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Advantages and Limitations with usingVarious Substrates in Manure Biogas Plants

Anna Crolla1, Chris Duke2, Chris Kinsley1 and Terrence Sauv2

1 Ontario Rural Wastewater Center at University of Guelph Campus dAlfred2 Ontario Ministry of Agriculture, Food and Rural Affairs

4th Annual Canadian Farm & Food Biogas Conference and ExhibitionLondon Convention Center, London, ON

March 5 7, 2012

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Co-digestion of Manure

Addition of co-substrates to manure improves nutrient balanceof carbon, nitrogen and phosphorus

Manure dilutes high strength wastes

Dairy manure has good buffering capacity with alkalinity ashigh as 9000 mg CaCO3/L

Organic rich substrates improve methane yields

255

385

290

546

675

638

514

375

300

575

500

600

550

450

775

1000

0 200 400 600 800 1000 1200

Cow manure (9%TS)

Pig manure (7%TS)

Chicken manure (15%TS)

Corn (whole Crop)*

Wheat (grain)*

Grass*

Sugar beets*

Harvest re sidues (straw, stems)

Sewage sludge

Expired animal feed

Food Industry Waste

Stillage from breweries

Green wastes (markets)

Biowastes (source separated)

Flotation sludge/animal fat

Waste fat

Mean Biogas Yields of Substrates (m3gas/t VSsubstrate)

[Compilation of data from Braun et al. (2009), Braun and Wellinger (2003) and Weiland (2000)]

Europe: A lot of interest inenergy crops (e.g. grass,clover, cereals, corn)

Ontario: Focus in using

wastes (e.g. waste grease,stillage, food leftovers)

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Sources of Possible Substrates

Compounds Sources Possible Inhibition

Carbohydrates:

Sugars

Starch

Cellulose

beets, corn, fruit

potatoes, corn

straw, grass, wood

pH drop

Proteins animals & animalproducts

pH drop

ammonia increase

Fats animals & animal

products

VFA increase

pH drop

Volatile FattyAcids (VFA)

fats, oils, grease (FOG) pH drop

inhibition of some bacteria

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Parameters for Stable DigestionSubstrates will affect these values

pH 6.8 to 7.2

Alkalinity 1500 to 4000 mg CaCO3/L

IA/TA 0.1 to 0.2 (

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Testing of Substrates

Substrate Characterization Digester Stability

pH

AlkalinitytCOD, sCOD

VS, TS (VS/TS)

VFAs (acetic, propionic, butyric)

Ammonium Nitrogen (NH4+-N)

C:N

pH*

IA/TA (at start of changing OLRs)* VFAs (at start of changing OLRs)

Biogas production andcomposition

VFA Analysis at ORWC Laboratory

Important parameters to monitor

pH monitoring alone may prove tobe unreliable

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BMP & ATA Batch Tests

MesophilicIncubator

ThermophilicIncubator

Manometer 500 mL Wheaton bottles

Incubators for temperature

control and agitation (120 rpm) Manometer for gas volume

Acclimatized inoculum fromon-farm manure digester

Incubated for >30 days

Biochemical Methane Potential(BMP)

Indication of biodegradabilityof substrate to produce CH4

Anaerobic Toxicity Assay (ATA) Determines substrate

inhibition on CH4 production

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Semi-Continuous Bench-scale Digesters

30 L bench-scale digesters(20 L operating volume)

Intermittent mixing

Housed in heat room (35 2oC)

Biogas volume measured usingwet tip meters

CH4 and CO2 composition

determined using gaschromatograph

Typically run for several months

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Characteristics of Cellulosic Substrates

ParameterLiquid Dairy

ManureCorn Silage Switchgrass Woodchips

pH 7.35 (0.17) 7.22 6.99 7.73

Alkalinity, mg CaCO3/kg 7564 (223) 111 130 120

TS, g/kg 78 (20) 900 922 470

VS, g/kg 57 (19) 851 869 450

VS/TS, % 73 95 94 96

tCOD, g/kg 74.6 (14.1) --- --- ---

sCOD, g/kg 8.9 (3.5) --- --- ---

C:N 22:1 (3) 27:1 24:1 500:1

TN, g/kg 4.1 (0.7) 11.9 9.8 2.1

TP, g/kg 0.6 (0.1) 1.7 1.2 0.4

Corn Silage Switchgrass Woodchips

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Co-digestion of Dairy Manure with

Switchgrass or Corn SilageManure Co-digestion with Switchgrass and Corn Silage

(Co-substrates contribute 20% (w/w) of feed VS)

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Duration of Digestion (hours)

C

umulativeBiogasYield(Lbioga

s/gVS

Dairy Manure + Switchgrass Dairy Manure + Corn Silage Dairy Manure

30 days of Digestion

SubstratesBiogas Production(L biogas/g feed)

Biogas Yield(L biogas/g VS)

Manure + Switchgrass 0.06 0.49

Manure + Corn Silage 0.05 0.45

Dairy Manure 0.04 0.38

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Co-digestion of Dairy Manure with

Switchgrass or Corn SilageManure Co-digestion with Switchgrass and Corn Silage

(Co-substrates contribute 40% (w/w) of feed VS)

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0 200 400 600 800 1000 1200 1400


Cumu

lative

Biogas

Yield(Lbioga

s/gVS)

Dairy Manure + Switchgrass Dairy Manure + Corn Silage Dairy Manure (12% TS)




Manure + Switchgrass 0.07 0.52

Manure + Corn Silage 0.06 0.51


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Co-digestion of Horse Manure with Woodchips

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0.70

0 500 1000 1500 2000 2500 3000


Cumu

lative

Biogas

Yield(L

biogas

/gVS

Woodchips - 25% of Feed VS Woodchips - 50% of Feed VS

Woodchips - 75% of Feed VS Horse Manure - 100% of Feed VS


Co-digestion of Horse Manure

with Woodchips

Substrates Biogas Production(L biogas/g feed) Biogas Yield(L biogas/g VS)

Woodchips 25% of Feed VS 0.14 0.51



Horse Manure 0.15 0.64

Study in Collaboration with H. H. Angus & Associates Ltd.

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Characteristics of Fat Based Substrates


ManureHorse & Giraffe

ManureDAF Grease Waste

pH 7.35 (0.17) 8.33 5.87 3.99


TS, g/kg 78 (20) 408 172 468

VS, g/kg 57 (19) 263 147 461

VS/TS, % 73 65 85 99

tCOD, g/kg 74.6 (14.1) --- 102.1 207

sCOD, g/kg 8.9 (3.5) --- 38.3 74.5

C:N 22:1 (3) 32:1 37:1 34:1

TKN, g/kg 3.9 (0.9) 3.3 2.7 6.1

Ammonium (NH4+-N), g/kg 1.9 (0.7) --- 0.8 0.9

TP, g/kg 0.6 (0.1) 0.6 0.3 0.4

Horse & Giraffe Manure DAF Grease Waste

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Co-digestion of Dairy and Poultry Manure Mix (14%TS) with DAF

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1.00

1.20

0 200 400 600 800 1000 1200 1400 1600


CumulativeBiogasYield(Lbio

gas/gVS)

DAF - 20% of Feed VS DAF - 30% of Feed VS

DAF - 48% of Feed VS Manure (Dairy + Poultry)


Co-digestion of Dairy and Poultry Manure

Mix with DAF



DAF 20% of Feed VS 0.08 0.74

DAF 30% of Feed VS 0.10 0.83

DAF 48% of Feed VS 0.10 0.98

Dairy & Poultry Manure Mix 0.09 0.62

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Co-digestion of Horse & Giraffe Manure Mixture with Waste Grease

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BiogasYield(Lbiog

as/gVS)

Grease - 30% of Feed VS Grease - 58% of Feed VS

Grease - 80% of Feed VS Manure - 100% of Feed VS


Co-digestion of Horse and Giraffe Manure

Mix with Waste Grease


SubstratesBiogas Production

(L biogas/g feed)

Biogas Yield

(L biogas/g VS)

Grease 30% of Feed VS 0.28 0.92



Horse & Giraffe Manure Mix 0.16 0.61

Waste grease

as 70% of feedVS may bemore realistic

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Characteristics of Food Wastes


ManureHorse &GiraffeManure

Food Waste(ORRS)

Fish Offal

pH 7.35 (0.17) 8.33 5.69 6.86


TS, g/kg 78 (20) 408 196 349VS, g/kg 57 (19) 263 191 300

VS/TS, % 73 65 97 86

tCOD, g/kg 74.6 (14.1) --- 95.3 218

sCOD, g/kg 8.9 (3.5) --- 27.1 46

C:N 22:1 (3) 32:1 36:1 19:1

TKN, g/kg 3.9 (0.9) 3.3 2.6 12.1

Ammonium (NH4+-N), g/kg 1.9 (0.7) --- 1.2 5.9

TP, g/kg 0.6 (0.1) 0.6 0.4 1.0

Horse & Giraffe ManureORRS Organic Resources Recovery System (form Organic Resource Management Inc.)

Food Waste Fish Offal

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Co-digestion of Dairy Manure with Food Waste (ORRS)

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0 100 200 300 400 500 600 700 800 900


CumulativeBiogas

(Lbiogas/gVS)

Food Waste - 35% of Feed VS Food Waste - 45% of Feed VS

Food Waste - 55% of Feed VS Dairy Manure - 100% of Feed VS

Study in Collaboration with Organic Resources Management Inc.

Co-digestion of Dairy Manure and Food Waste


(L biogas/g feed)

Biogas Yield

(L biogas/g VS)

Food Waste 35% of Feed VS 0.02 0.41




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Co-digestion of Horse & Giraffe Manure Mixture with Food Waste

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0.90

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Duration of Digestion

CumulativeBiogasYield(Lbiogas/gVS)

Food Waste - 35% of Feed VS Food Waste - 62% of Feed VS

Food Waste - 82% of Feed VS Manure - 100% of Feed VS



Co-digestion of Horse and Giraffe Manure

Mix with Food Waste


(L biogas/g feed)

Biogas Yield

(L biogas/g VS)Food Waste 35% of Feed VS 0.18 0.77



Horse & Giraffe Manure 0.16 0.61

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Co-digestion of Fish Offal with Sawdust

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0.90

1.00

0 200 400 600 800 1000 1200 1400 1600 1800


Cumu

lative

Biog

as

Yield(Lbiogas

/gVS)

Fish Offal - 25% of Feed VS Fish Offal - 50% of Feed VS Fish Offal - 75% of Feed VS

Fish Offal - 88% of Feed VS Fish Offal - 100% of Feed VS


Co-digestion of Fish Offal with Sawdust



Fish Offal 25% of Feed VS 0.10 0.36Fish Offal 50% of Feed VS 0.20 0.57

Fish Offal 75% of Feed VS 0.30 0.71

Fish Offal 88% of Feed VS 0.29 0.76

Fish Offal 0.35 0.89

Study in Collaboration with Meeker Aquaculture Inc.

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Industrial Wastes

Characteristics of Thin StillageParameter Liquid Dairy Manure

ThinStillage

pH 7.35 (0.17) 3.64

Alkalinity, mg CaCO3/kg 7564 (223) 0

TS, g/kg 78 (20) 85

VS, g/kg 57 (19) 67

VS/TS, % 73 79

tCOD, g/kg 74.6 (14.1) 141.4

sCOD, g/kg 8.9 (3.5) 63.6C:N 22:1 (3) 39:1

TKN, g/kg 3.9 (0.9) 2.1

Ammonium (NH4+-N), g/kg 1.9 (0.7) 0.8

Total Phosphorus, g/kg 0.6 (0.1) 1.1

Liquid Dairy Manure Corn Thin Stillage

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Co-digestion of Dairy Manure with Thin Stillage

0

0.1

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0.6

0 100 200 300 400 500 600 700 800 900 1000


CumulativeBiogasYield(Lbiogas/gVS)

Stillage - 20% of Feed VS Stillage - 40% of Feed VS

Stillage - 60% of Feed VS Dairy Manure - 100% of Feed VS

Co-digestion of Dairy Manure withCorn Thin Stillage

Substrates

Biogas Production

(L biogas/g feed)

Biogas Yield

(L biogas/g VS)

Thin Stillage 20% of Feed VS 0.02 0.43

Thin Stillage 40% of Feed VS 0.03 0.56

Thin Stillage 60% of Feed VS Complete Inhibition


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0.0

0.5

1.0

1.5

2.0

2.5

0 500 1000 1500 2000 2500 3000 3500 4000 4500

Duration of Digestion, hours

Bioga

sProduction,m

3/m3/day

Two Phase Digestion (Dairy Manure & Stillage)Single Phase Digestion (Dairy Manure & Stillage)

Single Stage Two-Stage

Acid Production

Methane Production

Biogas

Biogas

Co-digestion of Dairy Manure withCorn Thin Stillage

(Two-Stage Digestion System)

Thin stillage is 50% of feed VS

Two stage system will be used to push

digestion to 70% stillage as feed VS

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Impact of Rumensinon Biogas Production



Dairy Manure (No Rumensin) 0.02 0.30

Beef Manure (With Rumensin) 0.02 0.38

Dairy Manure (No Rumensin) + Beef Manure(with Rumensin)

0.02 0.28

Toxicity assays (ATA) are currently being conducted

Impact of Rumensin in Biogas Production

0.00

0.05

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0.15

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0.25

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0.35

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0 500 1000 1500 2000

Duration of Digestion, hoursCumulativeBiogasY

ield(Lbiogas/g

VS)

Dairy Manure (No Rumensin)Beef Manure (With Rumensin)

Dairy Manure (No Rumensin) + Beef Manure (With Rumensin) [50% w/w]

Rumensin

fed at 29 ppm

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Summary

Good co-substrates available

Need to characterize co-substrates toevaluate potential in digester performance

Batch lab studies are useful to determine

optimum addition of co-substrates todigestion

Need to monitor digester performance to

detect for possible digester upset

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Managing and Diagnosing Digester

Start Up Digester start-up phase is critical and can take 2 to 10 months

Increasing temperature takes external heat Incoming substrates are cold

Biology ecology not developed Gas quality is normally better than quantity Very unstable, low gas production means limited heat, slow digestion

Substrate feeding rate optimises: Biological consumption Heat requirements

Gas yield Substrate feeding recipe evolves, requires management

Parameters : temperature, gas quality, gas quantity, pH, FOS/TAC, C:N, TS, VS, VFA, eyes Variables : heat demand, mixing schedule, feeding schedule, substrates

Engine commissioning requires substantial biogas production to enable extendedrun-time

Delayed start up delays revenue 500 kW ~ $1800/day 100 kW ~ $400/day

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FOS/TAC Acid concentration and the buffer capacity in the digester

substrate:

pH - measure of a liquid's acidity - neutral is 7, FOS stands for Flchtige Organische Suren (volatile organic

acids) TAC stands for Totales Anorganisches Carbonat (total inorganic

carbonate (alkaline buffer capacity)

The FOS/TAC ratio is a guidevalue for assessing digestionprocesses.

It enables detecting imminentdigester biology disruptions atan early stage so that correctiveactions can be taken

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40

50

60

70

80

04-Oct 24-Oct 13-Nov 03-Dec 23-Dec 12-Jan 01-Feb 21-Feb 12-Mar

Date

CH4Conc

entration

%

20

25

30

35

40

Tem

pC

CH4% Digester T

Example start-up Liquid dairy, off-farm substrates are grease trap liquids

1500 m3, continuous stirred, mesophilic, heating startedin September

No gas flow meter

Farmer working with digester firm, seeking assistance,conducting daily measurements

Gas analyser not calibrated

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0

24

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8

10

12

14


Date

pH

0

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0.8

1

FOS,TAC,FOS/TA

Digester pH FOS TAC FOS/TAC

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120


Date

Substratesm3

20

25

30

35

40

TempC

Manure Input [m3] Of f-farm Input [m3] Digester T

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Important Lessons Digester acidification was narrowly avoided but start-up is still slow

and ongoing

Daily+ measurement Digestate and gas measurement equipment on-site is very useful Recipe development for start-up phase and normal Consult with biogas system firm, consultants Substrates having different digestion rates and gas yields manage

accordingly Fats, high sugar substrates cause rapid responses and increase in

acid levels Substrates may have inhibition effects (i.e. Rumensin) Heat demand is critical Delayed start-up means thousands

of dollars delayed revenue

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Acknowledgments

Funding for these projects was provided by:

OMAFRA Organic Resources Management Inc. (ORMI)

H. H. Angus & Associates Ltd.

Meeker Aquaculture Inc. Fisheries and Oceans Canada

Iogen Corporation

2012 - B5A - Crolla

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Transcript of 2012 - B5A - Crolla