Analysis of Petroleum Leaching Behaviour from Cement-Solidified Oily Sludge

Abstract

Stabilization/solidification is a process widely applied for the immobilization of inorganic constituents of hazardous wastes. But knowledge of the exact leaching behaviour of contaminants is limited. In this study, the effects of parameters including time, temperature and the cement/ sludge ratio on the diffusion behaviour of petroleum after the solidification of oily sludge were investigated by using extraction and UV spectrophotometer. These experimental results indicated that the quantity of petroleum diffusion varies from 1.18 at 24 h to 3.48 mg/L at 72 h. The amplitude of petroleum diffusion within 72 h is the most distinct and thereafter, the variation becomes slower. The diffusion quantity enhances from 2.01-2.77 mg/L with the increment of temperature under the range of 298-308 K. The trend displays flat when the temperature is beyond 308 K. The amount of petroleum diffusion reduces from 3.82 to 2.80 mg/L with the increasing of the cement/sludge ratio under the range of 1.0-1.8. The diffusion quantity reaches 2.69 mg/L at 120 h after adding reinforcing agent of melamine resin, which is lower than without reinforcing agent. The diffusion quantity could arrive at 5 mg/L through 120 h, which meets the first order dispatching demands requested. These results could be used to assess the extent of leaching and understand the leaching mechanism.