EVALUATION OF THE ASSOCIATION OF SLOW FILTRATION AND QUICK FILTRATION FOR THE REMOVAL OF COLOR AND MICROPARTICLES FROM THE WATER OF A COASTAL LAGOON
Giardia and Cryptosporidium. Multiple stage filtration. Quick Filtration. Removal of color and microparticles.
The protozoa Giardia and Cryptosporidium are among the leading causes of outbreaks of enteric diseases transmitted by water around the world. The infective forms of these protozoa are difficult to remove and inactivate in the most usual processes of water treatment, and there is evidence of disease outbreaks caused by the transmission of these protozoans via water supply. Thus, there is a need for the development of water treatment technologies that combine efficiency in the removal of protozoa with low operation and maintenance costs. The aim of this research is to evaluate the association of multiple stage filtration with quick filtration (preceded by chemical oxidation and coagulation) in the removal of color and microparticles in the size range of Giardia cysts and Cryptosporidium oocysts. For this, experiments will be carried out with a pilot plant, composed of Gravel Pre-filter (GPF) followed by Slow Filter (SF), which will be associated to bench scale tests in jar test equipment with quick lab filters (QLF) coupled. The water used in the study will come from a coastal lagoon that typically presents low turbidity and moderate color. Different operating conditions will be tested regarding filtration rate, particle size characteristics of the slow filters and the operation of the pilot plant with or without gravel pre-filter, as well as doses of oxidant and coagulant in the jar test experiments. The quality of the treated water will be evaluated through bacteriological examinations (Total Coliforms and Escherichia coli) and "conventional" physico-chemical analyzes such as turbidity, true color, and pH, as well as particle size distribution analysis. For analysis of the data an Analysis of Variance (ANOVA) will be used, with a Tukey Test to verify the difference in performance between the different treatments.