Algal Harvesting in the Partitioned Aquaculture System

W. Caswell, E. Zanin, R. Thurmes, K. Norvell

Clemson University - Biosystems EngineeringBE 4750 Senior Design Presentation

December 2, 2016

Table of Contents1. Introduction

a. Carbon Emissions and The Partitioned Aquaculture Systemb. Definition of Problemc. User, Designer and Client Questions

2. Literature Reviewa. Governing Equationsb. Design Options

3. Experimentation4. Design Methodology and Materials

a. Sedimentation Systemb. Turtle Escape Structure

5. Sustainability Measures6. Budget7. Conclusions8. Timeline

INTRODUCTION

Recognition of Problem• Carbon capture from an ever increasing

carbon concentrated atmosphere is needed

○ Nov. 28, 2015: 400.63 ppm CO2

○ Nov. 28, 2016: 404.38 ppm CO2

• Partitioned Aquaculture System (PAS) has potential for increased carbon capture and output of valuable algal-based product

• Algae must be harvested regularly for effective carbon reduction

http://nok6a.net/

PAS Use• Open raceway system• Dissolved oxygen (DO) is

growth limiting factor for fish• Maximizes algal growth

productivity to increase DO in an aquaculture pond

Drapcho, Caye. 1999. Schematic diagram of the partitioned aquaculture system at Clemson University.

Photo taken by William Caswell

PAS Initial ConditionsAugust 31,

2016

Photos taken by William Caswell

Definition of Problem• Grow algae for carbon capture and implement

algal harvesting technique

• Algae - 5 g C/m2/day (Drapcho, Brune. 1999)

○ Forest - 0.616 g C/m2/day (Kraxner et. al. 2003)

○ Algae is 8x more effective at sequestering carbon

• Current value of carbon credit = 5¢/kgC (http://calcarbondash.org/)

• Clemson’s Sustainability Action Plan projects a need to offset an additional 60,000 metric tons CO2 for Net Zero 2030 goal

https://www.clemson.edu/sustainability/documents/Sustainability-Action-Plan.pdf

Design Goals: Biological• Carbon capture rate:

5 gC/m2/day

• Algal Growth: 13.75 g/m2/day

1274.9 gXB/day

• Harvest concentration: 10 gXB/L (Halim, 2012)

Photo taken by Elizabeth Zanin

Design Goals• Structural:

○ Refurbish algal growth system○ Include turtle escape structures○ Maintain 30 cm (+/- 5 cm) depth○ Design harvesting method

• Mechanical:○ Flow mixing and cultural suspension○ Achieve retention time of 1-2 days (Drapcho,

Brune, 1999) for a flow rate of 966 L/hr○ Water velocity of 12 cm/s

Photos taken by Dr. Drapcho (top) and William Caswell (below)

Google Earth, 2013

Google Imagery of the PAS

Photo taken by William Caswell

Dammed portion of Hunnicutt Creek

Constraints & Considerations

● Skills: Construction● Budgetary: Need to maximize

economic return to compete with other carbon sequestration methods

● Space: 92.7 m2 portion of PAS● Logistics: Growth rate of algae

and max diffusion of carbon● Time: 13 weeks

• Safety: Chemical use○ Wildlife○ Electricity

• Ethical: Energy use○ Habitat for wildlife

• Ecological: Low-impact harvesting techniques

○ Use of Hunnicutt Creek• Ultimate use: Efficient carbon

sequestration

Constraints Considerations

The 3 QuestionsUser (Clemson University Employee)

1. How much maintenance will this require?2. How much time will I spend collecting the final product?3. What happens when unusual weather patterns occur (e.g. floods and droughts)?

Client (Clemson Facilities Department)

4. How much will this cost, both operating and overhead?

5. Is there any potential to make money from the products?

6. Is there any potential for growth in future research opportunities?

Designer (PAS Design Team)

7. What are the current chemical characteristics of the water?

8. What utilities will be available at the site?

9. What is the desired lifespan of the system?

LITERATURE REVIEW

Governing Equations•Photosynthesis:

106CO2 + 16NO3- + HPO4

2- + 122H2O + 18H+

→ C106H2630110 N16P + 138O2

•Dissociation of carbonate compounds:H2O + CO2 ↔ H2CO3 ↔ HCO3

- + H+ ↔ CO32- + 2H+

•Mass Balance at Steady State:

(QCi/V) - (QC/V) ± r = 0

Governing EquationsCarbonate Chemistry:

Adapted from:Kuan-Yeow Show, Duu-Jong Lee & Arun S. Mujumdar (2015) Advances and Challenges on Algae Harvesting and Drying

Flotation● Sparging: Collision causes

particles to adhere to the surface of the bubbles

● Can be energy intensive○ After flocculation ○ Microbubbles○ Fluidic Oscillator

http://oilprice.com/Alternative-Energy/Biofuels/New-Technique-Discovered-to-Help-Harvest-Algae.html

Flocculation● Occurs naturally (auto-flocculation)

○ Environmental stress○ Changes in nitrogen○ pH changes ○ Dissolved oxygen

● Organic○ Cationic polyelectrolytes (e.g. Starch)○ Chitosan - from shells of crustaceans○ Bacteria growth

● 25-99% percent removalhttp://www4.ncsu.edu/~hubbe/CST.htm

Sedimentation● Uses gravity to settle algae from water● Depends on density difference

○ Chlorella density: 1070 kg m-3

○ Can be slow○ Better for larger cells

● Inexpensive

http://www.fao.org/docrep/003/v9922e/V9922E04.htm

Electroflocculation• Electrolytic oxidation releases metal coagulants

(Fe2+, Al3+) for algae flocculation• Alternative to chemical coagulants (e.g. FeCl3)

• Water oxidized at sacrificial anode and reduced at cathode

• Produces H2 & O2 bubbles as byproduct (flotation)

• Requires electricity - Solar Panel/MFC• Limited research as harvesting technique

http://onlinelibrary.wiley.com/doi/10.1002/bit.23199/abstract

Photo taken by William Caswell

EXPERIMENTATION

Electroflocculation Removal Curve

Flocculants Removal Curve

Sedimentation Removal Curve

Percent Removal at 55 min

DESIGN METHODOLOGY & MATERIALS

Turtle Escape Structure

Photo taken by Will Caswell October 31, 2016

• Stability to support 30 lb

snapping turtle

• Sturdiness to withstand

weathering

• Traction strips

• Removable

• $15 / structure

Design ComparisonDesign Method PROS CONS

Electroflocculation

● Most effective algal recovery method (73.6%)

● New method with research appeal

● Could be fully automated

● Electricity and aluminum usage

● May not be effective for low concentrations (Singh, M. et. al. 2013)

Cationic Starch ● Nearly as effective as EF (73%)

● Derived from a cheap material in Corn Starch

● Toxic chemicals required

● Potentially difficult and expensive to remove from recovered algae

Sedimentation ● Inexpensive and simple● Can be used as a “first step”● No harm to final product● Continuous collection

● Longer settling time

● Not as high of a removal rate at 55%

Synthesis of Design● Stella Model

○ Determination of biomass growth and collection given:

■ Retention time

■ kLa of CO2

■ Removal efficiency

■ μmax, death rate constant, and Ks

○ Performs 5 mass balances: Substrate, biomass, water, phosphorus, nitrogen

Biomass MBE

At steady state:- μ = 0.04 hr-1

- b = 0.0026 hr-1

- XB2 = 26.67 mg/L- rXBout = 0.92 mg/L*hr

Carbon MBE

At steady state:- YB = 2.78 gXb/gC- S2 = 9.96 mg/L- S3 = 0.08 mg/L- rCO2dif = 0.0128 mg/L*hr- rSCO2 = 0.36 mg/L*hr

Water MBE- Average yearly rainfall is 57.5 inches:

15.45 L/hr- Evaporation based on 0.5 cm/day:

19.3 L/hr- Water Removed:

1.34 L/hr- Water Input:

5.19 L/hr- Maintained reactor volume:

28,282 L

Phosphorus and Nitrogen MBE

- up = 0.0087 gP/gXB

- uN = 0.063 gN/gXB

- rPO4-3 = 0.01mg/Lhr- rNO3- = 0.06 mg/Lhr

Synthesis of Design● Sedimentation● Based on:

○ Feasibility○ Environmental impact○ No need for higher biomass recovery

● Economic consideration that other design options would be the same but have added cost

Synthesis of Design

(Boyd, 2012)

For algae:VS=2.4 m/hr

(Milledge, Heaven, 2012)

Synthesis of Design● Norwesco

● 225 gallon

● $317 + shipping

● Polyethylene

● VCS = 1.18 m/hr

Adapted from: http://www.norwesco.com/_site_components/uploads/pdfs/Horizontal%20Leg/225%20Gallon%20Horizontal%20Leg%20Tank.pdf

InletWater Outlet

SludgeOutlet

Synthesis of Design● $176.23 + shipping● Flow rate: 240 gph (900 Lph)● Thread size: ½” NPT● Nominal speed: 1725 rpm● Priming: 6’ vertical lift● Suitable Motor:

○ Can be powered by 7.5kW solar panel

○ Cost: $119.99 + shipping○ Output: ¼ hp, 115 V-AC

http://www.proconpumps.com/products/Series-4-Pump.html

Synthesis of Design● freshwatersystems.com● 1 - ½” X ½” NPTF swivel elbow

connection○ $9.24 + shipping

● 5’ OD LLDPE Polyethylene tubing○ $2.85 + shipping

● 3 - ½” OD X ½” OD Quick-connect union elbow

○ $9.27 + shipping

Synthesis of Design● Collect every week● 3.7 gal● 5 gal bucket

○ $11.75/bucket○ Closeable○ Shippable

https://www.uline.com/Product/Detail/S-13652W/Pails/Screw-Top-Pail-5-Gallon-White-Lid

SUSTAINABILITY MEASURES

Sustainability Measures● Economic:

○ Value created from already existing structure● Ecological:

○ CO2 Capture○ Low impact on surrounding areas○ Water from Hunnicutt Creek○ Turtle escape structures

● Ethical: ○ Reduction of CO2 for Clemson’s 2030 Net Zero Goal

BUDGET

Budget

CONCLUSIONS

Design Overview• Method chosen: Sedimentation• Can remove 2.59 gC/m2-day

○ Requires 0.111 gC/m2-day○ Hindered by diffusion rate○ Could be improved with higher kLa

• Cost○ Upfront: $800○ Continuous: $1250/year○ Sales: $275

• Would require 4,165 acres of algae raceway systems to reach Clemson’s goal

○ Would require 17,983 acres of forest to reach Clemson’s goal

User Questions1. How much maintenance will this require?

○ Weekly removal of settled algae in basin○ Addition of fertilizer every week: 280g N and 50g P

2. How much time will I spend collecting the final product?

○ Less than 1 hour per week3. What happens when unusual weather patterns

occur (e.g. floods and droughts)?○ System will not run in drought○ Decreased productivity in flood

Client Questions1. How much will this cost, both operating and

overhead?○ Upfront: $800○ Continuous: $250

2. Is there any potential to make money from the products?

○ Sale of algae3. Is there any potential for growth in future

research opportunities?○ Creative Inquiry (CI) on alternative carbon capture○ Removal of oil from algae

Designer Questions1. What are the current chemical characteristics of

the water?○ pH: 7.17○ Alkalinity: 35.7 mg/L as CaCO3○ Total inorganic carbon: 0.834 mmol/L (Drapcho, Brune. 1999)

2. What utilities will be available at the site?○ Solar panel with 12V and 750 A

3. What is the desired lifespan of the system?○ 10 years○ Limited by the pump

TIMELINE

REFERENCES & PATENTS

ReferencesBarros, A. I., Gonçalves, A. L., Simões, M., & Pires, J. C. M. (2015). Harvesting techniques applied to microalgae: A review. Renewable and Sustainable Energy Reviews, 41, 1489–1500. http://doi.org/10.1016/j.rser.2014.09.037Boyd, C., (2012). Settling Basin, Operations. Global Aquaculture Advocates.Brune, D., Collier, J., Schwedler, T. 1998. Partitioned aquaculture system. U.S. Patent No. 6192833 B1Data, U. C. (n.d.). Temperature - Precipitation - Sunshine - Snowfall. Retrieved November 29, 2016, from http://www.usclimatedata.com/climate/clemson/south-carolina/united-states/ussc0059 Drapcho, C., Brune, D. 2000. The partitioned aquaculture system: impact of design and environmental parameters on algal productivity and photosynthetic oxygen production. Aquaculture Engineering, 21, 151 -168Cassidy, K. O. (2011). Evaluating Algal Growth At Different Temperatures.Clemson University Sustainability Action Plan, version 1.0.9. (2011).Edzwald, J. K. 1993. (1993). Algae, bubbles, coagulants, and dissolved air flotation. Water Science Technology, 27(10), 66-81.Gao, S., Yang, J., Tian, J., Ma, F., Tu, G., & Du, M. (2010). Electro-coagulation-flotation process for algae removal. Journal of Hazardous Materials, 177(1-3), 336–343. http://doi.org/10.1016/j.jhazmat.2009.12.037Hanotu, J., Bandulasena, H. C. H., & Zimmerman, W. B. (2012). Microflotation performance for algal separation. Biotechnology and Bioengineering, 109(7), 1663–1673. http://doi.org/10.1002/bit.24449Halim, R., Danquah, M. K., & Webley, P. A. (2012). Extraction of oil from microalgae for biodiesel production: A review. Biotechnology Advances, 30(3), 709–732. http://doi.org/10.1016/j.biotechadv.2012.01.001Hemaiswarya, S., Raja, R., Kumar, R. R., Ganesan, V., & Anbazhagan, C. (2011). Microalgae: A sustainable feed source for aquaculture. World Journal of Microbiology and Biotechnology, 27(8), 1737–1746. http://doi.org/10.1007/s11274-010-0632-zIntegrated, A. N., Intensive, S., & Production, B. (n.d.). Confined PAS Technology for Finfish.

ReferencesJones, S., Zhu, Y., Anderson, D., et. al (2014). Process design and economics for the conversion of algal biomass to hydrocarbons: Whole algae hydrothermal liquefaction and upgrading. PNNL: NREL.Kraxner, F., Nilsson, S., Obersteiner, M. (2003) Negative emissions from BioEnergy use, carbon capture and sequestration (BECS)—the case of biomass production by sustainable forest management from semi-natural temperate forests. Biomass and Bioenergy, 24(4-5), 285-296Milledge, J. J., & Heaven, S. (2013). A review of the harvesting of micro-algae for biofuel production. Reviews in Environmental Science and Biotechnology, 12(2), 165–178. http://doi.org/10.1007/s11157-012-9301-zMolina Grima, E., Belarbi, E. H., Acién Fernández, F. G., Robles Medina, A., & Chisti, Y. (2003). Recovery of microalgal biomass and metabolites: Process options and economics. Biotechnology Advances, 20(7-8), 491–515. http://doi.org/10.1016/S0734-9750(02)00050-2Papers, C. (2011). ASABE Guide for Authors. Time, (July), 1–9.Posten, C. and Schaub, G. (2009) Microalgae and terrestrial biomass as source for fuels – a process view. J. Biotechnol. 142, 64–69.

ProOxygen. (2016). Earth's CO2 Home Page. Retrieved October 18, 2016, from https://www.co2.earth/

Rogers, J. N., Rosenberg, J. N., Guzman, B. J., Oh, V. H., Mimbela, L. E., Ghassemi, A., … Donohue, M. D. (2014). A critical analysis of paddlewheel-driven raceway ponds for algal biofuel production at commercial scales. Algal Research, 4(1), 76–88. http://doi.org/10.1016/j.algal.2013.11.007Singh, R., Shukla, R., Das, K. (2013). Harvesting of Microalgal Biomass. Biorefining and Carbon Capture Program

ReferencesShelef, G., Sukenik, A., & Green, M. (1984). Microalgae harvesting and processing: A literature review. doi:10.2172/6204677 Stumm, W., Morgan, J.J., 1962. Stream pollution by algal nutrients. Transactions of the 12th Annual

Conference on Sanitary Engineering, University of Kansas Press, Lawrence, KS.Systems, P. A., Site, T. F., Articles, F., This, S., Sponsors, O., Articles, R., … Showcase, I. (2016). Partitioned Aquaculture Systems The Fish Site, 1–7.Uduman, N., Qi, Y., Danquah, M. K., Forde, G. M., & Hoadley, A. (2010). Dewatering of microalgal cultures: A major bottleneck to algae-based fuels. Journal of Renewable and Sustainable Energy, 2(1). http://doi.org/10.1063/1.3294480Vandamme, D. (2014). Flocculation based harvesting processes for microalgae biomass production. Status: Accepted. http://doi.org/D/2013/11.109/34 ISBN 978-90-8826-307-1Vandamme, D., Foubert, I., & Muylaert, K. (2013). Flocculation as a low-cost method for harvesting microalgae for bulk biomass production. Trends in Biotechnology, 31(4), 233–239. http://doi.org/10.1016/j.tibtech.2012.12.005Vandamme, D., Pontes, S. C. V., Goiris, K., Foubert, I., Pinoy, L. J. J., & Muylaert, K. (2011). Evaluation of electro-coagulation-flocculation for harvesting marine and freshwater microalgae. Biotechnology and Bioengineering, 108(10), 2320–2329. http://doi.org/10.1002/bit.23199Watson, MK. 2009. Growth And Modeling Of Freshwater Algae As A Function Of Media Inorganic Carbon Content, Unpublished. WEMT. (2012). Chapter 5-2 Environmental Biotechnology. Retrieved from http://wemt.snu.ac.kr/lecture%202012-2/ENV/Ch%205/2012%20Ch%205-2%20Reactors%20[%ED%98%B8%ED%99%98%20%EB%AA%A8%EB%93%9C].pdfZhang, X., Mcgowen, J., & Sommerfeld, M. (2014). Progress and Perspectives of Large Scale Algae Biomass Harvesting : A Case Study at the ATP 3 Testbed.

AcknowledgementsWe want to personally thank the many people who helped us pull this together!

• Dr. Walker, for your immense knowledge and steering us in the right direction.

• Mr. Tom Jones, for pushing us to perfection and loaning out your bag of power tools for the turtle ramps.

• Dr. Owino, for pulling weeds in the PAS and constantly encouraging us.

• Dr. Richard Blob, for general turtle advice.

• Dr. Drapcho, for constantly blowing wind into our sails and for originally fabricating the PAS.

• Mr. Shawn Jadrnicek, for showing us how to pull water from Hunnicutt and for keeping the gate open to us.

• The many authors of great research literature that guided us along the way.

APPENDICES

A-1: BG-11 Growth Medium

A-2: Electroflocculation Data

A-3: Flocculation Data

A-4: Vcs Data

Dry Weight Curve

Dry Weight Samples

Photo taken by Libby Zanin

QUESTIONS?