BETWEEN W ASTEW-ATER TREATMENT PLANTS AND RECEIVING WATER BODIES

POSSIBILITIES FOR CONTROLLING THE

CO~N""ECTION

BETWEEN W ASTEW-ATER TREATMENT PLANTS AND RECEIVING WATER BODIES

J. A. ROSERO and K. Buz_.ts

Department of Hydraulic Engineering.

Technical University, H-1521 Budapest Received Julv 14. 1986 Presented by Pr~f. Dr. ~r. I~ozak

Allstract

\Vith increasing water supply and canalization the quality of the ,,-ater playing the role of receiver often deteriorates. Among other problems, the not sufficient removal of plant nutrients by the traditional purification technology causes difficulties. Considering that the removal of fertilizers results in a significant increase in the costs of wastewater treatment. it is expedient to keep the extent of re~oval just at the yet acceptable l"vel of the pollutant. .

This paper deals with the removal of phosphorus as fertilizer on a transport theoretical basis.

As a result, a qualitative connection is established between water quality and water management on the one hand and the operation of the wastewater treatment plant on the other hand.

The ohjectives and method of the research work

With the increase in -water supply and canalization the quality of the receiving water bodies often deteriorates, not only in Hungary, but all over the world. This deterioration is caused at present mainly hy the introduction of the wastewater of dwellings into the receiving 'water bodies in spite of the increasing numher of wastewater treatment plants being built. According to the literature and experience, the main reason of this prohlem is that - in addition to other effects as e.g. the not point-like nature of pollutants - tra- ditional purification procedures do not remove fertilizers satisfactorily. The enrichment of these substances, in turn, may lead to the breaking of the ecolog- ical equilibrium in the receiving water body. Since the removal of fertilizers results in a rapid increase in the costs of purification, it is expedient to keep the level of pollutants at the allowed value. The necessary extent of removal can he determined from the receiving capacity for the fertilizer in question.

Therefore it is justified technically and economically to analyse the ecology of the receiver and the procedure of wastewater treatment as well as the connec- tion between them in order to make a sound foundation of design and opera- tion.

As it became clear from earlier, mainly from biological research, the main energy source of eutrophisation processes is phosphorus, problems of the trans- port of phosphorus have been investigated in our study. Upon considering the economically feasible solutions here and in other countries, emphasis was

86 J. A. ROSERO-K. BuzAs

given to the technical realization of results achievable by completing the puri- fication processes utilizing activated sludge.

As a general goal, the description of the purification technology of com- munal wastewater by activated sludge (AS) has been set. A parametric treat- ment is elaborated for the third purification step 'with special regard to the removal of fertilizers (P), by starting from observations concerning the effect of the dynamic-kinetic change of AS on the AS base line.

The normalization of the system may increase the efficiency of the second- ary clarifier when considering the macro- and sub macro-arrangements and the microdynamics of differentiated sedimentation. It also improves the relation of the wastewater treatment plant and the receiving water body, since at the separation of phases the mechanism of mass transport during adsorp- tion-storage and the kinetics of coagulation-flocculation may be brought in harmony by the consideration of the normal distributions of critical concentra- tions and time.

Other components of the connection between the wastewater treatment plant and the receiving water body, as -well as the composite processes of technology, such as e.g. filtration, ozonization desinfection, etc. will be neglect- ed here.

Field experiments were carried out in the wastewater treatment plant at Keszthely based on the critical evaluation of technical literature. The analysis and evaluation of the experiments occurred by the use of the ITO (Input, Transformation, Output) system. Technical literature was considered from the viewpoint of transport theory.

System approach in the removal of phosphorus

The results of field experiments carried out in 1983-84 were compared with the data found in the literature. Correlations thus obtained were classified by using transport theory.

The overall equation system of the conditions for the removal of phos- phorus at macro-, micro- and submicrolevels of purification processes using activated sludge is the follo"ing:

C_{f =} F

[e

^{i if :]}

Kc. = C_{f :} t I C_f

t!

^{= F [Y}Xk]

Yh

=

F [XI< !ASp'pi]

Let the transformation interpreting the removal of phosphorus he X" = F

I

^{AS p,p'}

I

(1) (2) (3) (4)

WASTEWATER TREATMEJ,T PLA .. "ITS A,,"D RECEIVING WATER BODIES 87 what is a correlation between the mass of floes and that of the wastewater in its en"'vironment (Fig. 1).

The removal of phosphorus may occur by either biological assimilation or by the combination of this and chemical precipitation, the time course of which may be characterized by distribution factor Kc_x together with equations

e

I

i' P

I [I' ^'

^{KpOI .'}

^{. f3} ----p-

^{BOIJ -+ max}

where each

i"p =

[i

j Poly-P

<

^{i" A T P]}

i'" p

=

[pH; icat ; iinh], in "'which icat is the intensive of cations and

icat

=

ⁱ [Ca, Fe,

AI]

^-+ max

iinh = the intensive of inhibitors

iinh

=

ⁱ [lVIg2 +, bicarbonate, Poly-P] ^-+ min

(5)

(6)

(7) (8)

(9)

(10) The storage of Poly-P is a precondition for choosing arrangement XI: '\V-ith respect to liT which ensures the variation of the anaerobic-aerobic states of the sludge,

The effect of this change in X" appears as a variation in intensive i p at the sub micro level according to

X" = F (ASp,p,)

.y.L_=_·_.e_ch_n_o_'o .... g_y_+~K:::: design

U---

- - - - l

. X=f(AS p,p') i I

:2 =- plclning <!-;1:...= .;:.ba.;:.r..;;d .... en..;;p;...'n..;;o _ _ ,.:-~ regulation I ~ Waste-water (,

~2 ::; phoredox t V

~3 = operation' *:! :::: modified PhO I' I ! I

1:: 2~T / tJ7~L-7J-_D_S~::d ~-j

~.:. :::: investment Vs :::: combined

: aspects

Yn

: l

~ ~"- ^e(:p)

':-'.---'...--

r- - - - - - - - - ----%.---,

1

r;;s:;,

~ 2

o

P-in preCipitating I e(lp}

substances :

I _______ ...1 I

Interchangeable RNA-P

Not interchangeable DNA-P

Po\assium-P lron-?

[

AIUminium-p Absorbed-P

POly-P Cell wall-P

Fig. 1. System approach in the removal of phosphorus

PO -p Poly-P Orgonlc-P

88 J. A. ROSERO-K. BL"z:is

The acceleration or deceleration of ip

=

ⁱ

i1 ;

^i~

sho'ws the effect of the introduction of arrangement X" in the distribution of Kc: P (Fig. 2). From this it can be concluded that in aerobic systems 'where the transport of energy and matter occurs according to the equation

(11) phosphorus is also precipitated (Figs 1, 2). Thus Kc: could be measured experimentally what makes the solution of equation system (1)-(4) possible.

Thus from the 'viewpoint of the transport of energy and matter, five mechanisms can be set as the most probable ways of the biologically assisted chemical removal of phosphorus:

1. The hasic mechanism is the normal assimilation of phosphorus which is always operating and the efficiency of which depends on ip (it results 1-

? ~ 0/ . ^I ·1 )

"";) /0 In an e I ^{Lp j •}

2. The storage of Poly-P which is ensured by changing the anaerobic and aerobic environments of the activated sludge, in dependence of ip (A storage of P as high as 5-8% may be achieved).

3. Ordinary precipitation in the wastewater occurring due to the change in the aerobic-anoxic-aerobic states as a function of i';'.

4. Accelerated precipitation in the wastewater when function i~ is near to its maximum value or even reaches it.

Aerobic state e(!;)

Q/

6-/

cC-I

.# "

~Q /

Q'~/

; ' ; '

_---~.JI/ ^{.. ,.}

',,=(et ^COD; n B09)...max.

p p

Accumulation of pOtassium phosphate Mineral phase in the sludge

Fig. 2. Scheme of thc system intensitively induced for P

WASTEWATER TREATJIEST PLA.'-YS ASD RECEIf1SG WATER BODIES 89

Biofilm precipitation occurring in the case of hacterial denitrification if the wastewater environmeEt of the biofilm is favourable, in dependence of i~.

The honity of the optimizatioE of functions and the aspects of the given system depend strongly on the conectness and consistence of qualitative and quantitative data required in the application of the different mechanisms.

The role of the differentiated settling in the transport of nutrients

Since the main energy source of eutrophisation is phosphorus, prohlems concerning the transport of phosphorus ·were studied.

The connection between the wastewater treatment plant and the receiving water body is discussed on the hasis of the ecology of the above mentioned nutrient-transport and the system of the purification system with activated sludge which ·was examined from the viewpoint of the phosphorus removal (ITO/ASe). The scheme of the system is illustrated in Fig. 3.

The most sensitive unit of the system is subsystem 3. This is partly due to the strongly stochastic characteristics of the input intensives, Tp and T c in transport T_{23 •} The intensives of the AS base line are partly also quasi-stochas- tic.

In the general case, the output of subsystem 3 is the output of the sec- ondary clarifier.

The ohservation of this change in the transition section of the settling curve (Fig. 4) and its mathematical modelling makes possihle the ohservation

Rain,sncw

i2---i~~---~

:

IUrDQ~

'oao! :

I I

I I

r~--- ---1

1 j 1

,

,

I A I

! ( r 'I r,-....:..;.~--L-~~~~=-.:.J ^{I I} I I I I

I

I

I I I I I

I I

L----t---.J

bYO!

1 _ _ _ _ _ _ -

Recevier

:

I I I

1

I _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ..J I

Fig. 3. Connection between the wastewater treatment plant and the receiver

gO J, A, ROSERO-K, BUZ_4S

, -bk'(r,,~li,jk bk' (r"g)~,jo - - bk'(r"g)i,j,.

(~I~ Oh) T) min j ; /10

:';lk,T;,g =1,2 .. =(V,t)=se-t of real numbers (b'k,b~ ... ):: set of complex numbers

C = (C', C"\e-)::: nOl'"malised set of probability variable

Fig. 4, 1fathematical modelling of the transition reaction

.---i

Transpoil cycle of the close-C water system (macro cycie) CWPR

Submacro section

_________________

~~c:::.u~~~o_s.:~~n

___ _

CWPR- connection between WQstewater treatment plant and receiver

iTO -input- transformation-output

eO} -algoritm for exlensive-~ntensive transport AS - activated sludge technology

Fig,5

of ASe from the vie-wpoint of phase separation. In turn, this provides a pos- sibility for the regulation of the connection bet'ween the wastewater treatment plant and the receiving water body hy means of intensive k_c•

Disregarding the effect of intensive V₃₀ on the environment, this study is aimed at investigating the changing process of changing of matter-energy intensive V_34•

The incorporation of the mathematical model of settling process into the connection system wastewater treatment plant - receiving water body oc-

WASTE WATER TREATME1YT PLAi'iTS AiVD RECEIVIlVG WATER BODIES 91

KeSzthely, July 21-22, i983 Nm,n(Cc, t) =f(b''[<ij)

m=24

10 ^I, If ^h 14 n:65

~-i --r

-:-j

^-~)

, -C~.

le " "I '31

~\

^\

f\

^I

_l r'\'

I \,~)

^{I I ' \ ' \ -,~ '.} _:) ^{! I \ \ I \. ,,~,-0, I"} I " , I ^\.

-',2

^"

I ..y i \ ' - , / ,)

I ,,-

L

^{I /;''' I}

^,x:

^{/~ ,}

1/ ^"

^{~/ I .}

L

^{I,' 1/ /,) ,}

^"

^,

^.

^{.1" ."}

i )

' /

-

..

^-

.. ^k'

1=0 I:::::; I:::; 1=0 i:O

,:,) ):::0 :;:"" I: f,

Fig, 6. Effect of (i, j) system on (system)

curred by the utilization of the current biochemical results from the study of purification processes with activated sludge. This was the basis for designing our system. This system applies the sub micro, micro, submacro and macro sections for describing the operation ofITO/AS_e (Fig. 5).

One of the possible approaches for characterizing ITO/ASe is the con- struction of the interactions of the (i, j), (~, 17) and N(G_e, t_c) systems. System (i, j) forms space, (~, 17) represents the description of the stochastic flow of mat- ter and energy in time, and regulating system N(G", te) ensures the possibility of standardization of the whole ITO/AS system.

The result of this interaction is the distribution ke (Fig. 6) which shows that differentiated settling manifests itself in different effect-differences in the directions of the two axes. The existence construction and utilization of this distribution occurs in inductive and deductive ways based on experience from experiments and data from the literature. By using this distribution

(QI'e - QkC) and (Vpmin - ApmaJ

can be given for the separation of phases, whereas the resultant differentiated settling rate may he written as

(12) where

inverse function of mass flow from the viewpoint of differentiated settling.

GDP';P = roughness factor in which the characteristics of sub macro system DS_{ke -} GF_ke are reflected,

DS = adaptive-learning mechanism

92 .1. A. ROSERO-K. BCZ.4S

CF = coagulation-flocculation mechanism ke = effect of the above mechanism on airing

kc = effect of the above mechanism on secondary clarifier [

f: DSi:e ; CF"c!

f: DS{e ; CF/cc :

Thus the equilihrium conditions of the initial state can be ·written in the fol- lowing ne"\\t form:

(13) The unknown CD cannot be determined for individual flocculating par- ticles, at least not in a deterministic way as the general curves (CD, Re) are unknown for the third step of the AS technology. Hence if ,,-e consider that during the phase-separation process in the micro section the transport mecha- nism primal'ily characteristic for AS (the so-called adsorption-storage cycle) does not play a secondary role with respect to the coagulation-flocculation kinetic mechanism in the separation of phases as it is proved by photomicro- graphs, but it appears as a harmonic equilibrium alternative being the most sensitive indicator of the equilihrium state, then III the secondary clarifying process CD would he

(14) and at simultaneous precipitation

(15) This is advantageous from the viewpoint of theoretical treatment, since inten- sive ASjkc may he determined in an empirical way hy direct meaSUl'ements.

Regulation possibilities of the connection between wastewater treatment plants and receiving water bodies

In addition to intensives (Clke - ClkC); (Vp min A p maJ appearing in phase separation, the normalising effect of ITO' AScIN(Cc• tc) ^{in (~, I) may he} interpreted as a smoothing effect on the sUl'face of flocculae due to the effect of different coagulating agents.

This "smoothing", erosion, and fraction, percussion and aggregation of the sUl'fa~ can be characterized by probabilities m(~, '1]). The resultant prob- ability, M(~, 1) may he obtained by aggregating the probabilities of individual processes:

.iW(~, 1) = I. FR (~, lj) =.E FR(~' 17) and lW( ~,I) = 1. 111 (

g,

¹⁾

(16) (17)

WASTElFATER TREATJIK\T PLANTS ASD RECEIFISG WATER BODIES 93

In transport, V(23, 34<), vector Jf provides the total amount of 'work used for purification. The direction and numerical value of vector

.:11

^{may be}

utilized in the synchronization of airing and secondary clarifier in subsystem 3 (Fig. 3), what mea~s a possihility for improving the efficiency of the plant.

With vectors JI[ determined for plants operating with activated sludge, in larger regions a vector polygon can be constructed which provides informa- tion on the resultant mO'vement of the AS systems in the region and makes the setting of regional ecological balance possible for the determination of the extent and direction of regulation required.

One of the means for regulating the connection hetween the waste'water treatment plant and the receiving water body is the distribution of load ~VvC17,

0") .

In Figure 7 the distrihution of the optimum intensive ko for phase sepa- ration is shown in

%.

From this, the difference in loads can be forecasted for the mass transport V(OC, 2; 34·). The pointing out of mechanisms ensuring the dynamic equilibrium of the system became necessary for establishing just this.

1. \Ve introduce the concept of delayed transport process Td (Fig. 8).

Then

(18)

"\-v-here function

f

is defined in coordination system (i, j), i.e. it is of extensive nature, correspondingly to Fig. 8A.

_In,~

r:-

Oh: fu'! tu

O'h:C1j=iu2-iul

Il,:C;:.Cc

O"v=O'i =ju2-ju1

T

Fig. 7

N"(...,, a) ::: distribution of load In 'I. (C,t) N~(~. 0;) ::: oistribution of the concentrction

, In time in 'I. (t,C) N;.i(~' ~) : standard bas~ load curve

94 ^J. A. ROSERO-K. BUZ,{S

Fig. 8. Regulation of subsystems 2 and 3

AS..\. aerafton tank of AS AS c ⁼ secondary clariiier of A~

Fig. 9. Subsystem of e = operation shift and r f(e) reeireulation in the macro section of system (i, j)

2. In the macrosection of subsystem 3 the peaks in load different from standards can be smoothed by recirculation and simultaneous temporary stor-

age as is shown in Fig. 9 This requires the adjustment of Td according to the function of the intensive p (Fig. 8B), where p is the probability of the removal of loading pollutants. Optimum removal efficiency can he estahlished ohv-iously only when kno,dng the load V2.3(P)'

In the first case the time of transport is invariant, since the distrihution of output V_{3 .1}(P) is similar to that of input Vdp). This is not consistent with the other parameters of the connection system of waste water treatment plants

WASTEWATER TRE.·1TJfE.YT PLA.\TS A,\'D RECEln,YG WATER BODIES 95 and recei'dng water body. Hence, considering that Td(p) is not time-invariant, the load intensive of 0 <: p(;, 17) <: 100% is given by distrihution iVrn , ,,(Cc' t) (Fig. 7), as the optimum efficieu(;y of the plant in system (i, j) (Fig. 8).

The V23(P)

>

n(Cc' t) means ^a state load 'which requires modification of Td(p) hy temporary storage or recirculation. The role of recirculation is illustrated in Fig. 9. Storage may be realized similarly to a facultative pool before subsystem 3 by Td(t) 5 and after it hy Td(tL. It may also he realized inside the suhsystem on the hasis of the standard removal efficiency P;\,(%) (Fig. 8).

Considering all this and hased on earlier experience the connection het- ween the waste\\'ater treatment plant and the receiving water hody, the ana- lysis of the flov.- of matter m( V_{3 !,} V_{lO )} is written 'with the transport approxi- mation

Interaction of water management and water quality in the connection of wasi:ewater treatment plant and receiving water body

(19)

The description of the above connection has heen attempted on the basis of the law of the conservation of matter hy using the intensive parameters of mass transport. It is supposed that the yearly normal distribution of the inten- siye characterising the receiver water hody can he given and let it he

iV",(i!o: e).

If the ratio of extensive is nearly constant in flow (V3!' VIOL the distribution of the intensives of the transport from the side of the plant is characterised by 1Yrn, n(Cc' t) ⁼ iV_m(i34' e).

Thus

(20) In this case information can be obtained concerning the necessary intervention for synchronising the plant and the receiving water hedy in order to protect water quality.

The general form of Eq. (20) is:

(21) If this is solved so that the extensiyes are considered state variants, then in- formation can he ohtained for water management. The general form of the equation may be given as:

(22) 3 Periodica Polytechnic a Ch-B 31/3-4

96 J. A. ROSERO-K. Buz/is

~Td!!)3

~'Ii

o ^;.~

-2.;

Fig. la. Connection to the receiving system

From this it follows that the total solution of the connection proyides the com- plete exploration of the interaction between water quality and water manage- ment Fig. 10. The most general form of this interaction can be written as

(23)

The detailed elaboration of the practical applicability of this latter correlation is the most important task of future research.

e e(ip)

Denotations

change of the intensiYe

intensiYe change of phosphorus

effect of the technological subsystem of AS macrosection on the liquid around the organic mass

effect of the technological subsystem of AS macro section on the organic mass

amount of matter or energy

amount of matter or energy in function of the intensive of phos- phorus

kinetic change in the transport of matter,- energy time distribution of the kinetic change in intensive c AS macrosection, vector of its subsystem

technology

WASTEWATER TREATMK,-Y PLA,,-YS ASD RECEIVn,C WATER BODIES 97 Y z planned

Y₃ operational

X_k arrangement of k in the subsytem of Y Y1(X1) ^hardenpho

Y1(X_Z) Phoredox Y_{1(X 3 )} UCT, etc.

kinetic acceleration or deceleration of the P-intensive

acceleration or deceleration of the intensive as a result of intro- ducing arrangement x

Y(X) introduction of arrangement X carried out in the suhsystem of macro section AS

X effect of change in arrangement X of suhsystem AS on organic material or se"wage at submicro level (ASp, p')

u_ij technological coefficient matrix Tp nutrient load (transport)

Tc phosphorus load (transport)

AS_c dynamic effect of activated sludge technology in the settling pool.

References

1. ANDREWS, L- GRAEF: Dynamic modelling and simulation of the anaerobic digestion process Ad\'ances in Chemistry Ser. lOS, 126 (1971)

2. A2'ODREWS, 1.: Kinetics of biological processes used for wastewater treatment Proc. Amer.

Soc. Civ. Engr .• 95. 95 (1970)

3. A2'ODREWS, I.: Dynamic models and computer simulation of ,,'astewater systems Yansteln- kiste (ed.). Amsterdam p. ,1557 (1975)

4. BECK, 1I. B.: Operation water quality management: Beyond planning and d<:sign HASA, 32 (1981)

5. BELcorRT. A.: Effect of various anions and biological macromolecules on bacterial aggre-

gation J. Bio!. Bucce!.. 3, 223 (1975) ~ ~~

6. BISOGl'iI, C.-HVERE:';CE: Relationship between the retention time of bilogical solids and set- tling characteristics of activated sludge Water Research, 5, 735 (1971)

7. BRIAl'iT, J., \yiILCOX: Real-time simulation of the com'entional activated sludge process Proc. JACe, p. 701 USA, California (1972)

8. BUSTY. Al\DREWS, 1.: Dynamic modelling and control strategies for the actiyated sludge pro~ess Water pollution Control Conf~rence USA 1973 - ~ 9. Buz,.is. K.: Determination of the volume of resen'oirs in unified and canalized svstems

Hidrol6gia Kozlony, 8 (1978) (in Hungarian) .

10. Rcz,.is, K.: Pollutant load and its decreasing in receiying water bodies Dissertation, Buda- pest, Hungary (1983) (in Hungarian)

11. Buz,.is, K.: Technical-economical analvsis of direct loads and their decreasing due to ca- nalization of settlements IY. Orsz. Vandorgyules, Gyor, Hungary (1983) (In-Hungarian) 12. C-URDS, C.: Theoretical study of factors influencing the microbul population dynamics

Water, Research, 7, 1269 (1973)

13. CSAO, A.- KEI:\"ATH, T.: Influence of process loading intensity on sludge clarification and thickening characteristics Water Research, 13, 1213 (1979)

14. D'AsTous, F.: Analyzing environmental time series J. Em'ir. Engr., 1979, 979

IS. DILL02'O- RIGLER: .Model predicting the phosphorm concentration in lake water Res.

Board. Can .. 3, 1771 (1974)

16. DOBOLYI. E.: Data on the bottom sediment in Lake Balaton Proc. 2nd Joint MTA, Vol.

2, p. 66 (1980) 3*

93 J. A. ROSEIW-K. BUZ-f."

1 7. DOBOLYI, E.-BIDLO, G.: Some data on the bottom sediment of Lake Balaton Hidrol6giai

KiizliillY. 60. 72 (1980) (in Hungarian) ~

18. DrLOYICs. D. et al.: Up-to-date canalization systems and the aspects of their design Hidrologiai Kiizlony, 6 (1978) (in Hungarian)

19. DrLoncs. D.:, Dimensioning of artificial biological wastewater purification equipments T"fvcze:;i Utmutato, B1fE manuscript. (1980)

20. FRISK, T.: Modifications of phosphorus models Aqua Fenicia, 11, 7 (1931)

21. Ft"YEs, L.: Tllf"rmostatics and thermodynmnics 1Hiszaki h:on:n-kiad6. Budape:,t. Hun- gary, 1967. (in Hungarian)

22. FOSTER,

c.:

Activated sludge mrfaces in relHtion to the ,"olume index of slud,,(· \\'ator

Researeh . .5. 861 (1971) ~ ^c

23. FOSTER, C.: The nature of actiyated sludge floes W'atcr Research. 10. 2:) (1976)

:c-1. FORD--EcKE"FELDER: Effect of prOCC5S yariables on sludge floc formation J\YPCF, 39, 850 (1967)

:cS. GELE:,cstR, P.: Srecific method" for the studying of water quality with respC'ct to micro- element" and plant nutrients YITCKI 7783₁3/29-1 (1980)

26. GW"A. A.: Kinetic parameters for municipal ,,-astewater JWPCF, .51. 5 (1979)

27. GrsTAYSSO", 1.: Parametric identification of multiple input Report 6907. Sweden, 1969 :28. GrsTAY550". 1.: Sun-cy of applicatio!l5 of identification in chemical and physieal prOCC5-

ses Eybhoff (cd.) Amsterdam. Holland 1973.

29. EI"O. )1.: Ecohydrodynamics Adv. in Hydroscience Academic Press, Japan 1981. p. 12 30. KALLE 1L\.TTI: Phosphorus retention model Water Research, 60 (1981)

31. REcKLOw. K.: "Cncertainty analysis, applied to YolIC'nweider's phosphorus loading crite- rion J\VPCL .51. 8 (1979)

32. KOLL.-I.R, Gy. et a!.: Eutrophisatioll processes in lakes Acta BioI. Debrecenina 13, 163 (1976)

33. LAPPALAI"E,,: Phosphorus load of lakes and a mathematical model for prognosis 11i!jovard Descr. BulL 1. 42.5 (1975)

3-1. LARSSO,,- SCHODER: Dynamic models for primary sedimentation in wastewater treatment Report-RE 14-6, Swcden. 19H

35. LArBE"BERGER. G.: Physical structure of activated slud"e in aerobic stabilization \'\' ater

Research, .5, 335 (1971) ^c

36. LEE"TVAAR- REBHr)I: Strf'ngth of phenic hydroxide floes WatC'r Research. 17, 8, 395 (1983)

37. LITERA-TY. P. H a!.: Im-cstigation of the interstitial water in bottom sediments private communi ca tion

38. LOTKA, K.: Elemcnts of mathematical biology Donr Publicatiol15 :\. USA. 198-}' 39. 1ETt: The phosphorus retention on the sedil~ent of Lake Balaton Yeszprem. 1981 ,10. 1lULLER, P.: Sedimentbildung im Plattensee in Ungarn i\aturwissenschaften, .56, 606 (1969) 41. OL.-I.H, J. et aI.: Phosphorus metabolism of Lake Balaton 11TA BioI. Oszt. Kozlemenyei, 20,

11 (1973) (in Hungarian)

42. OL.-I.H. 1.: Biomass and production of bacterioplankton in Lake Balaton Hidro16giai Koz- lony, .53, 181 (1973) (in Hungarian)

43. OLSSO", G. et al.: Control problems in wastewater treatment plants Proc. Eng. ConL USA California 19i3.

44-. OLSSO", G.: State of the art in sewage treatment plant control. Chemical Process ControL .. liSA California (1976)

45. OLLOS, G.: The reuse of water in water supplies Hidro16giai Kozlony, 1978,12 (in Hungar- .. ian)

46. OLLOS, G.: Reconstruction of water and canal works Hidrologiai Kozlony, 1978. 3 (in Hungarian)

47. RosERo, J. A.: Treatment of butcher's sewage B~rE Diplom work, Budapest 1982 (in Hungarian)

43. RosERo, J. A.: Connection between enyironment protection and foreign trade MKKE Szakdolgozat, Budapest 1984

49. RosERo, J. A.: Connection between waHewater treatment plant and receiving water body Dissertation, Technical University, Budapest (1985)

50. RosERo, J. A.: Extensive-intensive connection between enYironment protection and for- eign trade Dissertation in economics, MKKE Budapest 1986

51. SCHWARTZ, 1\1.: Models for water reuse and wastewater planning J. Environm. in. 15, 109,5 (1984 )

52. SCHAW, G .. BROOKS, J.: Origin and development of living systems Academic Press London 1981.

WASTEWATER TREADrK\T PLA:lTS ASD RECEITTYG WATER BODIES 99

53. SO)ILYODI, L. et aI.: Uncertain system identification and the prediction of water quality Pergamon Press. Oxford 1982.

54. SO;,ILy6DI L.: IV at~r quality management General report, case study 1982 Yeszprem (in Hungarian)

55. SO)!LYODI, L.: Eutrophisation of "hallow lake,.: modelling and management IIASA. CP- 83- 53 Laxenhurg. Austria

56. Sziics, E.: Basis of si~nilarity theory JIu5zaki Konyvkiad6, Budapest. 1967. (in Ehmgarian) 57. Sziics, E.: DiaIogs about technical sciences JHisZGki Konyvkiad6, Budapest. 1971. (In _ ... Hungnric.n) . . . . " . . .

;:,8. Szucs, E.: Processes III :<amtal'Y engmeermg :'ullszakl Konyvkiad6. Budapest 1975. ^(Ill

Hungarian) . ~ ~

59. Sziics. E.: Similitude und modellillg E!sevier. Amsterdmn 1980.

60. Tun!. L.: Phosphorus metabolism~ of Lake Balatoll Bulaton Yizvcdelmi Bizottsag. 59 197,). (In Hu'ngari[:ll)

61. Ton!. L,: \'fater quality of Lake Bnlaton ~o. 7 Jlart of ,('port YITl'KI 7782/nS (1976) (In Hungarian)

62. TonI. L.: Sediment samples from Lake Balaton \'ITl'KI 1781j3129 (1978) (in Hungurian) 63. Y£:HIIOF:::"". ~\.: :\lcHnent rnethods for the unuly.sis of rh-er 11lodc-ls \\~!th application to point

sonr(:~ phosphorll:" Water Research. 1.5. -b93 (1930)

6·1.. \-GLLE~VEIDER. R.: The :.:cieniifie hns!s for lake and streanl euthrophi~ation \\:jth particular reference to pho:ophorus and nitrogen GECD. Paris, DAS;CS!68.27.1. 1968.

65. YOLLE"YEIDER. R.: Input-output models with special n.ference to the pho:<phorus loading concept in limnology Schweiz. Hidrol. 37. no. 1 .53 (1975)

66. \"'ELLS.

c.:

On the application of u nOll-lincur regulator for a model of biological \,'aste treatment IEEE, AC-16. 385 (1971)

67. \\f~HITFIEI~D~ P.: Selecting a l!1ethod for c:stili1ating substance loading \\:-ater Resources

Bull.. 18. :: (1982) ~ "

68. \VIJ SE!'G: Phosphorus models for eutrophic lakes \\'ater Resec:rch. 1.5. '1~~ ~19Z~) 69 Y01:2'."G. P.: The modelling and ('olltro! of water quality Automatics. la. ,b.) 09'-i)

Dr. Jose ,A .. ROSERO

D" KaIIl1<~n BCZAS } H-1521 Budapest