Ct values required for degradation of microcystin-LR by free chlorine

Research Article| June 01 2006 Ct values required for degradation of microcystin-LR by free chlorine Irene Xagoraraki; Irene Xagoraraki 1Department of Civil and Environmental Engineering, Michigan State University, A136 Engineering Research Complex, East Lansing, MI, 48824, USA E-mail: xagorara@egr.msu.edu Search for other works by this author on: This Site PubMed Google Scholar Kimberly Zulliger; Kimberly Zulliger 1Department of Civil and Environmental Engineering, Michigan State University, A136 Engineering Research Complex, East Lansing, MI, 48824, USA Search for other works by this author on: This Site PubMed Google Scholar Gregory W. Harrington; Gregory W. Harrington 2Department of Civil and Environmental Engineering, University of Wisconsin-Madison, 1415 Engineerign Dr, Madison, WI, 53706, USA Search for other works by this author on: This Site PubMed Google Scholar Benjamin Zeier; Benjamin Zeier 3EarthTech, Inc., 200 Indianan Avenue, Stevens Point, WI, 54481, USA Search for other works by this author on: This Site PubMed Google Scholar William Krick; William Krick 4Wisconsin State Laboratery of Hygiene, 2601 Agricultrure Dr., Madison, WI, 53718, USA Search for other works by this author on: This Site PubMed Google Scholar Dawn A. Karner Dawn A. Karner 4Wisconsin State Laboratery of Hygiene, 2601 Agricultrure Dr., Madison, WI, 53718, USA Search for other works by this author on: This Site PubMed Google Scholar Journal of Water Supply: Research and Technology-Aqua (2006) 55 (4): 233–245. https://doi.org/10.2166/aqua.2006.0008 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Share Icon Share Twitter LinkedIn Tools Icon Tools Cite Icon Cite Permissions Search Site Search nav search search input Search input auto suggest search filter All ContentAll JournalsThis Journal Search Advanced Search Citation Irene Xagoraraki, Kimberly Zulliger, Gregory W. Harrington, Benjamin Zeier, William Krick, Dawn A. Karner; Ct values required for degradation of microcystin-LR by free chlorine. Journal of Water Supply: Research and Technology-Aqua 1 June 2006; 55 (4): 233–245. doi: https://doi.org/10.2166/aqua.2006.0008 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex Recently, there has been increased interest in microcystin-LR and other fresh water cyanotoxins because of their toxicity and occurrence throughout the world. Although previous studies have shown that free chlorine can degrade microcystin-LR, there are insufficient data to develop the contact times and free chlorine doses that achieve targeted levels of microcystin-LR degradation. Furthermore, there are insufficient microcystin-LR degradation data that would allow for the development of feasible microcystin-LR criteria or standards. To systematically develop this critical information, a total of 34 batch chlorination experiments were performed at different pH values, chlorine doses, and toxin concentrations. For all conditions, Ct (C = chlorine concentration, t = contact time) values required for degradation of microcystin-LR were calculated and safety factors were estimated. Twenty seven of the 34 experiments were conducted with reagent-grade water and seven of the 34 experiments were conducted with natural waters. At all pH values tested, the degradation of microcystin-LR increased with increasing Ct. For Ct values usually observed in drinking water treatment, a 1-log degradation of microcystin-LR in reagent-grade water was observed only at pH 6.0. The results also suggest that the Ct values obtained from reagent-grade water experiments are appropriate for application to natural waters that have been subjected to conventional coagulation, flocculation, sedimentation, and filtration prior to chlorine addition. blue-green algae, chlorination, Ct, cyanobacteria, microcystin-LR, safety factor This content is only available as a PDF. © IWA Publishing 2006 You do not currently have access to this content.