Treating urban dredged silt with ethanol improves settling and solidification properties

The organic matter content in urban dredged silt is high for the indraft of municipal sewage, and it seriously influences the utilization of urban dredged silt. It is necessary to find a method to solve this problem. This paper presents a method of treating the silt with ethanol (STE), considering that ethanol is a good organic solvent which can dissolve many kinds of organic matter, and optimizes the treatment conditions through Box-Benhnken design (BBD) experiment with organic matter removal efficiency as the response. The ideal conditions were as follows: action time, 47 min; ethanol concentration, 41%; ratio of ethanol to silt, 54: 1 ml/g with organic matter removal efficiency of 51.12%. Then, settling and solidification properties of raw silt and STE were explored through laboratory experiments. The results show treating urban dredged silt improved the settling and solidification properties of silt.