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�• to certain microorganism population growth were reduced or eliminated, thereby boosting metabolic activity The burgeoning population of certain of the microorganisms was able to utilize the most readily available food source, diesel fuel. The population of microorganisms that was able to feed off the fuel increased rapidly as they were able to out-compete their neighbors who had no liking or use for diesel. This population explosion reached a plateau when the amount of food was no longer sufficient to support further increase of microorganism expansion, i e., when the diesel was gone. When the food source was sufficiently depleted, the population of these organisms declined until a level of equilibrium was reached. The equilibrium population levels of microorganisms most likely resembles that which was initially present. Making the Beds x The diesel-saturated soil was mixed with sterilized mushroom compost at a a 'o,of 909 ��- pprci�tirnaf ly ane;�pa t compo t sand tvi+nt;k"pa�rts� of inirigt cl o :, The mixing was accomplished by spreading out alternating layers of soil and compost over a broad area using a front end loader. A tractor with a rototiller was then used to mix the compost with the soil. x The beds were then constructed. Ten milliliter thick polyethylene liners were laid down A 3-6 inch thick Iayer of sand was spread on top of the liners. The sand provided drainage and served to protect the liners during subsequent rototilling of the beds. The soil/compost mixture was spread on top of the sand to a thickness of about one foot. The beds were watered so as to provide the moisture that the active organisms needed. The beds were then covered with 10 milliliter polyethylene covers to prevent deterioration of the beds and hold moisture in. Berms around each bed were constructed out of 2" x 6" lumber fixed to the ground. The beds were rototilled twice during the four month treatment period and watered as required Approximately 300 cubic yards of contaminated soil were treated. - Two sampling events of the treatment beds were carried out. In both events, sixteen samples were collected and shipped to the SCS laboratory where they were mads into four composite samples The first sampling event occurred on May 29, 1990 and the second on rune 27, 1990 Levels of diesel initially found in the soil ranged as high as 7,370 parts per million (ppm) The May sampling of the remediation beds detected from 50-216 ppm diesel The June sampling event chemical analysis detected no diesel in the soil. Table 1 shows the diesel concentrations for the three sampling events The data indicates that the lens of diesel-saturated soil which was removed from beneath the footprint of the former tile plant was completely remediated The bioremediation treatment using microbes indigenous to the diesel-saturated soil resulted in the level of diesel found in the soil being reduced to a non-detectable level. °i