Differences between CPO and CPKO Waste
The palm oil industry has two main processing lines: the production of CPO (Crude Palm Oil) and the production of CPKO (Crude Palm Kernel Oil). Although both come from oil palm fruit, they are produced through different processing routes.
- CPO is produced from the palm fruit flesh (mesocarp).
- CPKO comes from the palm kernel after cracking and pressing processes.
Because the processes are different, the resulting wastewater also has different compositions and treatment challenges.
2. Sources of CPO and CPKO Wastewater
Each processing stage generates wastewater with different characteristics. Understanding the source of the wastewater helps determine the appropriate treatment technology.
Table: Sources of CPO vs CPKO Wastewater
| Wastewater Source | CPO | CPKO |
| Fruit / raw material washing | Yes | Yes |
| Sterilization | Yes | No |
| Digesting & Pressing | Yes | Yes |
| Clarification | Yes | No |
| Nut / Kernel processing | No | Yes |
| Hydraulic press / expeller | No | Yes |
| Scrubbing & polishing | Common | Common |
These differences in wastewater sources cause variations in organic content and oil concentration.
3. Differences in CPO vs CPKO Wastewater Characteristics
Table: Characteristics of CPO and CPKO Wastewater
| Characteristic | CPO Wastewater | CPKO Wastewater |
| Oil & Grease (O&G) | Very high | Medium |
| COD/BOD | Very high (8,000-20,000 mg/L) | Medium-high |
| pH | Acidic (3-5) | More stable |
| Surfactants / Emulsions | Low | Higher (due to washing & degumming processes) |
| Organic solids | High | Lower |
| Odor | Strong (due to organic degradation) | Milder |
| Putrefaction potential | Very high | Medium |
Brief Explanation
- CPO → rich in organic matter from the mesocarp, making it more prone to putrefaction and resulting in high COD/BOD loads.
- CPKO → contains more surfactants, emulsifiers, and residual kernel oil, making it harder to separate physically and more dependent on chemicals.
Compliance Challenges for Both Types of Wastewater
CPO and CPKO wastewater have different levels of difficulty in meeting discharge standards:
CPO Wastewater Challenges
- COD and BOD are very high
- Organic sludge decomposes quickly (septic)
- Biological processes require stable aeration
- O&G dominates, causing excessive floating
CPKO Wastewater Challenges
- Surfactants and emulsions are difficult to break
- Interfere with DAF and coagulation processes
- Require specific chemicals
- Significant fluctuation in wastewater characteristics between batches
Therefore, the design of a palm oil mill WWTP must consider both wastewater characteristics.
Wastewater Treatment Technologies for CPO and CPKO
There is no single technology suitable for all conditions. A combination of physical, chemical, and biological processes is usually required.
Table: Common Technologies for CPO and CPKO Wastewater
| Technology | CPO | CPKO | Remarks |
| Oil Trap | Yes | Yes | Effective for free oil |
| Coagulation-Flocculation | Moderate | Very important | CPKO is more “chemical-dependent” |
| DAF | Common | Highly recommended | For surfactants & emulsions |
| Anaerobic (CSTR / UASB) | Very effective | Common | Produces biogas |
| Biological aeration | Important | Important | Clarified water flows to subsequent processes |
| MBR / Filtration | Polishing option | Polishing option | For strict effluent targets |
Key Explanation
- CPO wastewater is highly suitable for anaerobic processes due to its high organic content → large biogas potential.
- CPKO wastewater requires chemical + DAF treatment to break emulsions before entering biological processes.
Selecting the right technology greatly influences operational costs.
Modern WWTP Trends in Palm Oil Mills
The palm oil industry is moving towards:
- Zero Discharge
- Sludge load reduction
- Biogas utilization for energy
- Combination of MBBR + DAF
- Use of modular bolted tanks for fast installation
- AOP for polishing color & hard-to-degrade emulsions
These trends are emerging due to stricter regulations and increasing demands for energy efficiency.
Although both originate from the palm oil industry, CPO and CPKO wastewater have very different characteristics, especially in terms of oil, surfactants, emulsions, and organic levels. These differences mean that their treatment systems cannot be made identical. A successful WWTP must be able to combine multiple processes, from physical and chemical to biological, tailored to each wastewater source.
If you need wastewater characterization studies, WWTP design for palm oil mills, process optimization, or integration of technologies such as anaerobic, DAF, or MBR, PJL Enviro can provide technical solutions designed to meet your capacity needs and regulatory requirements.
