ARCHIVED REPORTS_2011 - Laserfiche WebLink

Home Browse Search

With the completion of that operation, all equipment, structures, and wells had been disposed of , and only the contaminated soil remained to be treated. The following section discusses the remediation and proposed disposition of that spoil , DETAILS OF SOIL REMEDIATION: After reviewing several options, JTO decided to employ an exper-- amental technique for remediating the appro^imately BO00 cubic yards of spoil which was stored on site. The method employed a large Pug Mill , (normally used to make dry-max asphalt,) to thoroughly max the bacteria with the soil prior to placement in piles for remediation. JT0 contracted with Terra Environmental Services of Pane Grove, CA to provide services for injecting the bacteria and monitoring the degradation of the hydrocarbons in the spoil. Details of the remediation technique are summarized below. On July 10, 1992, 40 soil samples were taken under the super- vision of a representative of the County Environmental Health Division from areas, of apparent high levels of contamination. These were then combined into five (5) composites, which were tested for BTEX, Kerosene, Diesel , and Oil in order to estimate the average levels of contamination in the soil samples. Table I summarizes the results of that analysis, which revealed Benzene was not present, Toluene was detected in only one of the compo- site samples, and Ethylbenzene & Xylene were present in very low amounts. Kerosene was not detected, but diesel and oil were measured at significant levels in all 5 of the composite samples. Exhibit f includes copies of the laboratory reports and chain of custody for those samples. f A pug mall was set up on the property approximately as shown on 4 Plate VII. Contaminated spoil was picked up by a large front loader and dumped into a grizzly equipped with 6" screens to remove the larger material; from there it went by conveyor to another grizzly with 1" screens to remove additional large rocks , and concrete pieces. The material passing through was sprayed with a surfactant as it was transported on another conveyor belt to the pug mill . While the material was being mixed in the hopper, bacteria and nutrients were added and thorough mixed with the soil. The pug mall capacity was about 5,000 lbs, (1.3 CY) per batch; approximately .085 lbs. /CY of bacteria, .008 lbs./CY Of surfactant, and .0488 lbs./CY of nutrient were used for treatment. Material safety data sheets for the bacteria, nutrient, and surfactant are included in Exhlbat K. Water was also added to bring the soil mixture up to about 40% of the maximum field holding capacity; (approximately 12--15% by weight. ) 4 ,