Separating Oil from Wastewater

November 21, 2014

Many wastewater solutions require ‘oil separation and removal’ for meeting treatment requirements such as: BOD/COD, suspended solids, oil & grease, metal levels, and turbidity.

The WaterCare line offers solutions to many oil treatment applications. 

GMF applications: 

Spent Cleaner Oil/Solids Removal: By adding a cationic polymer to spent alkaline or acidic cleaners, such as OMEGA CP-1155, OMEGA CP-1154, or OMEGA CP-1162, the oil layer is ‘cracked’ and separated to the top of the waste cleaner solution.  At this point, the oil can be skimmed or decanted off or filtered, and the cleaner/solution can be possibly recycled via the addition of more product.  

Below is an example of an alkaline cleaner treated/filtered with OMEGA CP-1162 at 5,000 ppm (or 0.5 Kg of CP-1162 per every 100L treated):

Hydraulic Oil Spills: Sometimes a wastewater tank, or system, can be contaminated with hydraulic oils from equipment leaks. Without treatment, the oily waste can plug strainers, pumps, and inhibit floc formation in wastewater treatment systems. The best approach is to “agglomerate and absorb” the waste oily solids via a coagulant such as OMEGA BP-4123 (iron based) or OMEGA BP-4145 (aluminum based). 

Below is an example of a hydraulic oil spill ‘continuously treated in the flow through system’ with OMEGA BP-4145 at 5,000 ppm, pH adjusted to 9.5, and flocculated with OMEGA AP-2040.

Oil contamination of wwt system

Oil contamination to
wastewater treatment system


Treatment of wwt with OMEGA BP-4145

Treatment of wastewater treatment system
with OMEGA BP-4145

Oily Parts Cleaning Dragout to Waste Treatment: Processed metal parts from stamping or forging operations are commonly observed with an oily surface coating. During the pretreatment cleaning cycle, this oil is emulsified and sent to the wastewater treatment system. Primary oil/solids removal can be accomplished via the use of a batch tank and coagulant OMEGA BP-4145 and flocculent OMEGA AP-2140. The solids are ‘skimmed off’ and the water layer is routed for further treatment if required.  

Below is an example of this process: Adding OMEGA BP-4145 at 2,000 ppm, a pH adjustment to 9 with NaOH and flocculent OMEGA AP-2140.

Oily waste before treatment

Oily waste before treatment


Oily waste after treatment

Oily waste after treatment

Non-GMF applications:

If oil is involved in the process, WaterCare has a wastewater treatment solution! 

Here are a few examples:

Oil Dewatering and Reclaim Process: Reclaiming oil by dewatering and separating debris and water layers is common in the following industries: steel production, refinery, forging & castings, metal quenching & heat treating, metal forming & coining, oil & gas drilling, and many others.  

It is very attractive to recycle oil for reclaim vs. disposal. In addition, wastewater treatment is required in many applications; therefore primary oil separation is needed and the wastewater portion must be further treated to meet discharge.        

The use of primary treatment OMEGA CP-1169 (cationic) and secondary treatment OMEGA AP-2210 (anionic) provides excellent oil-water separation in many cases.  

Below is an example of an oil separation. The top layer is the debris (or rag layer), the middle layer is the water layer, the bottom layer is the oil to be recycled: OMEGA CP-1169 was added at 300 ppm and mixed. OMEGA AP-2210 was then added at 50 ppm. Once the oil is removed, the water portion is then treated with OMEGA BP-4123 coagulant and pH adjusted to 9 with NaOH, and flocculated with OMEGA AP-2210



As treated: 40% oil / 55% water / 5% debris

Need help with your specific application? Please fill out the WaterCare Survey Form and our experts will review and advise on the best approach moving forward with WaterCare as your Partner.

Posted in News Blog By

Coventya WaterCare

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