Access to an adequate supply of clean, fresh water is critical to REA’s ability to operate and to the livelihoods of the surrounding communities, the majority of which are traditionally river dwelling. It is therefore imperative that this precious resource is used efficiently and equitably.
Fortunately, REA’s plantations receive plentiful rainfall, so irrigation is only necessary for the oil palm nurseries. Treated river water is used to process oil palm fruit in the mill and for domestic purposes. The group aims to reduce as far as possible the volume of water used per tonne of FFB processed in each palm oil mill and has installed water flow meters to monitor this.
The greatest risk of water pollution associated with REA’s operations is from palm oil mill effluent (POME) and run-off or leachates from fertilisers. The high organic matter content of untreated POME means that it has a high biological oxygen demand (BOD) and will starve aquatic flora or fauna of oxygen if it enters a water course. However, by utilising as much of this organic matter as possible to produce fertiliser and electricity the group obtains valuable resources whilst also mitigating the risk of water pollution.
The group’s first strategy for extracting value from POME is to capture the methane produced when the organic matter content is digested anaerobically and convert the biogas collected to electricity. Unlike the traditional open pond system for digesting POME, the methane capture facilities are enclosed systems and thus reduce the risk of untreated POME polluting the environment.
The group’s second strategy for extracting value from POME is to mix it with empty oil palm fruit bunches and convert it into organic compost on site. The availability of this compost has enabled inputs of inorganic fertilisers to be reduced significantly. This in turn has reduced the associated risk of water pollution from leaching or run-off.
POME that exceeds the requirement for compost production, as well as the POME that has been processed by the methane capture plants, is treated in the traditional anaerobic open ponds. This helps to reduce the BOD of the POME before it is pumped to flat beds in between the rows of oil palm so that the remaining nutrient content can be utilised as fertiliser. The BOD of the POME in the final open pond is tested on a monthly basis to ensure that it is below the legal limit for land application in Indonesia, being 5,000mg/litre.