Evaluation of clogging effects on nonwoven geotextile filters by negative-ion treatment

Clogging effects on nonwoven geotextile filters can reduce the drainage capacity of vertical drainage materials installed in clay deposits. The preceding clogging retention improvement can be increased if the nonwoven geotextile filter is treated by negative ion material in accordance to the knowledge that fine soil particle is negatively charged material. In this study, column tests were conducted to examine the effects of negative-ion treatment by using various types of ion-treated nonwoven geotextile filters. It was found that the negative ion treatment gave apparent increase of drainage capacity after long time as describe on this paper. Clogging effects of two nonwoven geotextile filters treated by negative ion (10 %; NI-10 and 20 %; NI-20) were compared to non-ion treated one (control) by long term filtration test. Finally, the highest drainage capacity was obtained by NI-20 followed by NI-10.