The document describes an experiment to test biological carbon capture using algae. Algae cultures were grown in plastic cups with and without added baking soda over 10 days. Baking soda was added to provide extra carbon dioxide to boost algae growth. Secchi disk visibility readings showed the algae with baking soda captured more carbon at a rate of 24.26 gC/m2/yr, compared to 18.65 gC/m2/yr for algae without baking soda. While results did not meet the goal of 500 gC/m2/yr, longer experiments may improve outcomes.

1. Algae Carbon
Capture System
with Added
Carbon
Shirin Udwadia

2. Introduction
• Biological carbon capture makes use of phototrophic micro-organisms to
take up CO2 from the atmosphere.
• The purpose is to see how much atmospheric carbon can be captured by
the batch algae culture systems
• Recognition of Problem
o The high levels of carbon in the atmosphere are causing global climate change so we need to reduce that
amount.

3. Project Specifics
• Process:
o Goal is to have a carbon capture rate 500gC/m2/yr
o Scale up to 10 tonC/yr
• Constraints
o Limited resources
o Imprecise measuring tools
o Not long enough testing period
• Considerations
o Environmental
• There may be contaminants in the lake so it could affect how the algae grows
o Sustainability
• Recycle materials after use
• Made Secchi disk out of material that was being thrown away

4. Literature Review
• Researchers in Montana State University found that adding baking soda to
algae dramatically increases the production of oil precursors for biodiesel.
o It must be added at a specific time in the growth cycle. If the baking soda is added too early or too late, the
algae won’t respond. When added at the right time, algae produces two to three times the oil in half the time of
conventional growth models.
o Baking soda works because it gives algae extra carbon dioxide necessary for its metabolism at a key point in its
life cycle.
https://phys.org/news/2010-11-soda-boosts-oil-
production-algae.html

5. Literature Continued
• Ongoing research at Montana State
University
o Sequence algae’s DNA and perform
metabolic mapping to identify which
genes correspond with algae’s
biochemical strategies under different
conditions
o The results are used to determine the
amount of minerals to be added to the
cultivation tanks to grow algae most
effective.
https://www.montana.edu/news/18410/msu-algae-
research-could-make-biofuel-production-more-economical

6. Materials
• Secchi Disk (chopstick, ruler, marker,
bottom of cup, tape)
• 6 plastic cups
• Baking Soda
• Lake water
• Algae from lake
*Alternative to Secchi Disk is
filtering the algae and weighing
using a kitchen scale

7. Where?

8. Methods
• Collected algae cultures and lake water from the lake behind my apartment
• Filled 6 plastic cups up with the same amount of algae and lake water
• Added appropriate calculated amount of baking soda (NaHCO3)to three of
the cultures
• I placed the cultures on my deck in direct sunlight
• Stir once every day and took Secchi Disk Visibility readings everyday for
about a week and a half (10 days).

9. Calculation for Baking Soda

10. Results
100
110
120
130
140
150
160
170
180
190
200
0 1 2 3 4 5 6 7 8 9 10
Concentration
(mg/L)
Time (days)
Added Baking Soda
Control
Figure 1. Growth of algae cultures by SDV

11. Initial
Baking Soda No Baking Soda

12. Final
Baking Soda No Baking Soda

13. Rate Calculations for Treated Algae
• SDVi for treated algae = 0.1016 m
• SDVf for treated algae = 0.0381 m

14. Rate Calculations for Untreated Algae
• SDVi for untreated algae = 0.1016 m
• SDVf for untreated algae = 0.0508 m

15. Calculations Condensed
Treated Untreated
Algae Grown (g algae) 0.021045 0.01618
Carbon Captured (g C) 7.60*10-3 5.854*10-3
Rate of Carbon Capture (gC/m2yr) 24.26 18.65
Table 1: Calculated Data

16. Discussion – How to improve
• Add the baking soda at the correct time in the algae's growth cycle.
• Add different amounts of baking soda, could have doubled the calculated amount
• Add different nutrients
• Do it at a bigger scale
• Accurate measurements
• Time of the year - not raining and more sunlight
• Stir continuously with a stir bar
o Would allow circulation

17. Scale Up

18. Conclusion
• My results were not close to the carbon capture rate 500 gC/m2/yr goal.
• The carbon capture rate for my treated algae culture was 24.26 gC/m2/yr.
• If I had conducted the experiment over a longer time period, I think the
results would have a better outcome.
• Cost effective because baking soda is inexpensive

19. References
• https://www.montana.edu/news/18410/msu-algae-research-could-make-
biofuel-production-more-economical
• https://www.hydrocarbononline.com/doc/msu-baking-soda-dramatically-
boosts-0001

20. Day Depth (m) Concentration (mg/L)
1 0.1016 131.8489
2 0.1016 131.8489
3 0.09525 136.8973
4 0.0889 142.1389
5 0.08255 147.5812
6 0.0762 153.2319
7 0.0762 153.2319
8 0.0635 165.1907
9 0.0508 178.0828
10 0.0381 191.981
Table 2: Daily Average Concentration of Treated Algae
Cultures

21. Day Depth (m) Concentration (mg/L)
1 0.1016 131.8489
2 0.1016 131.8489
3 0.1016 131.8489
4 0.09779 134.8551
5 0.0889 142.1389
6 0.08255 147.5812
7 0.0762 153.2319
8 0.06985 159.099
9 0.0635 165.1907
10 0.0508 178.0828
Table 3: Daily Average Concentration of Untreated Algae
Cultures