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Using Rapid Small Scale Column Testing to Evaluate Granular Activated Carbon Adsorption of Cyanotoxins from Drinking Water

Kelley, Thomas M
http://rave.ohiolink.edu/etdc/view?acc_num=ucin150514901618082

Abstract Details

2017, MS, University of Cincinnati, Engineering and Applied Science: Environmental Science.
Increases in cyanotoxin containing harmful algal blooms in recent years has raised the level of concern within the water treatment industry to remove these dangerous bacteria and chemicals. Typical methods used to remove intracellular and extracellular cyanotoxins include pretreatment oxidation, coagulation/sedimentation/filtration, membranes, dissolved air flotation (DAF), ozone, chlorination, powdered activated carbon (PAC), and granular activated carbon (GAC). In some cases, extracellular cyanotoxins will require additional removal. Various treatment options are available, however, in many cases water utilities already have GAC installed for reducing disinfection byproduct formation. While GAC can be effective for removing cyanotoxins, there is not much information available on GAC bed life when the source water contains cyanotoxins. Furthermore, GAC adsorption of cyanotoxins in the presence of natural organic matter (NOM) and with various amounts of NOM preloading is not well studied. Therefore, the objectives of this research were to assess the effectiveness of GAC in treating cyanotoxins, particularly microcystin-LR (MC-LR), determine if NOM affects the removal of cyanotoxins through simultaneous competitive adsorption, and evaluate the adsorption capacity when GAC columns are preloaded with NOM at various levels. This study was conducted with granular activated carbon influent (GACI) water collected from an Ohio water utility using an impounded river water source and freshly regenerated GAC from the same utility, which was supplemented with 15% virgin makeup. MC-LR was found to be the dominant cyanotoxin in this source water during a bloom event. Rapid Small Scale Column Tests (RSSCTs) were used to simulate full scale GAC processes by applying the proportional diffusivity (PD) design. NOM, measured by TOC and UV254, and MC-LR, measured by LC/MS/MS, were monitored before and after the GAC PD-RSSCTs. Initial experiments resulted in MC-LR biodegradation in the influent water. To overcome biodegradation in the influent water and throughout the experimental system, sodium azide and sterilization techniques were used. Experiments were conducted with GACI water supplemented with MC-LR. MC-LR breakthrough exceeded the Ohio EPA action level of 0.3 µg/L for 0%, 55%, and 100% NOM preloading in 3,900, 2,400, and 200 bed volumes respectively, and reached full breakthrough in an average of 50,100 bed volumes. The MC-LR breakthrough curve was very gradual, indicating a long mass transfer zone within the GAC bed. At various levels of preloading (0%, 55%, and 100%), the GAC columns behaved differently at the start of the breakthrough curve, but full MC-LR breakthrough remained similar. Also, an analysis was conducted with respect to the MC-LR biodegradation observed. MC-LR biodegradation rate constants (k) were determined to vary from 0.040 1/h to 0.071 1/h and the average half-life of MC-LR was determined to be 14.0 hours. The results of these experiments shed light on GAC performance during an algal bloom event and the role that NOM can play in the treatment of cyanotoxins, specifically with varying amounts of NOM preloading, which represent issues that occur in real-world operation by water utilities that use GAC.
Dionysios Dionysiou, Ph.D. (Committee Chair)
Jonathan Pressman, Ph.D. (Committee Member)
George Sorial, Ph.D. (Committee Member)
45 p.
Environmental Engineering
cyanotoxins; GAC; MC-LR; adsorption; biodegradation; RSSCT

Recommended Citations

Citations

  • Kelley, T. M. (2017). Using Rapid Small Scale Column Testing to Evaluate Granular Activated Carbon Adsorption of Cyanotoxins from Drinking Water [Master's thesis, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin150514901618082

    APA Style (7th edition)

  • Kelley, Thomas. Using Rapid Small Scale Column Testing to Evaluate Granular Activated Carbon Adsorption of Cyanotoxins from Drinking Water. 2017. University of Cincinnati, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin150514901618082.

    MLA Style (8th edition)

  • Kelley, Thomas. "Using Rapid Small Scale Column Testing to Evaluate Granular Activated Carbon Adsorption of Cyanotoxins from Drinking Water." Master's thesis, University of Cincinnati, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ucin150514901618082

    Chicago Manual of Style (17th edition)

ucin150514901618082
972
© 2017, some rights reserved.Creative Commons License Using Rapid Small Scale Column Testing to Evaluate Granular Activated Carbon Adsorption of Cyanotoxins from Drinking Water by Thomas M Kelley is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License. Based on a work at etd.ohiolink.edu.
This open access ETD is published by University of Cincinnati and OhioLINK.