Large quantities of sludge is produced in oil storage tanks every year. The sludge is formed make out through absorbing oil on the solid particles and sediments. There is no comprehensive management about these sludge in our country right now, and only some of the cases are consider enough to remove water and finally burial of remaining sludge. As this sludge is include of large quantities toxic organic compounds and heavy metals, it is considered as a pollution source and disposal of these will be adverse effects on the environment without to apply treatment methods. In this project, samples of sludge from gasoline storage tank were provide and analyzed. Therefore physical and chemical characteristics of samples and rate of pollution were determined. The following parameters were determined: pH, turbidity, total dissolved solids content (TDS), total solids (TS), chemical oxygen demand (COD), biochemical oxygen demand (BOD), Oil and grease (O G), phosphate, nitrate, soleplate, phenol indicator, iron, zinc, nickel, lead, chromium, calcium and chloride. The analysis revealed that the value of pH was 8, turbidity was 1126, TDS was 684, TS was 1478, COD was 1745, BOD was 862, O G 1352, phosphate was 8, nitrate was 28, soleplate was 38, phenol indicator was 1.8, iron 84, zinc was 23, nickel 3, lead was 27, chromium was 1.2, calcium was 89 and chloride was 633 mg/L. All parameters exception chromium were more than the Department of Petroleum Resources (DPR) limits and Iran environment organization standards. Then the sludge of gasoline tank contains high potential of pollution. For the purpose of reducing of sample turbidity was applied coagulation and flocculation (chemical treatment) method. In this method Alum and Ferric Chloride coagulants were applied. Amounts of Alum turbidity reduction more than Ferric Chloride. For reduction of organic compounds is used activated sludge (biotreatment). About 98% turbidity, 97%TS, 98% COD, 98% BOD, 99% O G, 25% nitrate, 37% phosphate reductions were achieved by these treatment method. All of parameters are at scope of standards. Therefore the systems are extra sufficient at decreasing of the pollutants of the gasoline sludge tank, treatment methods could reduced heavy metals, however only amount of nickel and calcium are range of standards. For purpose is need to use advanced treatment methods for more reduction of other metals. In addition it can apply treatment method proposed in this project were effective in reduction of pollution load of gasoline sludge, and it will be applied for treatment of the oily sludge at large scale. Key words: oily sludge, pollution load, physical and chemical characteristics, chemical treatment, biotreatment.