Using Chlorination and UV treatment for the removal of toxins in Water Treatment Hernesto Tellez

Outline Introduction Chlorine used as a water treatment disinfectant Waste Water History Clean Water Act Widespread use of Chlorination Chlorine used as a water treatment disinfectant Chlorine used to kill microbes Disinfection by-products production Reactions of DBPs UV light used as a water Disinfectant UV used as disinfectant microorganisms DNA damage

Waste Water History Water supply systems during the Roman Empire Network of Aqua ducts to supply.. Large cities with fresh water Elaborate Public Baths Fountains, Latrines Irrigation and Industry Waste Water Systems Waste water collection from numerous sources Sewer Channels Cloaca Maxima, Rome’s sewer system Reconstruction of a sewer channel in the Archaeological Park Xanten in Xanten (Germany) The famous Cloaca Maxima which drained the Forum was not the only sewer in ancient Rome, see map. The sewers were large enough for men and, in some places, boats to move around underneath the city. http://www.romanaqueducts.info/picturedictionary/framepicturedictionary.htm

Waste Water History http://www.romanaqueducts.info/picturedictionary/framepicturedictionary.htm

Clean Water Act Industrial Revolution, population explosion Large Cities across US Waterborne outbreaks in early 1900s 1908 Chlorine used in New Jersey EPA Clean Water Act 1974 EPA, History of Drinking Water Treatment

History of Chlorination 1908 Chlorine used to treat drinking water By 1995 EPA survey, 64% of community ground water disinfected by use of Chlorine Widely used because effectiveness and cost Used to kill Typhoid, Cholera, Dysentery, and… Bacteria: Salmonella genus (Typhoid) and Escherichia Coli. Outbreak in Walkerton, Ontario in 2000 Viruses: Polio virus, hepatitus-A Protozoans: Cryptosporidium and Giardia lamblia.

Chlorine used to kill Microbes Most widely used is Hypochlorous Acid (HOCl) made on site Easily passes through cell membranes to kill bacteria, viruses, and protozoans Cl2(g) +H2O(aq)  HOCl(aq) + HCl HCl  H+ and Cl- Cl gas dangerous to store and handle

Disinfection By-products (DBPs) Chlorine can react with numerous chemicals in water and in micro pollutants Rxns with Fe, As, pesticides, pharmaceuticals, phenols, … Cyclohexane, Benzene and Phenols Chlorine Rxns Phenol reactions Chloroform production

Phenol Reactions

Other DBPs, Steroids

UV light as a disinfectant UV light uses high energy to directly damage the DNA of any microbe involved Creates the formation of Thymine-Thymine dimers Also creates Oxygen radicals that react quickly with cellular components

Nucleotides

DNA Base Pairing

DNA Double Helix

Thymine Dimers

DNA Replication and Mutations http://www.web-books.com/MoBio/Free/Ch7F5.htm

DNA Repair

References Bougeard, C. M. , Goslan, E. H. , Jefferson, B References   Bougeard, C. M., Goslan, E. H., Jefferson, B., & Parsons, S. A. (2010). Comparison of the disinfection by-product formation potential of treated waters exposed to chlorine and monochloramine . Water Research , 729-740. Hader, R. P.-P. (2002). UV-induced DNA damage and repair: a review. Photochemical & Photobiological Sciences , 225-236. S.J. De Mora, S. D. (2000). environment, The effects of UV radiation in the marine. Cambridge University Press . Tan, Y., Kilduff, J., & Karanfil, T. (2007). Disinfection by-product (DBP) formation and speciation in chlorinated waters after anion exchange treatment. American Chemical Society, (pp. 574-574). US EPA. (2000). The History of Drinking Water Treatment. US EPA, Office of Water. V, B. (2006, June). Technical Briefs. Journal of Environmental Health , 61-63. Zimmer JL, S. R. (2002). Potential Repair of Escherichia coli DNA following exposure to UV radiation from both medium and low-pressure UV sources used in drinking water treatment. Applied and Environmental Microbiology , 3293-3299.