1. Selection based on wastewater source: Fully automatic integrated oil-water separators with high integration and no odor are preferred for catering wastewater; The use of coalescing or air floating oil-water separators for oily wastewater in industries such as petrochemicals and mechanical processing can effectively treat emulsified oil; Centrifugal oil-water separators are used for oilfield produced water and ship bilge water, with high processing capacity and strong resistance to impact loads.

2. Selection based on oil properties: Gravity or coalescence separators made of 304 stainless steel are used for processing animal and vegetable oils; Heating devices and explosion-proof systems are required for processing mineral oil and heavy oil; To process high concentration emulsified oil, it is necessary to use air flotation or membrane separation separators with demulsification function.

3. Select according to the effluent requirements: Gravity separators are selected for effluent that meets the third level standard of the Comprehensive Wastewater Discharge Standard (oil content ≤ 100mg/L); The first level standard for effluent requirements (oil content ≤ 10mg/L) is to use a coalescence separator; The effluent requirements for reuse water standards (oil content ≤ 5mg/L) use a combination of "coagulation+filtration" or "air flotation+membrane separation" equipment.

4. Selection based on processing scale: For small projects with a daily processing capacity of less than 50m ³, an integrated fully automatic oil-water separator should be selected; Modular combined oil-water separators are selected for medium-sized projects with a daily processing capacity of 50-500 cubic meters; Large scale projects with a daily processing capacity greater than 500m ³ use reinforced concrete structures for large-scale oil-water separation systems.