On the Removal of Alagl Bloom by Pressure Flotation

在龟马县前桥市的Goryo Numa进行了几次实验，那里的藻华非常明显。实验结果表明，估计结果与模型吻合较好。但实验所用的实验装置（浮选池）略大。因此，更换浮选池中的水需要很长时间。那么，在我看来，有些计算失误可能包含在实验结果中。为了避免这种遗漏计算，作者采用了小型浮选试验机。利用该浮选试验装置对三种混凝剂进行了试验。这些混凝剂正是作者以前做过实验的那种。它们是Al_2(SO_4)_3， PAC, Fe_2Cl_3。混凝剂用量为5 ~ 20mg/1。使空气溶入水中的水压为3.5kgf/cm^2。然后作者把这种加压的水加到有藻华的水里。然后在直径为5cm的圆筒中测量浮选速度。在良好条件下，浮选速度为1.9cm/s。当储槽深度为3m时，羊群从底部到水面的漂浮时间仅为3分钟。因此，10分钟的漂浮时间足以清除藻群。根据试验结果，笔者认为浮选法是去除灌溉水中藻类最合适的方法。

Several experiments were conducted at Goryo Numa in Maebashi city in Gumma pref. where algal bloom were remarkable. As the results of these experiments showed that estimation was coincided well with it. However, experimental apparatus (flotation tank) which was used there was slightly large for experiment. Therefore, it took long time to replace the water in the flotation tank. Then it seems to me that some miss calculations might included into the experimental results. To avoid this miss calculation, the writer used small flotation tester. Experiment was conducted again for three kinds of coagulant using this flotation tester. These coagulants were just the same one in which the writer conducted experiments before. These were Al_2(SO_4)_3, PAC, Fe_2Cl_3. The amounts of coagulants used were 5-20mg/1. The water pressure to dissolve air into water was 3.5kgf/cm^2. Then the writer added this pressurized water to the water which contained algal bloom. Then the writer measured flotation velocity in the cylinder whose diameter was 5cm. The floatation velocity was 1.9cm/s at the good conditions. The flotation time of flock from bottom to surface is only 3 minutes when depth of tank is 3m. Consequently, 10 minutes of flotation times is enough to remove algal flock. As the results this experiments the writer thinks that flotation method is most suitable one to remove algae from irrigation water.