Abstract

CONTRERAS LOZANO, Karen Paola et al. Nopal (Opuntia ficus-indica) as a complementary natural coagulant to clarify water. Rev. P+L [online]. 2015, vol.10, n.1, pp.40-50. ISSN 1909-0455.

Introduction. Clarification is a process performed before purifying water, and consists in applying a coagulant that groups the suspended particles and makes them flocculate.They are, then, separated by means of filtration. Vegetables are being explored as a clean and inexpensive option to replace the primary coagulants, which are inorganic compounds. Objective. Evaluate the efficiency of the mucilage extracted from the nopal (Opuntia ficus-indica) as a natural coagulant that complements aluminum sulfate in the clarification of water from the Magdalena river. Materials and methods. The clarification process was performed by the use of the jar test, taking into account factors such as the concentration and the proportion of the coagulants, the pH and the agitation speed, in order to evaluate the turbidity (NTU), the color (UPC), the total dissolved solids (mg/L), the pH and the electric conductivity (μS/cm) in the water treated. Results. By applying a maximum quantity of 20 % of nopal mucilage in the proportion of coagulants and an agitation speed of 200 rpm, the turbidity of the water can be reduced to values below 2 NTU, achieving efficiencies above 50 % in the removal of the turbidity. The most effective efficiencies achieved are between 96-98 %.The color was totally reduced to zero UPC and the STD content was reduced to values below 200 mg/L.The natural coagulant did not significantly affect the pH of the water treated and the conductivity increased in some of the treatments, perhaps due to the primary coagulant. Conclusion. The mucilage of nopal as a coagulant to complement the aluminum sulfate is effective to clarify water.

Keywords : Opuntia mucilage; clarification; coagulant; turbidity.

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