Separation of sago starch from model suspensions by tangential flow filtration

Sago starch producing mills in Malaysia generate approximately 20 tons of effluent per ton of starch produced. The effluent contains mainly starch and very low concentrations of nitrogenous compounds. The starch could be recoverable by Tangential Flow Filtration (TFF). The aim of this study was to apply TFF to separate the starch from 1% (w/v) model suspensions in simulated sago effluent. Polysulfone membrane filter cassettes of 0.45 mu m pore size and 0.1 m(2) were used for these experiments. Fifty-liter of a starch suspension was concentrated to less than 10-L. The main finding in this study was that increasing membrane filtration area improved the filtration efficiency from 81% to 85.4%, when lower transmembrane pressure (TMP) was employed. Turbidity, total suspended solids, and chemical oxygen demand before and after the treatment were significantly different (p < 0.05). In conclusion, TFF functioned efficiently to separate sago starch from suspensions. It was found that membrane area and low TMP enhanced the flux rate and minimized the reversible clogging. Moreover, membrane permeability was recovered and cleaned almost to its original permeability.