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Treatment of Palm Oil Mill Sludge: A Comparative Analysis of Co-Treatment and Separate Processing with Regional Insights from Southeast Asia
Treatment of Palm Oil Mill Sludge: A Comparative Analysis of Co-Treatment and Separate Processing with Regional Insights from Southeast Asia
14 May 2025
Palm oil mill sludge (POMS) management remains a critical challenge for the palm oil industry, particularly in major producing countries like Thailand, Malaysia, and Indonesia. POMS typically consists of two distinct types: flocculant-laden sludge (generated from chemical coagulation processes in wastewater treatment) and flocculant-free sludge (derived from primary settling tanks). This article explores the technical and operational considerations for co-treating or separately processing these sludge streams, alongside regional practices and future sustainability trends, with a focus on integrating innovative technologies like TDG TIC Technology’s disc-type sludge drying technology for enhanced efficiency.
1. Characteristics and Classification of POMS
1.1 Flocculant-Laden Sludge
This sludge type contains synthetic polymers (e.g., polyacrylamide-based flocculants) used to enhance solid-liquid separation in wastewater treatment plants (WWTPs). Key characteristics include:
1.2 Flocculant-Free Sludge
Generated from primary sedimentation, this sludge is rich in organic matter (e.g., fibers, oils) and nutrients (N, P, K). It exhibits:
2. Co-Treatment vs. Separate Processing
2.1 Co-Treatment Approach
Mixing both sludge types simplifies handling and reduces operational costs. Common co-treatment methods include:
2.2 Separate Processing
Targeted treatment maximizes resource recovery and minimizes environmental risks:
3. Regional Analysis in Thailand, Malaysia, and Indonesia
3.1 Thailand
Thailand currently has about 60 oil palm crushing mills and over 20 refineries. Around 33 large palm oil crushing mills are treating palm oil mill effluent (POME). The ponding system is the most common treatment method due to its low cost and simplicity, which includes anaerobic ponds, aerobic ponds, and settling ponds. However, this system requires large areas of land and long processing times. In recent years, some mills have started adopting anaerobic digesters for wastewater treatment, which can produce biogas to meet part of the mill's energy needs. Additionally, a few mills are also exploring advanced technologies like the integrated anaerobic-aerobic bioreactor (IAAB) and photocatalytic technology to improve treatment efficiency and meet environmental regulations.
3.2 Malaysia
Malaysia currently has around 400-450 oil palm mills. About 85% of these mills are treating palm oil mill effluent (POME) using the ponding system which involves biological treatments of facultative, anaerobic and aerobic processes. Around 45% of the mills are using the aerobic activated sludge process as a polishing treatment after anaerobic treatment. Some mills are also exploring advanced technologies like membrane bioreactors (MBR) and electro-coagulation to further improve treatment efficiency. However, the ponding system remains the dominant method due to its low construction and operation costs, as well as easy maintenance.
3.3 Indonesia
Indonesia has more than 700 palm oil mills. Most of them are treating palm oil mill effluent (POME), with the open pond system being the dominant method due to its low cost and simplicity. This system includes anaerobic ponds, aerobic ponds, and settling ponds. However, it requires large areas of land and long processing times. Some mills are also exploring alternative technologies like anaerobic digesters and photocatalytic technology to improve treatment efficiency.
4. Future Directions
4.1 Technological Innovations
4.2 Policy and Economics
4.3 Research Priorities
5. Conclusion
The palm oil industry must transition from reactive sludge disposal to proactive resource management. While co-treatment offers operational simplicity, separate processing with advanced technologies like TDG TIC Technology’s disc-type sludge drying provides a targeted solution for flocculant-laden sludge, addressing toxicity and disposal challenges efficiently. In Southeast Asia, scaling up energy-integrated drying systems, adopting bio-based flocculants, and strengthening policy frameworks are critical to achieving sustainable sludge management. By integrating technological innovation with regional collaboration, the industry can mitigate environmental liabilities while unlocking economic opportunities in waste valorization.