Wastewater generated by industrial activities (especially petroleum, automotive, machinery manufacturing, and metalworking) contains large amounts of free and emulsified oil. The discharge of these oils into treatment plants causes significant damage to the environment and sewer infrastructure while being subject to strict legal limitations. Oil Separator Systems (Grease Traps) are critical equipment designed to separate oil and solids from wastewater, primarily using the density difference (gravity) principle. At Yongrad, we manufacture and install all oil separation solutions, including traditional API and high-efficiency CPI (Coalescing Plate Interceptor), from corrosion-resistant materials such as Polypropylene (PP) or HDPE, tailored to your facility’s flow rate and wastewater characteristics.

What are Oil Separator Systems and How Do They Work?

An oil separator is a sealed tank designed to separate oil, grease, and other light hydrocarbons that have a lower density than water.

Working Principle: Density Difference and Slow Flow

1. Inlet and Slowing Down: Oily wastewater is introduced into the separator tank, and the flow rate is critically slowed down in the inlet chamber. This deceleration increases the effect of gravity.
2. Separation: As the flow slows, oil molecules rise to the water surface due to the density difference; sand and heavy solids settle at the bottom of the tank.
3. Oil Collection: The layer of oil rising to the surface is collected by automatic or manual skimmers and directed to a separate oil storage compartment.
4. Clean Water Outlet: Water stripped of its oil content is discharged in a controlled manner from the lower level of the tank, directed towards subsequent treatment steps or the discharge line.

Oil Separation Technologies and Classification in Wastewater?

Oil separator models are classified according to their separation efficiency and the technology used. Yongrad implements the following main technologies as needed:

1. Gravity Separators (API – American Petroleum Institute):

• Principle: Separation is achieved solely by gravity and long retention time.
• Efficiency: Generally effective in separating large, free oil droplets.
• Model: Requires a large footprint and high volume.

2. Coalescing Plate Interceptors (CPI):

• Principle: Uses inclined coalescing (combining) plates placed inside the separator tank. The plates allow small oil droplets to merge on the surface, forming larger droplets that rise quickly.
• Efficiency: Separates much smaller oil droplets and emulsions with high efficiency.
• Model: Takes up significantly less space than conventional API and has a high flow capacity.

3. DAF (Dissolved Air Flotation):

• Principle: The most advanced technology. Micro air bubbles are created by injecting air under pressure into the water to lift oil droplets to the surface.
• Application: Used for separating emulsified, stable oils and fine solids.

Oil Separation Technologies and Classification in Wastewater?

Oil separator models are classified according to their separation efficiency and the technology used. Yongrad implements the following main technologies as needed:

1. Gravity Separators (API – American Petroleum Institute):

• Principle: Separation is achieved solely by gravity and long retention time.
• Efficiency: Generally effective in separating large, free oil droplets.
• Model: Requires a large footprint and high volume.

2. Coalescing Plate Interceptors (CPI):

• Principle: Uses inclined coalescing (combining) plates placed inside the separator tank. The plates allow small oil droplets to merge on the surface, forming larger droplets that rise quickly.
• Efficiency: Separates much smaller oil droplets and emulsions with high efficiency.
• Model: Takes up significantly less space than conventional API and has a high flow capacity.

3. DAF (Dissolved Air Flotation):

• Principle: The most advanced technology. Micro air bubbles are created by injecting air under pressure into the water to lift oil droplets to the surface.
• Application: Used for separating emulsified, stable oils and fine solids.

Yongrad Expertise and Critical Criteria in Oil Separator Design

The efficient operation of an oil separator depends not just on the tank’s size, but on the engineering calculations applied by Yongrad.

• Material Selection (PP/HDPE): Oil Separator Tanks are typically manufactured from Polypropylene (PP) or High-Density Polyethylene (HDPE) to ensure high corrosion resistance, impact durability, and leak-tightness, as they are often buried underground or used outdoors.
• Hydraulic Load Calculation: The tank’s retention time is precisely calculated based on the wastewater flow rate to ensure sufficient time for the oil droplets to rise to the surface.
• Plate Design (CPI): The angle of inclination and spacing of the plates used in CPI units are optimized to ensure even the smallest oil droplets coalesce on the surface.
• Sludge and Oil Management: The sludge collection hopper at the bottom of the tank and the surface oil skimming systems are designed to allow for regular cleaning without shutting down the separator.

Primary Sectoral Application Areas for Oil Separators

Oil separator systems are mandatory in all industries where the oil content in wastewater is high or where sewer standards are stringent:

• Petroleum and Petrochemical Facilities: API and CPI type separators are used to purify process and rainwater from hydrocarbons.
• Automotive and Machinery Manufacturing: Separation of grease and motor oils from wastewater discharged from lubrication, washing, and parts cleaning processes.
• Metal Surface Treatment (Plating) Facilities: Pre-treatment of high-concentration oil waste discharged from chemical degreasing baths.
• Food Industry: Separation of animal fats and greases from facilities producing meat and dairy products before they enter the sewer.