Oil Interceptor & Dissolved Air Flotation (DAF)
 |
Oil Interceptor is used generally if the treatment objective is just to reduce the free oil and grease level found at the effluent, as found in many conventional oily storm water treatment facilities. Hydrocyclone is selected as primary/ secondary treatment unit in more advanced facilities such as produced water treartment system on offshore platform. The difference between Oil Interceptor and Hydrocyclone is the efficiency of free oil removal, beside one operates in gravity flow and another always in pressurized environment. The efficiency of the former is much below that of Hydrocyclone. Hydrocyclone typically achieves oil and grease limit of < 50 mg/L. Product water from Hydrocyclone will be further treated in tertiary treatment unit, i.e. flotation system or filtration system. Dissolved air flotation (DAF) system, one of this tertiary treatment unit, is commonly installed in oleo-chemical industry and pulp and paper industry. |
 |
When DAF is used to treat oily waste water, typically 8-15% of clarified water shall be recycled. Typical operating pressure of the recycled stream shall be within the range of 6 to 8 bar depends on system design, which minute air bubbles shall be form to break the oil emulsion from the water to floated sludge. The filtration system in oil-water separation can be coalescence, media filter or membrane elements. They act as final safeguarding unit so that consistent discharge quality is met. |