FLOCCULATION AND DEHYDRATION CONTROL DURING SOIL WASHING PROCESS USING SOIL PLASTICITY INDEX AND pH
Soil washing is physical-chemical separation for removing the portion of the soil that is most polluted mainly by screen, hydrocyclone, and flotation. This reduces the amount of soil needing further cleanup. In most cases, the contaminants, such as fuels and heavy metals, reside and concentrated in fine-grained soils. The overflow from the hydrocyclone, consisting of fines and water, is treated and converted to a 45％-55％ dry solids sludge cake by flocculants addition, sedimentation, thickening, and dewatering.This sludge cake contains the target contaminants and therefore must be managed by disposal at a properly permitted off-site disposal facility. The fines treatment is very important for the recovery of water and for making the sludge cake as dry as possible, in order to create an economical and efficient soil washing system. The proper selection of type and dosage of flocculants is crucial to the success of the fine treatment. This paper describes and proposes a new theory to determine the optimum dosage of flocculants (polymers) based on the soil plasticity index and the pH value. This theory concerning the optimum dosage was verified by subsequent data in the soil washing plant.
Clay Suspension Soil Washing Flocculants Plasticity Index pH
HIROKAZU AKAGI MITSUO MOURI
Department of Civil and Environmental Engineering,Waseda University,3-4-1,Ohkubo,Shinjuku,Tokyo 169- Soil Remediation Division,Engineering Headquarters,Shimizu Corporation,1-2-3,Shibaura,Minato, Tokyo
国际会议
第三届中日岩土工程研讨会(Proceedings of the 3rd Sino-Japan Geotechnical Symposium)
重庆
英文
30-45
2007-11-05（万方平台首次上网日期，不代表论文的发表时间）