DEWATERING METHOD OF MUDDY WATER

To provide a dewatering method of muddy water which can dewater the muddy water containing a soil having a small particle diameter in a relatively short time.SOLUTION: A dewatering method comprises: adding a surfactant to muddy water containing a soil having a particle diameter made to be 75 μm or less with classification; after the surfactant causes flocculation settling of the soil, concentrating the muddy water; adding a flocculant to the concentrated muddy water; after the flocculant causes flocculation settling of the soil, concentrating the muddy water; and compression-dewatering the soil obtained from the flocculation settling by the flocculant. In the dewatering method, concentrating before compression dewatering can cause a decreased water content of the muddy water and the surfactant causes water to easily come out of soil particles during the compression dewatering.SELECTED DRAWING: None 【課題】含まれている土壌の粒径が小さい泥水を比較的短時間で脱水することができる、泥水の脱水方法を提供する。【解決手段】分級により粒径を７５μｍ以下とした土壌を含む泥水に界面活性剤を添加し、界面活性剤による土壌の凝集沈殿が生じた後に泥水を濃縮し、濃縮した泥水に凝集剤を添加し、凝集剤による土壌の凝集沈殿が生じた後に泥水を濃縮し、凝集剤によって凝集沈殿した土壌を圧縮脱水する。この脱水方法では、圧縮脱水する前に濃縮によって泥水の含有水量を低減できること、及び、界面活性剤によって圧縮脱水時に土壌粒子間から水が抜けやすくなる。【選択図】なし