There are several ways to prevent or limit the amount of oil that mixes in with water during your operations. However, some oil usually escapes and contaminates your wastewater. To comply with regional regulations and protect the environment, many industrial facilities clean their wastewater before recycling or releasing it into the local wastewater system.
Types of Oil Water Separators
Whatever your motivating factors for installing an efficient oil-water separator in your facility, it is paramount that you get the right equipment for the job. Each type of industrial filtration system listed here has unique features that make it suitable for specific applications and inefficient in others. The following are the three main oil-water separation systems in use today.
• Hydrocyclone Oil Water Separators
• Coalescing Plate Separators
• Vertical Gravity Separators
1. Hydrocyclone Oil Water Separators
Hydrocyclone separators are the most efficient oil water separators in the market. They can handle high-pressure water at flow rates of between 3,000 and 500,000 litres per hour efficiently reducing the oil presence in the water to below 5 ppm. They are also compact, which is great as they don’t require much space.
Hydrocyclones use centrifugal force to separate the oil from the water. The hydrocyclone spins the oil-water mixture generating centrifugal forces of up to 1,000 times the force of gravity. The water molecules are pushed outward to the walls of the hydrocyclone and fall due to gravity for collection. The lighter oil molecules move towards the centre of the centrifuge and are drawn up to the top of the separator.
2. Coalescing Plate Separators
Coalescing Plate Separators use oleophilic media packs to attract oil particles that are mixed in the wastewater. The oleophilic material is used to make corrugated plates that are laid in layers 6 to 12 millimetres apart. The oil particles on the plates come together to form larger oil molecules that are buoyant, and they rise to the top of the separator where they are skimmed off to a waste oil chamber.
Coalescing Plate separators are medium range oil water separators and operate on flow rates of between 1,000 and 50,000 litres per hour. The system can achieve water purity of up to 10 ppm.
The main disadvantage of this system is that the equipment occupies more space than its counterparts. Moreover, the oleophilic plates need to be cleaned regularly to work efficiently and can lead to increased maintenance costs.
3. Vertical Gravity Separators
Oil is less dense than water and naturally rises to the surface when the mixture is allowed to settle. However, when the oil molecules are tiny, they sometimes remain suspended or mixed in with water molecules.
Vertical Gravity Separators or VGS systems are designed to speed up the natural oil-water separation process. The VGS system contains conical shaped layers of oleophilic material which attract the oil particles in the water, much like the coalescing plate separator’s mechanism. Small oil particles in the water stick to the oleophilic surfaces and combine to form molecules that are large enough to float. Sludge settles at the bottom of the tank as oil molecules rise to the top where they can be extracted, and water remains in the middle.
Vertical Gravity Separators are suitable for fluids with a low flow rate of between 720 and 3,000 litres per hour. They have lower purification efficiency than the other two systems and can purify water up to 50 ppm. VGS systems present affordable water purification and recycling solutions that can save your costs and reduce reliance on the public water supply.