Date of Graduation

5-2023

Document Type

Thesis

Degree Name

Master of Science in Environmental Engineering (MSEnE)

Degree Level

Graduate

Department

Environmental Dynamics

Advisor/Mentor

Haggard, Brian E.

Committee Member

Suarez, Celina A.

Second Committee Member

Miller, David M.

Keywords

Biochar; Harmful algal blooms; Water quality

Abstract

Harmful Algal Blooms (HABs) are an increasing global concern for water management due to their increased frequency, distribution, and toxin production. In freshwaters the growth of cyanobacteria (commonly known as blue-green algae), due to anthropogenic nutrient enrichment is the primary driver of HABS; these are often referred to as cyanoHABs. The management of cyanoHABs should be focused on in the watershed through best management and conservation practices or the physical, chemical and biomanipulation of the lake or reservoir that is experiencing these blooms. In this study, we examine the use of biochar as an option for the management or treatment of cyanoHABs. Biochar is organic carbon produced from the pyrolysis of wood or other organic material. Biochar has been previously used in wastewater treatment and environmental remediation, and this project will test the ability of biochar to remove nutrients such as phosphate, nitrate and ammonia from freshwaters, and how biochar affects algal growth and microcystin concentrations. A series of adsorption experiments were completed in the lab to evaluate how Biochar Now, a commercially available product, removed dissolved nutrients from water, and several bioassays were completed to evaluate its effect on cyanoHABs and microcystin concentrations. The main objectives of this study will be to 1) to determine the capacity of biochar to remove dissolved nutrients from aqueous solution, 2) to evaluate the effect of biochar on algal growth and cyanoHABs using bioassays, and 3) to evaluate the effect of biochar on free and total microcystin concentrations in cyanoHABs using bioassays. Results showed that biochar did not readily absorb nutrients or metals from aqueous solutions, and biochar did not have a relationship with microcystin production in the bioassays. However, while results were variable, bioassays showed that biochar might influence chlorophyll-a concentrations.

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