XANTHAN GUM AS A NOVEL FLOCCULANT AID EMPLOYED IN DRINKING WATER TREATMENT

Flávia Vieira Silva-Medeiros,Patrícia Valderrama,Laís Gimenes Vernasqui

doi:10.3895/rebrapa.v7n3.3772

Flávia Vieira Silva-Medeiros, Patrícia Valderrama + Show 1 more

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https://doi.org/10.3895/rebrapa.v7n3.3772

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Abstract

Aluminum salts used for drinking water treatment are strongly related to environmental implications and health hazards. In order to reduce aluminum concentration in water and enhance the quality of the flocs formed, flocculant additives are employed. This paper evaluated polyaluminum chloride as coagulant in combination with xanthan gum as a novel flocculant to improve drinking water quality. Optimum results for color removal of 97.4 %, were observed with 5.0 ppm of polyaluminum chloride combined with 0.6 ppm of xanthan gum, prepared at 65 oC. Turbidity removal was complete with 5.0 ppm of polyaluminum chloride combined with xanthan gum solution, prepared at 65 oC in all evaluated concentrations. Moreover, PACl combined with xanthan gum at 0.6 ppm, prepared at 65 oC, enhanced the removal of other contaminants, which could improve posterior stages of water treatment, as filtration and disinfection, resulting in greater control of organic load and DBPs formation.

Highlights

Dissolved organic matter (DOM), colored DOM, is currently increasing in surface water and, as a result, enhancing the color of the water
Surface water used in the assays was retrieved from Campo River watershed managed by Companhia de Saneamento do Paraná (SANEPAR), in Campo Mourão, Paraná, Brazil
According to the results shown and discussed the combination of polyaluminum chloride (PACl) and xanthan gum presented in this paper allows the possibility to reduce chemical coagulants, minimizing costs and health hazards, the contribution in organic matter

Summary

Introduction

Dissolved organic matter (DOM), colored DOM, is currently increasing in surface water and, as a result, enhancing the color of the water. This non-expected color in surface water requires higher doses of chemical coagulants and disinfectants to maintain a high drinking water quality. (LAVONEN et al, 2015; EIKEBROKK et al, 2004) This addition of conventional chemicals is prohibitively expensive, especially in developing countries, and generates disinfection by-products (DBPs), known for their negative health effects (RICHARDSON, 2011; PRITCHARD et al, 2009; RICHARDSON, 2007). Aluminum-based coagulants are not able to control the enhancement in DOM and turbidity caused by dumping of domestic sewage and industrial effluents on watersheds, even in higher dosages (RONG et al, 2013; WEI et al, 2009; SHI et al, 2007)

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