nitrification denitrification of raw municipal...
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NITRIFICATION‐DENITRIFICATION OF RAW MUNICIPAL WASTEWATER WITHOUT
RECIRCULATION, USING ENCAPSULATED MICROBIAL SYSTEMS
School of Environmental EngineeringTechnical University of Crete
M. Farazaki, H. Marakas and P. Gikas
ΕΕΛ2
Typical wastewater treatment plant
School of Environmental EngineeringTechnical University of Crete
Primary clarifier
Inlet
Barscreen
Secondary clarifier
Tertiaryfilter
OutletAeration Disinfection
Air
Biosolids
BackWash flow
Denitrification
R
R
Conventional activated sludge process with nitrfication/denitrification
School of Environmental EngineeringTechnical University of Crete
Energy distribution in conventional municipal wastewater treatment plant
School of Environmental EngineeringTechnical University of Crete
Aprox. 12% of the energy consumption is used for primary sludge management
Energy requirements in an issue of increased concern, as about 0.5-0.7 kWh/m3 are required for treatment
Aprox. 60% of the energy consumption is used for aeration
How It WorksMicroscreen ‐ Operating principle
School of Environmental EngineeringTechnical University of Crete
Microscreen
a. Microscreen with open housing
b. Sludge removal (~45% TS)
c. Microscreen cloth (100-350μm openings)a
b c
Microscreen (Patra, Greece)
School of Environmental EngineeringTechnical University of Crete
How It Works Footprint requirements
1 ÷ 20
Wastewater flow: 4000m3/d:Microscreen footprint: 4 m2
Clarifier footprint: 82 m2
School of Environmental EngineeringTechnical University of Crete
Upflow sand filters, Adelanto, California(15000 m3/d)
School of Environmental EngineeringTechnical University of Crete
Inlet
Barscreen
Microscreen
BackWash flow
R
Trickling filter
B/WB/W
Outlet
Denitrification
Primaryfilter
Tertiaryfilter Disinfection
Biosolids
Solids removal Removal of dBOD & N
Polishing
Upfront solids removal (USR) process with biosolids gasification
DryerSyngas
co-generation engine
Heat
Solid residue
Gasifier
Electric energy
School of Environmental EngineeringTechnical University of Crete
Inlet
Barscreen
MicroscreenPrimary
filter
Upfront solids removal (USR) process with biosolids gasification
School of Environmental EngineeringTechnical University of Crete
BOD=240-320mg/LdBOD=90-130mg/LN-NH4+=25-50mg/LN-NO3
-=0-2mg/L
BOD=130-160mg/LdBOD=90-130mg/LN-NH4+=25-50mg/LN-NO3
-=0-2mg/L
BOD=90-130mg/LdBOD=90-130mg/LN-NH4+=25-50mg/LN-NO3
-=0-2mg/L
BOD=90-130mg/LdBOD=90-130mg/LN-NH4+=0-2mg/LN-NO3
-=25-50mg/L
BOD=90-130mg/LdBOD=90-130mg/LN-NH4+=0-2mg/LN-NO3
-=2-5mg/L
Air
τ>μhtr&
retainedautotrophs
CH3OH
μheterotrophic >μautotrophic
Oxic Anoxic
dBOD≈3.75N-NH4+
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 EngineeringTechnical University of Crete
Δρ. Πέτρος Γκίκας
Biomass encapsulation process
School of Environmental EngineeringTechnical University of Crete
Δρ. Πέτρος Γκίκας
Biomass encapsulation process
School of Environmental EngineeringTechnical University of Crete
Δρ. Πέτρος Γκίκας
Lens shape encapsulated biomass
School of Environmental EngineeringTechnical University of Crete
Δρ. Πέτρος Γκίκας
Encapsulated biomass
School of Environmental EngineeringTechnical University of Crete
Lentikats Biocatalyst – Nitrification bacteria Nitrosomonas europaea and Nitrobacter winogradskyi
Lentikats Biocatalyst – Denitrification bacteria Paracoccus denitrificans and Pseudomonas fluorescens
Nitrification/Denitrification dual CSTR system
School of Environmental EngineeringTechnical University of Crete
Examined bioreactors
Nitrification/Denitrification bioreactors system
Inlet Outlet
Stage 1 Stage 2 Stage 3
Nitrification Denitrification
School of Environmental EngineeringTechnical University of Crete
Nitrification/Denitrification CSTR system
Ammonium removal rates: 79% - 99%
School of Environmental EngineeringTechnical University of Crete
Nitrification/Denitrification CSTR system
Nitrate as nitrogen removal rates: 95% - 98%
School of Environmental EngineeringTechnical University of Crete
Nitrification/Denitrification CSTR system
BOD removal rates: 73% - 90%
School of Environmental EngineeringTechnical University of Crete
Nitrification/Denitrification CSTR system
COD removal rates: 70% - 89%
School of Environmental EngineeringTechnical University of Crete
Nitrification/Denitrification CSTR system
TOC removal rates: 70% - 89%
School of Environmental EngineeringTechnical University of Crete
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 EngineeringTechnical 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
Conclusions
Once through nitrification/denitrification process canbe achieved using encapsulated biocatalysts
BOD5, NH4+-N and NO3
--N outlet concentrations arebelow the limits imposed Directive 98/15/EC,especially for the lower hydraulic retention times.
The reactor volume for nitrification/denitrificationmay be reduced by 16 times, if encapsulatedsystems are used
The system also saves pumping energy, while therein no need for the use of external organic carbon
School of Environmental EngineeringTechnical University of Crete