Surreal illustration of oil droplets and plant fibers representing hidden value in palm oil waste.

Unlocking Hidden Value: How to Recover Residual Oil from Palm Oil Waste

Lena Kashyap in Climate & Environment September 2025 • 4 min read.

"Discover how a deeper understanding of palm oil mill effluent (POME) can lead to new economic opportunities and a more sustainable industry."

Palm oil is a major commodity, but its production generates a large amount of wastewater known as palm oil mill effluent (POME). POME has a high organic content, which poses environmental challenges. However, this organic content also presents an opportunity: the potential to recover residual oil.

While the oil loss in POME is less than 1.0%, the accumulated loss over a year is substantial and worth investigating. Recovering this residual oil could create new economic opportunities for the palm oil industry, increase overall oil extraction rates, and boost revenue for mills.

Moreover, the palm oil industry faces increasing pressure to meet stringent environmental regulations. POME contains a significant amount of oil and grease, exceeding allowable discharge limits. Removing residual oil from POME is therefore critical for addressing treatment and disposal challenges, paving the way for more sustainable practices.

The Hidden Oil: Understanding Residual Oil in POME

Surreal illustration of oil droplets and plant fibers representing hidden value in palm oil waste.

Research reveals that the residual oil in POME exists in different forms: free oil, dispersed oil, and soluble oil mixtures. Most of the oil droplets are quite small, less than 100µm in size. These tiny droplets can be created by the turbulent conditions of palm oil processing, where the oil cells from the palm fruits are ruptured, creating an oil-in-water emulsion. These small droplets are surprisingly stable due to natural surfactants like monoglycerides, phospholipids, and glycolipids.

The study highlights the crucial role of solid particles within POME. These particles, mainly composed of lignocellulosic materials, are oleophilic, meaning they have a natural affinity for oil. This affinity leads to a significant portion of the residual oil being adsorbed onto these solid particles.

The highest quantity of oil droplets and solid particles was found in the bottom layer of POME after settling.
This indicates that solid particles impede the movement of oil droplets, effectively trapping them and preventing them from rising to the surface for recovery.
Contact angle measurements confirm that the solid particles in POME exhibit amphiphilic properties, meaning they are both hydrophilic (attracted to water) and oleophilic (attracted to oil). This dual affinity further contributes to the adsorption of oil onto the particles.

Ultimately, the research pinpoints small oil droplet sizes and the adsorption of oil onto fiber particles as the primary reasons for the presence of residual oil and subsequent oil loss in POME. By understanding these mechanisms, the industry can develop more effective strategies for oil recovery.

Turning Waste into Opportunity: The Future of POME

This research provides a foundational understanding of the complex nature of residual oil in POME, paving the way for the development of innovative oil recovery technologies. By targeting the mechanisms that contribute to oil loss, the palm oil industry can transform a problematic waste stream into a valuable resource.

Imagine a future where POME is no longer viewed as an environmental burden, but as a source of sustainable biofuel feedstock. Recovered oil can be used for biodiesel production, reducing reliance on fossil fuels and contributing to a circular economy.

Further research into optimizing the sludge pit retention system and exploring novel extraction methods can unlock the full potential of POME, driving both economic and environmental benefits for the palm oil industry and beyond. This requires a deeper study into the feasibility and efficiency of the sludge pit retention system.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.15376/biores.10.4.7591-7603, Alternate LINK

Title: Presence Of Residual Oil In Relation To Solid Particle Distribution In Palm Oil Mill Effluent

Subject: Waste Management and Disposal

Journal: BioResources

Publisher: BioResources

Authors: Wan Siti Shazzelyn Aida Wan Sharifudin, Alawi Sulaiman, Noriznan Mokhtar, Azhari Samsu Baharuddin, Meisam Tabatabaei, Zainuri Busu, Karuppuchamy Subbian

Published: 2015-09-23

Everything You Need To Know

What is palm oil mill effluent (POME), and why is recovering oil from it important?

Palm oil mill effluent, or POME, is the wastewater generated during the production of palm oil. It contains a high concentration of organic matter, which is why it poses environmental concerns. However, this organic content also presents an opportunity to recover residual oil and create new economic opportunities for the palm oil industry, increase overall oil extraction rates, and boost revenue for mills.

In what forms does residual oil exist within palm oil mill effluent (POME)?

Research has identified three forms of residual oil in POME: free oil, dispersed oil, and soluble oil mixtures. The majority of these oil droplets are quite small, usually less than 100µm in size. These tiny droplets are stabilized by natural surfactants such as monoglycerides, phospholipids, and glycolipids, which makes their recovery more challenging.

How do solid particles in palm oil mill effluent (POME) contribute to oil loss?

Solid particles, primarily composed of lignocellulosic materials, play a crucial role in oil loss from POME. These particles are oleophilic, meaning they attract oil. As a result, a significant portion of the residual oil is adsorbed onto these solid particles. This adsorption hinders the movement of oil droplets and prevents them from rising to the surface for recovery. Contact angle measurements have confirmed that these solid particles exhibit amphiphilic properties, further contributing to oil adsorption.

Where is the highest concentration of oil droplets and solid particles found in palm oil mill effluent (POME) after settling, and what does this indicate?

The highest concentration of both oil droplets and solid particles is found in the bottom layer of POME after settling. This indicates that solid particles impede the movement of oil droplets, effectively trapping them and preventing them from rising to the surface for recovery. Understanding this mechanism is crucial for developing effective oil recovery technologies.

What are the primary reasons for oil loss in palm oil mill effluent (POME), and what are the implications for the palm oil industry?

Small oil droplet sizes and the adsorption of oil onto fiber particles are the primary reasons for the presence of residual oil and subsequent oil loss in POME. Addressing these factors through innovative oil recovery technologies can transform POME from a problematic waste stream into a valuable resource, promoting sustainability and economic benefits for the palm oil industry. This could involve developing methods to destabilize the oil-in-water emulsion and prevent the adsorption of oil onto solid particles.