A¦ülvaro Torres - Anaerobic membrane bioreactor for biogas production and ammonium recovery from spent microalgae

8/22/2019 Alvaro Torres - Anaerobic membrane bioreactor for biogas production and ammonium recovery from spent microalgae

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Anaerobic membrane bioreactor for biogas

production and ammonium recovery from

spent microalgae.

ALVARO TORRES ARAVENA

.

Financiado por


2/22

Why microalgae?

North of Chilepresents idealconditions formicroalgae

cultivation:

Solar radiation Space availability No competition

with foodproduction(desertic area)


3/22

Efficient conversion of solarenergy

High biomass productivity High lipid accumulation

Microalgae for bioenergy production


4/22

Biodiesel production frommicroalgae:

High nutrient requirements. High energy demand due to

biomass harvest and oil

extraction

Low overall energy yield



5/22

Biogas production: Energy recovery from oil extracted

biomass

Tool for nutrient release andrecovery/reuse

Cogeneration can produceelectricity and heat valuables forbiodiesel production (heat forsolvent extraction)



6/22

Figure 1. Scheme of nitrogen recovery from anaerobic digestion in microalgae biodiesel production.

AnaerobicDiges.on

Energy(Biogas)

Microalgaeculture

LipidExtrac.on

Spent

microalgae

Biodiesel

produc.on

Lipids

Biodiesel

Microalgae

NITROGENUPTAKE

Stabilizedbiomass

NITROGENRELEASE

PHOSPHORUSRELEASE


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AnaerobicDiges.on

Energy(Biogas)

Microalgaeculture

LipidExtrac.on

Biodiesel

produc.on

Spent

microalgae

Lipids

Biodiesel

Microalgae

NITROGENUPTAKE

Stabilizedbiomass

NITROGENRELEASE

PHOSPHORUSRELEASE


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Energy

ENERGETIC POTENTIALbiodiesel production (microalgae) + biogas production (spentmicroalgae)

485L

Methane 17 MJThermal

Energy

5.5 MJElectrical

Energy

0,28 kg VS

Biodiesel11 MJ(40MJ/kg )

1 kg VSMICROALGAE

0,3 kg VS

0,45 kg SV

0,25 kg SVCarbo-hydrates

Proteins

Lipids

SPENT

MICROALGAE

28 MJ/kgTOTAL ENERGY


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BIO-METHANE POTENTIAL determination (BMP)

Inoculum= Anaerobic consortia

T= 35 C

substrate/inoculum ratio= 1:1 (g VS / gVS)

Buffer capacity= sodium bicarbonate

Anaeobic biomass

Media

Microalgae (Substrate)

CH4 +

CO2


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Energy

Total and spent microalgae

Figure 1. Bio-methane potential of total and spent microalgae B.braunii.

Total microalgae

Spent microalgae

0

100

200

300

400

500

600

0 20 40 60 80 100 120

BMP(mLCH4/g

SV)

Time(d)

TotalMicroalgae SpentMicroalgae


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Lipid Extraction

Figure 2. Confocal microscopy for total(a) and spent(b) microalgae B.brauniistained with calcofluor white.(non-specific cellulasestaining)

(a) (b)

ENERGY


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19 -26% of no degraded organic matter in this assay may be

related to residues containing resistant biopolymers.

Oil extraction has no effect as pretreatment.

Energy


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0

100

200

300

400

500

0 10 20 30 40 50

BMP

(mLCH4/gVS)

Time(d)

Botryococcusbraunii

0

100

200

300

400

500

0 5 10 15 20 25 30 35

BMP

(mLCH4/gVS)

Time(d)

Nanochloropsisgaditana

Energy

Total and spent microalgae

449mL CH4/g VS

16 MJ/kg VS457mL CH4/g VS

16,2 MJ/kg VS


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AnaerobicDiges.on

Energy(Biogas)

Microalgaeculture LipidExtrac.on

Biodiesel

produc.on

Spent

microalgae

Lipids

Biodiesel

Microalgae

NITROGENUPTAKE

Stabilizedbiomass

NITROGENRELEASE

PHOSPHORUSRELEASE


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Figure 4.Ammonium and phosphate release assessment in anaerobic digestion assays. (a) Botryococcus braunii. (b)

Nannochloropsis gaditana.

Nitrogen release68-72%Nutrients Release

0

50

100

150

200

250

300

350

400

0 10 20 30 40 50

So

lublefrac

.on

(mg

/L)

Time(d)

NH4+

PO43-

0

50

100

150

200

250

300

350

400

0 5 10 15 20 25 30 35

So

lublefrac

.on

(mg

/L)

Time(d)

NH4+

PO43-

Botryococcus brauniiNanochloropsis gaditana


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Nutrients Nitrogen Release capacity

4.2 Nitrogen release in AD

Figure 3. Estimation of un-ionized ammonia in hypothetical anaerobic digestion reactor considering effect of pH and substrate

concentration.

IC5050 150 mg NH3 /L

0

50

100

150

200

250

300

350

400

6 6,5 7 7,5 8

NH3(mg/

L)

pH

1%(w/v)

4%(w/v)

7%(w/v)

10%(w/v)

13%(w/v)

16%(w/v)

NH3Inhibion

Botryococcus braunii


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0

20

40

60

80

100

TM SM

28

51

sPO

43- /tPO

43- (%)

Phosphorus

Nutrients Nitrogen Release capacity

Phosphorus from

medium itself

50-70% phosphorus was

present in original sample as

soluble phosphate

Figure 5. Fraction of soluble phosphate presents in total and spent microalgaeBotryococcus braunii.

Botryococcus braunii


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1. INTRODUCTION


Microalgaeculture LipidExtrac.on

Biodiesel

produc.on

Spent

microalgae

Lipids

Biodiesel

Microalgae

NITROGENUPTAKE

AnaerobicDiges.on

Energy(Biogas)

Stabilizedbiomass

NITROGENRELEASE

PHOSPHORUSRELEASE


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Nutrients Nitrogen microalgae uptake

0

2

4

6

8

10

12

0 10 20 30 40 50 60

O2pro

duc

.on

(mg

/L)

Time(min)

0mg/L

50mg/L

100mg/L

125mg/L

150mg/L

175mg/L

200mg/L

250mg/L

Nanochloropsis gaditanaEffect of different NH4+concentration

Oxygen

production


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Nutrients Nitrogen microalgae uptake

0

0,05

0,1

0,15

0,2

0,25

0 25 50 75 100 125 150 175 200 225 250 275

O2Pro

duc

.onrate

(mg

/L*m

in)

N-NH3(mg/L)

Culture conditions:

2 g/L TS

N added in culture:

135mg N/L

NO inhibitionin microalgae

culture

Max. N concentration

150mg N/L

Nanochloropsis gaditana


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CONCLUSION

1. No total nitrogen release is observed in B. braunii (only 68% nitrogenrelease), which could be related to resistant biopolymers reported for

this microalgae.

2. Anaerobic digestion of spent microalgae seems as a viable alternative inorder to recover energy.

3. Phosphorus present in microalgae may be associated to phosphate

from medium itself.

4. No inhibition is expected into microalgae culture for N.gaditana


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Acknowledgements

Consortium Desert Bioenergy S.A.

Center of Waste Management and Bioenergy BIOREN

Universidad de Antofagasta

Conicyt Scholarship

Beca Apoyo tesis Doctoral - Conicyt

Beca Tesis en la Industria - Conicyt

Dr. David Jeison

Patricio Neumann

Hernn Daz

Documents

A¦ülvaro Torres - Anaerobic membrane bioreactor for biogas production and ammonium recovery from spent microalgae