The reduction of oil pollutants of petroleum products storage-tanks sludge using low-cost adsorbents

Disposal of storage tank sludge in oil depots is a major environmental concern due to the high concentration of hydrocarbons involved. This paper investigates the reduction of the sludge oil pollutants with initial oil and grease concentration of about 50 mass% using low cost adsorbents. Among the examined adsorbents, sawdust indicated the maximum removal of oil and grease. The screening and optimizing of process parameters were evaluated employing Plackett-Burman design and response surface method. For the optimized conditions, more than 60 mass% of oil and grease from the sludge was removed. Moreover, it was found that sawdust adsorption of the oil and grease approximately followed the Freundlich isotherm. The results indicated that oil pollutants of sludge could be reduced using sawdust as a low-cost, available and flammable adsorbent so that thus saturated adsorbents could be used as fuel in certain industries