Comportamento de sistemas pós-filtros adsorvedores na remoção de compostos orgânicos precursores e subprodutos da desinfecção. / Behavior of post-filter adsorbers in the removal of organic precursors and disinfection byproducts.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

The main purpose of this work was to evaluate the performance of a Granular Activated Carbon (GAC) post-filter adsorbers in the removal of organic precursors and in the formation of disinfection byproducts, especially trihalomethanes (THM) in Alto da Boa Vista Water Treatment Plant (ABV WTP), which takes raw water from a highly eutrophized reservoirs. The tests was conducted on a Pilot WTP composed of filtered water tank, ozonator, ozonized water tank, and four post-filter adsorbers: two units with mineral GAC media and two units with vegetal GAC media. The filters were operated in parallel, with two columns fed with filtered water from ABV WTP (F3 Filter mineral GAC and F4 Filter vegetal GAC) and the other fed with ozonized water (F1 Filter mineral GAC and F2 Filter vegetal GAC). The evaluation of the removal of organic precursors and the formation of disinfection byproducts was made through analysis of Total Organic Carbon (TOC), UV-254 nm and THM formation. The results generated from July 2007 to December 2008 showed that 93% of THM is formed in the first 24 hours of contact with the chlorine in the sample, simulating the post chlorination and post alkalinization of ABV WTP in samples of filtered water, ozonized water, and post-filter adsorbers effluent. Ozone oxidation process was not effective in removing THM. Was found the same instantaneous THM values in the filtered water (17.8 g/L± 5.6 g/L) and in the ozonized water. During the first three months of post-filter adsorber operation, THM removal efficiencies were around 80% for F1 and F3 (mineral GAC media) and around 70% for F2 and F4 (vegetal GAC media). After four months of operation, THM removal efficiencies decreased to 34% average value, thus indicative of GAC saturation. Regarding THM and TOC removal efficacy, the mineral GAC performed better than the vegetal GAC.

ASSUNTO(S)

carvão ativado adsorção (tratamento de água) trihalomethanes (thm) ozonation adsorption granular activated carbon (gac) desinfecção com ozônio total organic carbon (toc)

ACESSO AO ARTIGO

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