Elimination of Coliform Bacteria in Water via Filtration, Lime juice, and Sunlight
This experiment evaluated methods to sanitize water at home and with minimal expense. Water samples were collected from a local park pond; initial coliform contamination of the raw source water equaled 1.43 log CFU/ml. Raw water was sanitized via sand-filtration, lime juice, and sunlight in a completely randomized design using a 2 x 3 x 3 factorial treatment structure. One-half of the samples were filtered through a homemade sand filter, whereas the balance were unfiltered. Filtered and unfiltered samples were mixed with lime juice, at 0, 1, or 10% concentrations, and then exposed to 2, 4, or 8 hours of direct sunlight. Sand-filtration did not reduce coliform counts (P = 0.92). A lime juice x sunlight interaction (P < 0.01) demonstrated poor water sanitation at the intermediate lime juice concentration (1%) and 2 hours of sunlight but notably improved levels of sanitation at lesser or greater lime juice concentrations and longer duration of sunlight. Raw water samples mixed with 10% lime juice or exposed to 8 hours of sunlight were unable to grow colonies of coliform bacteria. This experiment demonstrates the ability to sanitize surface water using readily available fruit acid and ultraviolet light from the sun.