COMPARISON OF THE IMPACT OF 3 HANDLING PROCESSES ON THE - - PowerPoint PPT Presentation

COMPARISON OF THE IMPACT OF 3 HANDLING PROCESSES ON THE CHARACTERISTICS OF WASTEWATER SLUDGE

• M. Collard, B. Teychené, L. Lemée

laurent.lemee@univ-poitiers.fr ic2mp.labo.univ-poitiers.fr

1 Limassol, Cyprus, 23 June 2016

But could also be considered as an unlimited resource for

• Water via re-use,
• Energy (methane),
• Phosphorous,
• Fertilizer

treatment generates sludge

Wastewater

(13 Mt dry sludge expected by 2020)

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Landfarming

main solution for sludge management (72%),

• sustainable contrarily to incineration or landfill
• accelerates the restoration of soils
• reverse global warming (4%0 initiative)

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Implemented prior to land farming, aims at

• Reducing the volume thus transportation cost
• producing energy
• Sanitizing (stabilizing)
• Improving agronomic properties
• Degrading contaminants

Handling process

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Evaluate the impact of processes on sludge characteristics, to envisage the environmental fate of this organic matter

Objective

Compared dried, irradiated and digested sludge at the global and molecular scale

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Wastewater treatment plant of Poitiers (France)

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Floated sludge 3L sludge

• 1 kGy (sanitisation dose)
• 50 kGy
• Dried sludge 85°C
• Pellets 120°C

AOP : HO• and e-

aq

4 weeks Thermal drying treatment plant Digestion Laboratory-scale digester e-beam irradiation real scale pilot

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Infrared Spectroscopy

 O-H , N-H  C=C  C=O  C-H δ C-O

0,05 0,07 0,09 0,11 0,13 0,15 0,17

1 kGy IC-O/C-H 50

Increase for e-beam  oxydation of OM

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Chemical fractionation

« Humin » « humic Acids » « fulvic Acids» Lipids sludge residue CH2Cl2/MeOH HCl NaOH

acido-soluble alcalino-soluble

• rgano-soluble

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Changes in soluble fractions

20 40 60 80 100

Floated sludge dried 85°C pellets 120°C 1 kGy 50 kGy 1 w 2 w 3 w 4 w Lipids Fulvic acids Humic acids Humin ash

Weakening at 120°C Decrease in OM and particularly lipids Digestion e-beam thermal

Impact of treatments at the global level

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DSC: 2 exotherms

• 1 : desorption of volatiles (350°C)
• 2 : oxidation of heavy weight compounds (500°C)

TGA : Weight loss associated with exo1/exo2 increases with weakening of OM

Temperature

1 2

Weight loss (%) temperature difference(C/mg)

Thermal analysis

FS 85 120 0,50 0,55 0,60 0,65 0,70 0,75 0,80 0,85 0,90

WLexo1/exo2

Thermal drying

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Double-shot pyrolysis

• 1. low temperature : desorption of volatile molecules
• 2. Higher temperature : breaks covalent bonds of high Mw

compounds

analyser ionisation

Pyrolysis = use of thermal energy only to break chemical bonds

Information at the molecular scale

GC MS

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First-shot 350° C

‐0,1 0,1 0,2 0,3 0,4 0,5 0,6 20 40 60 80 100 120 200 400 600 800 1000 Tem perature ( ° C)

DSC

Thermal drying 120°

Fatty acids Steroïds

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Second-shot 600° C

Aromatic monomers from refractory biopolymers (liginin, proteins, chitin,…)

‐0,1 0,1 0,2 0,3 0,4 0,5 0,6 20 40 60 80 100 120 200 400 600 800 1000 Tem perature difference( ° C/ m g) Tem perature ( ° C)

Thermal drying 120°

DSC

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Double-shot pyrolysis

mg/g OM

Digestion e-beam thermal

10 20 30 40 50 60

floated sludge dried 85°C pellets 120°C 1 kGy 50 kGy 1 w 2 w 3 w 4 w

FaMe Sterols aromatics

• Visible changes at the molecular level for FaMe and sterols

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First-shot 350°C : fatty acids

C16 C18

plant Ion extract (m/z 74)

C17

• Decrease with thermal drying
• Stable after 2w digestion

Branched (i+a)/linear

floated 85 120

, , , , ,

Bacterial origin

i a n C15 i a n

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First-shot 350°C : steroids

Stanols Sterols

Rstanols/sterols

Ion extract(m/z 213,215)

85°C floated 120°C

, , , , , , , , ,

Increase with thermal drying coprostanol cholesterol

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• Elemental analysis, Infrared spectroscopy :

decrease in OM content with 1kGy and digestion

• xidation with e-beam
• Chemical fractionation, thermal analysis :

Weakening with thermal drying and 50 kGy Complexification with 1 kGy

• Py-GC/MS : information at the molecular scale

Changes in fatty acids and steroids Degradation of aromatics with e-beam only

Conclusion

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Thanks for your attention

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