Water turbidity removal by faba bean (Vicia faba) in relation to composition of aqueous extract of seed

Efficiency of aqueous extracts of seed from five cultivars of faba bean in the removal of water turbidity was perceived through content of components known for the ability to clarify water as well as through their interactions. Concentrations of protein, phenolics (tannins) and phytic acid differed significantly between aqueous extracts of cultivars' seed. At applied dosages of aqueous extracts concentrations of protein, phenolics and phytic acid in coagulation tests varied within the ranges 0.11-0.77 mg/L, 0.8-6.2 mu g/L and 0.2-0.7 mu g/L, respectively. Experiments carried out in model water with initial 45 nephelometric turbidity units and at pH 7 resulted in turbidity removal from 28 to 65%. Data analysis revealed that under applied conditions the major determinant of coagulation activity was concentration of phenolics (very significant) followed by that of protein (significant). The removal of water turbidity was also significantly affected by the interaction between concentrations of phenolics and phytic acid as well as that between concentrations of protein and phytic acid. In addition, increase in the content of organic matter in treated water was below the value recommended by council drinking water directive