M )

    Fig. 1. Trophic web in the activated-sludge process.

    C i l ia t ed p r o t ozo a i mp r ove t he q ua l i t y o f t he e f fl u-

    ent . In thei r absence the ef f luents f lowing f rom the

    sys t em, have an e l eva t ed B O D and a r e h i gh l y t u r b i d

    due t o t he p r e sence o f man y d i spe r sed bac t e r i a

    ( C u r d s e t a l . 1968) . I n t he a e r a t i on t ank o f b i o l og i ca l

    processes a t rue t rophic web i s es tabl i shed. A s im-

    pl if ied d iagra m of thi s i s i l lus t ra ted in Fig. 1 . The

    b i o l og i ca l sys t ems o f t hese p l an t s cons i s t o f popu-

    l a t ions i n con t i nu ous com pe t i t i on w i t h each o t he r f o r

    f ood . T he r e l a t i onsh ips o f com pe t i t i on and p r eda t i on

    c r ea t e osc i ll a t ions and succes si on o f pop u l a t i ons un t il

    dynamic s tabi l i ty i s reached (Fig. 2) . This i s s t r i c t ly

    d e p e n d e n t o n p l a n t m a n a g e m e n t c h o i c e s b a s e d o n

    des i gn cha r ac t e r i s t i c s a i med a t gua r an t ee i ng op t i -

    mum ef f ic iency (Madoni , 1986) .

    R esu l t s f r om r e sea r ch on t he moda l i t i e s o f co l o -

    n i za t i on and o f popu l a t i o n succes s i on in ac t i va t ed

    s l udge have been o f g r ea t i mpo r t ance i n unde r s t and-

    i ng the r o l e o f p r o t o zoa a s p l an t p e r f o r m ance i nd i -

    ca t o r s and demons t r a t ed t he de t e r mi n i ng e f f ec t o f

    env i r onment a l cond i t i ons i n t he ae r a t i on t ank on t he

    c i li a te com mu ni t y e s t ab li shed ( C ur ds , 196 6 , 1971 ;

    M ado n i and Po l i , 1981 ; M adon i , 1982; Ma don i and

    Antonie t t i , 1984) .

    + F l a g e l l a t e s

    1 0 0 F • S w i m m i n g c i l i a te s

    | O A t t a t c h e d c i l i a t e s

    ,- -- , 8 0 b [] D i sp e r se d b a c t e r i a ~ z r ~

    . ~ j n C r a w li ng c i l i a t e s f

    ~ 6 0 b / + / t : f / . . . .

    I+' + \ y m l

    \ f

    _~ ,

    I ~ ' X - . , ~ ? .. L + ~

    ~ . ~ . - r ~ o ~ _ ~ ¢ ~ Q_

    0 10 20 30 40 50 60

    T i m e ( d a y s )

    Fig. 2. Successions of microorgan isms during the establish-

    ment o f an act ivated sludge.

  • 8/18/2019 Madoni, 1994 (SBI)

    3/9

    Sludge Biotic Index

    Table 2. Some situations regarding he plant performance ndicated by the dominant group of the m icrofauna (from

    M adon i, 1986, 1988 modified)

    69

    Do min ant group Performance Possible causes

    Sm all flagellates Low

    Small swim ming iliates Mediocre

    Large swim min g ci l iates Mediocre

    Craw ling ciliates Goo d

    Sessile and crawling Good

    ciliates

    Sessile ciliates Decreasing

    Small naked amoebae Poor

    and flagellates

    Testate amoebae Good

    Poorly aerated sludge; overloading; ermentingsubstances nvolved

    Too shor t sewage retention time; poorly aerated sludge

    Overloading; poorly aerated sludge

    Transient phenomena discontinuous oad, recent sludge extraction)

    Very high load, n ot ea sily degradable

    T h e s t r u c t u r e o f t h e m i c r o f a u n a is in d e e d a v a l i d

    i n d i c a t o r o f p u r i f i c a t i o n p l a n t p e r f o r m a n c e . I n s y n -

    t h e s i s , a n e f f ic i e n t a c t i v a t e d s l u d g e p l a n t p r e s e n t s t h e

    f o l l o w i n g c h a r a c t e ri s t ic s :

    ( 1 ) H i g h n u m b e r s o f m i c r o f a u n a c e l ls (> 11 06 o r -

    g a n i s m s / l ) ;

    ( 2) M i c r o f a u n a c o m p o s e d c h i e fl y b y c r a w l i n g a n d

    a t t a c h e d c i l i a t e s , w i t h a l m o s t n o f l a g e l l a t e s ;

    ( 3 ) T h e s p e c ie s a n d c i l ia t e g r o u p s a r e h i g h l y d i v e r -

    s if ie d a n d n o n e d o m i n a t e s n u m e r i c a l ly o v e r t h e

    o t h e r s b y a f a c t o r g r e a t e r t h a n 1 0 .

    W h e n t h i s is n o t t h e c a s e, t h e i d e n t i f i c a t i o n o f th e

    d o m i n a n t g r o u p ( k e y g r o u p ) o f t h e m i c r o f a u n a a l lo w s

    d i a g n o s i s o f t h e p a r t i c u l a r s t a t e o f f u n c t i o n a l i t y o f t h e

    p l a n t ( M a d o n i , 1 98 6) . S o m e e x a m p l e s o f th e s e s it u -

    a t i o n s a r e r e p o r t e d i n T a b l e 2 .

    T H K Y G R O U PS

    Q u a n t i f y i n g th e i n d i c a t o r v a l u e o f t h e m i c r o f a u n a

    i s a d i f f i c u l t t a s k b e c a u s e t h e r e a r e g r o u p s wh i c h a r e

    m o r e o r l es s to l e r a n t t o a w i d e r a n g e o f e n v i r o n m e n -

    t a l f a c to r s , w h i l s t th e p l a n t p e r f o r m a n c e r e s u l t s f r o m

    t h e s i m u l t a n e o u s a c t i o n o f m a n y o f t h es e e x t e rn a l a n d

    o p e r a t i o n a l c o n d i t i o n s . I n t h i s in v e s t i g a t i o n , t h e r e -

    l a t i o n s h i p b e t w e e n t h e v a r i o u s g r o u p s o f t h e m i c r o -

    f a u n a a n d t h e m a i n o p e r a t i o n a l c o n d i t io n s o f th e

    p l a n t w e r e s t u d i e d b y a w i d e s u r v e y . F o r t y - f o u r

    a c t i v a t e d s l u d g e p l a n t s , i n c l u d i n g o x i d a t i o n d i t c h e s ,

    c o n v e n t i o n a l a e r a t i o n p l a n t s a n d e x t e n d e d a e r a t i o n

    u n i t s , w e r e s a m p l e d a n d t h e i r ch o i c e w a s m a d e i n

    o r d e r t o e x p l o r e a d i v e r s e s p e c t r u m o f d i f f er e n t

    o p e r a t i o n a l c o n d i t i o n s . T a b l e 3 s h o w s t h e c o r r e l a t i o n

    c o e f f i c i e n t s b e t w e e n n i n e g r o u p s o f t h e m i c r o f a u n a

    a n d s ix p h y s i c o - c h e m i c a l a n d o p e r a t i o n a l p a r -

    a m e t e r s . T h e s e r e s u lt s c o r r o b o r a t e t h e o b s e r v a t i o n s

    o f p r e v i o u s a u t h o r s , a n d e n a b l e o n e t o s e l ec t a n d

    g r o u p m i c r o f a u n a o r g a n i s m s i n t o p o si t iv e a n d n e g a -

    t i v e k e y g r o u p s . T h e p o s i t i v e k e y g r o u p s a r e c r a w l i n g

    a n d a t t a c h e d c i l i a t e s , a n d t e s t a t e a m o e b a e ; n e g a t i v e

    k e y g r o u p s a r e s m a l l fl a g e ll a te s , s w i m m i n g b a c t e r i v o -

    r o u s c i l i a t e s , a n d t h e p e r i t r i c h c i l i a t e s

    V o r t i c el l a m i -

    c r o s t o m a a n d O p e r c u l a r i a s p p . D e n s i t y a n d d i v e r s i t y

    o f t h e m i c r o f a u n a , m o r e o v e r , r e s u l t s to b e h i g h l y

    c o r r e l a t e d t o t h e p l a n t p e r f o r m a n c e .

    D e n s i t y a n d d i v e r s i t y

    M a n y r e c e n t s t ud i e s h av e d e m o n s t r a t e d t h a t t h e

    n u m b e r o f c i l ia t ed p r o t o z o a l i v in g in a n o r m a l l y

    f u n c t i o n i n g p l a n t i s a b o u t l 06 i n d i v i d u a l s / l . W h e n t h e

    n u m b e r f a l l s b e l o w 1 0 4/ 1, i t i n d i c a t e s i n s u f f i c i e n t

    p u r i f i c a t i o n ( C u r d s , 1 97 5; D r a k i d e s , 1 98 0; M a d o n i ,

    1 9 81 ). I n t h i s c a s e , t h e r e i s a p r o l i f e r a t i o n o f d i s p e r s e d

    b a c t e r i a w h i c h m a k e t h e e f f l u e n t t u r b i d a n d c o n s e -

    q u e n t l y c a u s e a g re a t l y in c r e a s e d B O D i n th e o u t p u t

    w a t e r . A h i g h n u m b e r o f c i l ia t e s ( > 10 7/ 1) o n t h e

    c o n t r a r y , a l m o s t a l w a y s i n d i c a t e s g o o d p u r i f i c a t i o n

    a n d o p t i m u m p l a n t p er f o rm a n c e . T h e m i c r o f au n a o f

    a n o r m a l l y f u n c t i o n i n g s y s t e m i s a l m o s t a l w a y s

    h i g h l y d i v e r s i f i e d , n a m e l y c o m p o s e d b y d i f f e r e n t

    g r o u p s o f o r g a n i s m s , e a c h g r o u p w i t h s e v e ra l s pe c ie s .

    N o g r o u p o r s p e ci es i s e v e r n u m e r i c a l ly d o m i n a n t

    o v e r t h e o t h e r c o m p o n e n t s , e v e n i f t h e r a t i o s b e t w e e n

    v a r i o u s g r o u p s o r s p e c i es c a n d i f fe r . O n t h e c o n t r a r y ,

    a m i c r o f a u n a w h i c h i s d o m i n a t e d b y o n e s p e c i e s o r

    g r o u p i s a l m o s t a l w a y s a n i n d e x o f t r o p h i c i m b a l -

    a n c e s d u e t o t h e e x i s te n c e o f l i m i t i n g f a c t o rs i m p e d i n g

    t h e d e v e l o p m e n t o f m o s t o f t h e o t h e r s p e c i e s a n d

    f a v o u r i n g th e g r o w t h o f f o r m s m o r e t o l e r a n t t o t h e s e

    f a ct o rs . T h e m o s t c o m m o n l i m i ti n g c o n d i t i o n s a r e

    g e n e r a l l y th e p r e s e n c e o f a s h o c k l o a d o f t o x ic

    Table 3. C orrelation coefficientsbetween protozoans and plan t operationalconditions,obtained from 44 activated sludge

    plants (*P < 0.01, **P < 0.001)

    Nitrifying BOD Effluent Sludge

    DO ability removed colour age MLSS

    Small flagellates -0.652* *

    Swimmingciliates - 0.651**

    Craw ling ciliates 0.616"*

    Sessile ciliates 0.340

    V. mk rostoma -0.676**

    Opercularia spp -0.745**

    Testate amoebae 0.727**

    Micro fauna density 0.626**

    No. of species 0.778**

    -0.596** -0.798** 0.836** -0.583** -0.736**

    -0.549** -0.829** 0.725** -0.668* * -0.753* *

    0.620** 0.784** -0.6 11* * 0.534** 0.534**

    -0.0 29 0.432* -0.5 16" * 0.171 0.266

    -0.504** -0.679** 0.648** -0.638** -0.722**

    -0.597** -0.763* * 0.676** -0.008 -0.181

    0.912"* 0.760** --0.583** 0.464* 0.464*

    0.429* 0.762** --0.768** 0.335 0.495**

    0.645** 0.923** -0.8 41" * 0.487** 0.591"*

  • 8/18/2019 Madoni, 1994 (SBI)

    4/9

    70 P OLO MJdgONI

    d i scha r ge , t he unde r - o r t he ove r l oad i ng , t he s t r ong

    s l udge ex t r ac t i on , t he l ack o f ae r a t i on .

    R e c e n t d a t a o b t a i n e d f r o m a s u r v e y o f p r o t o z o a i n

    seve r a l ac t i va t ed - s l udge p l an t s ( D e Mar co e t a l . ,

    1991) , co r r o bor a t e t hese r e su l ts ob t a i ned i n p r ev i ous

    w or ks . T hese au t hor s c la ss if ied t he abu ndan ce o f the

    microfauna into three c lasses (< 104, 104-106, > 106)

    according to the ef f ic iency of the plant (not ef f ic ient ,

    poorly efficient , well efficient respectively) and, by

    mean s o f t he K r us ka l - W al l i s t e s t o f va r i ance , w ere

    a b l e to p o i n t o u t t h a t b o t h o r g a n i c l o a d r e m o v e d a n d

    met a l co ncen t r a t i on i n t he mi xed l i quor w er e s i gn if i-

    can t l y d i f f e r en t i n t he t r ea t men t p l an t s , a ccor d i ng t o

    t he t h r ee c l as se s o f p r o t ozo a abu ndanc e . S t a ti s ti ca l

    ana l ys i s app l ied t o t he s t udy o f c i li a te s and o f

    phys i co - chem i ca l va ri ab l e s i n ac t i va t ed s l udge s ew age

    t r e a t m e n t p l a n t s s h o w e d t h a t t h e n u m b e r a n d d i v er -

    s i ty o f c il i at e comm uni t i e s change accor d i ng t o t he

    qua l i t y o f en t e r i ng s e t tl ed s ew age and ope r a t i ng

    c o n d i t i o n s o f t h e p l a n t ( E s t eb a n

    et al . ,

    1991; Esteban

    and Tellez, 1992).

    C r a w l i n g a n d a t t a c h e d c i l i a t e s

    T hese t w o c i l i a t e g r oups nor ma l l y co - domi na t e t he

    mi c r o f auna i n ac t i va t ed s l udge p l an t s . T h i s i s due t o

    t he i r d i f f e r en t f ood hab i t s p r even t i ng t he i r compe-

    t i ti on . N eve r t he l e s s , t he r a t io be t w een t he t w o g r oup s

    tends to change wi th s ludge loading. Crawl ing c i l i a tes

    d i mi n i sh t he i r p r e sence a s s l udge l oad i ng i nc r eases so

    t h a t a b o v e 0 . 6 k g B O D / k g M L S S • d , m o s t s p ec ie s o f

    t h i s g r oup d i s appea r ( C ur ds and C ockbur n , 1970b ;

    Kl im ow icz, 1 970) . Craw l ing c i li a tes are a l so inversely

    re la ted to SVI . H igh d ensi t ies of crawl ing c i l ia tes

    ( > 2000 ml - ~ ) a r e a l w ays a s soc i a t ed t o SV I va l ues

    sma l l e r t han 200 ; a t SV I va l ues g r ea t e r t han 400

    crawl ing c i l i a tes reduce dras t ica l ly in number

    ( Pagno t t a and T ommas i , 1979) .

    T e s t a te a m o e b a e

    T es t a t e amoebae i n ac t i va t ed s l udge a r e r ep -

    r e sen t ed by t he t h r ee gene r a :

    Arce l la , Di f f tug ia

    a n d

    E u g l y p h a . T hese p r o t ozoa co l on i ze t he s l udge o f

    p l an t s a t ve r y l ow s ludge l oad , i n pa r t i cu l a r t hey a r e

    f o u n d n o r m a l l y i n t h e a e r a ti o n b a s i n o f N r e m o v a l

    p l an t s ( Poo l e , 1984). T es t a t e amoe bae a r e mo r e abun-

    dan t o r domi nan t i n s l udges cha r ac t e r i zed by l ow

    l oad i ng , l ong r e t en t ion t i me , and h i gh D O i n ae r a t i on

    t ank t ha t enab l e compl e t e n i t r i f i ca t i on ( D r ak i des ,

    1978; C h i e r ic i and Ma don i , 1991) . U nd e r t hese con-

    di t ions , the q ual i ty o f the ef fluent i s excellent and high

    pe r f o r m ance o f t he p l an t is r eached . T es t a te am oebae

    a r e mor e abundan t i n p l an t s w i t h a l a r ge s l udge age

    s i nce t e s t a t e s have l ow g r ow t h r a t e s . T hey o f t en a r e

    s e a s o n a l b e i n g m o r e c o m m o n i n s u m m e r w h e n t e m -

    pe r a t u r e and g r ow t h r a t e s i nc r ease . Sasaha r a and

    O g aw a ( 1983) f ound t ha t E u g l y p h a a n d Di f f tug ia w er e

    a l w ays abundan t i n ac t i va t ed - s l udge p l an t s f o r b r ew -

    e r y e ff l uen t w i th l ow s l udge l oad and goo d qua l i t y o f

    the ef f luent . When the s ludge load was high

    ( > 1 k g B O D / k g M L S S . d ) a n d t h e C O D o f th e ef flu -

    ent was e levated, these species were replaced by the

    per i t r i ch c i l i a te Op e r c u l a r i a and by f r ee - sw i mmi ng

    ci l ia tes . Madoni et al . (1993) were able to f ind high

    corre la t ion coef f ic ients between the presence

    nd

    a b u n d a n c e o f te s ta t e a m o e b a e a n d s o m e p r e v a il in g

    env i r onm ent a l f ac t o r s and n i t r i f y ing cond i t i ons o f t he

    plant . These species , in fact , were associa ted wi th low

    a m m o n i a c a l - N c o n c e n t r a t i o n s , h i g h D O v a l u e s a n d

    l ow s l udge l oad and SV I va l ues .

    A t t a c h e d c il ia t es ( > 8 0 )

    Per i t r i ch c i l i a t e s a r e nor ma l l y co - domi nan t i n t he

    act ivated s ludge. Never theless , a mass ive increase in

    t h e ir n u m b e r ( > 8 0 % o f t h e w h o l e m i c r o f a u n a ) o c -

    cur s i n occas i on o f t r ans ien t s i t ua t i ons t h a t r edu ce t he

    p l an t pe r f o r mance ( D r ak i des , 1978 ; Madon i , 1981) .

    Such t r ans i en t cond i t i ons a r e ( 1 ) a qu i ck i nc r ease o f

    t he s l udge l oad due t o l os s o f s ludge and ( 2 ) a

    d i s con t i nuous i npu t o f o r gan i c l oad f r om t he i n f luen t .

    C ur ds and C ockbur n ( 1970b) f ound t ha t s e s s i l e c i l i -

    a r e s w er e ab l e t o g r ow t h r oughou t a l a r ge r ange o f

    s l udge i oad ings ; neve r the l e ss , a t va l ues r ang i ng f r om

    0.3 t o 0 .6 kg B O D / k g M L S S. d , t he se c il ia te s dom i -

    na t ed , and f o r s l udge I oad i ngs o f 0 .6 - 0 .9 s es si le

    c i li a tes an d f lagellates c o-d om inate d. Evide nce was

    f o u n d b y B e d o g n i

    et al .

    (1991) which suggested that

    t he abundance r a t i o be t w een c r aw l i ng and a t t ached

    c il ia te s w as a s soc i a t ed w i t h t he pe r f o r man ce o f t he

    p l an t . When r a t i o va l ues w er e h i gh ( >0 .5 ) a be t t e r

    qual i ty of the f inal ef f luent was achieved.

    A m on g a t t ached c il ia te s some f o r m s such a s V o r t i -

    c e l ia m i c r o s t o m a

    a n d

    Op e r c u l a r i a

    spp can su r v i ve and

    gr ow i n ac t i va t ed s l udge sub j ec t ed t o s eve r e con-

    d i t i ons ( l ack o f oxygen , t ox i can t s , e t c. ). W hen t hese

    spec i e s a r e p r e sen t i n h i gh number s , t hey mus t be

    cons i de r ed a s s epa r a t e keygr oups ( s ee be l ow ) .

    Op e r c u l a r i a s p p

    T hr ee speci es a r e com mo nl y f ound i n ac ti va t ed

    s ludge: O. coarc ta ta , O. microd i scus , and O . m i n i m a .

    L ow num ber s o f these c il ia te s a r e o f t en obse r ved i n

    act ivated s ludge. Never theless , Op e r c u l a r i a show s a

    c l ose a s soc i a t i on w i t h t he va r i ab l e s conce r ned w i t h

    t he qua l i t y o f t he ac t i va t ed s l udge and s t a t i s t i ca l

    analys i s conf i rm s that these c i li a tes are qui te useful as

    b i o i nd i ca t o r s , because t he i r number i nc r eases w hen

    t he ac t i va t ed s l udge is o f bad qu a l i t y ( E s t eban et al . ,

    1991) . C ur d s and C ock bur n ( 1970b) f o und t ha t

    O p e r -

    cularia spp were associa ted wi th high f inal ef f luent

    B O D concen t r a t i ons , and K l i mow i cz ( 1970) f ound

    t ha t t hese spec i e s w er e among t he mos t abundan t

    f o r ms a t h i gh l oad i ngs .

    Op e r c u l a r i a

    s p p m o r e o v e r c a n

    sur v i ve i n s t r e s sed env i r onment s be t t e r t han o t he r

    p r o t o z o a n s . S o m e a u t h o r s ( A n t o n i e t t i

    e t a l . ,

    1982;

    Becares , 1991; Card inale t t i and Zi te l li , 1991) , in fact ,

    f o u n d t h a t l a r g e n u m b e r s o f

    Op e r c u l a r i a

    occur i n

    s l udge o f p l an t s r ece i v i ng i ndus tr i a l w as t e con t a i n i ng

    toxic substances .

    Op e r c u l a r i a c o a r c t a t a

    m a y b e t h e

    o n l y c o m p o n e n t o f t h e m i c r o f a u n a , i n s lu d g es o f

    p l an t s t r ea t i ng i ndus t r i a l w as t e con t a i n i ng me t a l

  • 8/18/2019 Madoni, 1994 (SBI)

    5/9

    Sludge Biotic Index

    71

    sa l t s . O . mi c r o d i s c u s i s a b l e t o s u r v i v e t o s e v e r e la c k

    o f o x y g e n f o u n d i n s e d i m e n t a t io n t a n k s w i t h l o w

    r e t u r n - s l u d g e r a t i o . M o r e o v e r , t h e s e s p e c i es w e re

    a s s o c i a t e d w i t h h i g h fi n a l e f f lu e n t B O D a n d a m m o n i -

    a c a l - N c o n c e n t r a t i o n s ( P o o l e , 1 9 84 ; M a d o n i et al . ,

    1993).

    Op e r c u l a r i a

    s p p o f t e n a r e a s s o c i a t e d w i t h V .

    m i c r o s t o m a .

    V o r t i c e l l a m i c r o s t o ma

    T h e c i l i a t e V . m i c r o s t o ma i s q u o t e d i n t h e s a p r o b i c

    s y s t e m a s a p o l y s a p r o b i c s p e c ie s ( S l a d e c e k , 1 9 73 ;

    F o i s sne r , 1988) . T h i s c i l i a t e is f r equen t ly p re sen t i n

    t h e p l a n t d u r i n g t h e f ir s t p h a s e o f c o l o n i z a t i o n b u t i s

    s u b s t i t u t e d b y o t h e r s p e c i e s V. conva l lar ia ) w h i c h

    b e c o m e d o m i n a n t d u r i n g s t a b l e c o n d i t i o n s . W h e n

    t h e r e i s a d r a s t i c r e d u c t i o n i n t h e d i s s o l v e d o x y g e n

    c o n c e n t r a t i o n i n t h e m i x e d l i q u o r , a n a l t e r n a t i o n o f

    t h e t w o s p e c i es is o b s e r v e d , d u e t o t h e i r d i f f e r e n t

    d e g r e e o f t o le r a n c e t o t h e l a c k o f o x y g e n ( M a d o n i

    and A nton i e t t i , 1984) . V . m i c r o s t o ma t hus , i nd i ca t e s

    a l a c k o f d i s s o l v e d o x y g e n i n t h e a e r a t i o n t a n k ; t h e

    g r e a t e s t r e s i s t a n c e t o t h e i n f l u e n c e o f a n o x i c e n v i r o n -

    m e n t w a s n o t i c e d f o r t h i s s p e c ie s a l s o b y o t h e r

    au thor s (B ick , 1972 ; T om an and R e j i c , 1988) . M as -

    s iv e g r o w t h o f t h i s s e s s il e c i l i a te w a s o b s e r v e d i n t h e

    a e r a t i o n t a n k s i n o c c a s i o n s o f h i g h w a s t e w a t e r f l o w

    a r r i v a l t o t h e s e w a g e p l a n t a n d l o w v a l u e s o f m a s s i c

    l o a d i n g a n d w a t e r c o l o u r o f t h e e f f l u e n t ( E s t e b a n

    e t a l . , 1 9 9 0 ) . L a r g e n u m b e r s o f V . m i c r o s t o ma in

    o c c a s i o n s o f l o w v a l u es o f D O , M L S S , a n d h i g h

    v a l u e s o f s lu d g e l o a d a n d S V I , w e r e f o u n d a l s o b y

    P o o l e ( 1 9 8 4 ) a n d E s t e b a n et al . (1991).

    F r e e - s w i mmi n g c i l i a t e s

    S w i m m i n g b a c t i v o r o u s c i l i at e s a r e m o r e a b u n d a n t

    i n t h e e a r l y p h a s e s o f a d e v e l o p i n g p l a n t , w h e n s l u d g e

    f locs a r e s t i l l s ca rce and , co nseq uen t ly , s e s s i l e c i l i a t e s

    a r e a b s e n t . N e v e r t h e l e s s , th e y a r e s o o n s u b s t i t u t e d b y

    a t t a c h e d c i l i a te p o p u l a t i o n o w i n g t o c o m p e t i t i o n f o r

    d i s p e r s e d b a c t e r i a . A t t a c h e d c i l i a t e s , i n f a c t , a r e

    f i lt e r - fe e d e r s m o r e e f fi c ie n t t h a n f r e e - s w i m m i n g f o r m s

    t o e n f o r c i n g s u s p e n d e d b a c t e r i a i n t o t h e o r a l r e g i o n

    b y m e a n s o f c i l i a r y c u r r e n t s . C u r d s ( 1 97 1 ) w a s a b l e

    t o s h o w , b y m e a n s o f c o m p u t e r s i m u l a t io n o f m i c r o -

    b i a l p o p u l a t i o n d y n a m i c s , t h a t h i g h - q u a l i t y e f f l u e n t

    w a s p r o d u c e d w h e n a t t a c h e d a n d c r a w l i n g c i l i a t e s

    w e r e d o m i n a n t , a s l i g h t l y w o r s e e f f lu e n t q u a l i t y w h e n

    f r e e - s w i m m i n g c i li a t e s w e r e d o m i n a n t , a n d a l o w -

    qua l i t y e f f l uen t w hen no c i l i a t e s w ere p re s en t a t a l l .

    S m a l l f r e e - s w i m m i n g c i l ia t e s ( su c h a s

    C o l p i d i u m, C y -

    c l i d i u m, T e t r a h y me n a , a n d U r o n e m a ) s o m e t i m e s

    d o m i n a t e t h e m i c r o f a u n a o f p l a n t s o p e r a ti n g a t

    s l u d g e t o o s h o r t a g e d o r a t b o t h h i g h s l u d g e l o a d i n g

    a n d l a c k o f o x y g e n . T h e s e b a c t e r i v o r o u s p r o t o z o a n s

    r e q u i r e h i g h c o n c e n t r a t i o n s o f d i s p e r s e d b a c t e r i a

    b u t s u r v i v e b e tt e r t h a n o t h e r c o m p o n e n t s o f t h e

    m i c r o f a u n a t o t h e t o x i c i t y o f t h e in f l u e n t a n d t o

    l a c k o f o x y g e n . S m a l l f r e e - s w i m m i n g c i l i a t e s e v e r

    c o u p l e w i t h h e t e r o t r o p h i c f l a g e ll a t e s a n d s o m e t i m e s

    t h e s e t w o k e y g r o u p s c o - d o m i n a t e t h e m i c r o f a u n a .

    C u r d s a n d C o c k b u r n ( 1 9 7 0 b ) f o u n d t h a t s w i m m i n g

    f o r m s w e r e d o m i n a n t a t h i g h s l u d g e l o a d i n g s

    ( 0 .6 - 0 .9 k g B O D / k g M L S S . d ) .

    I t s h o u l d b e e m p h a s i z e d t h a t t o t h i s k e y g r o u p

    b e l o n g o n l y b a c t e r i v o r o u s c i l i a t e s ; f r e e - s w i m m i n g

    c a r n i v o r o u s f o r m s s u c h a s A mp h i l e p t u s , L i t o n o t u s ,

    S p a t h i d i u m, e t c . ( s ee T ab l e 1 ) m us t no t be i n se r t ed

    i n t o t h i s k e y g r o u p .

    Flage l la te s

    S m a l l h e t e r o t r o p h i c f l a g e l l a t e s s u c h a s B o d o , P o l y -

    t o ma , a n d T e t r a mi t u s , n o r m a l l y d o m i n a t e t h e m i c r o -

    f a u n a d u r i n g t h e s t a r t i n g p h a s e o f th e p l a n t w h e n

    f l o c - f o r m i n g b a c t e r i a a r e s t il l s c a rc e l y p r e s e n t . T h e y

    f e e d o n d i s p e r s e d b a c t e r i a a n d , i n t i m e , a r e s u b s t i -

    t u t e d b y b a c t e r i v o r o u s c i li a t es . B y c o n t r a s t , t h e m a s -

    s i v e p r e s e n c e o f t h e s e p r o t o z o a n s i n a m a t u r e

    a c t i v a t e d s l u d g e , i s a s s o c i a t e d t o b a d p e r f o r m a n c e o f

    t h e b i o l o g i c a l d e p u r a t i o n , d u e t o t h e f o l l o w i n g

    c a u s e s : ( a ) p o o r l y a e r a t e d s l u d g e , ( b ) o v e r l o a d i n g ,

    ( c ) f e r m e n t i n g s u b s t a n c e s i n v o l v e d ( D r a k i d e s , 1 9 7 8 ;

    M a d o n i , 1 9 8 6) . F l a g e l l a t e s b e c o m e t h e o n l y p r o t o -

    z o a n f o r m p r e s e n t i n s l u d g e s s t r o n g l y l o a d e d

    ( > 0 . 9 k g B O D / k g M L S S . d ) ( C u rd s a n d C o c k b u r n ,

    1 9 70 b ). F l a g e l l a t e s c o n t i n u o u s l y e n t e r t h e p l a n t b y

    t h e s e w a g e i n fl u e n t w h e r e t h e y a r e v e r y n u m e r o u s . I n

    a n o r m a l l y - f u n c t i o n i n g a c t i v a t e d s l u d g e t h e s e p r o t o -

    z o a o u t c o m p e t e t h e b a c t e r i v o r o u s c i l ia t e s a n d , i n

    a d d i t i o n , t h e y a r e s t r o n g l y s u b j e c t e d t o p r e d a c e o u s

    a c t i v i t y o f o t h e r p r o t o z o a ; s o , t h e i r p r e s e n c e i n

    t h e a c t i v a t e d s l u d g e i s l i m i t e d t o f e w i n d i v i d u a l s

    ( < 1 0 i n d . c o u n t e d a l o n g t h e d i a g o n a l i n t h e

    F u c h s - R o s e n t h a l c h a m b e r ) . I n t h e c a s e o f d i sf u n c -

    t i o n s o f th e p l a n t , t h e i r n u m b e r c a n i n c r e a s e

    ( > 1 0 i n d . c o u n t e d ) a n d , c o n s e q u e n t l y , t h i s i n d i c a t e s

    a d e c r e a s e i n t h e p l a n t p e r f o r m a n c e . T h e d o m i n a n c e

    o f f l a g e ll a t e s b e c o m e a p p a r e n t w h e n t h e y r e a c h t h e

    d e n s i t y o f m o r e t h a n 1 00 in d i v i d u a l s a l o n g t h e d i a g -

    o n a l i n t h e F u c h s - R o s e n t h a l c h a m b e r . I n t h i s l a s t

    c a s e t h e y s h o u l d b e c o n s i d e r e d a s t h e d o m i n a n t

    k e y g r o u p .

    L a r g e f l a g e l l a t e s s u c h a s E u g l e n a a n d P e r a n e ma ,

    a r e i n f r e q u e n t l y o b s e r v e d i n t h e a c t i v a t e d s l u d g e

    w h e r e t h e y g r o w h a r d l y i n l a r g e n u m b e r s . T h e i r

    p r e s e n c e i s r e la t e d t o i n f lu e n t s c h a r a c t e r i z e d b y v e r y

    d i l u t e d o r g a n i c m a t t e r .

    THE SLUDGE BIOTIC INDEX

    T h e s l u d g e b i o t i c i n d e x ( S B I ) h e r e p r o p o s e d i n

    T a b l e s 4 a n d 5 , h a s b e e n s e t u p o n t h e b a s i s o f t h e

    r e s u l ts o b t a i n e d b o t h b y t h e n u m e r o u s r e s e a r c h c o n -

    d u c t e d o n t h e a c t i v a te d - s l u d g e m i c r o f a u n a d u r i n g

    t h e l a s t 2 0 y e a r s a n d i n t h e p r e s e n t r e s e a r c h a s

    w e l l ( T a b l e 3 ) , a s s u m m a r i z e d a b o v e . T h e s e n s i t iv i t y

    o f t h e p r o p o s e d m e t h o d w a s a s s e ss e d o n t h e b a s i s o f

    p h y s i c a l , c h e m i c a l , a n d o p e r a t i n g c o n d i t i o n s o f t h e

    p l a n t s . T h i s m e t h o d i s b a s e d b o t h o n t h e d i f f er e n t

    s e n s i t iv i t y s h o w e d b y s o m e k e y g r o u p s t o p r i n c i p a l

    p h y s i c o -c h e m i c a l a n d o p e r a t i n g p a r a m e t e r s , a n d o n

  • 8/18/2019 Madoni, 1994 (SBI)

    6/9

    7 2 P A O L O M A D O N I

    T a b l e 4 . T w o - w a y t a b l e t o d e t e r m i n e t h e S l u d g e B i o t ic I n d e x ( S B I ) o n t h e b a s i s o f k e y g r o u p s , d e n s i ty a n d n u m b e r o f t a x o n o m i c u n i t s o f

    t h e m i c r o f a u n a

    D o m i n a n t g r o u p a n d d e n si ty o f t h e m i c r o f a u n a

    t h a t d e f i n e th e h o r i z o n t a l r o w o f e n t r a n c e i n

    t h e t a b l e

    T o t a l n u m b e r o f t a x o n o m i c u n i ts t h a t c o n s t i tu t e t h e m i c r o f a u n a o f

    t h e a c t i v a t e d s lu d g e a n d n u m b e r o f s m a l l f la g e l la t e s ( F ) c o u n t e d

    a l o n g t h e F u c h s - - R o s e n t h a l c h a m b e r d i a g o n a l

    > 10 8- -10 5-7 < 5

    D o m i n a n t D e n s i t y

    k e yg r ou p (in d. /I ) F < I 0 1 0 < F < 1 0 0 F < 1 0 1 0 < F < I 0 0 F < I 0 1 0 < F < I 0 0 F < I 0 1 0 < F < I 0 0

    Cr awl ing + s ess i le* > /106 10 8 9 7 8 6 7 5

    c i l i a t e s an d/ or < 106 9 7 8 6 7 5 6 4

    t e s ta t e a m o e b a e

    Sessile /> 106 9 7 8 6 7 5 6 4

    ci l iates* < 106 8 6 7 5 6 4 5 3

    > 8 0 %

    Opercularia spp /> 106 7 5 6 4 5 3 4 2

    < 106 6 4 5 3 4 2 3 I

    Vorticella microstoma /> 106 6 4 5 3 4 2 3 1

    < 106 5 3 4 2 3 I 2 0

    Sw imm ing bac t e r i - > /106 5 3 4 2 3 1 2 0

    vo rou s c i l i a t e s < 106 4 2 3 1 2 0 1 0

    Sm al l - s w imm ing t> 106 4 3 2 1

    flage l lates < 106 3 2 1 0

    (> lOO)~

    Opercularia s p p a n d Vorticella microstoma n o t a b u n d a n t ; t a l o n g t h e F u c h s - R o s e n t h a l c h a m b e r d i a g o n a l .

    t he abun danc e and t he d i ve rs i ty o f the mi c r o f au na : i t

    enab l e s us t o de fi ne t he b i o l og i ca l qua l i t y o f t he

    s l udge by means o f conven t i ona l numer i ca l va l ues

    ( b i o t i c i ndex) . T he SB I cons i de r s a l so t he f o l l ow i ng

    po i n t s :

    - - t he spec ie s r i chnes s t ends t o change w i t h t he s l udge

    l oad . T he h i ghe r n um ber o f spec ie s has been

    obse r ved w hen l oad i ngs a r e r ang i ng f r om 0 .2 t o

    0 .3 k g B O D / k g M L S S - d ( C u rd s a n d C o c k b u r n ,

    1970b);

    - - t h e d e n s i ty o f th e m i c r o f a u n a d r o p s d o w n a s th e

    s l udge l oad l ow er s . I n t he ae r a t i on bas i n o f N

    r emov a l p l an t s , a mi c r o f auna l e ss abu nda n t t ha n i n

    conven t i ona l p l an t s i s expec t ed .

    T he i ndex t o be a sc r i bed t o t he ac t i va t ed s l udge

    und e r t e s t is ob t a i ned b y means o f a t w o- w ay t ab l e

    ( T ab l e 4 ). T he key gr oup s f o l low i ng one ano t he r

    f r o m t h e u p p e r p a r t t o w a r d t h e lo w e r p a r t o f t he

    t ab le , i nd i ca t e a w or se and w or se b i o l og i ca l qua l i t y o f

    t he s l udge . I n t he co l umn head i ngs f our r anges i n

    w h i c h t h e t o ta l n u m b e r o f t a x o n o m i c u n i t s o f th e

    mi c r o f auna f al ls a r e r epor t ed . T he t w o- w ay tab l e

    T a b l e 5 . C o n v e r s i o n o f S B 1 v a l u e s i n t o f o u r q u a l i t y c l a s s e s a n d

    r e s p e c t i v e j u d g e m e n t s

    S B I

    v a l u e C l a s s J u d g e m e n t

    8 - 1 0 I

    6 - 7 I I

    4-5 I I1

    0 - 3 I V

    V e r y w e l l c o l o n i z e d a n d s t a b l e s l u d g e , e x c el -

    l e n t b i o l o g i c a l a c t i v i t y ; v e r y g o o d p e r f o r m -

    a n c e

    W e l l c o l o n i z e d a n d s t a b l e s l u d g e , b i o l o g i c a l

    a c t iv i t y o n d e c r e a s e; g o o d p e r f o r m a n c e

    I n s u f f ic i e n t b i o l o g i c a l d e p u r a t i o n i n t h e a e r -

    a t i o n t a n k ; m e d i o c r e p e r f o r m a n c e

    P o o r b i o l o g ic a l d e p u r a t i o n i n t h e a e r a t i o n

    t a n k ; l o w p e r f o r m a n c e

    m o r e o v e r c o n si d e rs t h e a b u n d a n c e o f b o t h m i c r o -

    fau na (exclu ding flagellates) a nd flagellates. T o deter-

    mine the SBI i t i s necessary to se lect the hor izonta l

    w a y - i n o n t h e r o w t h a t c o r r e s p o n d s t o t h e d o m i n a n t

    keyg r oup oc cupy i ng t he l ow er pos i t i on , t ak i ng i n t o

    account i t s dens i ty (more or l ess than 106ind. / l ) .

    T he ve r ti ca l w ay- i n i s de t e r mi ned by t he t o t a l num ber

    of t axon om i c un i t s and dens i t y o f f lagel la te s a s

    well.

    O nce bo t h hor i zon t a l and ve r t i ca l w ays a r e i den t -

    i f i ed, the SBI value can be determined and thi s i s

    s i t ua t ed i n co r r e spondence o f t he i r c r os s . T he t w o-

    w ay t ab l e a l l ow s us t o pu t i n a number f r om 0 t o 10

    f o r t he b i o l og i ca l qua l i ty o f t he ac t iva t ed s l udge on

    the bas i s of two ind icators : the di f ferent sens i t ivity

    s h o w e d b y s o m e m i c r o f a u n a l g r o u p s t o e n v i r o n m e n -

    ta l condi t io ns o f the s ludge, and the ef fect that these

    c o n d i t i o n s p r o d u c e o n b o t h a b u n d a n c e a n d r i c h n e s s

    o f t h e p r o t o z o a n c o m m u n i t y .

    F i na l l y , the va l ues o f SB I have been g r ouped i n t o

    f o u r q u a l i t y c l a s s e s m a r k e d b y a R o m a n n u m b e r

    (Table 5) . These c lasses a l low to represent the biologi -

    ca l qua l it y o f t he ac t iva t ed s l udge t h r oug h f o ur

    r anges o f j udgem ent s r a t he r w i de, a nd t hus o f re l iab l e

    diagnost ic value .

    V E R I F I C A T I O N

    T he s t r i c t app l i cab i l i t y o f t he p r oposed me t hod

    was tes ted by inves t igat ing 45 act ivated s ludges . In

    each ac t i va t ed s l udge t he mi c r o f auna w as bo t h i den t -

    i f i ed and enumer a t ed , and t he p r i nc i pa l phys i ca l ,

    chemi ca l , and ope r a t i ona l pa r ame t e r s such a s B O D

    a n d a m m o n i u m r e m o v a l , D O , s l u d g e a n d s e w a g e

    retent ion t ime, MLSS, ni t r i fying abi l i ty , e tc . were

    regis tered. This t es t showed that the method gives

  • 8/18/2019 Madoni, 1994 (SBI)

    7/9

    Sludge Biotic Index 73

    c o r r e c t a n a l y s i s o f th e p l a n t p e r f o r m a n c e , i n a l l t h e

    c a s e s i n v e s t i g a t e d . T h e t w o - w a y t a b l e d i s p l a y s 8 8

    d i f f e r e n t s i t u a t i o n s t h a t c a n b e o b s e r v e d , a n d t h e s e

    e v e n t s f a l l i n t o t h e f o u r q u a l i t y c l a s s e s i n t h e p r o -

    po r t i o n o f 9 , 18 , 24 , and 37 , r e spec t i ve ly . T he t e s t ,

    o b v i o u s l y , w a s u n a b l e t o v e r i f y a l l s i t u a t io n s ; n e v e r -

    t he l e s s , s i nce i t w as p oss ib l e t o v e r i fy t he r e l i ab i l i t y o f

    t h e m e t h o d a t t h e e x t r e m e S B I v a lu e s f o r e ac h q u a l i t y

    c l a s s , i t s e e m s w e l l - f o u n d e d t o e x p e c t a f u l l r e l i a b i l i ty

    o f t h e m e t h o d t o t h e i n t e r m e d i a t e S B I v a lu e s t o o .

    P R O C E D U R E P R O T O C O L

    S i n c e t h e m e t h o d h e r e p r o p o s e d i s b a s e d o n d i v e r -

    s i t y a n d d e n s i t y o f t h e m i c r o f a u n a , p a r t i c u l a r a t t e n -

    t i o n s h o u l d b e p a i d t o b o t h i d e n t i f i c a t i o n a n d

    e n u m e r a t i o n o f t h e s e o r g a n is m s .

    Identification of the microfauna

    A l t h o u g h a l a r ge n u m b e r o f o r g a n is m s c a n b e

    o b s e r v e d i n t h e a c t i v a t e d s l u d g e p r o c e s s , s o m e f o r m s

    s u c h a s b o t h n a k e d a m o e b a e a n d d r i f t in g o r g a n i sm s

    ( a l g a e , c ru s t a c e a n s , i n s e c t s ) , a r e n o t c o n s i d e r e d i n t h i s

    m e t h o d . O r g a n i s m s t o i n c l u d e i n t h e m i c r o f a u n a

    a re : sm a l l and l a rge f l age l l a t e s , c i l i a t e s , t e s t a t e am oe-

    b a e , r o t i f e r s , a n d n e m a t o d e s . A l l t h e s p e c i e s o f c i l i-

    a t e d p r o t o z o a a n d t e s ta t e a m o e b a e c o n t r i b u t e t o t h e

    d e t e r m i n a t i o n o f t h e m i c r o f a u n a d i v e r s i t y ( v e r t i c a l

    w a y i n t he S B I t ab l e ) . S ince fl age l l a t e s , r o t i f e r s and

    n e m a t o d e s a r e v e r y d i f f i c u l t t o i d e n t i f y a t s p e c i e s

    l e v el , t h e s e g r o u p s c o n t r i b u t e e a c h w i t h 1 s y s t e m a t i c

    u n i t o n l y .

    C o n c e r n i n g k e y g r o u p s ( h o r i z o n t a l i n t h e S B I

    t a b l e ) , i t s h o u l d b e r e m e m b e r e d t h a t o n l y b a c t e r i v o -

    r o u s c i l i a t e s b e l o n g i n t h e t h r e e f u n c t i o n a l g r o u p s

    ( f r e e - sw i m m i n g , c r a w l i n g , a t t a c h e d ) . C a r n i v o r o u s c i l -

    i a t e s c o n t r i b u t e o n l y t o t h e t o t a l d e n s i t y a n d d i v e r s i t y

    o f th e m i c r o f a u n a . S w i m m i n g p r e d a c e o u s c i l ia t e s

    s u c h a s

    Litonotus, Amphileptus, Spathidium,

    m u s t b e

    e x c l u d e d b y t h e " f r e e - s w i m m i n g c i l i a t e s " k e y g r o u p ;

    i n t h e s a m e w a y a t t a c h e d p r e d a c e o u s c i l ia t e s s u c h a s

    t h e s u c t o r i a n s

    Podophrya, Tokophrya,

    a n d

    Acineta,

    m u s t b e e x c l u d e d b y t h e " s e s s i l e c i l i a t e s " k e y g r o u p .

    T h e i d e n t i f i c a t i o n o f t h e v a r i o u s s p e c i e s o f p r o t o z o a

    i s i m p o r t a n t , i n o r d e r t o o b t a i n a n a c c u r a t e S B I

    v a l u e ; h o w e v e r , s o m e k e y s w r i t t e n s p e c i fi c a l ly a b o u t

    t h e p r o t o z o a f o u n d i n a c t i v a t e d s l u d g e t r e a t m e n t

    p r o c e s s a n d p o l l u t e d w a t e r s a r e a v a i l a b l e ( C u r d s ,

    1969; M ad on i , 1981, 1988; S t r eb l e and K r au t e r , 1981;

    F o i s s n e r

    et al.,

    1991, 1992).

    I n o r d e r t o l i st t h e s p e c i e s p r e s e n t i n t h e s l u d g e , th e

    f o l l o w i n g p r o c e d u r e i s s u g g e s t e d :

    - - t o c o m p l e t e a n a l y s e s w i t h i n 5 h f r o m c o l l e c t i o n .

    S a m p l e s o f m i x e d l i q u o r f o r m i c r o s c o p i c a l o b s e r -

    v a t i o n s m u s t b e k e p t a l i v e d u r i n g b o t h c a r r i a g e a n d

    a n a l y s i s p e r i o d , b y a e r a t i n g t h e m s u f fi c i en t l y t o

    k e e p a l l s o l i d s i n s u s p e n s i o n ;

    - - t o t a k e a l i tt l e d r o p ( 5 0 - 1 0 0 /H ) o f m i x e d - l iq u o r

    f o r e x a m i n a t i o n u n d e r m i c r o s c o p e . C o v e r g l a s se s

    2 4 x 2 4 m m o r 2 4 x 3 2 m m a r e r e c o m m e n d e d .

    Enumeration of the mierofauna

    T w o d i f f e r e n t c o u n t s a r e r e q u i r e d : e s t i m a t e o f t h e

    m i c r o f a u n a a b u n d a n c e ( e x c l u d i n g s m a l l f l a g e l l a t e s ) ,

    a n d e s t i m a t e o f t h e a b u n d a n c e o f s m a l l f l a g e l l a t e s .

    T h e f i rs t c o u n t i s n e c e s s a r y t o e s t a b l i s h b o t h t h e c l a s s

    o f a b u n d a n c e i n to w h i c h t h e m i c r o f a u n a f a ll s ( < o r

    /> 1 06 /1 ), a n d t h e a b u n d a n c e r a t i o ( % ) a m o n g g r o u p s

    a n d s p e c ie s . E s t i m a t e o f p o p u l a t i o n d e n s i t y sh o u l d b e

    b a s e d o n e n u m e r a t i o n f r o m s u b - s a m p l e s e x t r a c t e d

    w i t h a n a u t o m a t i c m i c r o p i p e t te . F o r t h e m o s t a p p r o -

    p r i a t e d r o p s i ze a n d n u m b e r o f r e p l i c a t e c o u n t s ,

    t o r e f e r t o s u b - s a m p l i n g t e c h n i q u e s d e s c r i b e d b y

    M a d o n i ( 1 9 8 4 ) a n d A u g u s t i n

    et al.

    (1989) speci f ical ly

    f o r t h e s lu d g e m i c r o f a u n a . M o s t l y , 2 5 # 1 s u b - s a m p l e s

    o f a c t i v a t e d s l u d g e a n d 1 o r 2 r e p l i c a t e s o f t h is

    vo lum e a re su f f i c i en t . I n t h i s ca se , cove rg l a s ses o f

    1 8 x 1 8 m m a r e r e c o m m e n d e d i n o r d e r t o p r e v e n t a

    q u i c k d r y i n g o f t h e s u b - s a m p l e s . C o u n t s s h o u l d b e

    m a d e u n d e r m i c r o s c o p e a t l o w m a g n i f i c a t i o n ( × 1 0 0 ).

    W h e n c o l o n i a l s p e c i e s a r e o b s e r v e d

    Carchesium,

    Epistylis, O percularia, Zootham nium ),

    a l l in d i v i d u a l s

    o f t h e c o l o n y m u s t b e c o u n t e d . I n t h e c a s e o f sp e c i e s

    f o u n d i n t h e s c r e e n i n g b u t n o t o b s e r v e d d u r i n g

    c o u n t s , t h e s e s h o u l d b e c o n s i d e r e d a s p r e s e n t i n t h e

    p r o p o r t i o n o f 1 i n d i v i d u a l/ m l .

    E s t i m a t e o f s m a l l f la g e l l a t e p o p u l a t i o n r e q u i r e s

    a n a p p r o p r i a t e c o u n t t e c h n i q u e , d u e t o t h e i r v e r y

    r e d u c e d s i z e a n d h i g h d e n s i t y , o f t e n r e a c h i n g

    1 0 7 - 1 0 8 in d . /l . F o r t h i s p u r p o s e , a 3 . 2 / ~ 1 F u c h s -

    R o s e n t h a l c h a m b e r c a n b e u s e f u ll y e m p l o y e d . T h e

    c h a m b e r i s 4 x 4 × 0 .2 ( d e p t h ) m m s i z e d a n d i s

    sub- d iv id ed i n to 256 squa res , 250 /~ m s i zed : f l age l -

    l a t e s i n s i d e th e 1 6 s q u a r e s a l o n g t h e d i a g o n a l o f t h e

    c h a m b e r s h o u l d b e c o u n t e d . W h e n f l a g e l l a t e s

    c o u n t e d a l o n g t h e d i a g o n a l a r e l es s t h a n 1 0, i t m e a n s

    t h a t t h e i r d e n s i t y i n t h e a c t i v a t e d s l u d g e m i x e d l i q u o r

    i s l e s s t han 50 , 000 m l ; ov e r 100 f l age l l a t e s a lon g t he

    d i a g o n a l c o r r e s p o n d t o t h e d e n s i t y o f 5 . 1 0 8 i n d . / l .

    F l a g e l la t e c o u n t s s h o u l d b e m a d e u n d e r m i c r o s c o p e

    a t x 200 m ag n i f i ca t i on .

    A n e x a m p l e o f e n u m e r a t i o n o f t h e m i c r o f a u n a a n d

    u t i l i z a t i o n o f t h e S B I i s r e p o r t e d i n T a b l e 6 .

    F I N A L R E M A R K S

    I t w a s p o s s i b l e t o c o n s t r u c t a S l u d g e B i o t i c In d e x

    b a s e d o n b o t h s t ru c t u r e a n d a b u n d a n c e o f t he m i c r o -

    f a u n a i n h a b i t i n g t h e a c t i v a t e d s l u d g e m i x e d l i q u o r .

    A s m e t h o d s , t h e S B I w a s a l s o s e t u p o n t h e b a s i s o f

    t h e r e l a t i o n s h i p o c c u r r i n g b e t w e e n p l a n t p e r f o r m a n c e

    a n d o p e r a t i n g c o n d i ti o n s o n o n e h a n d , a n d s t r u ct u r e

    o f t h e m i c r o f a u n a w i t h i n t h e a c t i v a t e d s lu d g e r e a c t o r

    o n t h e o t h e r . T h e m e t h o d w a s f o r m u l a t e d w i t h t h e

    n e e d s o f a t r e a t m e n t p l a n t o p e r a t o r i n m i n d , s o b o t h

    i d e n t if i c at i o n a n d e n u m e r a t i o n o f t h e m i c r o f a u n a

    w e r e s u i t a b l e . A f u r t h e r a d v a n t a g e o f t h i s m e t h o d

    o v e r o t h e r s c h e m e s i s t h a t i t p r o v i d e s n u m e r i c a l

    v a l u es w h ic h e n a b l e t h e o p e r a t o r t o c o m p a r e d a y b y

    d a y t h e p r e v a l e n t p l a n t o p e r a t i n g c o n d i t i o n s .

  • 8/18/2019 Madoni, 1994 (SBI)

    8/9

    74

    PAOLOMADON

    Table 6. Example of the est imation of the microfauna density and

    use of the sludge biotic index SB to predict the biological quali ty

    of the sludge

    Taxa No . 25 pl No./ml %

    Swimming cil iates

    Paramecium caudatum 1 40 < 1

    Crawling ciliates

    Aspidisca cicada 312 12,480 45

    Aspidisca lynceus 23 920 3

    Chilodonella uncinata

    16 640 2

    Euplotes af f inis - - I - -

    Trochilia minuta 24 960 3

    Attached ciliates

    Vorticella convallaria 203 8120 29

    Vorticella m icrostoma 3 120 < 1

    Vorticella octava 71 2840 10

    Epistylis plicatilis 9 360 1

    Opercularia coarctata 18 720 3

    Carnivorous ciliates

    Litonotus fasciola

    8 320 I

    Podophrya

    sp. 2 80 < I

    Testate amoebae

    Arcella

    3 120 < 1

    E ugly pha - - 1 - -

    Large flagellates I 40 < 1

    Rotifers 3 120 < 1

    Total microfau na 697 27,882 100

    Sma ll flagellates* < 10

    Free-swimming cil iates 1 40 < 1

    Craw ling ciliates 375 15,001 54

    Attached ciliates 304 12,160 44

    Testate amoe bae 3 121 < 1

    Do mina nt keygroup : crawling + attached cil iates; microfauna den-

    sity: > 106/I; total num ber of taxa = 17; small flagellates: < 10;

    SBI = 10; quality class = 1.

    *Along the Fuchs-Rosenthal chamber diagonal.

    I t s h o u l d b e e m p h a s i z e d h o w e v e r t h a t t h e S B I w a s

    s e t u p s p e c i f i ca l ly f o r t h e e v a l u a t i o n o f t h e b i o l o g i c a l

    r e a c t o r p e r f o r m a n c e . T h i s i n d e x t h u s , is u n a b l e t o

    r e v e a l a n y d i s f u n c t i o n i n th e f in a l s e d i m e n t a t i o n t a n k

    ( i. e. b u l k i n g , r i s in g ) , e v e n i f s o m e o f t h e s e p r o b l e m s ,

    s u c h a s l o s s e s o f s lu d g e , c a n c a u s e , i n t im e , c h a n g e s

    i n th e c o m m u n i t y s t r u ct u r e .

    T h e i n d e x w a s d e s i g n e d t o b e u s e d i n al l a c t i v a t e d

    s l u d g e p l a n t s i n c lu d i n g o x i d a t i o n d i t ch , c o n v e n t i o n a l

    a e r a t i o n p l a n t s a n d e x t e n d e d a e r a t i o n u n i t s. T h e

    m i c r o f a u n a u s e d i n t h e in d e x g e n e r a ll y h a v e a c o s m o -

    p o l i t a n d i s t r i b u ti o n ; w e t h e r e f o r e a s s u m e t h a t t h e

    i n d e x i s a p p l i c a b l e t o t h e a c t i v a t e d s l u d g e p l a n t s i n al l

    t h e c o n t i n e n t s .

    A c k n o w l e d g e m e n t s - - T h e

    a u t h o r w o u l d l i k e t o t h a n k D r

    D o n a t e l l a D a v o l i a n d a l l m e m b e r s o f t h e A G A C l a b o r a t o r y ,

    R e ggi o E mi l i a , fo r t he i r a s s i s t a nc e i n t e s t i ng t he p ropose d

    m e t h o d a n d P r o f e s s o r N i c o l a R i c c i, P r o f e s s o r I r e n e o F e r r a r i ,

    a n d o n e a n o n y m o u s r e v ie w e r f o r p r o v i d i n g h e l p f u l c r it ic i sm s

    on t he ma nusc r i p t . T he i nve s t i ga t i on wa s f i na nc i a l l y sup-

    por t e d by I t a l i a n M i n i s t ry fo r Uni ve r s i t y a nd Sc ie n ti fi c &

    T e c h n o l o g i c R e s e a r c h ( M U R S T 6 0 % , P . M a d o n i ) .

    R E F E R E N E S

    A I - S h a h w a n i S . M . a n d H o r a n N . J . (1 9 91 ) T h e u s e o f

    p r o t o z o a t o i n d i c a t e c h a n g e s i n t h e p e r f o r m a n c e o f

    a c t i v a t e d s l u d g e p l a n t s . W a t . R e s . 25 , 633-638 .

    A n t o n i e t t i R . , B r o g l io P . a n d M a d o n i P . ( 19 8 2) V a l u t a z i o n e

    d i pa ra me t r i b i o l og i c i c ome i nd i c i d i ef f i c ie nz a d i

    d e p u r a z i o n e i n i m p i a n t i a f a n g h i a t t i v i,

    l n g e g n . A m b i e n -

    t a l e I1 , 472-477 .

    A u g u s t i n H . , F o i s s n e r W . a n d B a u e r R . ( 1 9 8 9 ) D i e Z a h l u n g

    v o n P r o t o z o e n u n d k l e in e n M e t a z o e n i m B e l e b ts c h l am m .

    A c t a h y d r o c h i m , h y d r o b i o l . 17 , 375-386 .

    B e c a r e s E. ( 1 9 9 1 ) M i c r o f a u n a o f a n a c t i v a t e d s l u d g e p i l o t

    p l a n t t r e a t i n g e f f l u e n t s f r o m a p h a r m a c e u t i c i n d u s t r y .

    In B i o l o g i c a l A p p r o a c h t o S e w a g e T r e a t m e n t P r o c e s s :

    C u r r e n t S t a t u s a n d P e r s p e c t i v e s

    ( E d i t e d b y M a d o n i P . ) ,

    pp . 105-108 . C e n t ro B a z z uc c h i , Pe rug i a .

    B e dogni G . , Fa l a ne l l i A . a nd Pe dra z z i R . (1991) E va l ua t i on

    o f t h e a b u n d a n c e r a ti o b e t w e e n c r a w l in g a n d a t t a ch e d

    c i li a te s in t h e m a n a g e m e n t o f a n a c t i v a te d s l u d g e s e w a g e -

    t r e a t m e n t p l a n t . I n B i o l o g i c a l A p p r o a c h t o S e w a g e T r e a t -

    m e n t P r o c e s s : C u r r e n t S t a t u s a n d P e r s p e c t i v e s

    ( E d i t e d b y

    M a d o n i P . ) , p p . 2 2 9 - 2 3 3 . C e n t r o B a z z u c c h i , P e r u g i a.

    B i c k H . (1972)

    C i l i a t e d P r o t o z o a ,

    p . 1 9 8 . W o r l d H e a l t h

    O r g a n i z a t i o n , G e n e v a .

    C a r d i n a l e t t i M . a n d Z i t e l l i A . ( 1 9 9 1 ) T a x o n o m i c d i s t r i -

    b u t i o n o f m i c r o f a u n a i n a j o i n t u r b a n - i n d u s t r i a l a c t i v a t e d

    s l u d g e b e n c h - s c a l e u n i t . E f f e c t o f z i n c a d d i t io n . I n B i o -

    l o g i c a l A p p r o a c h t o S e w a g e T r e a t m e n t P r o c e s s : C u r r e n t

    S t a t u s a n d P e r s p e c t i v e s ( E d i t e d b y M a d o n i P . ) , p p . 5 9 - 7 4 .

    C e n t r o B a z z u c c h i , P e r u g i a .

    C h i e r i c i E . a n d M a d o n i P . ( 1 9 9 1 ) C o m p a r a t i v e a n a l y s i s o f

    t h e a c t i v a t e d s l u d g e m i c r o f a u n a i n s m a l l m u n i c i p a l p l a n t s .

    In B i o l o g ic a l A p p r o a c h t o S e w a g e T r e a t m e n t P r o c e s s :

    C u r r e n t S t a t u s a n d P e r s p e c t i v e s

    ( E d i t e d b y M a d o n i P . ) ,

    p p . 8 3 -8 7 . C e n t r o B a z z u c c h i, P e r u g i a .

    C u rds C . R . (1966) An e c o l og i c a l s t udy o f t he c i li a t e d

    p r o t o z o a i n a c t i v a t e d s l u d g e . O i k o s 15, 282 289.

    C u r d s C . R . ( 1 9 6 9 ) A n I l l u s t r a t e d K e y t o t h e B r i t i s h F r e s h -

    w a t e r C i l i a t e d P r o t o z o a C o m m o n l y F o u n d i n A c t i v a t e d

    S l udge . W a t e r P o l l u t i o n R e s e a r c h T e c h n i c a l P a p e r

    N o . 1 2 . H M S O , L o n d o n .

    C u r d s C . R . ( 1 97 1 ) A c o m p u t e r s i m u l a t i o n s t u d y o f p r e d a -

    t o r - p r e y r e l a t i o n s h i p i n a s i n g l e - s t ag e c o n t i n u o u s - c u l t u r e

    sys t e m. W a t . R e s . 5, 793 812.

    C u r d s C . R . ( 19 7 5) P r o t o z o a . I n

    E c o l o g i c a l A s p e c t s o f U s e d

    W a t e r T r e a t m e n t ( E d i te d b y C u r d s C . R . a n d H a w k e s

    H . A . ) , p p . 2 0 3 - 2 6 8 . A c a d e m i c P r e s s , L o n d o n .

    C u r d s C . R . a n d C o c k b u r n A . ( 1 9 7 0 a ) P r o t o z o a i n b i o l o g i -

    c a l s e w a g e - t r e a t m e n t p r o c e s s e s . I . A s u r v e y o f t h e p r o t o -

    z o a n f a u n a o f B r i t i s h p e r c o l a t i n g f i l t e r s a n d a c t i v a t e d

    s l udge p l a n t s . W a t . R e s . 4 , 225-236 .

    C u r d s C . R . a n d C o c k b u r n A . ( 1 9 7 0 b ) P r o t o z o a i n b i o l o g i -

    c a l s e w a g e - t r e a t m e n t p r o c e s s e s . I I . P r o t o z o a a s i n d i c a t o r s

    i n t h e a c t i v a t e d - s lu d g e p r o c e s s .

    W a t . R e s .

    4 , 237-249 .

    C u r d s C . R . , C o c k b u r n A . a n d V a n d y k e J . M . ( 1 9 6 8 ) A n

    e x p e r i m e n t a l s t u d y o f t h e r o l e o f t h e ci l ia t e d p r o t o z o a i n

    t h e a c t i v a t e d s l u d g e p r o c e s s . W a t . P o l l u t . C o n t r o l 67 ,

    312-329 .

    D e M a r c o N . , G a b e l li A . , C a t t a r u z z a C . a n d P e t r o n i o L .

    ( 19 9 1) P e r f o r m a n c e o f b i o l o g i c a l s e w a g e t r e a t m e n t p l a n t s :

    s o m e e x p e r i e n c e s o n m u n i c i p a l p l a n t s i n t h e p r o v i n c e o f

    P o r d e n o n e ( I t a l y ) . I n B i o l o g i c a l A p p r o a c h t o S e w a g e

    T r e a t m e n t P r o c e s s : C u r r e n t S t a t u s a n d P e r s p e c t i v e s ( E d -

    i t ed b y M a d o n i P . ) , p p . 2 4 7 2 5 1. C e n t r o B a z z u c c h i , P e ru -

    gia .

    D r a k i d e s C . ( 19 7 8) L ' o b s e r v a t i o n m i c r o s c o p i q u e d e s b o u e s

    a c t i v6e s a pp l i qu6e ~i l a su rve i l l a nc e de s i ns t a l l a t i ons

    d ' 6 p u r a t i o n : t e c h n i q u e d ' 6 t u d e e t i n t e r p r e t a t i o n . T . S . M . -

    L E a u

    73 , 85-98 .

    D r a k i d e s C . ( 1 9 8 0 ) L a m i c r o f a u n e d e s b o u e s a c ti v 6 es . E t u d e

    d ' u n e m 6 t h o d e d ' o b s e r v a t i o n e t a p p l i c a t i o n a u s u i v i d ' u n

    p i l o t e e n p h a s e d e d 6 m a r r a g e . W a t . R e s . 14, 1199-1207.

    E s t e b a n G . a n d T e l le z C . ( 19 9 2 ) T h e i n f l u e n c e o f d e t e r g e n t s

    o n t h e d e v e l o p m e n t o f c i l ia t e c o m m u n i t i e s i n a c t iv a t e d

    s l udge .

    W a r . A i r S o i l P o l l u t .

    61 , 185-190 .

    E s t e b a n G . , T e l le z C . a n d B a u t i s ta L . M . ( 1 9 90 ) E f f e c t s o f

    h a b i t a t q u a l i t y o n c i l i a t e d p r o t o z o a c o m m u n i t i e s i n

    s e w a g e t r e a t m e n t p l a n t s . E nv i r . T e c hno l . 12 , 381-386 .

    E s t e b a n G . , T e l le z C . a n d B a u t i s t a L . M . ( 1 9 91 ) D y n a m i c s

    o f c il i a te d p r o t o z o a c o m m u n i t i e s i n a c t iv a t e d - s l u d g e p r o -

    cess . W a t . R e s . 25 , 967-972 .

  • 8/18/2019 Madoni, 1994 (SBI)

    9/9

    Sludge Biotic Index

    75

    Foissner W. (1988) Taxo nomic and nomencla tura l re -

    v is ion of S ladecek ' s l i s t o f c i lia tes (Pro toz oa : C i l iophora)

    as ind ica tors o f water qua l i ty .

    Hydrobiologia 166

    1-64.

    Foissner W. , B la t te re r H . , Berger H . and Kohmann F .

    (1991) Taxonomische und 6kologische Revision tier Ciliaten

    des Saprobiensystem.

    Band I , Bayer ische und Landesamt

    fiir Wasserwirtschaft, M/in chen.

    Foissner W. , Berger H . and Koh man n F . (1992)

    Taxonomis-

    che und 6kologische Revision der Ciliaten des Saprobien-

    system.

    Band II, Bayeriscbe und Landesamt fiir

    Wasserwirtschaft, Miinchen.

    Kl imow icz H . (1970) Microfaun a o f ac t iva ted sludge . Par t

    I . Assemblage of microfauna in labora tory models o f

    activated sludge.

    Acta Hydrobiol.

    12, 357-376.

    Madoni P . (1981)

    1 Protozoi Ciliati degli Impianti Biologici

    di Depurazione pp. 1 -134 . CNR. AQ/1/167 , Rome.

    M adoni P . (1982) Grow th an d success ion of c i lia te popu-

    la t ions dur ing the es tab l ishment o f a mature ac t iva ted

    sludge.

    Acta Hydrobiol. 24

    223-232.

    M adoni P . (1984) Es t imat ion of the s ize of f reshwater c i lia te

    popula t ions by a sub-sampl ing technique .

    Hydrobiologia

    111, 201-206.

    Madoni P . (1986) Pro tozoa in was te t rea tment sys tems. In

    Perspectives in Microbial Ecology (Edi ted by Megusar F .

    and G antar M.) , pp . 86-90 . S lovene Soc ie ty of Microbio l -

    ogists, Ljubljana.

    M a d o n i P . ( 1 9 8 8 )

    I Protozoi Ciliati nel Controllo di

    Efficienza dei Fanghi Attivi

    pp. 1-82. C.I.S.B.A., Reggio

    Emilia.

    Ma doni P . (1991) Role of p ro tozoans and the i r ind ica tor

    value in the activated sludge process. In Biological Ap-

    proach to Sewage Treatment Process: Current Status and

    Perspectives (Edi ted by M adoni P . ), pp . 21-28 . C entro

    Bazzucchi, Perugia.

    Ma doni P . and A ntonie t t i R . (1984) Coloniza t ion dynam ics

    of c i lia ted pro tozoa po pula t ions in an ac t iva ted s ludge

    plant. Proc. IV Italian Symposium on Population Dynam -

    ics pp. 105-112.

    Ma doni P . and G het t i P . F . (1981) The s t ruc ture of c i lia ted

    pro tozoa communi t ies in b io log ica l sewage- t rea tment

    plants.

    Hydrobiologia 83

    207-215.

    Mad oni P . and Pol i M. (1981) S t ruc ture and dynamics of

    c i l ia ted pro toz oa popula t ions in ac t iva ted s ludge p lan ts .

    S . I t .E . A t t i

    1, 537.

    Madoni P . , Davol i D . and Chier ic i E . (1993) Compara t ive

    analysis of the activated sludge microfauna in several

    sewage t rea tment works .

    Wa r. Res .

    27, 1485-1491.

    P a g n o t t a R . a n d T o m m a s i M . ( 1 9 7 9 ) A p p l i c a zio n e d i

    parametr i b io log ic i a l lo s tud io de l fenom eno de l bu lk ing .

    lnquinamento

    21, 27-32.

    Poole J . E . (1984) A s tudy o f the re la t ionsh ip be tween the

    mixed l iquor fauna and p lan t per formance for a var ie ty

    of activated sludge sewage treatmen t works. Wa t. Res. 18,

    281-287.

    Sasahara T . and Ogawa T . (1983) Trea tm ent o f b rewery

    eff luen t . Par t VII I : p ro tozoa and metazoa found in the

    activated sludge process for brewery effluent. Monats.

    Brauwiss.

    11, 443-448.

    Sladecek V . (1973) System o f wate r quality from the biolog ical

    po in t o f v iew.

    Arch. Hydrobiol. Engeb. Limnol.

    7, 1-217.

    S t reb le H . and Krau ter D . (1981) Das Leben im

    Wassertropfen. W. Kel le r , S tu t tgar t .

    Tom an M. and Rej ic M. (1988) The e f fec ts o f low concen-

    t ra t ions and shor t -per iod lack of d isso lved oxygen upon

    the organ isms of the concom itan t b iocenos is in ac t iva ted

    sludge. Z. Wass.-Abwass.-Forsch. 21, 189-193.

    Woodiwiss F . S . (1980) B iological moni to r ing o f sur face

    water qua l i ty . Summary Repor t E .E .C . ENV/787/80-EN,

    Bruxelles.