1- Introduction to Aerobic Treatment 1-9-06

8/4/2019 1- Introduction to Aerobic Treatment 1-9-06

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Tech 110:Tech 110:

Pretreatment TechnologiesPretreatment TechnologiesBetween the tank and the soilBetween the tank and the soil


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OutlineOutline

IntroductionsIntroductions

Overview of pretreatmentOverview of pretreatment DefinitionsDefinitions General description ofGeneral description of

processesprocesses

Aerobic Treatment UnitsAerobic Treatment Units(ATUs)(ATUs) ProcessesProcesses TypesTypes SitingSiting

O&MO&M

Media FiltersMedia Filters ProcessesProcesses TypesTypes

SitingSiting O&MO&M

Field visitsField visits


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Overview of PretreatmentOverview of Pretreatment

Adapted from The University Curriculum forAdapted from The University Curriculum forDecentralized Wastewater ManagementDecentralized Wastewater Management

Prepared by: John R. Buchanan, Univ. of TN;Prepared by: John R. Buchanan, Univ. of TN;

Robert W. Seabloom, Univ. of WA;Robert W. Seabloom, Univ. of WA;

Dave Lenning, Alternatives NorthwestDave Lenning, Alternatives Northwest

Edited by: David Lindbo and Nancy Deal, NCSUEdited by: David Lindbo and Nancy Deal, NCSU


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NDWRCDP DisclaimerNDWRCDP DisclaimerThis work was supported by the National Decentralized WaterThis work was supported by the National Decentralized Water

Resources Capacity Development Project (NDWRCDP) withResources Capacity Development Project (NDWRCDP) with

funding provided by the U.S. Environmental Protection Agencyfunding provided by the U.S. Environmental Protection Agencythrough a Cooperative Agreement (EPA No. CR827881-01-0)through a Cooperative Agreement (EPA No. CR827881-01-0)

with Washington University in St. Louis. These materials have notwith Washington University in St. Louis. These materials have notbeen reviewed by the U.S. Environmental Protection Agency.been reviewed by the U.S. Environmental Protection Agency.

These materials have been reviewed by representatives of theThese materials have been reviewed by representatives of theNDWRCDP. The contentsNDWRCDP. The contentsof these materials do not necessarily reflect the views and policiesof these materials do not necessarily reflect the views and policies

of the NDWRCDP, Washington University, or the U.S.of the NDWRCDP, Washington University, or the U.S.Environmental Protection Agency, nor does the mention of tradeEnvironmental Protection Agency, nor does the mention of trade

names or commercial products constitute their endorsement ornames or commercial products constitute their endorsement orrecommendation for use.recommendation for use.


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CIDWT/University DisclaimerCIDWT/University Disclaimer

hese materials are the collective effort of individuals from academic,hese materials are the collective effort of individuals from academic,regulatory, and private sectors of the onsite/decentralizedregulatory, and private sectors of the onsite/decentralized

wastewater industry. These materials have been peer-reviewedwastewater industry. These materials have been peer-reviewedand represent the current state of knowledge/science in this field.and represent the current state of knowledge/science in this field.

They were developed through a series of writing and reviewThey were developed through a series of writing and reviewmeetings with the goal of formulating a consensus on the materialsmeetings with the goal of formulating a consensus on the materialspresented. These materials do not necessarily reflect the views andpresented. These materials do not necessarily reflect the views and

policies of University of Arkansas, and/or the Consortium ofpolicies of University of Arkansas, and/or the Consortium ofInstitutes for Decentralized Wastewater Treatment (CIDWT). TheInstitutes for Decentralized Wastewater Treatment (CIDWT). Themention of trade names or commercial products does not constitutemention of trade names or commercial products does not constitutean endorsement or recommendation for use from these individualsan endorsement or recommendation for use from these individuals

or entities, nor does it constitute criticism for similar ones notor entities, nor does it constitute criticism for similar ones notmentioned.mentioned.


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CIDWT/University DisclaimerCIDWT/University DisclaimerThese materials are the collective effort of individuals fromThese materials are the collective effort of individuals from

academic, regulatory, and private sectors of theacademic, regulatory, and private sectors of theonsite/decentralized wastewater industry. These materials haveonsite/decentralized wastewater industry. These materials have

been peer-reviewed and represent the current state ofbeen peer-reviewed and represent the current state ofknowledge/science in this field. They were developed through aknowledge/science in this field. They were developed through a

series of writing and review meetings with the goal of formulatingseries of writing and review meetings with the goal of formulatinga consensus on the materials presented. These materials do nota consensus on the materials presented. These materials do not

necessarily reflect the views and policies of North Carolina Statenecessarily reflect the views and policies of North Carolina StateUniversity, and/or the Consortium of Institutes for DecentralizedUniversity, and/or the Consortium of Institutes for DecentralizedWastewater Treatment (CIDWT). The mention of trade names orWastewater Treatment (CIDWT). The mention of trade names or

commercial products does not constitute an endorsement orcommercial products does not constitute an endorsement orrecommendation for use from these individuals or entities, norrecommendation for use from these individuals or entities, nor

does it constitute criticism for similar ones not mentioned.does it constitute criticism for similar ones not mentioned.


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Why Pretreat?Why Pretreat?

Pretreat wastewater so downstreamPretreat wastewater so downstream

component(s) can function more reliablycomponent(s) can function more reliably

for longer termsfor longer terms


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Pretreatment OptionsPretreatment Options

Traditionally, have been categorized as:Traditionally, have been categorized as: PrimaryPrimary solids removal solids removal SecondarySecondary organics and BOD removalorganics and BOD removal TertiaryTertiary generally, nutrient removal generally, nutrient removal

Microbes typically used to assistMicrobes typically used to assistAerobicAerobicAnaerobicAnaerobic FacultativeFacultative

Aerobic and anaerobic processes areAerobic and anaerobic processes are

compatiblecompatible


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So where doesSo where does

pretreatment begin?pretreatment begin?

In general, the septic tankIn general, the septic tank


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Septic TankSeptic Tank

FunctionsFunctions Separate solidsSeparate solids

from liquidfrom liquid

AnaerobicAnaerobicdecompositiondecomposition

AttenuateAttenuatesurgessurges

VentilationVentilation


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Septic TankSeptic Tank

Primary treatmentPrimary treatment Most common unit for OWTSMost common unit for OWTS Used alone or with other pretreatment unitsUsed alone or with other pretreatment units Simple and generally inexpensive ($100s)Simple and generally inexpensive ($100s)

30-50% reduction BOD30-50% reduction BOD55, 60-80% reduction, 60-80% reduction

TSSTSS


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Additional PretreatmentAdditional Pretreatment

Grease interceptorGrease interceptor Function remove grease and oilsFunction remove grease and oils Used where greases/oils expected (usuallyUsed where greases/oils expected (usually

commercial sites like restaurants)commercial sites like restaurants) Should not contain blackwaterShould not contain blackwater


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Grease InterceptorGrease Interceptor

Grease trapGrease trap Uses flotation, usually no mechanical partsUses flotation, usually no mechanical parts Typically want to cool wastewater before itTypically want to cool wastewater before it

reaches the tankreaches the tank


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Grease InterceptorGrease Interceptor

Grease separatorGrease separator Typically, proprietary productsTypically, proprietary products High maintenance productsHigh maintenance products

Historically, not good performanceHistorically, not good performance


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Advanced PretreatmentAdvanced Pretreatment

SecondarySecondary organics and BOD removalorganics and BOD removal

TertiaryTertiary generally, nutrient removal generally, nutrient removal

Microbes typically used to assistMicrobes typically used to assistAerobicAerobicAnaerobicAnaerobic

FacultativeFacultative


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Aerobic Treatment ProcessAerobic Treatment Process

ObjectivesObjectives review of how aerobic microorganisms canreview of how aerobic microorganisms can

biochemically oxidize soluble and colloidalbiochemically oxidize soluble and colloidal

organic compounds, and how nitrogenousorganic compounds, and how nitrogenouscompounds are oxidizes into nitrate.compounds are oxidizes into nitrate.

review the processes that create an oxygenreview the processes that create an oxygen

demand and how aeration can be used todemand and how aeration can be used tomeet the oxygen demandmeet the oxygen demand


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Primary GoalPrimary Goal

Use aerobic microorganisms to provideUse aerobic microorganisms to providesecondary treatment to domesticsecondary treatment to domestic

wastewaterwastewater secondary treatment focuses on the removalsecondary treatment focuses on the removal

of biodegradable organics and suspendedof biodegradable organics and suspended

solidssolids usually accomplished with biological reactorsusually accomplished with biological reactors

Biodegradable organics must be removedBiodegradable organics must be removedfrom wastewater stream to minimize thefrom wastewater stream to minimize theimpact on the subsequent processesimpact on the subsequent processes


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RespirationRespiration

CO2 O2

H2O


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Aerobic reactionsAerobic reactions If enough dissolved OIf enough dissolved O22 is in the effluentis in the effluent

then the effluent is Aerobicthen the effluent is Aerobic4e4e-- + O+ O22 + 4H+ 4H

++ 2H2H22OO

If all OIf all O22 is removed effluent becomesis removed effluent becomes

anoxic/anaerobicanoxic/anaerobic


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DenitrificationDenitrification

N2

gasNO3

CO2


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Overall, the Result.Overall, the Result.

If Dissolved Oxygen is Consumed Faster thanIf Dissolved Oxygen is Consumed Faster than

Aeration, then Anaerobic Conditions OccurAeration, then Anaerobic Conditions Occur anaerobic microbes will continue the degradation processanaerobic microbes will continue the degradation process

but at a much slower rate than aerobic microbesbut at a much slower rate than aerobic microbes aquatic species that depend on dissolved oxygen will eitheraquatic species that depend on dissolved oxygen will eithermove or perishmove or perish

aquatic species that cannot survive under anaerobicaquatic species that cannot survive under anaerobic

conditions add to the excess organic matter in the systemconditions add to the excess organic matter in the system


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Thus,Thus,

BOD can be used as a measure ofBOD can be used as a measure of

wastewater strengthwastewater strength a high BOD suggests that the organica high BOD suggests that the organic

compounds are easily biodegradablecompounds are easily biodegradable indicates the mass of dissolved oxygen thatindicates the mass of dissolved oxygen that

could be removed by aerobic microbescould be removed by aerobic microbes

Secondary-treatment devices reduce theSecondary-treatment devices reduce theoxygen demand of a wastewateroxygen demand of a wastewater


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Providing Dissolved Oxygen (DO)Providing Dissolved Oxygen (DO)

Advanced treatment systems are designedAdvanced treatment systems are designed

to provide lots of DOto provide lots of DO high-rate carbon removal and ammonificationhigh-rate carbon removal and ammonification occupies a small-footprintoccupies a small-footprint requires energy to maximize oxygen transferrequires energy to maximize oxygen transfer biological reactorbiological reactor


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Its all about the microbes (bugs)Its all about the microbes (bugs)

Microorganisms are usedMicroorganisms are used to convert colloidal and dissolvedto convert colloidal and dissolved

carbonaceous organic matter into variouscarbonaceous organic matter into various

gases and into cell tissuegases and into cell tissue gases evolve (COgases evolve (CO22, N, N22, and others), and others)

new cells can settle thus carbon is removednew cells can settle thus carbon is removed

break other nutrients out of organicbreak other nutrients out of organiccompoundscompounds nitrogenous compoundsnitrogenous compounds

phosphorus speciesphosphorus species


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MicrobesMicrobes

Good or Bad?Good or Bad?

(or just Ugly)(or just Ugly)


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Optimizing a natural processOptimizing a natural process

Bioreactors are built to maximize theBioreactors are built to maximize the

production of beneficial end-productsproduction of beneficial end-products alcohols (beer)alcohols (beer) insulininsulin other medicationsother medications

AndAnd convert wastewater into secondary-qualityconvert wastewater into secondary-quality

effluenteffluent


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Groundwater

Well

Aerobic soil needed for treatment

Shallow system = Aerobictreatment


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Groundwater

Well

Low OLow O22 results in less aerobic soilresults in less aerobic soil

therefore treatmenttherefore treatment

Deep system = Less aerobic toDeep system = Less aerobic to

anaerobic systemanaerobic system


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Wastewater TreatmentWastewater Treatment

Examples of Aerobic Bioreactors used forExamples of Aerobic Bioreactors used for

Secondary TreatmentSecondary Treatment activated sludge plantsactivated sludge plants rotating biological contactorsrotating biological contactors packed-bed media filterspacked-bed media filters

Highly-engineered systems that utilizeHighly-engineered systems that utilize

microbial metabolism to convert organicmicrobial metabolism to convert organiccompounds into cells and carbon dioxidecompounds into cells and carbon dioxide


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Microbial MetabolismMicrobial Metabolism

Chemical Activities Performed by CellsChemical Activities Performed by Cells CatabolismCatabolism

biochemical process that degrades substrate (food)biochemical process that degrades substrate (food)

down to end-products with the release of energydown to end-products with the release of energy energy is held in chemical form for future useenergy is held in chemical form for future use

AnabolismAnabolism biochemical process that synthesizes new cells.biochemical process that synthesizes new cells.

energy from catabolism is used to drive the processenergy from catabolism is used to drive the process


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CatabolismCatabolism

FermentationFermentation first step in biodegradationfirst step in biodegradation does not depend on presence of oxygendoes not depend on presence of oxygen

both aerobic and anaerobic microbes use thisboth aerobic and anaerobic microbes use this

stepstep this is why methane and alcohol production must bethis is why methane and alcohol production must be

anaerobicanaerobic

however, anaerobic microbes cannot further oxidize thehowever, anaerobic microbes cannot further oxidize the

VFAVFA

2 2 4

volatileCOHNS heterotrophic

fatty + CO + H O + CH + energy + residualsmicrobesorganic compounds

acids


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CatabolismCatabolism

RespirationRespiration second step for aerobic microbessecond step for aerobic microbes

simple organic compounds can be oxidized tosimple organic compounds can be oxidized to

carbon dioxide and watercarbon dioxide and water requires the presence of dissolved oxygenrequires the presence of dissolved oxygen

2 2 2

volatileaerobic

fatty + O energy + CO + H O + residualsmicrobes

acids


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AnabolismAnabolism

Building of cell protoplasmBuilding of cell protoplasm energy from fermentation and/or respiration isenergy from fermentation and/or respiration is

used to assemble the characteristic chemicalused to assemble the characteristic chemical

components of cells from simple precursorscomponents of cells from simple precursors precursors provide carbon, hydrogen, nitrogen andprecursors provide carbon, hydrogen, nitrogen and

other elements found in cellular structureother elements found in cellular structure

chemical energy in adenosine triphosphate (ATP)chemical energy in adenosine triphosphate (ATP)

60 87 12 23simple C H N O Pmicrobes

energyprecursors new cells


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Endogenous respirationEndogenous respiration

Aerobic Degradation of Cellular MaterialAerobic Degradation of Cellular Material microbes are organic compoundsmicrobes are organic compounds under substrate-limiting conditions, microbesunder substrate-limiting conditions, microbes

will feed on each other at a higher rate thanwill feed on each other at a higher rate thannew microbes can be formednew microbes can be formed

60 87 12 23 2 2 2 4 3C H N O P aerobic

+ O CO + H O + PO + NH + residualsmicrobescellular material


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Environmental EffectsEnvironmental Effects

Microbes need more than organic carbon,Microbes need more than organic carbon,dissolved oxygen and waterdissolved oxygen and water temperature must be life-sustainingtemperature must be life-sustaining

need steady supply of food to maintain stableneed steady supply of food to maintain stablemicrobial populationmicrobial population

pH needs to be monitoredpH needs to be monitored low alkalinity can cause large changes in pHlow alkalinity can cause large changes in pH

Be careful with biocidesBe careful with biocides acid drain cleaneracid drain cleaner

antibioticsantibiotics


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TemperatureTemperature

Overall, as temperature rises, microbialOverall, as temperature rises, microbialactivity increases (but not too hot)activity increases (but not too hot)

Microbes can be grouped by temperatureMicrobes can be grouped by temperature

preferencepreference Psychrophilic microorganismsPsychrophilic microorganisms

optimum temperature 12optimum temperature 12 to 18 C to 18 C

Mesophilic microorganismsMesophilic microorganisms optimum temperature 25 to 40 Coptimum temperature 25 to 40 C

Thermophilic microorganismsThermophilic microorganisms optimum temperature 55 to 65 Coptimum temperature 55 to 65 C


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SummarySummary

Aerobic Treatment of WastewaterAerobic Treatment of Wastewater takes advantage of a natural processtakes advantage of a natural process process can be easily engineered into aprocess can be easily engineered into a

biological reactor for high-rate wastewaterbiological reactor for high-rate wastewatertreatmenttreatment

removes the oxygen demand from wastewaterremoves the oxygen demand from wastewater

before being discharged back into thebefore being discharged back into thehydrologic cyclehydrologic cycle

Carbon is transformed into cell mass andCarbon is transformed into cell mass and

into carbon dioxideinto carbon dioxide


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Questions?Questions?


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N Cycle in Septic SystemsN Cycle in Septic Systems

Nitrification and SorptionNitrification and Sorption

Denitrification ?Denitrification ?

Min

eralizat

ion

Min

eralizat

ion

ImmobilizationImmobilization

Documents

1- Introduction to Aerobic Treatment 1-9-06