Biocrude production by activated sludge microorganisms

8/13/2019 Biocrude production by activated sludge microorganisms

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Biocrude Production by Activated Sludgeusing amended Pulp and Paper wastewater

as substrate

Kamal Lamichhane , Andro Mondala, Rafael Hernandez, Todd French, Magan Green,Linda McFarland, William Holmes

Dave C. Swalm School of Chemical Engineering, Mississippi State University


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Content

Objective

Introduction

Materials and methods

Results and

discussions

Conclusion


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Objective

The objectives of this study were to:

1. Test pulp and paper waste water to grow

microorganisms capable of lipid

accumulation, and measure the lipidaccumulation and biodiesel yield

2. Compare the lipid and biodiesel yield

using pulp and paper wastewater with

synthetic wastewater


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Wastewater Treatment Plant for Enhancement of lipid

yield

Screening/grit

removal

Aeration tank

Clarifie

r

Air

Air

Clarifie

r

Domestic/industrialWastewater

influents Effluent

Oily

sludge tolipid

extraction

steps

Belt press

Activated

sludge

Extruded

water

Clarifier

Lipid

accumulation

chamber

Carbon and

nutrient

sources

Recycle

Holdingtanks

Primarysludge to

anaerobic

digestion or

lipid

extraction

Effluent

Waste

sludge


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Pulp and Paper wastewater

Approximately 1551 billiongallons of wastewaterproduced annually in theUnited States1

For every ton of pulp

produced, 17,000 galloonsof industrial process waterrequired2

Almost half of the total

waste is produced in thesouthern regionFig1: International Paper, Vicksburg, MS

1Effluent Limitations and Guidelines, Pretreatment Standards, and New Source Performance Standards: Pulp, Paper and

Paperboard Category; National Emission Standards for Hazardous Air Pollutants for Source Category; Pulp and Paper

Production; Proposed Rule, Dec. 17, 1993

2. http://chlorinefreeproducts.org/images/Article3.pdf


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Pulp and Paper Wastewater:

characteristics and common

contaminants Characteristics

High COD (500-1500 mg/L)

Dark brown coloration

Adsorbable organic halide

Toxic pollutants

Common Contaminants

Sodium carbonate

Sodium hydroxide

Sulfates Chlorine dioxide

Calcium oxide


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Manufacturing Process

Wood

PreparationCooking(NaOH

and Na2S)

Pulp

Washing

Pulp

Screening

Bleaching

Wood Preparation: removes bark

Cooking: most of the lignin removed from the

wood

Pulp washing: wash out the cooking chemicals

and lignin from wood fiber

Pulp screening: remove the uncooked fibers

Bleaching: two stage bleaching-a) Pulp treated with NaOH in presence of

O2to break down the polymer

b) Pulp is treated with ClO2to remove the

remaining the lignin


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Wastewater From Pulp and Paper

Mills


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Wastewater Treatment

Process

Fig 2: Flow Scheme of general Pulp and Paper Wastewater Treatment Process*

*Ince, Bahar K., Cetecioglu, Zeynep., Ince, Orhan (2011).Pollution prevention in the pulp andpaper Industry. pp 231.


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Activated Sludge Process

Biological method that usesmicroorganisms to feed on

organic contaminants in

wastewater

The microorganisms form flocand settle at the bottom

leaving clear liquid at the top

The top liquid is free of

organic materials andsuspended solids*

*Expanding the Activated Sludge Process (2003). Retrieved September 23, 2012 from

http://www.nesc.wvu.edu/pdf/ww/publications/pipline/pl_sp03.pdf

Fig3: typical activated sludge processhttp://www.enotes.com/topic/Activated_sludge


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Oleaginous microorganisms

Activated Sludge contains amixed microbial community

Oleaginous microorganisms in

activated sludge can

accumulate a high percentageof lipids

Microorganisms require water

with high organic content (high

C:N ratio) to grow

Pulp and paper wastewatercould be a suitable growth

media for microorganisms

specialized in biocrude

production

Fig 4: Cells of an Oleaginous yeast*

*. Wynn, James P. Ratledge, Colin. (2005) Oils from Microorganisms pp 123.


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Wastewater Initial Characteristics

Fig 5: Different types of pulp andpaper wastewater

Characteristi

csPulp Wash

Mixed

WastewaterPond Effluent

Process

derived from

Wood pulping,

bleaching, and

washing.

Combined

wastewater

streams

from mill.

Effluent from

anaerobic

settling pond.

pH 2.25 6.26 8.59

COD (mg/L) 1478 1361 410

Ammonium

(mg/L)3.95 5.90 2.83

Sulfate

(mg/L)1400 840 400


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Materials and Methods

Following fermentation experiment wasset up in the bioflo 310 fermenter

2.4 L of the wastewater

20% Activated sludge ( 600 ml)

60 g/L sugar 1.3 g/L Ammonium chloride

1.5 g/L of Potassium phosphate and

1g/L of sodium phosphate

The initial pH was set to 6.5 and agitation

was maintained at 300 rpm and changedto maintain the DO at 60% saturation

Fig 5: Bioflo 310

Fermenter


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Experimental ProcedureActivated

Sludge+

wastewater

Fermentation

Centrifuge

NH4+, COD, sugar Freeze dry

Bligh and

Dyer+TurboVap

Transesterification

GCFID


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Kinetics: Biomass growth

Mathematical modeling was done following the methods by Satturet al. (1991), Karanth et al. (1991) and Mondala et al. (2011)

The biomass growth was determined using the logistic model given

by Weiss and Ollis

max

max

max0

maxmax

max

max

max

max

slopewithlinestraightagivestvslnofplot

ln1lnt

g,Reaggangin

biomassMaximum

rategrowthspecificMaximum

biomasslipidnonofionConcentratX(t)where,

)(1)(

XX

X

XX

X

X

X

X

X

tX

tXdt

dX


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Kinetics: Lipid Accumulation

Lipid accumulation was modeled using Luedking-Piretequation

Vs. ( X X 0) gives straight line

with slope mPlotting

After linearization, the final values of the kinetic parameters were

estimated by non-linear regression using the Levenberg-Marquardt

method in Polymath 6.1

Po = Initial Lipid concentrationn= stationary phase constant

m= growth phase constant


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Kinetics: Substrate

consumption Substrate consumption was modeled by a Luedeking- Piret

equation

XKdt

dP

Y

m

dt

dX

Ydt

dSe

SPSX

//

1e

SP

KY

n

/

SPSX Y

m

Y//

1

O

O

O XtX

tX

Xt

XStS

)()(

ln)( maxmax

max

S0, X0= initial concentration of sugar, and non lipid biomass respectively

max= Maximum specific growth rate

Ke= Maintenance coefficient,= constants used to predict residual sugar maintenance coefficient

Yx= biomass yield based on sugar consumed

Yp= Lipid yield based on sugar consumed


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Results : Pulp Wash

0

50

100

150

200

250

300

350

400

0

10

20

30

40

50

60

0 24 48 72 96 120 144 168

Ammonium(m

g/L)

Biomass,

Lipid,

Glucose

Time(hr)

biomass (g/L)

glucose(g/L)

lipid (%w/w)

ammonium(mg/L)


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Results : Pond Water

0

50

100

150

200

250

300

350

400

450

0

10

20

30

40

50

60

0 24 48 72 96 120 144 168

Ammonium

Biomass,

Lipid,G

lucose

Time (hr)

biomass(g/L)

lipid(%w/w)

glucose(g/L)

ammonium (mg/L)


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Results: Mixed wastewater

0

50

100

150

200

250

300

350

400

0

10

20

30

40

50

60

0 24 48 72 96 120 144 168

Ammonium

Biomass,

Lipid,

Glu

cose

Time (hr)

biomass (g/L)

glucose (g/L)

lipid (%w/w)

ammonium (mg/L)


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Result: Lipid and Fames

Wastewater

Biocrude

(%w/w)

Biodiesel

(%w/w)

Pulp Wash 16.04 6.22

Pond Water 29.59 7.45

Mixed wastewater 10.77 5.9

Fatty Acid Pulp Wash Pond Water Mixed Waste

Myristic (C14:0) % 1.16 0.38 1.03

Palmitic (C16:0) % 19.56 19.4 19.35

Palmitoleic (C16:1) % 3.42 3.44 3.9

Stearic (C18:0) % 11.4 11.03 11.37

Oleic (C18:1) % 44.94 50.26 44.82

Linoleic (C18:2) % 14.93 13.15 15.19Linolenic (C18:3) % 2.41 1.83 1.93

Arachidic (C20:0) % 0.69 0.36 0.52

Lignoceric (C24:0) % 0 0.15 1.64

Table: Fatty Acid Profile


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Kinetic Model Parameters

Biomass growth

Xo 7.7347

Xmax 15.110

max

0.008837

R2 0.7676

Lipid Accumulation

m 0.1352

n 0.0004697

R2 0.8054

Sugar Consumption

1.5849

0.021948

R2 0.9622

Lipid Accumulation

m 0.958

n 0.00304

R2 0.80158

Biomass growth

Xo 8.67

Xmax 17.05

max

0.003528

R2 0.40043

Sugar Consumption

8.5732

0.0172246

R2 0.90832

Lipid

Accumulation

m 0.0319

n 0.0005047

R2 0.76337

Biomass growth

Xo 8.29879

Xmax 19.2200

max

0.012329

R2 0.82707

Sugar Consumption

1.8159

0.0185692

R2 0.9598

Pulp Wash Pond Water Mixed Waste


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Remarks

1. All of the three wastewaters were suitable foroleaginous microbial growth when amended with

sugar and other nutrients

2. Microorganisms growing in pond water accumulated

most lipid (29.59 % CDW) at day 7 compared to pulpwash (11.69%) and mixed wastewater (8.19%)

3. The biodiesel yield was around 6-7 % W/W for all the

wastewater

4. Fatty acid profile was similar to those obtained fromdomestic wastewater


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Future Work

Optimization of fermentation conditions andinvestigation of fed-batch or continuous modes.

Identification of possible toxic compounds and

determination of their fate in activated sludge

lipid accumulation cultures.

Correlate BOD and COD reduction with

biocrude production.

Utilization of pulp and paper mill solid wastesand fiber as source of fermentable sugars.


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Documents

Biocrude production by activated sludge microorganisms