activated sludge modeling

8/18/2019 Activated Sludge Modeling

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Modeling SuspendedModeling Suspended

Growth SystemsGrowth Systems

CE421/521CE421/521

Environmental BiotechnologyEnvironmental Biotechnology


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!eactor per"ormance

as a "unction o" S!#$

%ails to account "or&

' (articulate removal rate

' )naero*ic conditions

' +aria*le "low and

loading

' Biological nutrient

removal

1)ˆ(

)1(

−−

+=

b

bk S

c

c s

µ θ

θ

θ

θ

θ

c

cb

S S Y

X +

−

=1

)( 0

Monod E,uation and -ni"ied ModelMonod E,uation and -ni"ied Model


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.nternational )ssociation on ater.nternational )ssociation on ater

0uality )ctivated Sludge Model 10uality )ctivated Sludge Model 1

.)0)SM 13.)0)SM 13' .n 167 .)0 appointed a tas8 group to

develop a model$

' .n 197 )SM 1 was completed$

' )SM 1 a*le to predict per"ormance o"solu*le and particulate su*strate removal7nitri"ication and denitri"ication under steadystate and dynamic conditions$


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)SM 1 )SM 1

' #rac8s 16 individual components through

eight separate processes$

' )ssumes heterotrophic growth under

ano:ic conditions$

' ;imited anaero*ic activity$


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.)0 )SM 2.)0 )SM 2

' .n 157 )SM 2 was released capa*le o"

trac8ing *iological phosphorus "lows$

'


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)SM 2 )SM 2

' #rac8s 1 separate components through 1 processes$

' 22 stoichiometric coe""icients and 42 8inetic parameters

' )mmoni"ication and hydrolysis simpli"ied to stoichiometricterms= i$e$ rates implicit$

' .ncludes anaero*ic "ermentation7 upta8e o" acetate7"ormation o" (>B and (>)s7 and release o" solu*le

phosphate "rom hydrolysis o" polyphosphate$

' Several assumptions made that constantly need revision as8nowledge evolves$


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)ctivated Sludge Models )ctivated Sludge Models

' Cannot solve analytically$

' -se computer algorithm *ased on numerical

techni,ues$

' B.?.


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Steadystate per"ormance Steadystate per"ormance

(articulate versus Solu*le(articulate versus Solu*le

' (articulate hydrolysis is a

rate limiting step$

' ) particulate "eedre,uires a longer S!# to

achieve treatment$

' (articulates compose allo" M;SS at low >!#s and

active "raction is washed

out$


10/20

Aynamic per"ormance (articulateAynamic per"ormance (articulate

and Solu*leand Solu*le

' %low su*strate

concentrations vary

giving a diurnal

pattern$

' (articulate and

solu*le "eeds have

di""erent e""ects on

per"ormance$


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Aenitri"icationAenitri"ication

' Aenitri"ication ?rganics are electron

donor


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Aenitri"icationAenitri"ication

' ?:ygen is pre"erred

electron acceptor@


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Aiurnal "low with di""erent aeration strategiesAiurnal "low with di""erent aeration strategies

' Single CS#! may *e

set to&

Maintain a constant

dissolved o:ygenconcentration in the

tan8

Constant o:ygen "low

into tan8


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Modi"ied ;udac8 Ettinger Modi"ied ;udac8 Ettinger

' -se an ano:ic *asinand an aero*ic *asinto select "ordenitri"ication a"ternitri"ication@

' hy denitri"yD

' here would youplace ano:ic selectorin "low schemeD


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E""ect o" S!# on M;EE""ect o" S!# on M;E

' S!# is *iomass in

system divided *y

*iomass wasted "rom

system where systemincludes *oth aero*ic

and ano:ic *asins@

CS#!

M;E


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M;EM;E

' !ecycle a""ectsper"ormance in M;E

' Greater recycle leadsto&

activated sludge modeling

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