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Neste-led project verified 50% methane emission reduction at palm oil mills using belt filter press

Crude palm oil is one of the more than ten renewable raw materials that Neste uses to produce a range of renewable products, including renewable diesel. Palm oil represents approximately 20% of Neste’s renewable raw material usage annually.

Neste has been exploring ways to contribute to improving palm oil industry’s environmental performance, particularly how to further reduce greenhouse gas emission from palm oil production. Recently, the focus has been on methane (CH4) emissions at the palm oil mills since milling process accounts for a significant share of life cycle emissions of palm oil products. Already 36% of the palm oil that Neste uses comes from mills with methane recovery systems or systems to prevent its formation.

In 2015, Neste initiated a two-year study project to verify the methane emission reduction for a newly applied effluent treatment method. The project took place in palm oil mills in Indonesia and Malaysia, and was conducted in collaboration with a palm oil company KLK, a Dutch sustainable trade organization IDH, and an international certification system ISCC (International Sustainability and Carbon Certification). The field work was conducted by Meo Carbon Solutions.

The method itself, separating solid organic matter from wastewater with a belt filter press is not particularly new. A belt filter dewaters by applying pressure to solids to squeeze out the water. The biosolids sandwiched, between two tensioned porous belts, are passed over and under rollers of various diameters. Increased pressure is created as the belt passes over rollers which decrease in diameter.

Bfp

Schematic of a belt filter press. Source: EPA.

Its use to remove solids from the palm oil mill effluent (POME) is new, however, and focuses directly on removing the root cause of methane emissions, i.e. the organic matter such as degrading parts of the oil palm fruit in the mill effluent.

What is also new is the Neste-developed method to calculate—i.e. to verify—the actual emission reduction resulting from such filtering. To validate the emission savings from adopting the belt press method, the mill simply needs to weigh the belt press cake removed with the belt filter press and measure its carbon content. The amount of the belt press cake together with its carbon content provides the means to calculate removed organic carbon which, according to the study results, correlates with the reduction in measured methane emissions.

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Belt press filtering of mill effluent reduced methane emissions at the POME pond by 50%. (Photo: Michael Giebels, Meo Carbon Solutions.)

Our project showed that removing organic matter from the palm oil mill’s wastewater by a belt press offers great environmental potential. In our study, removal of solid organic matter reduced greenhouse gas emissions by a staggering 50% at the POME pond compared to the conventional open pond emissions.

—Annamari Enström, Neste’s sustainability expert and one of the researchers involved in the project

The potential that the method offers is enormous, Neste said. In Indonesia and Malaysia, for example, approximately 70% of palm oil is produced without methane reduction methods. If all the producers in these countries were to adopt the studied new method, greenhouse gases would be reduced by approximately 4.5 million tons annually. This is equivalent to removing 1.6 million passenger cars from the roads.

For Neste, application of the method would mean that the greenhouse gas reduction potential of Neste MY Renewable Diesel produced from palm oil could be increased even further from the current 69% compared to conventional fossil diesel usage. The current life cycle emission figure is already much better than the 50% greenhouse gas emission reduction requirement defined in the Renewable Energy Directive (EU RED) for all biofuels.

The investment costs related to the belt press method are significantly lower than those related to methane capture method. In addition to reducing emissions at palm oil mills, the belt press method offers significant other benefits, as well.

Adopting the belt filter press reduces the need for dredging the solid waste from the bottom of POME ponds, which currently has to be done every five to seven years and requires operation shutdowns. By reducing the need to reserve land for dredging, it also frees land area for more productive uses. The belt press cake, dry leftover matter, is rich in nutrients and can be used at oil palm plantations as organic soil enhancer, decreasing need for store-purchased fossil fertilizers. The purified water from the press can be directed to an irrigation water system, reducing the need to derive irrigation water from other sources. The filtering also reduces the need for other physical or chemical treatments that have formerly been required before the discharge to the environment.

—Asta Soininen, Neste researcher

It would promote a good practice in the palm oil industry if the method were officially recognized in relevant certification systems. This would mean that the certification system would include a new emission factor that can be applied to greenhouse gas calculations for certification purposes by companies using the belt press method. The method and its emissions-saving potential have already raised interest in certification bodies.

This combination of an already known wastewater treatment method, and Neste-developed method to verify the emission reduction in a rather simple manner, has generated great interest. Besides offering global climate benefits and several local benefits, applying the method and verifying the emission reduction are also very cost-effective.

—Annamari Enström

Receiving a certification system recognition for the method would allow palm oil producers applying this method to verify their environmental benefits and lower emissions without having to conduct complicated and expensive actual gas emission measurements.

Background. Methane is a very potent greenhouse gas formed when organic material decomposes under anaerobic conditions. Its impact on global warming is much greater than that of carbon dioxide. In the palm oil production process, methane formation takes place in the oil mill effluents. The amount of methane released into the atmosphere can, however, be reduced by capturing the methane formed in the palm oil production process or by preventing its formation through removal of organic matter from the mill effluent. Both methods offer both global and local environmental benefits.

Some palm oil mills have already adopted methods to capture methane. This earlier method involves covering the open ponds containing palm oil mill effluent, i.e. POME, to capture the gas for electricity production, for example. Neste has encouraged this development over the years through including many of such mills in its supply chain.

Covering large wastewater ponds or building anaerobic digester tanks is expensive, however, limiting the deployment of the method mainly to the larger mills. Through engaging with suppliers, Neste has learned that in order to reach a higher level of environmental impact, a more easily adoptable method to reduce methane emissions has been needed. The new method meets this need.

All the crude palm oil that Neste uses has been fully traceable to the oil palm plantations since 2007, and 100% certified since 2013. Neste’s supply chain of crude palm oil is fully transparent and information regarding it can be found on https://nestepalmoildashboard.com/. This spring, Neste will publish comprehensive information about its palm oil supply chain in 2017.

Comments

Phanis9

Good for Environment especially tropics where Palm cultivation and Refining is high

Engineer-Poet

What they really need is some kind of biofilter which catches this matter.  Bogs are particularly good at catching both organic and inorganic sediment.  Another one I've seen hints about is the mycelia which are used to grow mushrooms; they do very well at capturing certain organic fractions in wastewater.

Being able to turn wastewater into a food product would be a huge gain.  Not as much of a gain as turning the palm plantations back into rain forest, though.

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