Application of ultrafiltration integrated with coagulation for improved NOM removal

Alum coagulation followed by ultrafiltration was studied in order to improve water quality for surface water treatment. The influence of pH (from 5 to 10) and coagulant dose (25, 40 and 50 g alum/m3 equal to 1.795, 2.872 and 3.59 g Al/m3) on the investigated process performance was analyzed. Two ultrafiltration membranes (cut-off 30 kD) made of regenerated cellulose and polyethersulphone were used. The experiments showed that even the lowest dose of alum significantly increased the quality of permeate. The maximum NOM separation was observed at pH 6 and a further increase of solution reaction resulted in a worsening of the permeate quality.