Resumo

CARRASQUERO-FERRER, Sedolfo J; GONZALEZ-SAHINIAN, Yandy G; COLINA-ANDRADE, Gilberto  e  DIAZ-MONTIEL, Altamira R. Efficiency of chitosan as a coagulant in the after-treatment of effluents from a pig slaughter plant. Orinoquia [online]. 2019, vol.23, n.2, pp.36-46. ISSN 0121-3709.  https://doi.org/10.22579/20112629.567.

Effluents from pig slaughter are a source of contamination due to high concentrations of organic matter, nitrogen, phosphorus, fats, total solids and fecal coliforms. This research evaluated the effectiveness of chitosan as a coagulant in the post-treatment of wastewater from the slaughter of pigs, in order to remove the remaining recalcitrant fractions from the biological process in a sequential batch reactor. The tertiary treatment consisted of coagulation, flocculation and sedimentation. The effluent was characterized by the parameters: pH, COD, turbidity, color, total solids (ST), Kjeldahl total nitrogen (NTK), nitrite, nitrate, total phosphorus (PT) and total alkalinity (AT). The treatment was carried out by using the jar test through exploratory runs with doses between 50 and 800 mg/L of chitosan dissolved in acetic acid. The effectiveness of chitosan with conventional coagulants in the treatment of wastewater, such as aluminum sulphate and polyacrylamide, was compared. The experiment was conducted using a completely randomized design with a total of three treatments and three replicates each. The evaluated range of doses of chitosan allowed to obtain percentages of turbidity removal of 83,1%, color of 64,7%, COD of 84,6%, and 78,2% NT for initial values ​​of 15,6 NTU, 26 UC, 865 mg COD/L and 89 mg NT/L, using as optimal dose 700 mg chitosan /L. Significant differences (P≤0,05) were found between chitosan and conventional coagulants in NT removal, with chitosan being the coagulant with the highest removal efficiencies. The treatment with chitosan represents a viable option for the tertiary treatment of the effluents coming from the slaughter of pigs.

Palavras-chave : Coagulation-flocculation; polyacrylamide; chitosan; aluminum sulphate; tertiary treatment.

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