浸漬型中空糸精密濾過膜濃縮装置による膜濾過物理洗浄排水の濃縮処理

相模川原水による実証実験

抄録

Pilot-plant studies were carried out to verify the applicability of a newly developed microfilter (MF) thickener for treatment and thickening of retentate coming out from membrane water treatment processes. The membrane thickener, which made use of the concentration polarization phenomena in the dead-end filtration process, was proved to be applicable to thickening of retentate having an average turbidity of 100 units and a maximum turbidity of up to 400 units at a filtrationflux of 0.5 m/day. The water recovery ratio against raw water from Sagami River was more than 99 percent in the whole process of combined membrane water treatment and MT thickening. However, a high turbidity over 420 units caused a sudden increase of filtration resistance. The filtration resistance was maintained lowerat a high filtration flux of 0.5 mlday than at a low flux of 0.3 m/day because turbid water was more rapidly excluded down to the bottom of the thickener at a higher filtration flux. Particle size distribution measurement revealed that the smaller particles with diameters of less than 3μm tended to remain suspended inthe thickener and attached to the membrane, causing an increase of the filtration resistance.