| 摘要 |
<p>PROBLEM TO BE SOLVED: To purify river water and protect ecological systems, by making water-purifying blocks of a porous material formed by mixing rice hulls with cement paste in a certain mixing ratio and laying them on a river floor. SOLUTION: The mixing ratio of cement and dried rice hulls is controlled to range about 1:1 to 1:3 in volume ratio. An appropriate volume of dried rice hulls is mixed and agitated with cement paste in which water-cement ratio is about 40-60%, to form a kneaded material of rice hulls. This material is pressed in the peripheral direction in a molding frame within 1.1-1.4 in the compression ratio, to form a hollow river water-purifying block 1. And further, the water-purifying blocks 1, 1... are set on a concrete base 26 integrally to form a water-purifying unit 25. These units are laid in a water stream to purify the river.</p> |
