Removal of model waste-water bacteria by magnetite in water and waste-water treatment processes

Abstract

Conventional disinfection processes used for water and waste-water treatment such as chlorination, and ozonation produce disinfection by products which are carcinogenic. The use of magnetite as an alternative method of removing pathogenic microorganisms from the water streams was proposed as it does not produce any harmful by products. The removal of three model bacteria Escherichia coli ATCC® 25922™, Pseudomonas putida ATCC® 17453™ and Micrococcus luteus ATCC® 4698™ using magnetite and the mechanism of removal has been studied in this thesis. It was found that at a cell : magnetite ratio of 1:50 the removal of bacterial cells was 96.8% for E. coli, 94.8% for P. putida and 99.7% for M luteus. To better understand the removal mechanism the effect of varying magnetite ratios, buffers, pH, and mixing times were also studied. The analyses indicate that magnetite could be efficiently used for disinfection processes in water and waste-water treatment industry.