MOBILITY AND ENHANCED BIODEGRADATION OF A DILUTE WASTE OIL EMULSION DURING LAND TREATMENT

The mobility and biodegradability in soil of a dilute waste oil emulsion generated by an aluminium rolling industry was investigated. Laboratory simulations and field evaluation of waste disposal suggested that the majority of the oil emulsion was retained in surface soil following application. However, potential leaching of waste to the subsurface was demonstrated, particularly at higher loading rates in soils of sandy texture. Strategies to enhance rates of biodegradation in surface soils were investigated, including fertilization and microbial inoculation. A single strain inoculum was obtained from a group of 81 isolates selected for their ability to partially mineralize the waste oil emulsion, and was tentatively characterized as a hydrocarbonoclastic Corynebacterium sp. Inoculation did not effectively stimulate waste removal in soil compared with fertilization, which significantly increased respiration and biodegradation. The maximum loss of the applied oil emulsion from soil was 30% during a 56-day in vitro incubation. Fertilized, aerated liquid waste emulsion was more rapidly degraded, resulting in loss of 65% of the waste emulsion within 18 days.