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ENG. ROBERTO BALDA MSc3153821789

WATER RESOURCE

cycle 1

2013

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Basic Reactors

Complete mixFEATURES :

Suspended cultureContinuous mixed tankImmediate particledispersion

High pollution loadremoval

Aerobic digestion ofsludge and concentrated

wastes

Aerated lagoons andactivated sludge

Q,Si Q,Sex

Substrate(BOD)

Biomass(g/L)

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Basic Reactors

Batch reactor MAIN FEATURES

Suspended cultureThere is no incoming oroutgoing flow

All the componentsinvolved are added beforethe start-up.

CyclesBOD testsVery high pollutionloads removal

SBR

Q,Si

x

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Basic Reactors

Plug Flow Reactor

MAIN FEATURESSuspended cultureNo complete mix as a whole

Variation of the substrate concentrations and ofmicroorganisms across the reactor

Used in activated sludge units, other aerobic andanaerobic treatment, stabilization ponds

Si decreases along the flow pattern

Si

Se

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Biofilm reactors

Packed bed reactorMAIN FEATURE

Attached biologicalgrowth

Stones /plastic media@ Plug flowNon-submersed(Trickling Filter)

If submersed in water:aerobic or anaerobic

filters

Average pollutionload removal

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Fluidized bedFEATURES

Attached growth, butsuspended

High upflow velocities (!)Bed expansion orrecirculationParticles with biofilmSand/GAC/diatomaceousearths: abrasion resistant

Plug flow/Complete mix

Low organicsconcentrations (aromatic

hydrocarbons): aerobictreatment

For denitrification andanaerobic treatment

UASB

Biofilm reactors (continue)

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Rotating BiologicalContactor (discs)

FEATURESAttached biologicalgrowth on fixed media

Discs or rotors on a shaftSubmersed piece absorbspollutants to be oxidized

Piece in contact with airabsorbs oxygen

Most cases are plug flow

Anaerobic conditionswhen covered

Complete mix whenthe flow is divided

perpendicular to the

total length of the tank

Biofilm reactors (continue)

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I. Recirculation of settled cells

Activated sludge processKeep enough population of m.o. inside the reactor

Q,Si

xxr

Qr,Xr

Se

Q+ Qr

Qw,Xr,Se

Q-Qw,Se

Xe

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II. Recirculation after sedimentation

Dilution of influent loadsAvoids: excess of oxygen demand, of organic acidproduction, or substrate toxicity.

Increases hydraulic loading (trickling filters, UASB,fluidized beds)

Q,Si

Qr,Ser

Se+Ser

Q+ Qr

Q,Se

Xe

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III. Recirculation of effluent from reactor

Q,Si

Qr,Ser

Se+Ser

Q+ Qr

Q,Se

Xe

Dilution of influent loadsAvoids: excess of oxygen demand, of organic acidproduction, or substrate toxicity.

Increases hydraulic loading (trickling filters, UASB,fluidized beds)

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In series

When different sorts of treatment are requiredOrganic oxidation nitrification denitrificationTo create plug flow conditionsCan be reactors of the same type or different types ofreactors

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In parallel

To be conservativeas designer

When a stand-byunit is required

When willing tohave complete mixreactors