Field Performance of Geotextile Reinforced Sludge Caps

Geosynthetic reinforced capping of highwater content waste materials is becoming an efficient and economic way of dealing with the confinement of the contaminants. To define the filtration performance of sludge-geotextile systems and investigate their durability, ten sludge lagoon test cells were constructed using of a lightweight fill, i.e. a wood chip/soil mixture over different geotextiles. Instrumentation of the cells included piezometers, settlement plates and surveying blocks. Various laboratory tests were performed on the field-exhumed geotextile samples to understand their filtration performance. The laboratory and field investigations showed that woven geotextiles could be effectively used in filtering contaminated wastewater treatment sludges. Considering the constructability, woven geotextiles should also be preferred due to their higher strength. Laboratory observations performed on the exhumed samples can provide valuable information about the performance of the geotextile.