Paz Kibutz Galuyot is a large gas-station that underwent complete renovation of its infrastructure, as well as remediation of the contaminated saturated and unsaturated zones, under the old tank farm and dispensers. The remediation project has started after one of the tanks in the old tank farm failed tightness test and appeared to contaminate the unsaturated zone down to groundwater (20 m below grade). One phase of the remediation train included the excavation of the old tank farm and remediation of the soil under the tanks. EHC-O was used to oxygenate the unsaturated zone (20 m deep) and support bacterial degradation of the petroleum hydrocarbons content. Computerized concealed drip irrigation system (Netafim) was installed to irrigate the unsaturated zone. This in tern will enhance the release of oxygen from the EHC-O and increase bacterial activity and subsequent petroleum hydrocarbons remediation.
LDD removed the 6 large USTs from the tank pit and spread 2 tones of EHC-O in the bottom. The EHC-O layer (powder form) was mixed with bottom soil using a large excavator. This layer was followed by a layer of stones (football size), to allow increased soil stability and prevent soil depression after irrigation. The stones layer was covered with gravel (Picture A) and both layers were covered with geo-textile. A concealed drip irrigation system was placed over the geo-textile layer (Picture B) and covered with more gavel and a second layer of geo-textile. After completion of the drip irrigation system installation, the pit was covered with several lifts of clean soil and compressed to the desired soil density.
This is the first application of EHC-O in combination with drip irrigation. This installation will ensure the continuous wetting of the soil and adequate microbial activity to speed the remediation of the thick unsaturated zone.