Design of Eco-Friendly Geo-Composite Liner for Fly ash Ponds

Abstract

This paper aims to design of geocomposite liner for fly ash ponds. Our country has many thermal plants, which generates huge amount of flyash as a waste and their disposal require some of the crucial treatment and engineered flyash pond. The problems from coal based thermal plants is disposal of such flyash. In the present research, Clayey soils, Sodium bentonite and black cotton soils used as a liner for fly ash pond, instead of HDPE sheet to reduce the heavy metal contaminants leachate. Recent GCL, HDPE or Geocomposite liners as bottom lining layers are a suggestive solution for preventing toxic materials from seepage into the surrounding areas. The obtained results of this research indicate that the more percentage of concentration of heavy metals like Arsenic, lead, cadmium and chromium are retained in sodium bentonite layer than the black cotton soil. Hence it is, recommended that among the different liners, sodium bentonite is the most appropriate geocomposite liner, as it’s self-healing and swelling properties provides more retention capacity of toxic heavy metals. The present invention relates to a geocomposite liner system for fly ash pond to reduce the leaching of toxic metals in ground water. The geocomposite liner system comprises of at least one fibrous layer having a layer of sodium bentonite material; a non-fibrous layer mechanically and non-adhesively affixed between fibrous layers. A suitable thickness of bentonite clay is encapsulated between the fibrous and non-fibrous layers, it can retain the Arsenic, Cadmium, Chromium and Lead metals in it. This Geo composite liner is most suitable, economical and easy to install over CCLs and GCLs.