Ultrafiltration to Treat Rendering Facility Wastewaters shusson@clemson.edu 864-656-4502 (work) 864-325-9062 (cell)

Overview of ACREC Research Jessica Meisinger, PhD Director of Education, Science, & Communication National Renderers Association/FPRF Annel Greene, PhD Director, ACREC Clemson University Highlighted Research Project Jinxiang Zhou, PhD Daniel Wandera, PhD Brian Baker (UG) Charlie Grimsley (UG)

Scott Husson, PhD Chemical and Biomolecular Engineering Clemson University Clemson, SC

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We are grateful for the financial support of this work by the Animal Co-Products Research and Education Center with funding from the Fats and Protein Research Foundation. We thank Hydration Technology Innovations (HTI) for providing ultrafiltration membranes and technical insights.

shusson@clemson.edu 864-656-4502 (work) 864-325-9062 (cell)

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Animal Co-products Research and Education Center

• To advance the science and technology of animal co-products and the rendering process

• To ensure microbial safety of rendered products for animal feeds and consumer protection

• To promote environmentally sound practices • To develop new market opportunities for the worldwide

rendering industry • To provides educational opportunities in animal co-product

utilization

Dr. Annel K. Greene ACREC Director agreene@clemson.edu Mission

shusson@clemson.edu 864-656-4502 (work) 864-325-9062 (cell)

ACREC Research Projects

– Chemical engineering – Microbiology – Materials science and

engineering – Bioengineering – Mechanical engineering – Animal science – Food science – Packaging science – Biological science – Experimental statistics

– Chemistry – Architecture – Environmental engineering – Automotive engineering – Agricultural engineering – Soils – Turfgrass – Environmental toxicology – Horticulture – Computer science

• Approximately 50 total since 2004 • More than 40 researchers • Interdisciplinary, innovative projects

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shusson@clemson.edu 864-656-4502 (work) 864-325-9062 (cell)

Odor Elimination

Daniel Whitehead and Frank Alexis Goal: develop materials that sequester or destroy malodorous volatile organic byproducts of rendering processes • Destroying malodorants with biodegradable nanoparticles • Using nanoparticles to target and eliminate odors • Proved the ability to capture short chain FA pollutants • Proved the nanoparticles are non-toxic, biodegradable • Working on proving selectivity for specific functional groups

– carboxylic acids – Sulfides

• Could lead to effective odor control

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shusson@clemson.edu 864-656-4502 (work) 864-325-9062 (cell)

Antioxidant Production

Vladimir Reukov and Alexey Vertegal

Goal: produce a novel antioxidant that is natural, effective, and cost-effective

• Potent antioxidant from animal by-products

• As effective or better than available antioxidants

• Prevent rancidity in feeds

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shusson@clemson.edu 864-656-4502 (work) 864-325-9062 (cell)

Salmonella Reduction

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Xiuping Jiang Goal: determine if bacteriophage treatment can be an effective and low-cost approach for controlling Salmonella contamination in the rendering environment. • FDA approved bacteriophages as food additive in 2006 to fight listeria

in ready-to-eat meats • Bacteriophages work in the lab against Salmonella, now testing in

rendering plant and versus biofilms

shusson@clemson.edu 864-656-4502 (work) 864-325-9062 (cell)

Validation of Rendering as a Kill Step

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Annel Greene Goal: validate that Salmonella and Clostridium perfringens are killed during rendering • Work is investigating thermal death time for several strains of

Salmonella in poultry and beef rendering materials.

shusson@clemson.edu 864-656-4502 (work) 864-325-9062 (cell)

Renderable Gloves and Totes

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Andrew Hurley Goal: reduce glove remains in post-milled protein by designing, developing, testing, and sourcing ‘renderable’ gloves. • Searched a number of candidate materials to find a replacement for

polyethylene collection bags. • Found new biodegradable polymers and developed improved bags

to line rendering collection barrels. • Improving finished fat and protein quality and safety.

shusson@clemson.edu 864-656-4502 (work) 864-325-9062 (cell)

Separating Fat from Protein

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Chris Kitchens Goal: investigate the use of carbon dioxide as a green solvent for enhancing the mechanical expression of fat from rendered materials. • Use liquid CO2 to more effectively extract fats from proteins • Re-engineering the press • Demonstrated in the lab and working on pilot-scale trials • Emerging market in low-fat meats for pet food

shusson@clemson.edu 864-656-4502 (work) 864-325-9062 (cell)

Value Added Fats

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Mark Blenner Goal: engineer yeast to grow on rendered animal fats to produce omega-3 fatty acids. • Polyunsaturated fatty acids are in high demand and sell for a

premium • Convert rendered animal fats into value added molecules like

polyunsaturated fatty acids that are found in fish oils

shusson@clemson.edu 864-656-4502 (work) 864-325-9062 (cell)

Composite materials

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Srikanth Pilla Goal: develop high-strength, hydrophobic, odor-free thermosets and composites from proteinaceous materials from the rendering industry • Engineering rendering protein materials for cars • Develop high strength composites • A high-value non-feed use

shusson@clemson.edu 864-656-4502 (work) 864-325-9062 (cell)

Final Notes on ACREC

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Other Research Projects • Carbon footprint • Lifecycle analysis for GHG

emissions • Feather meal safety • Identifying cost-effective

paths for new high value products from rendered fats

• Non-feed uses of rendered product

• Novel changes in operations

• Active, interdisciplinary research program

• Characterized by Innovation! • Currently focused on nutrition,

plant operation, environmental factors

• Exploring better lab-to-market paths for inventions

Ultrafiltration to treat rendering facility wastewaters shusson@clemson.edu 864-656-4502 (work) 864-325-9062 (cell)

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Dissolved air flotation (DAF) is used for primary treatment of rendering facility wastewater, but it requires costly chemical additions

- DAF removes suspended solids, grease, and oil from waste water using air bubble flotation method

- chemical additives used to improve flocculation - typical cost is $3.2/1000 gallon waste water

Membrane technologies have advantages for treatment of impaired waters

- provide a positive barrier to reject solids - can be conducted without addition of chemicals (unlike DAF) - offers flexibility in handling feed liquids with fluctuating properties - offers modular design that makes it easy to expand capacity as needed

Hypothesis: membrane filtration can be used to treat rendering facility wastewaters without the polymeric flocculants and chemical additions needed for DAF.

Overall Goal and Research Objectives shusson@clemson.edu 864-656-4502 (work) 864-325-9062 (cell)

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Goal Develop a membrane alternative to DAF for the low cost treatment of rendering wastewaters

Objectives Evaluate performance of ultrafiltration membranes (primary stage) Evaluate performance of nanofiltration/reverse osmosis membranes (polishing) Understand and model the effects of operating parameters on membrane performance Evaluate membrane cleaning protocols and estimate membrane lifetimes Perform a preliminary cost analysis for operating the membrane process in place of DAF

settling tank

sedimentpump

UF

permeate(treated)

retentate(concentrate)

feedP

P

P

pump

PRO

P

P

recycle

Proof of Concept shusson@clemson.edu 864-656-4502 (work) 864-325-9062 (cell)

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Compositions vary

Contains high levels of fats, oils and greases, and proteins that must be removed prior to discharge

Table. Pre-DAF waste water from our partner rendering facility

Preliminary Results shusson@clemson.edu 864-656-4502 (work) 864-325-9062 (cell)

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Performance of treated HTI cellulose acetate UF membrane reduced turbidity by 650-fold, without addition of

polymeric flocculant; reduced COD by 80% and total solids by 90%; yielded a stable, steady state, permeate flux over a 120-

hour period, without the need for intermittent cleaning

Preliminary Operating Cost Analysis for UF shusson@clemson.edu 864-656-4502 (work) 864-325-9062 (cell)

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Estimates based on data for a DAF unit operating at 160 gal/min flow rate. Included are costs for energy to pump the wastewater chemical additives replacement membrane modules membrane cleaning costs (not shown – pressure effect) Sizing of the membrane modules steady-state permeability of 0.09

L/(m2·h)/kPa pressure of 280 kPa Membrane cost estimate includes a chemical enhanced backwash every 3 day using 600 mg/L hydrochloric acid solution

Module costs provided by HTI, LLC (also provided in-kind support by providing membranes) Manufacturer suggested lifetime for the membrane modules is 2 years

DAF MEM (6 mo) MEM (1 yr) MEM (2 yr)

oper

atin

g co

st ($

/100

0 ga

l)

0

1

2

3

4energy costs for pumpingchemical costsmembrane module costs

flux (J)

-dP/

dt

[or d

(TM

P)/d

t]

J* (t

hres

hold

flux

)

d(TM

P)/d

t But Surely They Foul … Right?

shusson@clemson.edu 864-656-4502 (work) 864-325-9062 (cell)

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cake layermembrane

u

Time

Flux

Cake thickness

Below threshold flux

Time

Flux

Above threshold flux

J = permeate flux (volume/area/time) J* = threshold flux TMP = transmembrane pressure

Determination of Threshold Flux (Stable Performance) shusson@clemson.edu 864-656-4502 (work) 864-325-9062 (cell)

model for threshold flux:

Figure. Threshold flux measurements: a) different UF membranes at 3300 mg/ml TDS and b) different feed concentrations using UF membrane PSF1. TMP was 0.7 bar for CA and 0.2 bar for polysulfone. These are low!!

No difference was observed in threshold fluxes of CA and polysulfone membranes Results were highly reproducible and were not dependent on procedure Lower solid concentrations slowed fouling rate, resulting in higher threshold fluxes.

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0 20 40 60 80 100

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7original feed1/10 conc. of the feed1/45 conc. of the feedb

Flux (L/m2h)

d(TM

P)/d

t (b

ar/m

in)

0 5 10 15 20 25 30 35 40

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7PSF 1CAa

Flux (L/m2h)

d(TM

P)/d

t (b

ar/m

in)

Role of the Membrane shusson@clemson.edu 864-656-4502 (work) 864-325-9062 (cell)

Feed (Pin)

Permeate (Pperm)

Scheme: Direct flow

Roverall = Rmembrane + Rc𝐚𝐚𝐚𝐚𝐚𝐚𝐚𝐚

Resistance equation:

Transient and major resistance (obtained by measurements)

overall

1 dV PA dt R

∆=µ ⋅

Measured at various ∆P

cakelayer cVRA

= α ⋅ρ

( )s' Pα = α ∆s is a measure of cake compressibility s = 0 (incompressible) s = 1 (highly compressible)

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Role of Applied Pressure (Less is More) shusson@clemson.edu 864-656-4502 (work) 864-325-9062 (cell)

Figure: resistance versus the filtration volume. Rcakelayer increases with increasing V, as expected. (HTI polysulfone membrane)

Figure: determination of compressibility factor, s = 1.13 (highly compressible cake)

V (ml)

0 10 20 30 40 50 60 70

R c (X

1014

m-1

)

0

1

2

3

40.41 bar0.69 bar1.45 bar2.07 bar2.76 bar3.45 bar

ln (TMP)0 1 2 3 4 5 6

ln(

)

-37.5

-37.0

-36.5

-36.0

-35.5

-35.0

-34.5

-34.0

For the same permeate volume (V) processed, the mass of solids deposited is the same regardless of TMP

Yet, cake layer resistance is higher at higher TMP due to the cake compression Compressibility factor is used to quantify cake layer compressibility.

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Polishing Step Purification shusson@clemson.edu 864-656-4502 (work) 864-325-9062 (cell)

settling tank

sedimentpump

UF

permeate(treated)

retentate(concentrate)

feedP

P

P

pump

PRO

P

P

recycle

Figure: Comparison of membrane technologies [adapted from Koch Membrane Systems, Membrane technologies: Targeted technology makes the difference www.kochmembrane.com/Learning-Center/Technologies.aspx (accessed Oct. 2013).

Ultrafiltration (UF) removes high molecular weight organics but allows passage of salts and small molecules Polishing step purification therefore is needed to reduce COD and salt levels (TDS)

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Polishing Step Purification shusson@clemson.edu 864-656-4502 (work) 864-325-9062 (cell)

The best performing membrane achieved 1600 L/m2 capacity prior to cleaning. A cascade of UF/NF or UF/RO membranes can reduce COD and TDS levels by as much as 99% relative to the initial feed, without the addition of chemicals or polymers used in DAF Preliminary operating cost analysis found that a two-stage UF/NF or UF/RO system has 33-55% of the cost for DAF depending on the assumed membrane lifetime.

Nanofiltration Reverse osmosis

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Summary and Closing Remarks shusson@clemson.edu 864-656-4502 (work) 864-325-9062 (cell)

This project has demonstrated that membrane filtration is effective at treating rendering facility wastewaters without chemical additions.

A membrane cascade using an HTI low-permeability UF membrane followed by polishing with a Toray 70UB RO membrane yielded

- essentially 100% reduction in turbidity - 98.5% reduction in COD - 99.4% reduction in total solids

Knowing (and operating just below) the threshold flux will allow sufficiently high flux while keeping fouling rates at acceptable levels.

Determination of effective clean-in-place protocols will be needed for process implementation.

Preliminary operating cost analysis favors a membrane ultrafiltration separation process over dissolved air flotation process.

Knowledge of membrane lifetimes is important to provide accurate operating cost estimates.

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