Performance of the fixed-bed of granular activated carbon for the removal of pesticides from water supply

• Published in: Environmental technology 2019-07, Vol.40 (15), p.1977-1987
• Main Authors: Alves, Alcione Aparecida de Almeida, Ruiz, Giselle Louise de Oliveira, Nonato, Thyara Campos Martins, Müller, Laura Cecilia, Sens, Maurício Luiz
• Format: Article
• Language: English
• Subjects: Abbreviations; Activated carbon; Adsorption; carbamates; Carbaryl; Carbofuran; Carbon; Column chromatography; Diffusivity; Fixed beds; High performance liquid chromatography; Liquid chromatography; methomyl; Organic matter; Pesticides; Pollutant removal; Preferential flow; Public waters; Surface charge; Surface chemistry; Treated water; Water shortages; Water supply; Water treatment
• ISSN: 0959-3330; 1479-487X
• DOI: 10.1080/09593330.2018.1435731

The application of a fixed bed adsorption column of granular activated carbon (FBAC-GAC), in the removal of carbaryl, methomyl and carbofuran at a concentration of 25 μg L −1 for each carbamate, from the public water supply was investigated. For the determination of the presence of pesticides in the water supply, the analytical technique of high-performance liquid chromatography with post-column derivatization was used. Under conditions of constant diffusivity, the FBAC-GAC was saturated after 196 h of operation on a pilot scale. The exhaust rate of the granular activated carbon (GAC) in the FBAC-GAC until the point of saturation was 0.02 kg GAC m −3 of treated water. By comparing a rapid small-scale column test and FBAC-GAC, it was confirmed that the predominant intraparticle diffusivity in the adsorption column was constant diffusivity. Based on the results obtained on a pilot scale, it was possible to estimate the values to be applied in the FBAC-GAC (full scale) to remove the pesticides, which are particle size with an average diameter of 1.5 mm GAC; relationship between the internal diameter of the column and the average diameter of GAC ≥50 in order to avoid preferential flow near the adsorption column wall; surface application rate 240 m 3  m −2  d −1 and an empty bed contact time of 3 min. ABBREVIATIONS: BV: bed volume; CD: constant diffusivity; EBCT: empty bed contact time; FBAC-GAC: fixed bed adsorption column of granular activated carbon; GAC: granular activated carbon; MPV: maximum permitted values; NOM: natural organic matter; PD: proportional diffusivity; pH PCZ : pH of the zero charge point; SAR: surface application rate; RSSCT: rapid small-scale column test; WTCS: water treated conventional system