Particle Removal Efficiencies of a Barrier Board that Pre-Treats High-Turbidity Raw Water

摘要

It tends to produce high-turbidity raw water during the initial period of typhoons or storms and affect the operation of the purifying system. In this research, the particles size (D_(98)) in raw water was 100-125 μm; that in effluent water was ＜25 μm. When was under 8 ml/s, effluent water D_(98) was ＜10 μm. Flow ratio mitigation and the increase of overflow level can improve the particle removing ratio In aspect of particle size analysis, optimal operating conditions can be achieved setting an 8 ml/sec and 40 cm overflow level and D_(98) grain size can be reduced to 6.25μm as well, particle size removal ratio will gradually climb with the increase of accumulated percentage so that it can reach 70% for the respective effluent water under D_(50) and even becomes over 80% under D_(98). When under D_(90), the removing ratio can even go beyond 90% at an 8 ml/s of flow ratio. Therefore, the proposed pre-treatment reduces high turbidity due to the sudden increase of raw water to the barrier in front of the board.