srb biofilm growth simulation: effect of sulfate concentration and fluid flow velocity

姓名：韩洋导师：康勇教授

SRB Biofilm Growth Simulation: Effect of Sulfate Concentration and

Fluid Flow Velocity

Model Description

Simulation Strategy

X Induced Biofilm

Heterogeneity

How X Affect Biofilm

Heterogeneity

The Function of

Biofilm Structure

Sulfate Reduction Efficiency

Model Description

Simulation Domain

Model Description

Simulation Parameters

3.2 mm

0.8

mm

Model Description

Simulation Parameters

u(m/s)c(mg/l) 0.0001 0.001 0.00625 0.01 0.04

10 1 7 13 19 2518 2 8 14 20 2630 3 9 15 21 2745 4 10 16 22 2860 5 11 17 23 29

100 6 12 18 24 30

SRB Biofilm Heterogeneity

Effect of Sulfate Concentration (Low Re)

Sul

fate

Con

cent

ratio

n In

crea

ses


Effect of Sulfate Concentration (High Re)

Sul

fate

Con

cent

ratio

n In

crea

ses


Effect of Flow Velocity

Heterogeneity ParametersEffect of Sulfate Concentration

Heterogeneity ParametersEffect of Flow Velocity

Mass Transfer Parameters

Local Sherwood Number Sh

s h

s

k LSh

D

0( ) s

n s s s scJ k c c Dr

0

ss

ss s

cDrk

c c

0

- sh

s s

cLrSh

c c


Effect of Sulfate Concentration on Sh


Effect of Flow Velocity on Sh


Convection Flux vs. Diffusion Flux

2 2C S x yJ c u u

22

2 2S S

D Sc c

J Dx y



Flow

Vel

ocity

Incr

ease

s



Sul

fate

Con

cent

ratio

n In

crea

ses


Mass Transfer Within Biofilm

Mass Transfer ParametersMass Transfer Within Biofilm

Flow

Vel

ocity

Incr

ease

s

Mass Transfer ParametersMass Transfer Within Biofilm

Further Research 1

The function of Channels within SRB Biofilm

Pathway for Mass Transfer

Sulfate/Substrate

Sulfide/Other Production

Should mass transfer and biofilm growth be coupled?

Cavity Vortex

Mass Transfer

Sulfide Inhibition

Precipitation

Further Research 1

Total Sulfide Concentration Profile

Re = 0.08

Re = 8

Re = 32

Reaction Parameters

1 p S

Sh Sh dAA

( , )

d ( , )bb

reac S b S S zi j

Q r r c i j x yL

,reac

S Cx z

QL L

0 d

b

reac

S S b

Qr c

Reaction Parameters

Further Research 2

The Effect of Re on and

Further Research 3

Sensibility to Sulfate Concentration Limitation

Strategy For High Sulfate Concentration Simulation

Further Research 3

The Cause of Concentration sensibility - Limited Penetration Depth


Further Research 3

Limited Penetration Depth – Is it reasonable?


Further Research 3

Limited Penetration Depth – Microbial Reaction Intensity


𝜇𝑚=0.344h− 1

𝐾 𝑠=1.8 h𝑚𝑔 − 1

𝑌 𝑐𝑒𝑙𝑙 /𝑠𝑢𝑙=0.047

𝜇𝑚=0.061h−1

𝐾 𝑠=5 8 h𝑚𝑔 −1

𝑌 𝑐𝑒𝑙𝑙 /𝑠𝑢𝑙=0.567

𝑘𝑚=𝜇𝑚

𝑌 𝑐𝑋≈ 0.061𝑘𝑔𝑚− 3𝑠− 1 𝑘𝑚=𝜇𝑚

𝑌 𝑐 𝑋≈ 9.0×10− 4𝑘𝑔𝑚−3𝑠−1

𝑎=√ 2𝐷𝑐𝑠0

𝑘𝑚≈60𝜇𝑚 𝑎=√ 2𝐷𝑐𝑠0

𝑘𝑚≈486𝜇𝑚

√ √

√ √

Further Research 3

Limited Penetration Depth – Microbial Reaction Intensity


Further Research 3

Limited Penetration Depth – Maintenance Within The Bottom of Biofilm


Decay

Sulfate/Substrate Deficiency

Maintenance

Hydrolysis

Void Inert Biomass

Maintenance Product EPS Precipitation

Further Research 3

Limited Penetration Depth – Maintenance Within The Bottom of Biofilm


Decay

Hydrolysis

Void Inert Biomass

Maintenance Product EPS Precipitation

( , ) ( )m SS S X S X

XS S S

cr c c m c

Y c K

( , ) ( ( , ) )X S X XS S S X S Xr c c Y r c c m c

( , ) ( )Inh S X Inh X XS S Xr c c b c Y m c

S

Inh X

rR

b c

𝑅<𝑅𝑚𝑖𝑛

𝑟 h𝐼𝑛

Multi-species CA

Further Research n

Sulfide Inhibition• Does sulfide influence heterogeneity structure ?• Could SRB be inhibited by the sulfide produced by

themselves? • What factor influences the profile of different sulfide

species in biofilm? Precipitation

• CA or iBM: Should precipitation be modeled as individual particles or just a percentage of a controlled volume?

• Is there any interactive effect between sulfide, metal iron and SRB biofilm heterogeneity?

srb biofilm growth simulation: effect of sulfate concentration and fluid flow velocity

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