Palm Oil Mill Effluent (POME) Treatment in Southeast Asia: Practical Solutions for Sustainable Compliance

The POME Wastewater Challenge in Southeast Asia

Palm oil is a cornerstone of Southeast Asia’s economy, with Indonesia and Malaysia leading global production and Thailand also contributing significantly. Alongside this growth is a persistent environmental challenge: palm oil mill effluent, or POME, the high-strength wastewater generated by palm oil mills. Each tonne of crude palm oil (CPO) requires large volumes of water (often 5–7.5 tonnes of water per tonne of CPO), and more than half of that ends up as POME. The result is millions of tonnes of POME produced annually across Southeast Asia’s mills – a palm oil mill wastewater pollution problem on a vast scale.

Beyond water pollution, POME wastewater treatment in Southeast Asia has another critical dimension: climate impact. When POME is stored in open ponds, it decomposes anaerobically and releases methane – a greenhouse gas with a global warming potential roughly 25–30 times higher than carbon dioxide. In fact, one study estimates that the global methane emissions from POME could be around 600 million cubic meters per year, contributing significantly to the industry’s carbon footprint. Left unchecked, a single mill’s open effluent pond can emit thousands of tonnes of CO₂-equivalent annually just from methane. This not only undermines sustainability goals but also represents a lost opportunity, because that methane can be captured and used as energy. Clearly, treating POME effectively is not just about meeting regulations – it’s about protecting waterways, communities, and the climate.

This article will explore palm oil effluent management in Malaysia, Indonesia, and Thailand, examining why current practices often fall short and what new solutions are available. We’ll look at the best ways to treat POME, from improved pond systems to advanced biogas recovery, and how real-world mills are phasing in these technologies. Crucially, we will focus on practical, low-cost POME treatment solutions and phased approaches that mill operators and sustainability officers can implement, even with limited budgets.

(Keep reading to learn how innovative technologies and strategies are transforming POME wastewater from a liability into an asset. If you’re looking for hands-on solutions, you’ll also find clear steps and even modular options that companies like Bluewater Lab offer to tackle POME sustainably.) Explore Bluewater Lab’s modular treatment systems to see how your mill could turn effluent into value.

Ponding Systems: The Dominant but Limited Practice

Step into virtually any palm oil mill in Indonesia or Malaysia, and you’re likely to see vast lagoons or ponds of murky brown liquid. These are ponding systems, the traditional method for POME wastewater treatment in Southeast Asia. By some estimates, about 85% of palm oil mills use open pond or lagoon systems to manage POME. The reasons are understandable: ponding is simple in design, relatively low-cost, and requires little in the way of mechanical equipment or skilled operation. Mills pipe their hot effluent into a series of earth ponds and let natural microbial processes break down the organic matter over time. In theory, after sufficient retention time in anaerobic, facultative, and aerobic ponds, the POME’s BOD and COD are reduced to acceptable levels before discharge.

However, this simplicity comes with major drawbacks. Ponding systems require long treatment times and huge land areas to be effective. A typical pond system might need a total hydraulic retention time of 10–30 days or more, meaning the wastewater sits for months to achieve substantial treatment. To accommodate that retention, a large mill may devote 5–20 acres (12–18 hectares) of land just for effluent ponds – about the size of 3 to 15 football fields. In rapidly expanding palm oil regions, such land hunger for waste treatment is increasingly untenable.

Even with all that time and space, open pond systems often struggle to meet stringent discharge standards. They can reduce organics to a degree, but typically not much beyond basic regulatory limits, and certain pollutants persist. For example, anaerobic ponds remove a lot of BOD but cannot fully eliminate the dark color of POME or certain nutrients. Many pond systems barely meet minimum standards and would not comply if regulations tighten. As one Malaysian report noted, even as new techniques emerge, the Department of Environment (DOE) has difficulty ensuring pond systems can fulfill more stringent effluent discharge limits.

The environmental downsides of the open ponding system are also significant. These ponds are essentially shallow anaerobic digesters open to the air. They emit large volumes of methane directly into the atmosphere during the natural decomposition of POME. Methane not only contributes to global warming, it often gives off a strong, rotten smell – meaning communities near mills face odor pollution in addition to the risk of water contamination. Furthermore, maintaining consistent treatment in ponds is tricky: heavy rains (common in Southeast Asia) can cause ponds to overflow, flushing raw effluent into rivers. Droughts can upset the microbial balance. In short, conventional ponding is easy but inefficient – a stop-gap solution from an earlier era that is now showing its limitations.

Pressures to Change: Regulations and Market Drivers

Why should mill operators invest in better POME treatment if ponds are so cheap and easy? The answer: mounting regulatory and market pressures are making the status quo unsustainable. Governments and industry bodies in Southeast Asia are increasingly cracking down on POME pollution and encouraging (or mandating) cleaner practices. At the same time, market forces – from sustainability pledges to carbon credit opportunities – are pushing mills toward modern solutions. Let’s break down these drivers in Malaysia, Indonesia, and the region at large:

Stricter Environmental Regulations: Environmental authorities are tightening discharge standards for palm oil effluent. In Malaysia, for instance, regulations limit the permissible BOD in treated effluent (historically 100 mg/L for land application and lower for river discharge), and there’s pressure to reduce it further. Since 2014, the Malaysian Palm Oil Board (MPOB) has even mandated that all new palm oil mills install biogas capture facilities for POME treatment, as well as existing mills that seek to expand their throughput. This policy essentially forces mills to go beyond open ponds – at least by adding methane capture – if they want approval to operate or grow. While enforcement has its challenges (Sarawak state, for example, initially struggled with implementation due to lack of power grid access for biogas power), the direction is clear: future mills are expected to contain POME’s pollution, not just dump it in ponds.

Indonesia, the world’s top palm oil producer, is also ramping up requirements. The Indonesian Sustainable Palm Oil (ISPO) standard includes environmental management of POME, and provinces have started to enforce pollution limits more strictly. In practice, Indonesian regulations are moving toward compelling mills to treat POME to specific standards (for example, COD and BOD limits for effluent discharge) and to capture methane where possible as part of climate commitments. While not yet as uniformly mandated as in Malaysia, many Indonesian mills have felt the nudge – especially those supplying multinational companies concerned about sustainability reputations.

Sustainability and Certification Standards: Market-driven certification schemes like the Roundtable on Sustainable Palm Oil (RSPO) further raise the bar. RSPO’s criteria call for environmental responsibility, which includes proper waste management. Members (including major plantation companies) must report greenhouse gas emissions (Such as carbon dioxide, Methane and Nitrous oxide) and have plans to reduce them. Palm oil effluent management in Malaysia, Indonesia and beyond has thus become part of sustainability scorecards. Companies seeking RSPO certification or simply aiming to meet their own ESG (environmental, social, governance) goals are investing in better POME treatment to demonstrate compliance with international best practices. For instance, Musim Mas, a large Indonesian palm oil company, has equipped 17 of its mills with methane capture facilities and reports cutting hundreds of thousands of tones of CO₂-equivalent emissions per year as a result. This not only helps the environment but is also a selling point to eco-conscious buyers.

Economic Incentives – Energy and Carbon Value: On the flip side of stricter rules and green mandates, there are carrots: opportunities to monetize POME if treated properly. Chief among these is energy. POME is essentially a broth of organic matter, biogas from POME (which contains about 6 kWh per cubic meter) represents a significant renewable energy source with substantial power generation potential. If that energy is harnessed (for example, by capturing biogas), mills can generate electricity or thermal energy, offsetting their own energy costs or even selling power to the grid. Malaysia has explicitly encouraged this with a Feed-in-Tariff (FiT) for renewable energy. Under Malaysia’s FiT, mills that install biogas power plants can sell electricity to the national utility at premium rates (around RM 0.40–0.46 per kWh). Many mills in Peninsular Malaysia and Sabah have jumped on this, signing Renewable Energy Power Purchase Agreements for 16–21 years to guarantee income from biogas power.

Another incentive is the carbon market. Reducing methane emissions from POME can earn mills carbon credits under voluntary carbon standards or future compliance markets. Methane capture projects were popular under the Kyoto Protocol’s Clean Development Mechanism and continue today in forms like the Gold Standard or Verra’s programs. The logic is simple: if you prevent (or flare) methane that would otherwise escape, you generate emission reductions that can be sold. With growing demand for high-quality carbon credits, biogas from palm oil mill effluent is now seen as a prime opportunity. One analysis estimated that capturing methane from a single average mill’s POME could yield on the order of 150,000 tonnes of CO₂-equivalent reduction per year, which (at ~$10 per credit) translates to about $1.5 million in potential annual revenue. Even after accounting for project costs, that can significantly improve the return on investment for POME treatment projects. In practice, some mills have already registered projects that earn carbon credits for methane reduction or for the renewable energy generated by POME biogas.

In summary, doing nothing about POME is no longer the cheapest or safest option. Regulators are tightening the screws, buyers are demanding sustainability, local stakeholders expect responsible practices, and there’s money to be made (or saved) by treating POME as a resource. For mill operators and sustainability officers, the message is clear: it’s time to modernize POME treatment. The good news is that a range of technologies – from improved anaerobic systems to advanced aerobic polishing – are available to meet these needs. In the next sections, we’ll compare viable POME treatment technologies and how they can be phased in to upgrade your mill’s effluent management.

Need expert help navigating these options? Bluewater Lab’s team can assist in planning upgrades, from biogas capture to modular treatment units, tailored to Southeast Asian mills.

Modern POME Treatment Technologies: Best Ways to Treat POME

With pressure to act, what are the best ways to treat POME today? Fortunately, palm oil producers have more options than ever before. From capturing valuable biogas through anaerobic digestion for POME to using aerated lagoons and activated sludge systems for cleaner effluent, new technologies promise both environmental compliance and added revenue. Even small and remote mills, which historically found advanced treatment impractical, can now consider modular POME treatment systems in Southeast Asia that are scaled to their needs In this section, we’ll compare the most viable POME treatment technologies and management approaches being adopted across Malaysia, Indonesia, Thailand and beyond.

Anaerobic Digestion and Biogas Recovery: Turning Waste into Energy

One of the most transformative solutions for POME is anaerobic digestion (AD) with biogas recovery. Anaerobic digestion involves processing POME in sealed reactors or covered lagoons where microbes break down organic matter in the absence of oxygen, producing biogas (a mixture of methane and CO₂). This is essentially mimicking and optimizing what happens in an open pond, but in a controlled environment that captures the methane instead of letting it escape. Given POME’s high organic load, it is exceptionally well-suited for biogas production – as one industry source puts it, “POME is an excellent substrate for renewable biogas production”. When POME decomposes anaerobically, it naturally generates biogas; biogas from palm oil mill effluent is thus a readily available resource if we design systems to collect it.

Among the technologies used to harness this process, two reactor types are especially common: the Continuous Stirred Tank Reactor (CSTR) and the Upflow Anaerobic Sludge Blanket (UASB). A CSTR maintains uniform conditions by continuously mixing the contents, which helps prevent settling and ensures more consistent digestion. It’s especially effective for thick, homogeneous sludges like raw POME. UASB reactors, on the other hand, allow wastewater to flow upward through a dense bed of anaerobic sludge granules. As the effluent rises, microbes digest the organics and biogas bubbles to the top. UASBs are known for their compact footprint and high efficiency, particularly in pre-treated or diluted POME streams. Both systems are proven technologies that, when properly maintained, can significantly reduce organic loading while generating usable renewable energy.

The benefits of anaerobic digestion for POME are manifold:

• Energy Generation: The biogas (typically ~50–70% methane) can be used as a fuel. Mills can channel biogas to generator sets (gas engines) to produce electricity, or to boilers to generate steam for the mill’s operations. How much energy are we talking about? Studies show that 1 cubic meter of POME can yield roughly 28 m³ of biogas, containing about 15 m³ of methane. In practical terms, a medium-sized mill (say processing 30–60 tons of FFB per hour) can produce tens of thousands of cubic meters of biogas per day. For example, a 60 ton/hour mill might generate on the order of 30,000–50,000 m³ of biogas daily, enough to fuel a ~1 to 2 MW electric power plant.
• Waste Reduction and Treatment Efficiency: Anaerobic digestion dramatically lowers the BOD and COD of POME by converting organics into biogas. High-rate digesters can remove 85–95% of COD in POME before the effluent even moves to further treatment. This reduction makes it much easier (and faster) to meet discharge standards with a subsequent aerobic step. Some mills have implemented Integrated Anaerobic-Aerobic Bioreactors (IAAB) – essentially an anaerobic digester followed by an aerobic treatment in one system and achieved substantial treatment in a fraction of the time required by ponds. Even simpler covered lagoon systems, while less efficient than concrete or steel digesters, still achieve a big drop in BOD. The net effect is that AD greatly shortens the treatment timeline and reduces the land footprint needed, because much of the work is done in an engineered tank or covered pond with higher loading rates than open ponds. For instance, replacing an open lagoon with an enclosed digester can cut retention time from 100 days to perhaps 20 days for the anaerobic phase, enabling a far more compact layout.
• Operational and Local Benefits: Anaerobic digestion, especially when done in closed reactors or covered lagoons, results in better odor control. The sealed systems prevent the rotten-egg smell of anaerobic breakdown from wafting through nearby communities. Also, the residual sludge from digesters is rich in nutrients and partially stabilized; it can be further processed into organic fertilizer or compost, contributing to a circular economy approach (some mills mix this digestate with empty fruit bunches to make compost). Additionally, capturing biogas can improve safety – it eliminates the risk of methane accumulation in open ponds causing fires or explosions (rare but reported in some uncovered lagoon systems with trapped biogas pockets).
   

Given these advantages, it’s no surprise that anaerobic digestion for POME has been gaining momentum in Southeast Asia. Technologies in use include covered lagoon systems (the lowest-cost retrofit: stretching an impermeable membrane cover over existing ponds to trap biogas) and tank-based digesters (such as Continuous Stirred Tank Reactors, Up flow Anaerobic Sludge Blanket reactors, and expanded granular sludge bed systems). Covered lagoons are popular for retrofits and have been successfully deployed at many mills – for example, Cenergi, a renewable energy developer in Malaysia, has implemented numerous covered lagoon biogas projects under build-own-operate deals. These typically involve an HDPE geomembrane cover floating on the pond, creating an anaerobic “digester” that captures gas which is then piped to an engine or flare.

What about the cost? While any new treatment plant is an investment, the cost-benefit of biogas recovery is compelling. Revenue streams from electricity, heat substitution (using biogas instead of diesel), and carbon credits can potentially pay back the capital in a reasonable period.

In short, capturing biogas from palm oil mill effluent is often the smartest first step in upgrading POME treatment. It tackles the biggest environmental impacts (GHGs and BOD) and creates value. For mills in Southeast Asia, implementing anaerobic digestion can be seen as moving POME management into a win-win phase: waste becomes worth something.

Interested in leveraging biogas at your mill? Bluewater Lab can design and implement modular anaerobic digestion systems (including covered lagoon kits or compact digester units) to fit mills of various sizes.

Aerated Lagoons and Activated Sludge: Boosting Treatment for Cleaner Effluent

While anaerobic digestion addresses a large part of the POME problem, it usually isn’t the whole story. The liquid coming out of an anaerobic process (often called “POME permeate” or digester effluent) still contains residual organics, nutrients like ammonia, and that persistent dark color . To meet strict discharge standards (especially low biochemical oxygen demand or nutrient limits) aerobic treatment is usually required as a polishing step. This is where aerated lagoons and activated sludge systems come into play as effective solutions for medium-scale operations or as a second stage in larger ones.

Aerated Lagoons are essentially ponds or basins in which mechanical aerators (surface aerators, diffusers, or jet aerators) supply oxygen to the wastewater. By bubbling air through the POME, they support aerobic bacteria that further break down organic pollutants, converting them into CO₂, water, and biomass. Many mills have added aeration to some of their ponds to improve treatment. For example, after initial anaerobic ponds, a mill might have a series of aerated lagoons for 1–15 days to reduce BOD and nitrify ammonia. Aerated lagoons are simpler than fully engineered activated sludge plants but still significantly speed up oxidation of remaining organics compared to passive ponds. They are a middle-ground solution: more effective than unaerated ponds, but less complex than concrete tank systems.

The limitation of plain aerated lagoons is that they require more energy (for aerator motors) and can be less efficient than purpose-built reactors. This is why some operations opt for Activated Sludge Systems for POME, especially when high performance is needed in a smaller footprint. An activated sludge system involves an aeration tank where wastewater is vigorously aerated and mixed with a population of microbes (the “sludge”), followed by a settling tank (secondary clarifier) where biomass settles out, producing a clear effluent. The settled biomass is partly recycled to the aeration tank to maintain a high concentration of microbes, while the remainder, known as waste‑activated sludge (WAS), is withdrawn from the system and sent on to sludge‑handling steps such as thickening, digestion or dewatering before final disposal or beneficial use. Activated sludge is a standard in municipal sewage treatment and can achieve very low BOD (<20 mg/L) if designed right. In the palm oil industry, conventional activated sludge or variations like Sequencing Batch Reactors (SBR) have been used as a polishing step after anaerobic treatment. For instance, one study reported that post-treating anaerobically digested POME with an SBR achieved about 96% further COD removal and 99% BOD removal in under 24 hours. This brought the effluent to well within discharge limits, illustrating that combining anaerobic + activated sludge can produce high-quality effluent.

Key advantages of aerobic systems include:

• High Treatment Efficacy: Aerobic processes excel at polishing BOD to very low levels, and they can also nitrify ammoniacal nitrogen (converting ammonia to nitrate), which anaerobic systems cannot do. If regulations demand control of nitrogen or stricter BOD/COD, an aerobic step is essential. They also can tackle certain residual organics that cause color and odour. Some mills use activated carbon or coagulant additives in an activated sludge process to help strip out the brown tint from lignin/tannin compounds, yielding a much clearer effluent.
• Faster Throughput: Compared to passive ponds, aerated systems achieve results in days instead of months. As noted, an SBR can polish POME in a single day, and even larger continuous systems might need just a few days of retention. This dramatically reduces the land area needed for the polishing stage or allows a higher flow to be treated in the same space.
• Modularity and Scalability: Aeration tanks or SBR units can often be built in modules and scaled according to need. A mill could start with one or two units and add more if production increases. There are even containerized aerobic treatment units available that can be delivered and installed with minimal civil works – although these are more common for lower flows (they might be suitable for small mills or for treating the final portion of effluent after main treatment).
   

However, there are considerations: aerobic treatment is energy-intensive – running blowers or aerators continuously will increase the mill’s power usage (though this can be mitigated by using some of the biogas power). It also generates biological sludge (waste biosolids from microbial growth) that needs to be managed, typically dewatered and composted or used as fertilizer. This sludge management is an added operational task, though in palm mills it can often be co-composted with solid wastes like empty fruit bunches.

A specific approach gaining attention is the Integrated Anaerobic-Aerobic Bioreactor (IAAB) mentioned earlier. IAAB is basically a hybrid system where POME flows through an anaerobic reactor and then immediately into an attached aerobic reactor in series, sometimes within one combined structure. Malaysian researchers and engineers have developed IAAB designs that reportedly achieve high efficiency with relatively compact size. These systems can reduce COD/BOD to compliant levels often in less than two weeks total residence, much faster than ponding. IAABs require initial investment but can be a good solution for mills that want a proven, turn-key upgrade from an all-pond system to a modern treatment plant without piecemeal retrofitting.

In summary, aerated lagoons and activated sludge systems serve as the workhorses of POME polishing. For many mills, the optimal configuration is anaerobic pre-treatment (for methane capture and bulk BOD removal) followed by an aerobic step to finish the job. This combined approach yields a treated effluent that can meet government discharge standards or even be reused for irrigation or plant washing (after some further tertiary treatment perhaps). It’s a strategy that balances energy recovery and water quality compliance.

Modular and Shared Systems for Small Mills

Not all palm oil mills are giant operations with deep pockets. In Indonesia and Malaysia, many mills are independent or associated with smallholder cooperatives, processing lower volumes (perhaps 5–15 tons FFB per hour) and operating on tight margins. These mills face the same environmental pressures but often lack the scale to justify large, custom-built treatment plants. Here is where modular POME treatment systems in Southeast Asia are emerging as a game-changer, enabling even small mills to adopt effective wastewater solutions.

Modular systems are essentially pre-engineered, packaged treatment units that can be delivered to site and bolted on with minimal customization. They might include prefabricated tanks, skid-mounted biogas digesters, containerized aerobic reactors, or even mobile treatment units. The idea is to provide a “plug-and-play” POME treatment solution that can be rapidly deployed, with lower upfront cost and easier operation.

For small mills, there are a few ways this modular approach can manifest:

• Packaged Anaerobic Digesters: Instead of building large ponds or expensive concrete digesters, a small mill could install a modular digester unit. For example, a covered tank digester designed to handle, say, 100–200 m³ of POME per day could be prefabricated and installed near the mill. Some companies are now marketing CSTR digesters in steel tanks that come in sections and can be erected on-site quickly. These digesters might use high-rate bacteria or include membrane separation inside to allow higher loading. The footprint is small – important for mills that don’t have huge land areas. And they can be delivered with biogas engines sized appropriately (maybe a 200 kW genset instead of multi-megawatt). The modular nature also means they can be relocated or scaled (by adding more modules) if the mill’s capacity grows.

• Shared Biogas Facilities: In regions with clusters of small mills, a novel concept is a centralized or shared POME treatment facility. Instead of each mill investing in its own plant, several mills could jointly use one larger facility. This could be organized by the mills collectively or by a third-party company. For instance, a developer could build a biogas plant at a strategic location and either pipe POME from nearby mills to it, or truck in concentrated POME (some processes can concentrate the COD in POME by decanting water first). While piping raw POME is challenging due to its high water content and potential to go septic quickly, some pilot projects have explored it for mills in proximity. Alternatively, mills could pre-treat and transport the sludge portion. If logistics can be solved, a shared facility enjoys economies of scale – it might justify a bigger, more efficient digester and a larger generator that is economically attractive, whereas the mills on their own couldn’t reach that scale. In Sabah (East Malaysia), for example, there have been initiatives to create central biogas facilities where the power generated is fed into the grid, effectively turning multiple small mill wastes into one profitable operation (with revenue shared or fees paid by mills).

• Modular Aeration Units: Similarly, small mills can use compact aeration systems to polish effluent. One example is packaged extended aeration tanks or SBRs in container form. A 40-foot container can house an SBR that treats maybe 50–100 m³/day of wastewater. These systems come with integrated controls and aeration equipment. For a small mill, a couple of such units might handle their flow. They are insulated from weather and can be monitored remotely, which is helpful if local expertise is limited. Think of it like a mini sewage treatment plant in a box, but tuned for POME characteristics. Another modular solution is constructed wetlands or biofilter units – these require more land, but some designers have modules where POME flows through a series of tanks with attached growth media for microbes or through reed beds, etc., which can be assembled in modular fashion.

   

The advantages of modular and shared systems for smallholder mills include lower capital barriers and faster implementation. They often come with more standardized designs, which means lessons learned in one deployment carry to the next, reducing technical risk. They also tend to be less operator-dependent – a pre-packaged system might have automated controls, IoT sensors (some even offer remote monitoring dashboards), and simplified maintenance routines provided by the vendor. This is crucial for mills that do not have environmental engineers on staff. For instance, Bluewater Lab’s approach in the region has been to combine IoT monitoring with modular treatment units, so that even a small facility can be supervised and optimized with smart technology, ensuring efficient palm oil effluent management in Malaysia and Indonesia without requiring full-time on-site experts.

One notable benefit of sharing or third-party operated modular systems is financial flexibility. If a mill cannot afford the equipment, a third party might install it and charge a fee or share savings (like an “effluent treatment-as-a-service” model). Build-Operate-Transfer (BOT) schemes, discussed more later, align well with modular setups because the equipment can be more easily transferred or managed if it’s standardized and skid-mounted. In Indonesia, we’ve seen mills openly solicit for BOT partnerships to implement methane capture – essentially saying, “come build a biogas plant at our mill, use our POME, share the benefits”. Modular systems make it easier for service providers to replicate these deals across multiple small sites.

Of course, modular doesn’t mean magic. These systems must still handle the high strength of POME and deal with issues like oil and grease in the water (which can foul membranes or media if not managed) and variability in flow. But ongoing innovations are making them more robust. For example, some modular digesters include pre-treatment like an oil separator or mixing tank to even out the feed. Some containerized systems incorporate membranes to filter the treated water for reuse. In fact, water reuse is a big carrot for small mills: if they can recycle treated water for mill processes (sterilizer steam, cleaning, etc.), they reduce their freshwater consumption. A small mill in a water-scarce area of Indonesia noted that after installing a biogas plant, they were interested in using the final effluent for land application or even recycling, especially during dry seasons when water supply was short. Modular treatment units that produce higher quality effluent (e.g. through aerobic polishing and filtration) can enable such reuse, which is an extra benefit.
 

In conclusion, modular POME treatment systems offer a lifeline to the often overlooked smaller mills. They embody the principle that no mill is too small to be sustainable. By scaling technology to the right size and sharing resources where feasible, even independent mills in remote corners of Sumatra or Borneo can escape the trap of polluting ponds. The wastewater challenge can be met with creativity and the right partnerships.

If you operate a smaller palm oil mill and worry that advanced POME treatment is out of reach, think again. Bluewater Lab specializes in modular, scalable solutions that can be deployed at mills of all sizes, helping you comply with regulations and tap into energy generation without breaking the bank.

From Ponds to Profit: Phased Retrofit Strategies for Mill Upgrades

Upgrading a palm oil mill’s effluent treatment doesn’t happen overnight – nor does it have to be an all-or-nothing proposition. In many cases, the most practical approach is a phased retrofit strategy: stepwise improvements to the existing system that gradually turn an old pond setup into a modern treatment facility. Southeast Asian mills, especially those already running, often choose this path to manage costs and minimize downtime. Here’s how a phased approach to POME treatment typically works:

Phase 1: Cover the Ponds (Methane Capture Quick Win). The first and easiest upgrade is to convert existing anaerobic ponds into biogas digesters by installing floating covers. This involves laying a durable HDPE or polypropylene membrane over the pond’s surface and anchoring it around the edges. The cover traps biogas produced by POME digestion, which can then be sucked out via pipes. Simply covering a pond instantly cuts methane emissions by up to 80% or more (since most methane will be captured) and eliminates the direct venting of biogas to the air. It also helps with odour control – one project in Malaysia reported that after covering their lagoon, there was no more unpleasant methane smell and no gas bubbling out; all that gas was being collected for use. This phase can be done relatively quickly (weeks to a few months) and at moderate cost, especially compared to the benefits of emissions reduction and potential energy use. If a mill isn’t ready to use the biogas yet, they can simply flare it off to destroy methane (flaring is cheap and was commonly done under CDM carbon projects to earn credits). But many will choose to immediately set up a basic biogas boiler or genset to start getting energy. Even a simple biogas flare system with a gas blower and torch is a low-cost POME treatment solution in the interim, as it addresses the greenhouse gas issue.

Phase 2: Biogas Utilization (Energy Recovery). Once the gas is being captured, the next phase is to monetize that biogas. This could mean installing a biogas engine to produce electricity, or modifying the mill’s boiler to co-fire biogas for steam generation. The scale of this depends on the mill size and the gas volume from Phase 1. For instance, if Phase 1 covered one or two ponds, it might capture, say, 300–500 m³ of biogas per day initially. The mill could start with a small generator (100 kW or so) just to power some part of the operations. As they cover more ponds or optimize, gas production can ramp up and additional generator modules can be added (many installations use multiple engine gensets for flexibility). The phased approach to biogas power is prudent: start with a modest investment and expand as confidence and gas flow grow. During this phase, mills often seek partnerships or financing – for example, signing a Power Purchase Agreement (PPA) with the utility or a private off taker if they will export electricity. As noted earlier, developers like Cenergi or others will sometimes finance and operate the gensets if they get a share of the tariff; for the mill, this means getting a biogas plant with little upfront cost, just by committing their POME and land.

Phase 3: Aerobic Polishing (Meeting Discharge Standards). With anaerobic digestion and biogas usage in place, the effluent’s major pollution load is reduced – but it’s not yet typically clean enough to discharge. The next phase is to add an aerobic or other polishing treatment to reach the required effluent quality. Depending on the mill’s situation, this could be done by converting one of the existing ponds into an aerated lagoon (e.g., installing surface aerators in what might have been a secondary or tertiary pond), or building a new activated sludge tank or trickling filter. Sometimes a portion of the pond system is repurposed: for example, the first ponds get covered (Phase 1), and later ponds are retrofitted with aerators. This phased construction allows the mill to keep treating wastewater throughout – you cover a pond while others remain open for treatment; later you aerate a different pond while the digesters handle the base load. Aeration can be introduced gradually: maybe start aerating one pond and observe improvement, then scale up. The aim in Phase 3 is to consistently achieve final discharge parameters like BOD < 20 or 50 mg/L (as required), minimal suspended solids, and perhaps certain nutrient or color reduction if mandated. If regulations demand it, this phase might also include setting up settling tanks or clarifiers to remove biomass (if using activated sludge) and perhaps even a simple sand filter or constructed wetland for tertiary polishing. By the end of this phase, the POME should no longer be a “persistent wastewater challenge” but a treated water stream that can be safely released or reused.

The beauty of a phased approach is flexibility. A mill can stop at a certain phase if it meets their needs. For example, some mills might do Phase 1 and 2 (capture and use biogas) and find that their existing ponds with a bit of aeration are enough to meet current standards – they may postpone a full Phase 3 upgrade until regulations tighten further. Others may rush Phase 3 because they sit near sensitive ecosystems and need top-notch effluent quality, but they might delay Phase 2 if power sales aren’t lucrative (maybe just flaring methane in the meantime). Phasing allows tailoring the investment to the immediate drivers while keeping future options open.

Crucially, phasing also helps with financial planning and risk management. Each step can often be financed separately – e.g., carbon credit revenue from Phase 1 can help fund Phase 2; energy savings from Phase 2 can help justify a loan for Phase 3, and so on. It also means you can show quick wins early (like reduced odour and GHG in Phase 1, which can build stakeholder support for the project) and learn as you go, optimizing design for later phases based on real performance data from early ones.

Bluewater Lab can help to create step-by-step retrofit roadmaps, and supplies modular components to help you implement improvements one phase at a time.

Real-World Success: Case Study of POME Treatment Transformation

To show how these strategies play out on the ground, here are two case studies from Malaysia and Indonesia that demonstrate how palm oil mills are turning POME from a liability into a valuable resource.

Case Study: From Wastewater to Watts in Sabah, Malaysia

A mid-sized palm oil mill in Sabah processed about 300,000 tons of FFB annually, generating around 200,000 m³ of POME. Like many, it relied on open ponds and faced frequent methane emissions and discharge issues, especially during the rainy season. Following the 2014 MPOB mandate and plans to expand, the mill began retrofitting in 2018 with a renewable energy partner.

• Phase 1: Two anaerobic ponds were covered with geomembranes, transforming them into closed digesters. Methane (about 18 m³ per m³ of POME) was captured and initially flared, reducing emissions by thousands of tonnes of CO₂e.
• Phase 2: In 2019, a 1.6 MW biogas engine was installed under a Renewable Energy PPA, exporting electricity to the grid at FiT rates. The mill gained a new revenue stream and eliminated odour complaints from nearby communities, while contributing to grid stability.
• Phase 3: The existing aerobic ponds were upgraded into an aerated lagoon with surface aerators and a clarifier. By 2020, the final effluent consistently achieved BOD < 20 mg/L, suitable for land application and RSPO compliance.
   

Results: The mill’s emissions dropped by an estimated 50,000 tCO₂e/year. It earned carbon credits, gained revenue from power sales, and recovered about 800 tonnes of palm oil annually from residual scum, an unexpected financial bonus. Importantly, the project was financed via the energy developer under the FiT scheme, with the mill investing only in aerobic polishing (partially offset by a pollution control grant). Within two years, it became a showcase for sustainable POME management.

Case Study: Biogas Hub in North Sumatra, Indonesia

In 2021, a private energy firm led a shared biogas initiative for three small mills in North Sumatra—each too small to justify its own power plant.

●     Phase 1: Each mill installed covered lagoons to capture methane, which was scrubbed, compressed, and trucked to a centralized 3 MW biogas power plant within a 20 km radius.

 

●     Phase 3: Each mill also added modular aeration and filtration units to treat its effluent before discharge. One reported using treated water for cleaning and irrigation—modest reuse, but a meaningful sustainability step.
 

Results: The central plant sells electricity to the PLN grid, with proceeds shared across the mills. Despite lacking FiT support, the model worked—proving that shared infrastructure and modular systems can bring biogas solutions within reach for small mills. The project improved local water and air quality, supported energy decentralization, and helped mills maintain sustainability credentials.

These examples highlight how phased upgrades, strategic financing, and even cooperative models can transform POME treatment from a costly burden into a climate-positive, revenue-generating solution.

Conclusion: Turning POME from Pollution to Solution

Palm oil mill effluent (POME) has long been seen as a stubborn waste problem—but that’s changing. Across Southeast Asia, mills are proving that with the right strategy, POME can become a valuable resource. What was once a liability is now an opportunity to improve environmental performance, reduce emissions, and even generate revenue.

As we've explored, the scale of the challenge in Indonesia, Malaysia, and Thailand is significant, but solvable. Technologies like anaerobic digestion can cut pollution and produce renewable energy. Aerated lagoons and activated sludge systems help mills meet discharge standards and protect local waterways. And for smaller or budget-limited mills, modular systems and phased upgrades offer practical, scalable paths to compliance.

Crucially, these improvements make business sense. Treating POME helps avoid fines, lowers fuel costs, and creates new income streams through power sales or carbon credits. Buyers are increasingly demanding sustainable supply chains, and mills that manage effluent responsibly are better positioned to retain contracts and build long-term value.

While the transition from open ponds to modern treatment can seem daunting, case studies across the region show it’s achievable and often faster and more profitable than expected. Government policies, available financing, and proven technologies are aligning. What’s needed now is leadership on the ground: the initiative to start, pilot, and scale these solutions.

Southeast Asia is not only the heart of global palm oil; it can be a global leader in sustainable palm oil practices. Addressing POME is a critical step on that path.

Ready to explore solutions tailored to your mill’s needs? Consider reaching out for expert guidance. Visit Bluewater Lab to learn about our modular POME treatment systems.