Abstract

INIGUEZ-COVARRUBIAS, Gilberto  and  PERAZA-LUNA, Francisco. Reduction of solids and organic load concentrations in tequila vinasses using a polyacrylamide (PAM) polymer flocculant. Rev. Int. Contam. Ambient [online]. 2007, vol.23, n.1, pp.17-24. ISSN 0188-4999.

This study consisted of three experiments designed to evaluate the practicality of using a cationic polyacrylamide (PAM) polymer flocculant to reduce commonly used aquatic pollution indicators in tequila vinasses. A first experiment with a 2 x 2 factorial arrangement was used to observe the effects on vinasses of five different concentrations of PAM (20, 60, 100, 140 and 180 g/L) at two different temperatures, 25 and 90 °C. In a second experiment vinasses from different tequila factories were treated with 200 mg/L of PAM and the flocculated solids separated in a pilot-scale cylindrical rotating screen separator constructed of non-oxidized steel. In a third experiment the flocculation study was carried out in a small tequila factory using 4,500 liters of tequila vinasses treated with 200 mg/L of PAM discharged from three different pot stills. Recovered flocculated solids (g/L), settleable solids (SS, ml/L), total solids (TS, mg/L), total suspended solids (TSS, mg/L), total dissolved solids (TDS, mg/L) and chemical oxygen demand (COD, mg/L) concentrations were the evaluated answer parameters. The major effect in the PAM addition to vinasses samples in the two different temperature conditions, was reflected in the removal efficiency of SS and TSS. In SS concentration of treated vinasses there was a significant effect (p<0.05) due to temperature and PAM concentrations so as well as an interaction between both factors. TS removal efficiency was affected by the temperature and PAM concentration and there was no interaction among the temperature and coagulant concentration (p<0.05). COD concentration in vinasses samples, was affected only by the coagulant concentration, there was no interaction among temperature and coagulant concentration (p<0.05). Vinasse cooling and pH adjustment was not considered necessary for optimal polymer-amended vinasses solids separation. For vinasses with a SS of 400 mg/L or less an addition of 200 mg/L of PAM it is expected to have optimal removal values of SS and relatively acceptable values of TS, TSS and COD. Estimate costs associated with the level of PAM used in this study corresponded to 0.076 dollar per liter when the PAM cost was 3.8 dollar per kilogram.

Keywords : tequila vinasses; solids separation; rotating screen; polycrylamide (PAM).

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