adding value to pike perch culture wastewater via …...other advantages of the mab-floc sbr concept...

Van Den Hende S.1, Beelen V. 1, Bore G. 1, Boon N. 2, Vervaeren H. 1 1 Lab of Industrial Water and Ecotechnology (LIWET), Ghent University, Belgium 2 Lab of Microbial Ecology and Technology (LabMET), Ghent University , Belgium Aquaculture Europe 2014, 17th October

Adding value to pike perch culture wastewater via microalgal bacterial flocs: From concept to outdoor scale

http://www.west-vlaanderen.be/http://www.ugent.be/http://www.kbs-frb.be/index.aspx

Bacteria

Wastewater COD, N, P

O2

CO2

Microalgae

Photosynthetic aeration CO2 scavenging Solar energy into biomass Nutrient recovery

Bacteria


O2

CO2, N2

CO2, N2

O2

Algal bacterial system

Nutrient removal Nitrification/denitrification Mechanical aeration up to 50 % of working costs

Discharge norms for effluent

Conventional system

Needed: redesign of wastewater treatment

Bacteria


O2

CO2

Microalgae

Photosynthetic aeration CO2 scavenging Solar energy into biomass Nutrient recovery

Bacteria


O2

CO2, N2

CO2, N2

O2

Algal bacterial system


Nutrient removal Nitrification/denitrification Mechanical aeration ~50 % of working costs

Conventional system

Bacteria

Bioresource water COD, N, P

O2

CO2

Microalgae

Nutrient recovery CO2 scavenging Photosynthetic aeration (O2) Solar energy into biomass

Bacteria


O2

CO2, N2

CO2, N2

O2

Microalgal bacterial system Conventional system


Nutrient removal Nitrification/denitrification Mechanical aeration ~50 % of working costs

Needed: redesign of wastewater treatment

Problem

Microalgae are difficult to separate from the treated wastewater

Harvesting is expensive: up to 30 % of operational costs

Solution @ Ghent University/Howest

Biomass-free effluent

Bioflocculation of microalgae & bacteria

Microalgal bacterial flocs = MaB-flocs

Settle without flocculant addition

0.1 mm

200 µm

Microalgae Bacteria

Van Den Hende S., 2014. Microalgal bacterial floc for wastewater treatment: from concept to pilot scale.

PhD dissertation, Ghent Univ., 324p. Promotors: Prof. dr. Nico Boon (LabMET), dr. Han Vervaeren (LIWET).

Needed: cheap separation of algae & water

1. Collect a mix of microalgae outdoors

2. Collect wastewater

Wastewater, Alpro Sieve, Alpro Water tank, Alpro

The secret recipe of making MaB-flocs

3. Mix algae and wastewater in sequencing batch reactor (SBR)

Selection of fast-settling flocs in 1-2 weeks

Discharge

treated

wastewater

= effluent

Add

wastewater

= influent

Settling of

MaB-flocs

Stirring of

MaB-flocs

and

wastewater

The secret recipe of making MaB-flocs

Other advantages of the MaB-floc SBR concept

1. Costless separation of treated wastewater and MaB-flocs

MaB-flocs settle at night in the reactor

No additional settling tank for effluent discharge

2. Hydraulic retention time can be decoupled from sludge retention time

Dilution rate ≠ algal growth rate

Possible: treatment of low-strength wastewaters at high algal biomass densities

3. Flocs are large (200-500 µm) and easily harvested

Can be harvested by filter press (200 µm)

No flocculants needed: cost saving, no chemical contamination

Problem: wastewaters strongly differ

Nutrient composition, pH, toxic compounds, ….

Solution: screen various wastewaters

Pike perch culture (Inagro)

Manure treatment (Innova Manure)

Food-processing industry (Alpro)

Chemical industry (BASF)

Van Den Hende et al., 2014b. Treatment of industrial wastewaters by microalgal bacterial flocs in

sequencing batch reactors. Bioresour. Technol. 161, 245-254.

Which wastewaters?

Problem: wastewaters strongly differ

Nutrient composition, pH, toxic compounds, ….

Solution: screen various wastewaters

Pike perch culture (Inagro)

Manure treatment (Innova Manure)

Food-processing industry (Alpro)

Chemical industry (BASF)

Van Den Hende et al., 2014b. Treatment of industrial wastewaters by microalgal bacterial flocs in

sequencing batch reactors. Bioresour. Technol. 161, 245-254.

Which wastewaters?

Best !

Problem:

Lab data should not be extrapolated to outdoor scale with conversion factor of 1

Solution:

Up-scaling to raceway algae pond

Pilot Reactor Network

INTERREG IVB NWE project with 9 pilots

Lab PBR > 100 ton ha-1 y-1

Outdoor ponds ? ton microalgae ha-1 y-1

From lab reactor to open pond

Settling

MaB-floc SBR

Pike perch culture wastewater

Flue gas Dischargeable effluent

Shrimp Shrimp feed Dewatering

4. MaB-flocs as shrimp feed ?

Up-scaling to outdoor pond ? 1. Wastewater treatment 2. Biomass: bioflocculation and harvesting

3. MaB-flocs for biogas ?

Biogas

EnAlgae research questions

Picture: Tim Lacoere, Labmet

Outline

13

1. Wastewater treatment 2. Biomass: bioflocculation & harvesting 3. Biogas 4. Shrimp feed

Wastewater origin

Fish tanks Drum filter (30 µm)

Effluent discharge (10 % / day)

MaB-floc

SBR

Biofilter

Pike perch Sander lucioperca L.

UV O2 Water

Feed

Aquaculture Practice Center (Stefan Teerlinck, Laurens Buyse , Geert Bourgeois)

Sewerage

4 L indoor 40 L indoor Kortrijk (Belgium) Kortrijk (Belgium)

D: 0.350 m

L: 0.351 m

B: 0.325 m

20 L

day-1 20 L

day-1

Upscaling for aquaculture wastewater: reactors

400 L indoor Roeselare (Belgium)

D: 0.356 m

L: 1.170 m

B: 0.960 m

100 L

day-1

100 L day-1

Influent tank MaB-floc SBR Settling tank

Sieve on settling tank

Sludge


12 m3 outdoor Roeselare (Belgium) Pilot construction by 2 SMEs: CATAEL bvba, Bebouwen & Bewaren nv

D: 0.4 m

L: 11.7 m

B: 2.5 m

1.5-3 m3

day-1

Influent tank

MaB-floc SBR

Settling tank

1.5-3 m3

day-1

MaB-flocs

Effluent tank

PLC

Heater

CO2

Propeller pump

for SBR stirring

Sludge

pH,T DO

N S


Below effluent discharge norms for COD, BOD5, NH4+, TN, TP, PO4

3-

Low PO43- and TP concentrations in effluent (< 0.8 mg P L-1 ; as low as 0.1)

-> potential as P-polishing technology

40 L indoor 400 L indoor 12 m3 outdoor pond

Influent Effluent

Outdoor pond: effluent quality

Photosynthetic aeration by

microalgae was sufficient

Dissolved oxygen production

in line with solar radiation

No mechanical aeration

needed: cost saving

More land area needed !

MaB-floc ponds: 0.4 m deep

CAS : 4 m deep

Time

Outdoor pond: photosynthetic aeration is ok!

Diurnal pH fluctuations

Photosynthesis

increases pH during day

Respiration

decreases pH during night

Effluent discharge

after night to reach pH discharge norm

-> this strategy is not sufficient in summer

0

20

40

60

80

201

3-0

1-2

4

201

3-0

2-2

1

201

3-0

3-2

1

201

3-0

4-1

8

201

3-0

5-1

6

201

3-0

6-1

3

201

3-0

7-1

1

201

3-0

8-0

8

201

3-0

9-0

5

PP

FD

(m

mo

l P

AR

/ L

reacto

r /

SB

R c

ycle

)

Time

1 2 3 4 5 6 7 8

7

8

9

10

11

12

Reacto

r p

H

1 2 3 4 5 6 7 8

Problem 1: pH in outdoor pond

12 m3 raceway pond

Outdoors, flue gas (5% CO2) was needed to lower pH

Flue gas injection = extra cost !

But, low flue gas flow rates: 0.00004 vvm, so low cost

Flue gas injection in open pond ≠ CO2 credits !

MaB-floc SBR is not a flue gas treatment systems -> needed area !

7

8

9

10

11

0 50 100 150 200 250

1 2 3 4 5 6 7 8

No flue gas Time (days)

pH

Norm

Effluent

Influent

Problem 1: pH in outdoor pond

Indoors, nitrite concentration in effluent was not a problem

Outdoors, nitrite was often above the norm for discharge (0.9 mg N-NO2- L-1)

for reuse (1.8 mg N-NO2- L-1)

Solution: avoid nitrite formation in the influent buffer tank?

Discharge

Norm

Influent

Effluent

Time (days) Time (days)

400 L 12 m3 outdoor pond

0

2

4

6

8

0 50 100 150 200 2500

1

2

0 25 50 75 100

N-N

O2- (

mg

/ L

)

Problem 2: nitrite in outdoor pond

1. Photosynthetic aeration was sufficient, even in Belgium

2. Outdoor operation needed flue gas injection

Low loading, but extra cost

3. Effluent quality was ok, but …

Except for nitrite

Land area: 1 m2 MaB-floc pond area per m3 pike perch fish tank 0.05 m2 CAS

Pond heating: needed in winter -> waste heat?

Conclusions: upscaling

Outline

24


Up-scaling shifted the dominant algal sp.

Phormidium sp. indoor

(filamentous cyanobacteria)

to Ulothrix or Klebsormidum sp. outdoor

(filamentous microalgae)

400 L indoor

Raceway outdoor

Effect of scale-up on MaB-flocs: species

Up-scaling increased crystal content

Red = chlorophyll -> algae

Blue = crystals

Ash was up to 30% calcium -> CaCO3

Positive for wastewater treatment

Enhance settling of MaB-flocs

Hardness removal

Negative for biomass valorisation?

Decreased energy content of biomass

Reactor scaling

Unbalanced Ca:P:K ratio

400 L indoor

Raceway outdoor

Effect of scale-up on MaB-flocs: crystals

100 µm bars

*Scale-up conversion factor

Scale-up decreased the biomass productivity

Per reactor volume: 10 times less TSS, 13 times less VSS

Average outdoors: 33 ton TSS hapond-1 y-1 or 12 ton VSS hapond

-1 y-1

1.5-4 times lower compared to www-fed HRAP in cold climate (Park et al., 2011)

But, no optimisation yet!

Increased presence of predators

Tubifex sp. can increase palatability and appetites of fish (Lietz, 1988)

Reactor Productivity

(mg TSS

Lreactor day-1)

Productivity

(mg VSS

Lreactor day-1)

4 L indoor 236 ± 73 (10)* 109 ± 30 (13)

40 L indoor 65 ± 8 (2.9) 45 ± 6 (5.5)

400 L indoor 16 ± 23 (0.6) 12 ± 17 (1.3)

12 m3 outdoor 23 ± 54 (1.0) 8 ± 18 (1.0)

Effect of scale-up on MaB-flocs: productivity

MaB-floc SBR pilot

2.1. Filtering by gravity

2.2. Filtering by hydropress

1. Settling of MaB-flocs (1 hour)

MaB-floc cake

MaB-floc harvesting: 1. settling, 2. filtering

MaB-flocs

In pond Settled MaB-floc slurry 70 g TSS L-1

MaB-floc cake: 43 ± 8 % dry matter

1. Concentrating step: settling

2. Dewatering step: filtering 150-250 µm

Supernatant:

7.9 ± 5.7 % MaB-floc TSS loss, pumped back into pond -> No loss!

Gravity filtrate:

1.2 ± 0.9 % MaB-floc TSS loss

2.1. Gravity filtering

2.2. Hydropress filtering

Press filtrate:

0.05 ± 0.03 % MaB-floc TSS loss

MaB-floc harvesting: 98% biomass recovery

As for dominant algal species, lab results can not be extrapolated

Importance of outdoor pilot tests !

Upscaling improved settling of MaB-flocs !

Proof-of-principle that bioflocculation outdoors in NWE can be successful

Moderate biomass productivity

Should only be improved if a lucrative valorisation pathway is found

Very efficient dewatering with filter press at large pore size (200 µm) !!

Water powered filter press: 0.16 € kg-1 DM MaB-flocs (4 bar water)

Electricity powered filter press: 0.04-0.07 kWhel kg-1 DM (Udom et al., 2013)

-> Dewatering: < 0.01 € kg-1 DM MaB-flocs !

Van Den Hende et al., 2014a. Up-scaling aquaculture treatment microalgal bacterial flocs in sequencing

batch reactors: From lab reactors to an outdoor raceway pond. Bioresour. Technol. 159, 342-354.

Conclusions: biomass

Outline

31


Biomethane potential (BMP) of MaB-flocs

MaB-flocs from pilot: July - September 2013

Moderate MaB-floc BMP ~ activated sludge BMP

145-205 NL CH4 kg-1

MaB-flocs VS and 67 % CH4 in biogas

143-587 NL CH4 kg-1

algae VS (Ward et al., 2014)

Low anaerobic digestion efficiency

ƞAD 27 - 34 %

Only 51-65 % of chlorophyll was removed during AD batch

Needed: pretreatment of MaB-flocs

Biogas resource: MaB-flocs?

Only positive effect on BMP was microwave treatment (870 s, 700W)

9.4 ± 5.4 % increase of BMP with 2.3 MJ kg-1 MaB-floc TS

Compared to 27 % increase of BMP with > 20 MJ kg-1 TS (Passos et al., 2013)

-> Energetically not interesting

0 50 100 150 200

Control

Freeze/thaw

Autoclave

Microwave

Chlor. + sonication

BMP (NL CH4 kg-1 VS)

0 20 40

ƞ AD (%)

Biogas resource: pretreated MaB-flocs?

AD to biogas seems not economical interesting for these MaB-flocs

2500 Nm-3 CH4 hapond area-1

y-1 (= half of 1 ha of corn)

Biogas low price: 0.30 € kg-1 MaB-floc VS or < 0.01 € m-3 wastewater

Low compared to wastewater treatment cost of 0.30-0.60 € m-3 (Verstraete et al., 2009)

Practical constraints

Scaling (CaCO3) of reactors due to high ash content of MaB-flocs

Needed: biomass valorisation pathways with €

If MaB-floc market price of 2.5 € kg-1 DM -> 0.32 € m-3 wastewater

Conclusions: biogas

Outline

35


Research question:

Can MaB-flocs be included in diets of white Pacific shrimp?

Litopenaeus vannamei (Boone 1931)

0 - 2 - 4 - 6 - 8 % inclusion

Mainly wheat was replaced

1. Shrimp quantity?

2. Shrimp quality?

Problem:

What to do with these low-energy MaB-flocs ?

Compound Content (%)

Ash 62

Calcium 17

Protein 21

Lipid 4

Need and research question

0-2-4-6-8 % MaB-floc inclusion did NOT lead to significant difference of

Shrimp quantity Range of averages of all trials

Survival 93 - 97 %

Weight gain 0.32 - 0.34 g day-1

Feed conversion ratio 1.17 - 1.27

Shrimp quality

Proximate composition

Fatty acid profile

Shrimp production: no effect of diets

0

5

10

15

20

25

30

a b L

Re

fle

cta

nce

of

red

ness,

yello

wn

ess o

f co

oked

sh

rim

p

0% MaB 2% MaB 4% MaB 6% MaB 8% MaB

d

dc cb

ba a

b b b

a

a

b a ba ba b

Redness Yellowness

MaB-flocs effect pigmentation of

cooked shrimp tails

Enhanced redness and yellowness

MaB-flocs contain 0.25 % carotenoids

Increased market value of shrimp ?

Shrimp colour: significant effect of diets

Regulation EC No 767/2009: NO!

Restricts the use of waste from treatment of industrial wastewater in animal feed

Directive 91/271/EEC: BUT…

Industrial wastewater is ‘wastewater which is discharged’

e. g. aquaculture wastewater in closed RAS = process water ?

Regulation EC No 767/2009: BUT…

Restricts the use of faeces and urine including of fish (aquaculture) in feed that

enters the EU market

Opportunities: YES?

1. Don’t bring it on the market -> use it where it is produced -> integrated system

2. Food company process water = bioresource water

MaB-floc pilot operation in 2014 by Ghent University at food company Alpro

EU feed market regulations: is it legal?

High ash content of MaB-flocs from pikeperch wastewater treatment

Low inclusion of MaB-flocs enhance pigmentation

Increased inclusion of MaB-flocs in diets: 0-50 %?

Data needed on health and safety (biotoxins, heavy metals, pathogens, etc…)

Replace more expensive ingredients of > 300 € ton-1

Dewatering, drying and grinding of MaB-flocs: 200-300 € ton-1 MaB-floc DM

Wheat ~200 € ton-1

Region specific applications

NWE Europe: process water which does not contain manure particles

Tropical regions with large shrimp industry?

Van Den Hende et al., 2014c. Microalgal bacterial flocs originating from aquaculture wastewater treatment as diet ingredient for Litopenaeus vannamei (Boone). Aquacult. Res., DOI: 10.1111/are.12564.

Conclusions: shrimp feed

Settling of MaB-flocs

MaB-floc SBR

Wastewater

Flue gas Dischargeable

effluent

Dewatering of MaB-flocs

5. Fertilizer for tomatoes (J. Coppens, UGent)

4. Outdoor pilot at food industry

Shrimp Biogas Fertilizer

1. Economics (E. Vulsteke, UGent)

2. LCA (S. Sfez, UGent)

3. Growth modelling (Swansea University)

MaB-floc pilot: current research

http://www.google.be/url?sa=i&rct=j&q=&esrc=s&frm=1&source=images&cd=&cad=rja&uact=8&docid=WeC_Sv_kN64v4M&tbnid=SVefG2gibFPTPM:&ved=0CAcQjRw&url=http://www.alpro.com/corporate/en/powerful-stories-about-plants/things-we-do-to-sustain-the-planet&ei=l6wYVL3dKIiXaoutgNgK&bvm=bv.75097201,d.d2s&psig=AFQjCNGCxzHLevONQz_tx2OjnO35w454LA&ust=1410989561481683

Valorisation of MaB-floc biomass of Alpro

Proof-of-principle in an tropical aquaculture area Availability: light, heat, wastewater,

experience in algae and ponds,

large aquaculture industry

Need for: wastewater treatment and

aquaculture feed ingredients

Future research: interested in collaboration?

Size matters.

Micro-algae

MaB-floc

Size matters.

Size matters.

Sofie.VanDenHende @ugent.be Presentation on: www.enalgae.eu

Thank you ! Looking forward to a future MaB-floc collaboration !
http://www.enalgae.eu/

adding value to pike perch culture wastewater via …...other advantages of the mab-floc sbr concept...

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