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Evaluating the effectiveness of three different algaecides for use in Willard and Norwalk Reservoirs.

Gao, Anny X
http://rave.ohiolink.edu/etdc/view?acc_num=akron151059284100804

Abstract Details

2017, Master of Science in Engineering, University of Akron, Civil Engineering.
Due to climate change, cyanobacterial blooms have become common occurrence and have caused problems for many drinking water facilities. In addition to issues associated with oxygen depletion, cyanobacteria can also release toxins that are harmful to humans and other organisms. Many water treatment facilities have started using algaecide(s) in their reservoirs to control harmful algal blooms. PAK27, EarthTec, and Cutrine Ultra were three algaecides tested on source water and cyanobacteria samples collected from Willard Reservoir and Norwalk Reservoir. Each algaecide was tested at three different dose levels: full, half, and quarter of the manufacture's recommended dosage for the two different reservoir waters and cyanobacteria. Each source and dosage was conducted in triplicate and evaluated for their effectiveness in terms of overall cyanobacteria population reduction, minimum effect on non-target-organisms, and limited-to-no release of toxins at the baseline (time zero), 1.5 hours, and two days after application. Potential rebound period was measured at 7 and 14 days. Quantitative real-time polymerase chain reaction (qPCR) was used to determine if the total cyanobacteria population tested (16s) had the genes necessary to produce microcystins, saxitoxins, and cylindrospermopsins. Enzyme-linked immunosorbent assays (ELISA) was used to quantify presence of extracellular microcystins. Visual count was to identify the cyanobacteria present in these experiments. For the Willard Reservoir when treated with PAK27, the half dose result was more effective than its full and quarter dosage. The half dose decreased the cyanobacteria population by 38% at 2-day and increased 127% at 14-day while the full dose decreased by 50% but the rebound was 1591% and quarter dose decreased 9% at 2-day and rebounded 9%. The similar trend was exhibited with Cutrine Ultra where the half dosage result was more effective than its full and quarter dosage. Although the quarter dose of EarthTec only suppressed 71% (11,543 cells/mL) by the second day, the cyanobacteria rebounded 27% and the least amount of extracellular toxins were released. Based on the minimal release of toxins and impact on non-target organisms, EarthTec at the quarter dosage would be recommend for future experiments. EarthTec adequately suppressed the cyanobacteria population, released close range amount of toxins as well as had a lower rebound of cyanobacteria and a higher chlorophyll-a rebound compared to Cutrine Ultra. When comparing the results of PAK27 dose levels for Norwalk reservoir the half dose result was more effective than its full and quarter dosage. It provided highest suppression and lowest rebound of cyanobacteria concentration with no toxin released. The half dose resulted in Cutrine Ultra was more effective at decreasing cyanobacteria (39,501 cells/mL to 2,354 cells/mL) with a rebound of 416% and no toxin release than its full and quarter dosage. Quarter dose of EarthTec, performed better with a 77% suppressed rate, a continuous decline (3%) from 7 to 14-day, and least impact to chlorophyll-a concentration when compare to its full and half dosage. Like Willard result, EarthTec at quarter dose was the most efficient overall for treatment Norwalk Reservoir. Although the half dose Cutrine Ultra suppressed more of the cyanobacteria than quarter dose of EarthTec, the half dose of Cutrine Ultra had a higher rebound in the cyanobacteria after 14 days. A higher rebound could indicate the potential of the cyanobacteria to develop a resistance to the algaecide.
Teresa Cutright, Dr. (Advisor)
Donald Ott, Dr. (Committee Member)
Stephen Duirk, Dr. (Committee Member)
139 p.
Civil Engineering; Environmental Engineering

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Citations

  • Gao, A. X. (2017). Evaluating the effectiveness of three different algaecides for use in Willard and Norwalk Reservoirs. [Master's thesis, University of Akron]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=akron151059284100804

    APA Style (7th edition)

  • Gao, Anny. Evaluating the effectiveness of three different algaecides for use in Willard and Norwalk Reservoirs. 2017. University of Akron, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=akron151059284100804.

    MLA Style (8th edition)

  • Gao, Anny. "Evaluating the effectiveness of three different algaecides for use in Willard and Norwalk Reservoirs." Master's thesis, University of Akron, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron151059284100804

    Chicago Manual of Style (17th edition)

akron151059284100804
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This open access ETD is published by University of Akron and OhioLINK.