ARCHIVED REPORTS XR0012746 - Laserfiche WebLink

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Du Pont MR 399-87 The microbial activity as determined by ATP analysis In the scale-up test did Increase for both soil slurries, indicating that microbial growth was occurring over the two week period. There were decreases in the microbial levels until additional benzene, toluene, end xylene were added an The water was also measured to distinguish suspended microorganisms from those associated with the soil. The I absence of toluene and xylene an day 0 from the low nutrient scale-up vessel may be attributed to experimental error. There should be no way -to generate these two compounds In this system. The medium nutrient vessel demonstrated that the substrates did The deed disappear with the concomitant Increase in microbial activity. in vessels were sealed with a Teflon* cap and gsmplos were collected by syringe, so there was minimal loss due to volatilization. The microorganisms indigenous to the groundwater and soil from the Lodi site were stimulated by the addition of nutrients in the prseance of xylene and other contaminants which where associated with these materials, resulting in the mineralization of xylene and production of CO2, From the nutrient optimization studies we were able to choose nutrient combinations for subsequent scale-up studies. The scale-up study rapri%sented a 100-fold Increase in volume and increase in microbial activity an well as decrease in benzene, toluene, and xylene were documented. The medium nutrient solution (BO ppm phosphorus'and 100 ppm nitrogen) provided the highest microbial activity and removed all benzene, toluene, and xylene in two weeks. With these results and additional information regarding the low levels of phosphorus and nitrogen in the groundwater, the medium levels of nutrients used in this study era recommended for in situ bioreclamation at the Lodi site.