Separation of phosphorus uptake and carbohydrate storage for intensive algal treatment processes

Ackerman, Courtney Anne

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https://hdl.handle.net/2142/105939 Copy

Description

Title

Separation of phosphorus uptake and carbohydrate storage for intensive algal treatment processes

Author(s)

Ackerman, Courtney Anne

Issue Date

2019-07-15

Director of Research (if dissertation) or Advisor (if thesis)

Guest, Jeremy S

Department of Study

Civil & Environmental Eng

Discipline

Environ Engr in Civil Engr

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• Wastewater treatment
• algae
• phosphorus
• light
• photobioreactor

Abstract

Microalgal systems have the potential to be an effective tertiary treatment step to lower effluent nitrogen and phosphorus levels discharged from secondary clarifiers at water resource recovery facilities. This work leveraged a tubular photobioreactor (PBR) system to evaluate the effect of a natural microalgal consortium on amended secondary clarifier effluent from the Urbana, IL water resource recovery facility. The photobioreactor is critical to ensure algae dominance over heterotrophic bacteria, but phosphorus uptake has been shown to be achieved in a dark mix tank. The objective of the work was to determine whether the system could use light time in the photobioreactor for carbohydrate storage and still achieve the adequate nutrient removal in the dark. The system was cycled between light and dark conditions, on the timescale of hours, with the goal of creating phosphorus-deplete conditions in the light, to see if phosphorus removal occurred when fresh influent was added in the dark. Different experimental conditions were evaluated with the goal to achieve complete phosphorus removal, but ultimately, the system was unable to achieve the level of removal necessary for full-scale implementation under these conditions. Since complete phosphorus removal was not achieved, carbohydrates were not stored in the light and no phosphorus removal occurred in the dark. Many different troubleshooting steps were attempted (e.g., increased solids and liquids residence times, cycle time, light exposure, aeration and pH control) but even under the less conservative conditions, the removal was not achieved, presumably because the limiting factor was not identified. The results of this study will still be able to help inform full-scale design and operation of algal treatment processes, as insight was gained into the laboratory reactor setup.

Graduation Semester

2019-08

Type of Resource

text

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http://hdl.handle.net/2142/105939

Copyright and License Information

© 2019 Courtney Anne Ackerman

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