Progress on Pit Foaming (what we know, what we dont know, what were - - PowerPoint PPT Presentation

Progress on Pit Foaming

(what we know, what we don’t know, what we’re doing)

2015 Iowa Pork Congress

Dan Andersen, PhD Steve Hoff, PhD

• Dept. of Ag & Biosystems Engineering

Iowa State University Brian Kerr, PhD Steve Trabue, PhD USDA-ARS National Center for Agriculture and the Environment Ames, Iowa January 28, 2015

Objectives for Today

Update on IPPA-funded Pit Foaming Research Summarize Results Precautionary Measures

Overall Foaming Requirements

Three-phase Process:

• 1. Gas generation (i.e. methane, hydrogen sulfide),
• 2. Surface tension reduction (surfactants; bio- or otherwise),
• 3. Bubble support structure (i.e. small fibers).

H2S CH4 CH4 CH4 H2S H2S

A surfactant causes surface to “elasticize” Gases otherwise naturally escaping at very low concentrations are trapped Foam supported by bacteria

• r fine fibers or ??

Photo courtesy of Dr. Larry Jacobson, UMN Foam Creeping Through Slats (4 ft of foam case)

In-field Foaming

Foam Into Animal Occupied Zone Photo courtesy of Dave Preisler, MPB;

• Dr. Larry Jacobson, UMN

Curious Nature of Foaming

• Has occurred in one pit of side-by-side rooms

with equalizing channel.

• Commonly found in one barn of multi-barn sites

with common genetics, feed, management, etc.

• Attempts at correlating foaming vs non-foaming

barns with multiple factors has been elusive.

Photo courtesy of Dr. Larry Jacobson, UMN

IPPA Funded Research Project

GOAL: Finding and Correcting the Mechanisms of Foaming

Photo courtesy of Dr. Larry Jacobson, UMN

IPPA Funded Research Effort

• Multi-state effort (ISU, UMN, UILL) involving 20+ academic

professionals with expertise in manure management, chemistry, microbiology, feed rations, and digestibility

• $1M investment over three years (we are finishing YR2)
• Project managed by Iowa State University
• Our team is working diligently to solve this problem

Multi-state Research Collaboration

• Feed trials
• Chemical composition

analysis

• Methane production
• Foaming potential

testing

ISU/USDA-ARS UMN

• Extensive producer

survey

• Microbial analysis
• Foaming potential

testing

UILL

• Organize all manure

sampling and distribution

• Microbial analysis

Dan Andersen Brian Kerr Steve Trabue Chuck Clanton Larry Jacobson Bo Hu Brian Hetchler Rich Gates, Angela Kent, Laura Pepple

Theory

• Biogas

Generation of methane, CO2 and hydrogen sulfide.

• Surfactants

Materials that significantly change the surface tension.

• Stabilizer

Increases the stability of foam bubbles, like small fibers and

• ther hydrophobic particles.

Hypotheses - Mechanism

(1) Increased prevalence of foaming is due to increased biogas/methane production from the manure (2) Elevated concentrations of surface active agents in foaming manures are causing greater gas capture (3) Foam is being stabilized by small particles/proteins (4) Differing physical, chemical, and biological properties are related to dietary inputs.

Hypotheses - Microbial

• Brief Background
• ARISA & Sequencing
• Site, Management, and Environmental Factor Database
• Objective 1 – Microbial community differences
• Objective 2 – Identify relevant microbes using sequencing
• Objective 3 – Use relational database with Obj’s 1 and 2
• Methanogen Sequencing

Manure Sampling SOP

A B C D foam/crust transition slurry sludge Samples were collected from discrete depths in the manure storage pit. Samples from 2 Integrators Over 60 Sites Generated more than 2000 manure samples

Sample Summary: Cases

CLASSIFICATION INTEGRATOR A

• INTEGRATOR

B #

OF

SAMPLES #

OF

SAMPLES

• NON-FOAMING

250

• 183

FOAMING 255

• 362

NOT TREATED 178

• 163

TREATED 327

• 362

PREVIOUS PUMP OUT 24

• 18

FALL 2012 337

• 460

SPRING 2013 142

• 38

FALL 2013 2

• 9

CASE 1 (FOAMING) 115

• 76

CASE 2 (NON-FOAMING) 85

• 258

CASE 3 (TRANSITION) 157

• 111

CASE 4 (UNSTABLE) 148

• 80

TOTAL 505

• 525

Why Foam? Why Now? Diet composition and particle size effects on nutrient excretion

Diet ID Diet Composition Digestion/Excretion Coefficient Output, kg1 Output difference, kg Estimated C Equivalence, kg2

C-SBM 4.6% EE 63% (37%) 6,592 7.0% NDF 66% (34%) 9,223 17% CP 88% (12%) 7,905 45% Carbon 91% (9%) 15,694 C-SBM + FIBER 6.2% EE 63% (37%) 8,889 2,297 (+35%) 28% 13.8% NDF 68% (32%) 17,112 7,889 (+85%) 55% 17% CP 85% (15%) 9,881 1,976 (+25%) 17% 46% Carbon 87% (13%) 23,291 7,597 (+48%)

1Output based upon 310 kg feed/pig from wean-to-finish and 1,250 pigs/barn. 2Lipid = 76% carbon; Protein = 53% carbon; Fiber = 45% carbon.

Dietary Tidbits

• Averaged across 3 trials in our metabolism/tank studies, high fiber diets increased

manure carbon by approximately 40%.

• Intact fats are less digestible than ‘added’ fats (e.g., 65% versus 85%,

respectively).

• We do not know any interactive effects between fiber and lipid type, or between

fiber and lipid level.

• On average, grinding to a finer particle size, 374 vs 631 m, improved FAT

, FIBER, CP , and C digestibility by 30, 8, 3, and 3%, respectively. In general, finer grinding improves digestibility of low-digestible ingredients more than high-digestible ingredients.

• DDGS of 340 μm exhibited an FAT digestibility of 75% compared to 57% for DDGS of

650 μm

Diets in Practice:

More C in manure, more methane potential

How do you study the gas phase?

MPR L L ∗ day = (Methane % 1 100)(Biogas Produced mL + Vheadspace) × ρmanure( g mL) Mass of sample g × incubation period(minutes) × 1440 minutes day

Methane Production Rates

• Methane production rate was higher in foaming barn than non-foaming barns.
• Why?

What would cause this difference?

• Quantity of carbon inputs?
• TS, VS, VFA
• Source of carbon?
• BMP

, VFA

• Differences in microbes?
• Degraders, methanogens, sulfate reducers
• Microbial community structure
• Response to different carbon substrates?
• Differences in pathways/response to substrate?

Quantity of Food?

2 4 6 8 10 12 A B C D

Total Solids (%) Sample Depth

Foaming Non-Foaming A D E B C A A 1 2 3 4 5 6 7 8 9 A B C D

Volatile Solids (%) Sample Depth

Foaming Non-Foaming A C D B B A A

Quality of Food?

• Difference between foaming and non-foaming, but non-foaming is better and driven by VFA’s
• More solids deeper in the manure, but quality of those solids is lower

Microbial Data – What your looking at

Microbial Differences?

• Foaming and non-foaming

sites have distinct microbial communities

• Sequencing Data

Microbial Richness (Diversity)

Integrator A Integrator B

So which microbes are these?

• Differences in relative abundance of dominant taxa are associated with

foaming—but no new microbes.

0% 2% 4% 6% 8% 10% 12% 14% 16% 18% 20%

non.foaming foaming

So can these microbes be related to management practices?

So what is influencing these microbes?

Integrator B

Is this related to functionality?

Integrator B

So do they like a certain food better?

What about surfactants?

Difference between F and NF – driven by VFA concentrations Difference between B and C&D driven by ??? (oil/long chain fatty acids) What is role of particles/proteins?

Surfactant should drive capacity to foam

Generally small differences in ability of manure to foam.

What stabilizes foam?

1 2 3 4 5 6 7 8 9 A B C D

Volatile Solids (%) Sample Depth

Foaming Non-Foaming A C D B B A A

• What did we notice about samples that stabilized
• Solids rich, but finer looking solids, not big chunks
• Liquid drained more slowly from the foam
• Sort of set up, with solids in bubble matrix
• Good foams grey/brown (protein), bad foams were white/clear (fats/oils)

Foam is really stable

200 400 600 800 1000 1200 1400 1600 1800 A B C D Foam Half-Life (Minutes) Sample Depth Foaming Non-Foaming

A B B B B B

The foam stays wet - viscous

2 4 6 8 10 12 Foam Foaming Manure Non-Foaming Manure

Viscosity (cP)

As Is Centrifuged Filtered

A B B a b b 1 2 2

Its not just the solids, something else is giving us viscosity in the foam.

• sugar, oil, lipopolysaccharides, proteins? Microbial goo

but… Particles hold it together

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0.01 0.1 1 10 100 1000

Fraction of Particles Finner Particle Size (um)

Foam Foaming Manure Non-foaming Manure

20 40 60 80 100 120 140 160 180 200 Foam Foaming Manure Non-foaming Manure

Averag Particle Size (um)

Does diet influence these particles?

0.00 0.04 0.08 0.12 0.16 0.20 0.0 0.3 2.0 16.0 128.0 1,024.0

Fraction of Particles in Size Class Particle Size (μm)

C-SBM-C C-DDGS-C C-SH-C C-SBM-F C-DDGS-F C-SH-F

Greater percent of particles were fine silt particles from inoculated manure (p < 0.05) & courser grind (p = 0.1254)

If you add these particles will make foam?

Yes…. But they have to interact with proteins Add moving particles from foaming manure to non- foaming manure will make it foam.

So Proteins then?

5000 10000 15000 20000 25000 30000 35000 40000 Foam Foaming Manure Non-foaming Manure

Protein Conent (ug/mL)

As Is Centrifuged A B B a a a

So remove proteins, stop foam?

• Removal of protein strongly reduces foaming capability and stability

What’s holding the proteins together?

Total Carbohydrates mg g

• 1 manure

0.0 0.5 1.0 1.5 2.0 2.5 Foam Foam Manure C Non-Foam Manure C

Total Hemicellulose g g

• 1 manure

200 400 600 800 1000

Foam

Foam Manure C

Non-Foam Manure C

0.977 0.798 0.783

So what do we know now?

• High fiber feed ingredients have reduced nutrient digestibility increasing

levels of C reaching the pit.

• Efficiencies in both the processing of these new C inputs and

fermentation of fatty acid material have resulted in increased levels of methane production.

• Higher levels of methane production have resulted in separation (i.e.,

translocation) and concentration of biological material into a foam layer.

• The foam layer itself showed unique characteristics:
• Solids Enriched with Fine Particles (Proteins)
• Enhanced Foam Stability
• Higher Total Carbohydrates
• Liquid is viscous

Precautionary Measures

• Any attempt to break-up foam WILL release

explosive levels of methane. Therefore….

• 1. All ignition sources OFF (i.e. pilot lights, welding),
• 2. Set ventilation at 30 cfm/pig space minimum,
• Use open curtains if ≥ 10 mph wind, OR,
• Use fans* + ceiling inlets if calm
• 3. Make sure ceiling inlets operational,
• 4. Vacate barn, then finally,
• 5. Foam/pit can be disturbed.

* In a 1000-hd barn, equates to 2-48” or 3-36” or 6-24” fans

Ventilation Strategies

(1000-hd Finisher) 6-24” fans or 3-36” fans or 2-48” fans + operational ceiling inlet system + curtains closed OR Curtains Open with Wind of ≥ 10 mph But NOT Curtains Open, Calm Conditions Reliance on Fans

Precautionary Measures (NPB)

http://www.pork.org/filelibrary/November2009%20PCRSE.pdf

Precautionary Measures (ISU)

http://www.agronext.iastate.edu/immag/

Precautionary Measures (UMN)

http://www1.extension.umn.edu/agriculture/manure-management-and-air-quality/

Questions, comments, discussion?