Estudio de las características coagulantes/floculantes de polímeros orgánicos naturales, extraídos de materiales de desecho alimenticio, para la potabilización del agua

Abstract

In this research work, the coagulant and flocculant characteristics of three natural polymers: green plantain peel starch, orange peel pectin and tamarind seed extract in three solutions (water, sodium chloride and ammonium acetate) were evaluated in the purification of raw water with turbidity of 5,32 NTU. The natural polymers did not present coagulant activity due to the low turbidity of raw water; however they showed flocculant activity in combination with aluminum sulphate. The optimal combinations of aluminum sulphate + polymer were 50 mg/L+0,2 mg/L for starch, 60 mg/L+0,06 mg/L for pectin, 60 mg/L+0,6 mg/L for tamarind extract in water, 60 mg/L+0,5 mg/L for tamarind extract in sodium chloride and 60 mg/L+0,2 mg/L for tamarind extract in ammonium acetate. Removal value of turbidity and color was around 87% and 92%. The production of natural polymers was not economically viable due to their high extraction cost: $ 22,45/kg of starch, $ 306,11/kg of pectin and $ 25,44/kg of tamarind seed powder. The residual sludge exceeded the maximum permissible limits for discharging to the sewer system; in addition, it showed a toxic effect on the mitotic activity of onion roots at an IC50 of 0.5 to 2 %.