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NDWRCDP Disclaimer NDWRCDP Disclaimer This work was supported by the National Decentralized WaterThis work was supported by the National Decentralized WaterResources 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. CR827881through a Cooperative Agreement (EPA No. CR827881 --0101 --0)0)
with Washington University in St. Louis. These materials havewith Washington University in St. Louis. These materials havenot been reviewed by the U.S. Environmental Protectionnot been reviewed by the U.S. Environmental Protection
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representatives of the NDWRCDP. The contentsrepresentatives of the NDWRCDP. The contentsof these materials do not necessarily reflect the views andof these materials do not necessarily reflect the views andpolicies of the NDWRCDP, Washington University, or the U.S.policies 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 tradenames or commercial products constitute their endorsement ornames or commercial products constitute their endorsement or
recommendation for use.recommendation for use.
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CIDWT/University Disclaimer CIDWT/University Disclaimer
These materials are the collective effort of individuals fromThese materials are the collective effort of individuals fromacademic, regulatory, and private sectors of theacademic, regulatory, and private sectors of the
onsite/decentralized wastewater industry. These materials haveonsite/decentralized wastewater industry. These materials havebeen peer been peer --reviewed and represent the current state ofreviewed and represent the current state of
knowledge/science in this field. They were developed through aknowledge/science in this field. They were developed through aseries of writing and review meetings with the goal of formulatiseries of writing and review meetings with the goal of formulati ngnga 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 University ofnecessarily reflect the views and policies of University of Arkansas, and/or the Consortium of Institutes for Decentralized Arkansas, 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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CitationCitation
Seabloom, R.W. and J.R Buchanan. 2005. AerobicSeabloom, R.W. and J.R Buchanan. 2005. Aerobic
Treatment of WastewaterTreatment of Wastewater PowerPointPowerPointPresentation.Presentation. inin (M.A. Gross and N.E. Deal,(M.A. Gross and N.E. Deal,eds.) University Curriculum Development foreds.) University Curriculum Development for
Decentralized Wastewater Management.Decentralized Wastewater Management.National Decentralized Water ResourcesNational Decentralized Water ResourcesCapacity Development Project. University ofCapacity Development Project. University of
Arkansas, Fayetteville, AR. Arkansas, Fayetteville, AR.
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Aerobic Treatment of Aerobic Treatment of
Wastewater Wastewater ObjectivesObjectives
review of how aerobic microorganisms canreview of how aerobic microorganisms canbiochemically oxidize soluble and colloidalbiochemically oxidize soluble and colloidalorganic 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 provide todemand and how aeration can be provide tomeet the oxygen demandmeet the oxygen demand
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Primary GoalPrimary GoalUse aerobic microorganisms to provideUse aerobic microorganisms to providesecondary treatment to domesticsecondary treatment to domesticwastewater wastewater
secondary treatment focuses on the removalsecondary treatment focuses on the removal
of biodegradable organics and suspendedof biodegradable organics and suspendedsolidssolidsusually 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 the
impact on the subsequent processesimpact on the subsequent processes
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Biochemical Oxygen DemandBiochemical Oxygen Demand(BOD)(BOD)
Mass of Dissolved Oxygen Consumed byMass of Dissolved Oxygen Consumed by Aerobic Microbes while Biodegrading Aerobic Microbes while BiodegradingOrganic Compounds and while ConvertingOrganic Compounds and while Converting
Ammonium to Nitrate Ammonium to Nitratea measure of the potential impact a pollutanta measure of the potential impact a pollutant
may have on a receiving streammay have on a receiving streama higha high --BOD waste will cause the consumptionBOD waste will cause the consumptionof dissolved oxygen out of the water at aof dissolved oxygen out of the water at agreater rate than natural aeration.greater rate than natural aeration.
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BOD NomenclatureBOD NomenclaturecBODcBOD
Carbonaceous BODCarbonaceous BOD oxygen demand due to carbon oxidationoxygen demand due to carbon oxidation usually reported as BODusually reported as BOD 55 and potential nitrificationand potential nitrification
is suppressed during measurementis suppressed during measurement
nBODnBODNitrogenous BODNitrogenous BOD
oxygen demand due to nitrogen oxidationoxygen demand due to nitrogen oxidationuBODuBOD
Ultimate BODUltimate BOD oxygen demand measured over long time periodsoxygen demand measured over long time periods
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Oxygen Demand with TimeOxygen Demand with Time
From Academic Curriculum chapter: Onsite Nitrogen Removal, By Stewart Oakley
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Organics, Microbes & OxygenOrganics, Microbes & Oxygen
Bioavailable organic compounds provideBioavailable organic compounds provide
food and energy to microbesfood and energy to microbesnaturallynaturally --occurring microorganisms consumeoccurring microorganisms consumefood, and create more microorganismsfood, and create more microorganismsthe more microorganisms, the more foodthe more microorganisms, the more foodconsumedconsumed
the more food consumed, more dissolvedthe more food consumed, more dissolvedoxygen is requiredoxygen is required
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Basic EquationBasic Equation -- CarbonCarbon
2 2 2
aerobicmicroorganismsOrganic Carbon + O Energy + CO + H O + Residue
2 2 2new aerobic
microorganisms+ O Energy + CO + H O + Residue
2 2 2new aerobicmicroorganisms+ O Energy + CO + H O + Residue
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Biological NitrificationBiological Nitrification
Organically bound nitrogen is released whenOrganically bound nitrogen is released when
the organic compound is oxidizedthe organic compound is oxidizedreleased as the ammonium cation (NHreleased as the ammonium cation (NH 44 ++))Nitrification is a twoNitrification is a two --step autotrophic processstep autotrophic process
the conversion from ammonium to nitratethe conversion from ammonium to nitrate
Nitrosomonas NitrosomonasStep 1:Step 1: NHNH 44++ + 3/2O+ 3/2O 22 NONO 2222-- + 2H+ 2H ++ + H+ H 22OO
Nitrobacter Nitrobacter Step 2:Step 2: NONO 22-- + 1/2O+ 1/2O 22 NONO 33--
From Academic Curriculum chapter: Onsite Nitrogen Removal, By Stewart Oakley
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Biological NitrificationBiological NitrificationDuring this energy yielding reactionDuring this energy yielding reaction
some of the NHsome of the NH 44++
is synthesized into cellis synthesized into celltissue giving the following overall oxidationtissue giving the following overall oxidationand synthesis reaction:and synthesis reaction:
Nitrifiers use CONitrifiers use CO 22 instead of organic carboninstead of organic carbonas their carbon source for cell synthesis andas their carbon source for cell synthesis and
for the conversion of NHfor the conversion of NH 44 ++ to NOto NO 33 ----N.N.
Autotrophic Autotrophic1.00NH1.00NH ++ + 1.89O+ 1.89O 22 + 0.08CO+ 0.08CO 22 0.98NO0.98NO 33-- + 0.016C+ 0.016C 55HH77OO22 N + 0.95H N + 0.95H 22O + 1.98HO + 1.98H ++
Bacteria Bacteria new bacterial cellsnew bacterial cells
From Academic Curriculum chapter: Onsite Nitrogen Removal, By Stewart Oakley
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Overall, the Result.Overall, the Result.
If Dissolved Oxygen is Consumed FasterIf Dissolved Oxygen is Consumed Faster
than Aeration, then Anaerobic Conditionsthan Aeration, then Anaerobic ConditionsOccur Occur
anaerobic microbes will continue theanaerobic microbes will continue thedegradation processdegradation 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 willaquatic species that depend on dissolved oxygen will
either move or perisheither move or perish
aquatic species that cannot survive underaquatic species that cannot survive under
anaerobic conditions add to the excessanaerobic conditions add to the excessorganic matter in the systemorganic 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 strengtha high BOD suggests that the organica high BOD suggests that the organiccompounds are easily biodegradablecompounds are easily biodegradableindicates the mass of dissolved oxygen thatindicates the mass of dissolved oxygen thatcould be removed by aerobic microbescould be removed by aerobic microbes
SecondarySecondary --treatment devices reduce thetreatment devices reduce theoxygen demand of a wastewater oxygen demand of a wastewater
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Providing Dissolved OxygenProviding Dissolved Oxygen
Aerobic treatment Systems take Aerobic treatment Systems take
advantage of this Natural Process byadvantage of this Natural Process byProviding Plenty of DOProviding Plenty of DO
highhigh --rate carbon removal and ammonificationrate carbon removal and ammonificationoccupies a smalloccupies a small --footprintfootprintrequires energy to maximize oxygen transfer requires energy to maximize oxygen transfer
biological reactor biological reactor
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Microbes as WorkhorsesMicrobes as Workhorses
Microorganisms are usedMicroorganisms are used
to convert colloidal and dissolvedto convert colloidal and dissolvedcarbonaceous organic matter into variouscarbonaceous organic matter into variousgases and into cell tissuegases and into cell tissue
gases evolve (CO2, N2, and others)gases evolve (CO2, N2, and others) new cells can be settlednew cells can be settled thus carbon is removedthus carbon is removed
break other nutrients out of organicbreak other nutrients out of organiccompoundscompounds nitrogenous compoundsnitrogenous compounds
phosphorus speciesphosphorus species
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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 endproduction of beneficial end --productsproductsalcohols (beer)alcohols (beer)insulininsulinother medicationsother medications
And Andconvert wastewater into secondaryconvert wastewater into secondary --qualityqualityeffluenteffluent
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Wastewater TreatmentWastewater Treatment
Examples of Aerobic Bioreactors used forExamples of Aerobic Bioreactors used for
Secondary TreatmentSecondary Treatmentactivated sludge plantsactivated sludge plantsrotating biological contactorsrotating biological contactorspackedpacked --bed media filtersbed media filters
HighlyHighly --Engineered Systems that UtilizeEngineered Systems that UtilizeMicrobial 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 substratebiochemical process that degrades substrate
(food) down to end(food) down to end --products with the release ofproducts with the release of
energyenergy energy is held in chemical form for future useenergy is held in chemical form for future use
Anabolism Anabolism biochemical process that synthesizes new cells.biochemical process that synthesizes new cells. energy from catabolism is used to drive theenergy from catabolism is used to drive the
processprocess
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CatabolismCatabolismFermentationFermentation
first step in biodegradationfirst step in biodegradation
does not depend on presence of oxygendoes not depend on presence of oxygenboth aerobic and anaerobic microbes use thisboth aerobic and anaerobic microbes use thisstepstep
this is why methane and alcohol production must bethis is why methane and alcohol production must beanaerobicanaerobic
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 water carbon dioxide and water
requires the presence of dissolved oxygenrequires the presence of dissolved oxygen
2 2 2
volatileaerobicfatty + O energy + CO + H O + residuals
microbesacids
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Anabolism Anabolism
Building of Cell ProtoplasmBuilding of Cell Protoplasm
energy from fermentation and/or respiration isenergy from fermentation and/or respiration isused to assemble the characteristic chemicalused to assemble the characteristic chemicalcomponents of cells from simple precursorscomponents of cells from simple precursors
precursors provide carbon, hydrogen, nitrogen andprecursors provide carbon, hydrogen, nitrogen andother 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 Material Aerobic Degradation of Cellular Material
microbes are organic compoundsmicrobes are organic compoundsunder substrateunder substrate --limiting conditions, microbeslimiting conditions, microbeswill 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 12 232 2 2 4 3
C 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 water dissolved oxygen and water temperature must be lifetemperature must be life --sustainingsustainingneed steady supply of food to maintain stableneed steady supply of food to maintain stable
microbial populationmicrobial populationpH 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 cleaner acid drain cleaner antibioticsantibiotics
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TemperatureTemperatureOverall, as Temperature Rises, MicrobialOverall, as Temperature Rises, Microbial
Activity Increases (but not too hot) Activity Increases (but not too hot)Microbes can be grouped by temperatureMicrobes can be grouped by temperaturepreferencepreference
Psychrophilic microorganismsPsychrophilic microorganisms optimum temperature 12optimum temperature 12 to 18to 18 CC
Mesophilic microorganismsMesophilic microorganisms optimum temperature 25optimum temperature 25 to 40to 40 CC
Thermophilic microorganismsThermophilic microorganisms optimum temperature 55optimum temperature 55 to 65to 65 CC
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SummarySummary
Aerobic Treatment of Wastewater Aerobic Treatment of Wastewater
takes advantage of a natural processtakes advantage of a natural processprocess can be easily engineered into aprocess can be easily engineered into abiological reactor for highbiological reactor for high --rate wastewaterrate wastewatertreatmenttreatmentremoves the oxygen demand fromremoves the oxygen demand from
wastewater before being discharged back intowastewater before being discharged back intothe hydrologic cyclethe hydrologic cycle
Carbon is transformed into cell mass andCarbon is transformed into cell mass andinto carbon dioxideinto carbon dioxide
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QuestionsQuestions