Abstract:
The objective of this research was to study the treatment of oily sludge bysolidification method. The oily sludge used in this work is waste from distillation process inpetroleum industries. It is hazardous waste since the components include oil and heavy metalsthat cannot be destroyed or altered by chemical or thermal methods, and must be converted intothe most insoluble form preventing their leaching to the environment. In this work we studyphysical and chemical characteristics of oily sludge, the solidification processes of oily anddeoily sludge, compressive strength of the mortar, oil and heavy metal leaching from the mortarand economic cost of solidification.First, physical and cllemical characteristics of oily sludge were determined as follows :33.83 percent solid content, 35.61 percent moisture content, 30.56 percent oil content, pH of6.8-7.2 and heavy metals content such as Zn of 9.27 ppm, Pb of 18.55 ppm, Cd of 0.20 ppm, Niof 5.46 ppm, Cr of 21.20 ppm. A potential problem with solidification technology involveschemical interference with the hydration reactions of portland cement and pozzolan processes.Since oil affected the setting and the development characteristics of concrete so we had to extractoil from oily sludge by using hexane as extraction fluid. The result showed that deoily sludge hasoil content 15.21 percent and the oil that extracted from oily sludge can be used as fuel. Secondwe studied the solidification of oily sludge and deoily sludge. Portland cement (P), fly ash (F),lime (L) and diatomaceous earth (D) were used as solidifying materials. The results showed thatthe compressive strength of PF, PFL, PLD and PFLD were higher than the minimumrequirement of mortar for sanitary landfill. The leaching of oil and heavy metal from mortarwere lower than the EPA standard. Third, we studied the economic cost of solidification ofoily sludge and deoily sludge. The result showed that the cost of solidification of sludge byusing PFLD as solidifying materials was the lowest and those by using PLD, PF and PFLD washigher respectively. In comparison the cost of solidification of deoily sludge was higher thanthat of oily sludge due to the additional cost of hexane.