NITRIFICATION DENITRIFICATION OF RAW MUNICIPAL WASTEWATER WITHOUT - - PowerPoint PPT Presentation

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NITRIFICATION DENITRIFICATION OF RAW MUNICIPAL WASTEWATER WITHOUT - - PowerPoint PPT Presentation

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NITRIFICATION DENITRIFICATION OF RAW MUNICIPAL WASTEWATER WITHOUT RECIRCULATION, USING ENCAPSULATED MICROBIAL SYSTEMS M. Farazaki, H. Marakas and P. Gikas School of Environmental Engineering Technical University of Crete Typical wastewater

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NITRIFICATION‐DENITRIFICATION OF RAW MUNICIPAL WASTEWATER WITHOUT RECIRCULATION, USING ENCAPSULATED MICROBIAL SYSTEMS

School of Environmental Engineering Technical University of Crete

  • M. Farazaki, H. Marakas and P. Gikas
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ΕΕΛ2

Typical wastewater treatment plant

School of Environmental Engineering Technical University of Crete

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Primary clarifier Inlet Bar screen Secondary clarifier Tertiary filter Outlet Aeration Disinfection

Air

Biosolids BackWash flow Denitrifi cation R R

Conventional activated sludge process with nitrfication/denitrification

School of Environmental Engineering Technical University of Crete

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Energy distribution in conventional municipal wastewater treatment plant

School of Environmental Engineering Technical University of Crete

  • Aprox. 12% of the energy

consumption is used for primary sludge management Energy requirements in an issue

  • f increased concern, as about

0.5-0.7 kWh/m3 are required for treatment

  • Aprox. 60% of the energy

consumption is used for aeration

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How It Works

Microscreen ‐ Operating principle

School of Environmental Engineering Technical University of Crete

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Microscreen

a. Microscreen with open housing b. Sludge removal (~45% TS) c. Microscreen cloth (100-350μm openings)

a b c

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Microscreen (Patra, Greece)

School of Environmental Engineering Technical University of Crete

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How It Works

Footprint requirements

1 ÷ 20

Wastewater flow: 4000m3/d: Microscreen footprint: 4 m2 Clarifier footprint: 82 m2

School of Environmental Engineering Technical University of Crete

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Upflow sand filters, Adelanto, California (15000 m3/d)

School of Environmental Engineering Technical University of Crete

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Inlet Bar screen Microscreen BackWash flow R Trickling filter B/W B/W Outlet

Denitrification

Primary filter Tertiary filter Disinfection Biosolids

Solids removal Removal of dBOD & N Polishing

Upfront solids removal (USR) process with biosolids gasification

Dryer Syngas co-generation engine Heat Solid residue Gasifier Electric energy

School of Environmental Engineering Technical University of Crete

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Inlet Bar screen Microscreen Primary filter

Upfront solids removal (USR) process with biosolids gasification

School of Environmental Engineering Technical University of Crete

BOD=240-320mg/L

dBOD=90-130mg/L

N-NH4+=25-50mg/L N-NO3

  • =0-2mg/L

BOD=130-160mg/L

dBOD=90-130mg/L

N-NH4+=25-50mg/L N-NO3

  • =0-2mg/L

BOD=90-130mg/L

dBOD=90-130mg/L

N-NH4+=25-50mg/L N-NO3

  • =0-2mg/L

BOD=90-130mg/L

dBOD=90-130mg/L

N-NH4+=0-2mg/L N-NO3

  • =25-50mg/L

BOD=90-130mg/L

dBOD=90-130mg/L

N-NH4+=0-2mg/L N-NO3

  • =2-5mg/L

Air

τ>μhtr

& retained autotrophs

CH3OH μheterotrophic >μautotrophic Oxic Anoxic

dBOD≈3.75N-NH4

+

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Scope of work

  • Investigate the performance of encapsulated microbial

systems for nitrification/denitrification

  • Examine the feasibility of “once through”

nitrification/denitrification system, with no need for addition of external carbon source

  • Investigate the appropriate hydraulic retention time for

selective nitrification without BOD oxidation

  • Calculate the required reactor volume

School of Environmental Engineering Technical University of Crete

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Δρ. Πέτρος Γκίκας

Biomass encapsulation process

School of Environmental Engineering Technical University of Crete

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Δρ. Πέτρος Γκίκας

Biomass encapsulation process

School of Environmental Engineering Technical University of Crete

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Δρ. Πέτρος Γκίκας

Lens shape encapsulated biomass

School of Environmental Engineering Technical University of Crete

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Δρ. Πέτρος Γκίκας

Encapsulated biomass

School of Environmental Engineering Technical University of Crete

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Lentikats Biocatalyst – Nitrification bacteria

Nitrosomonas europaea and Nitrobacter winogradskyi

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Lentikats Biocatalyst – Denitrification bacteria

Paracoccus denitrificans and Pseudomonas fluorescens

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Nitrification/Denitrification dual CSTR system

School of Environmental Engineering Technical University of Crete

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Examined bioreactors Nitrification/Denitrification bioreactors system

Inlet Outlet Stage 1 Stage 2 Stage 3 Nitrification Denitrification

School of Environmental Engineering Technical University of Crete

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Nitrification/Denitrification CSTR system

  • Ammonium removal rates: 79% - 99%

School of Environmental Engineering Technical University of Crete

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Nitrification/Denitrification CSTR system

  • Nitrate as nitrogen removal rates: 95% - 98%

School of Environmental Engineering Technical University of Crete

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Nitrification/Denitrification CSTR system

  • BOD removal rates: 73% - 90%

School of Environmental Engineering Technical University of Crete

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Nitrification/Denitrification CSTR system

  • COD removal rates: 70% - 89%

School of Environmental Engineering Technical University of Crete

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Nitrification/Denitrification CSTR system

  • TOC removal rates: 70% - 89%

School of Environmental Engineering Technical University of Crete

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  • Nitrification reaction rates:
  • Activated sludge system: 0.21 gNH4

+‐Nremoved/(gnitrifiers∙d)

  • Encapsulated biocatalyst: 0.23 gNH4

+‐Nremoved/(gnitrifiers∙d)

  • Denitrification reaction rates:
  • Activated sludge system: 0.23 gNO3

‐‐Nremoved/(gdenitrifiers∙d)

  • Encapsulated biocatalyst: 0.25 gNO3

‐‐Nremoved/(gdenitrifiers∙d)

Comparisson of encapsulated/free biocatalyst

School of Environmental Engineering Technical University of Crete

At about 16 times saving space from nitrification/denitrification tanks

Encapsulated system contained about 16 times more nitrification or denitrification microorganisms per volume, compared to activated sludge system

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Conclusions

  • Once through nitrification/denitrification process can

be achieved using encapsulated biocatalysts

  • BOD5, NH4

+-N and NO3

  • -N outlet concentrations are

below the limits imposed Directive 98/15/EC, especially for the lower hydraulic retention times.

  • The reactor volume for nitrification/denitrification

may be reduced by 16 times, if encapsulated systems are used

  • The system also saves pumping energy, while there

in no need for the use of external organic carbon

School of Environmental Engineering Technical University of Crete

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petros.gikas@enveng.tuc.gr