Abstract

FUENTES MOLINA, Natalia; MOLINA RODRIGUEZ, Emiro José  and  ARIZA, Carla Patricia. Natural coagulants in continuáis flow systems as a substitute of Al₂(SO₄)₃ for water clarification. Rev. P+L [online]. 2016, vol.11, n.2, pp.41-54. ISSN 1909-0455.  https://doi.org/10.22507/pml.v11n2a4.

ABSTRACT Introduction. Surface water is most important as a source for supply, but not all of it is suitable for consumption. It is necessary to treat it by combining physical and chemical processes that require the use of coagulants such as the aluminum sulfate, a substance that is efficient but it is also harmful for health, as human beings bio-accumulate it. Objective. Evalúate the efficiency of the natural coagulants: Moringa Oleífera, Opuntia cactus, seaweed and starch, to clarify human consumption water, as a substitute of the aluminum sulfate in batch and continuous systems. Materials and methods. Water samples from the Cesar river were analyzed during sunny and rainy periods, representing low and high turbidity. The biomasses were analyzed with and without chemical pre-treatments (Ca(OH)₂, CaCL₂, NaOH y NaCl). Tests were performed by means of two systems that simulated the coagulation and flocculation stages, with several doses. The control variables were color, turbidity, OD, ST, conductivity, COD and pH. Results. The highest removal efficiencies were found with pre-treatments, except with the cactus, finding 88.26% for moringa using Ca(OH)₂, 79.73% for starch with NaOH; 81.14% for algae with CaCL₂ and 98.41% for cactus, which is the most efficient. An efficient behavior was obtained from the continuous system with similar conditions to those obtained from the batch system. Conclusions. The optimal conditions of the natural coagulants were determined, demonstrating their efficiency, safety and economy for water treating, with less mud generation, thanks to the adsorption and load neutralization mechanisms.

Keywords : natural coagulants; water treatment; batch and continuous system.