Nature’s Priceless Lesson on Palm Oil
Palm oil is, in itself, both a means and an end. Thanks to its multiple industrial applications, it is a means to obtain tasty and long-lasting foods, luxurious cosmetics and environmentally-friendly biofuels. The industry is so productive that trade in palm oil is a highly profitable activity.
The production process results in residues for which environmentally useful and economically viable uses have been found. In this, Nature teaches us yet another priceless lesson: that no single aspect or element of palm oil processing should be underestimated or left unutilised.
On a typical oil palm site, almost 70% of fresh fruit bunches are turned into waste. The palm oil production process results in a variety of by-products:
- At the plantation (pruned fronds and tree trunks)
- At the mill (empty fruit bunches, fibre and shells)
- At the effluent treatment plant (sludge cake, aerobic and anaerobic solids, and biogas)
These by-products can be recycled and converted into biomass, fuel for boilers, fertiliser and animal feed. The most recent scientific and technical findings suggest that they have additional uses, such as for the extraction of vitamins.
Examples of applications
Felled oil palm trunks are often burnt at the boiler with palm kernel shells in order to produce power in the context of self-sufficient mills. After that, the trunks are often left to decompose naturally in plantations. This practice arguably disturbs the plantation process, given that the trunks decompose slowly.
Pruned fronds and palm trunks can instead be used as a substitute for tropical grass by ruminant producers. The trunks can also be used to produce lumber.
Palm kernel meal is a by-product of the manufacturing of palm kernel oil. It is a dark brown protein meal with relatively high levels of oil and fibre. It contains biomaterials such as protein, cellulose and organic acids, and therefore makes great animal feed as part of a balanced diet for dairy cows, sheep and poultry, among other livestock.
Palm kernel shells and fibre (PKS) are the fractions left when the nut has been removed from the fruit, after it is crushed at the mill. PKS is a fibrous material traditionally used as solid fuel for steam boilers; the steam is used, in turn, to run turbines for electricity production.
Certain challenges presented by the use of PKS – such as the production of dark smoke and the carry-over of partially carbonised fibrous particulates when shells are burned – can be avoided by using high-pressure boilers.
EFB and POME
Another by-product that should not be disregarded is the empty fruit bunch (EFB), which is abundantly available as a fibrous material of a purely biological origin. EFBs do not contain chemical nor mineral additives.
Provided that they have been properly handled at the mill, they are free from alien elements such as gravel, nails and wood residues. EFBs are commonly used in making organic fertiliser, pellets, peeled palm lumber and fibre.
Recent scientific research suggests that EFBs could also be used to produce fermentable sugars. They contain carbohydrate material (cellulose and hemicellulose) that can be broken down and used in fuel and plastic production.
This is arguably an area that presents attractive market opportunities, given that an estimated 300 million tonnes of EFBs need to be disposed of every year. Still not convinced? Pioneer industries are also using EFBs to obtain high-grade paper pulp.
Palm oil mill effluent (POME) is the waste water discharged from the processes of sterilisation, crude oil clarification and cracked mixture separation. POME is a hot, acidic effluent that contains oil, plant debris and nutrients.
POME is discarded in disposal ponds, which could result in the leaching of contaminants that pollute the groundwater and soil, and in the release of methane gas into the environment. When managed with due care, POME facilitates the creation of biogas through anaerobic digestion; this is useful in producing power supply for the electricity grid.
Malaysia, as a leading producer of palm oil, has been supporting the use of by-products. This has proven to be an excellent way of minimising the environmental impact of waste disposal, while maximising the benefits of sustainable or renewable energy production.
There are both environmental and economic reasons to increase energy recovery from the waste generated in the palm oil production chain. Techniques such as direct combustion, gasification, pyrolysis, liquefaction, fermentation and anaerobic digestion help maximise energy recovery.
Sustainable development can be promoted by encouraging energy projects, relying on know-how and contributing to the creation of employment and economic development at the local level.
In Malaysia, the use of palm oil by-products has not only brought substantial profits to the businesses involved, but has also had positive implications for local communities.