Solid-liquid separation of effluent produced by a fixed media biofilm reactor

Bernard Patry, Étienne Boutet, Serge Baillargeon and Paul Lessard

10th International Conference on Biofilm Reactors,

9th – 12th May 2017, University College Dublin, Ireland

Outline

• Context

• Objectives

• Methodology

• Experimental results

• Conclusions

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Context

Why treat suspended solids (SS) ?

O2 limitationEutrophicationToxicity

Discharge standards: 25 g/m³ in Canada

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= f(detached solids properties)

Context

• Solid-liquid separation = limiting step in biological treatment processes

• Attached growth

= f(operating conditions)

Media

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Context

• Most available data Moving bed biofilm reactors (MBBR) and non-submerged media systems

Conditions Properties Performances

• Hydrodynamics

• Temperature

• Surface loading

rate and HRT

• Biofilm properties

• Detachment

processes

• Particles size

• Flocs morphology

• Effluent settled

and non-settled SS

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Context

• BIONEST® submerged fixed media technology

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Outline

• Context

• Objectives

• Methodology

• Experimental results

• Conclusions

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Objectives

Pilot study to :

• Characterize settleability of solids from submerged fixed media

biofilm reactors

• Measure influence of surface organic loading rate (OLR) and temperature

• Explain performance variations

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Outline

• Context

• Objectives

• Methodology

• Experimental results

• Conclusions

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Methodology

Experimental site :

Grandes-Piles,

Québec, Canada

(415 inhabitants)

Québec city

(Université Laval)

MontréalOttawa

Saint-Laurent river

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Methodology

• 12 pilot reactors

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12

13

14

Methodology

• Measured variables :

• Settleable solids: Standard Methods protocol

• Particle size distributions (PSD): Focused beam reflectance measurement (FBRM)

• Particle settling velocity distributions (PSVD): ViCAs (Vitesse de chute en

assainissement)

• Microscopic observations

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Outline

• Context

• Objectives

• Methodology

• Experimental results

• Conclusions

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Experimental results

Effluent samples SS concentrations

MBBR effluent SS

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Experimental results

Operating temperature influence

Mixed regression with repeated measurements:P-value < 0.01

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Experimental results

Operating temperature influence

Compositional data analysis:P-value < 0.01

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Experimental results

Relation between particles size and non-settleable solids

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Experimental results

OLR influence

>5 g soluble CBOD5/m2·d

SS concentration < 20 g/m³

Mixed regression with repeated measurements:P-value > 0.05

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Experimental results

OLR influence

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Outline

• Context

• Objectives

• Methodology

• Experimental results

• Conclusions

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OLR

Conclusions

T°

Operating

conditions

Particles

properties

Size

Morph.Settling

potential

Settleable

solids

Settling

velocity

• Intermediate T° highest settling potential

• High OLR ≈ potentially increased settling potential

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Thank you!

Solid-liquid separation after submerged fixed media reactors operating temperature must be considered

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