Sedimentation equipment for oily wastewater

Wastewater containing oily substances discharged during industrial production processes. The oil substances contained in oily wastewater include natural petroleum, petroleum products, tar and its fractions, as well as edible animal and vegetable oils and fats. In terms of water pollution, the main ones are oil and tar. The concentration of oil substances in wastewater discharged from different industrial sectors varies greatly. The oil content in the wastewater generated during the refining process is about 150-1000mg/L, the tar content in the wastewater of coking plants is 500-800mg/L, and the tar content in the wastewater of gas generation stations can reach 2000-3000mg/L. Oil substances usually exist in three states in wastewater: ① Oil particles dispersed in wastewater are relatively large, with a particle size greater than 100 μ m, making them easy to separate from wastewater. In petroleum wastewater, this type of oil accounts for 60-80% of the total oil content in water; ② The dispersed particle size of oil in wastewater is small and in an emulsified state, making it difficult to separate from the wastewater; ③ A small portion of the oil is in a dissolved state, with a solubility of about 5-15mg/L. Oil containing wastewater is commonly recovered from floating oil or heavy oil using oil separators.