CPI Oil Separators





Installing oil separators

Oil-water separators are used in the treatment of wastewater to separate free oil, grease and hydrocarbons from the water phase.

Used in a variety of industries, oil separators assist in projects — from very small separators for workshops and service stations to large separators for oil refineries; from mine sites to airports and for pre-treatment for desalination plants.

Coalescing Plate Interceptor (CPI) oil separators are a type of oil separator most commonly used to separate free oil from produced or effluent water or suspended solids for oily water treatment.




SWA’s industrial oil separator is the best in the world, with the proven ability to reduce oil concentration from 10,000ppm to less than 1ppm. If you would like to read more about our capability, please contact SWA for details of a case study.




Group of engineer working at the wastewater treatment

What are CPIs?

CPIs are sometimes referred to as gravity separators, as they use gravity to remove suspended solids, free oils and grease from wastewater.

In this process, wastewater enters the CPI tank (by gravity or pumped flow) that contains a series of interceptor plates, which are either cross flow interceptors (CFI) or tilted plate interceptors (TPI). CFIs use flat plates tilted at 45 degrees across the direction of flow, whereas TPIs use a stack of corrugated plates tilted at 45 degrees in a downward flow angle.




The oil particles rise until they reach the underside surface of these plates, where they come together and coalesce to form larger oil droplets that then float to the surface of the water and are easily skimmed off.




Group of engineer working at the wastewater treatment

Advantages of CPI water separators

There are several key advantages to using CPI oil-water separators.

Firstly, with no moving parts within the oil separator, CPI oil-water separators are easy to maintain and run at a very low operating cost.

There is little need for extensive or costly maintenance and there is a negligible requirement for spare parts.



Generally made from stainless steel or other suitable materials, this type of separator is also extremely reliable, with high efficiency and capacity, and improved process performance.

There are also no electrical parts, so no need for a power supply.

Once commissioned, these separators operate 24 hours per day, every single day — never stopping — and an annual service takes just two to three hours.

Additionally, these oil separators can be custom designed to meet plant performance or environmental needs.




Our CPI style oil water separators

SWA Water Australia manufactures industrial oil separators and has a range of CPI style oil separators available as Cross-Flow Interceptor (CFI) and Tilted Plate Interceptor (TPI) parallel plate gravity separators.

With both a commercial range (1m3/h to 5m3/h) and an industrial range (10m3/h to 500m3/h) available, SWA’s coalescing plate oil separators are modular in design and in concept.

Customers are able to nominate several operating conditions, including flow rate, influent oil concentration, the specific gravity of oil, and operating temperature. Available in a variety of materials, SWA’s range of CPI oil separators also has a range of customisable options, such as:




CPI style oil water separators
  • Integral waste oil tank
  • HLA in waste oil tank
  • Pre-chambers for removal of grit and heavy solids
  • Removable lids
  • Gas blanketing
  • Heavy oil separation
  • Hazardous zoned area requirements
  • Large and very large flow rate installations
  • Combination with chemical demulsification and Dissolved Air Flotation (DAF)
  • Duplex and super duplex materials available for high chloride containing waters.




Man standing in front of oil separators outside

20-year guarantee

At SWA Water Australia, we stand by the integrity of our design and the quality of our work by offering a twenty-year guarantee on our SWA CC range of CPI oil separators. Conditions do apply, so please get in touch.

We manufacture our proprietary equipment to stringent standards, using high-grade material, such as stainless steel, to ensure longevity and reliability. Our designs can be customised to fit the specifics of your plant and meet the specific standards and compliance requirements of your industry.




Are you looking for a wastewater treatment solution?

Contact the global leaders in industrial wastewater treatment today.




Read More Articles