Composting at Jugra Palm Oil Mill

Acknowledgment:  I would like to thank Jugra Palm Oil Sdn Bhd and especially Mr. Kester Chin the Technical Director of GreenEarth INTL Holdings Sdn. Bhd. for taking the time to explain the composting process for the agro-waste generated from Palm Oil mill. 

Introduction: This post presents the findings of the field visit to Jugra Palm Oil Mill on 1^st December 2012. The post will mainly focus on the methods used in the oil mill to compost the organic waste generated from palm oil production process.

Composting Process: The main organic “waste” materials generated from the palm oil production process are empty palm oil fruit bunches (shortly referred to as EFB), mesocarp fibers and Palm Oil Mill Effluent (POME). The solid organic waste are brought into the composting field in large Lorries, and piled into rows (referred to as windrow), with a help of an excavator in the open (Figure 1).

Figure 1 (Left panel) Lorry carrying Empty Fruit Bunches and husky material from the mill to composting area (Right panel) newly laid windrow fresh EFB

The new batch of organic waste is inoculated with microbes (aerobic bacteria such as ligninolytic bacteria and fungi). A trigger such as Ferrous sulphate or Urea is sometimes added (in very small quantity e.g. 1000 mg per 1 ton of compost) to kick start the microbial activity.

In addition, the sludge (rich in microbes) from the POME treatment pond is also added to the windrow to produce compost. POME treatment takes place via a series of anaerobic and aerobic treatment ponds; the sludge that settles on the bottom of the aerobic treatment tank is pumped out with a help of sludge pump and transferred to the compost pile.

Figure 2 (Left panel) Anaerobic POME treatment pond, (Right panel) aerobic POME treatment pond

The pile is kept damp with help of micro-sprinklers, which waters the pile continuously with POME. This also helps the oil mill to deplete the POME in a useful manner.

The compost process heats up the pile to up to 75 – 80 ^oC, and releases steam, Methane and Hyrdrogen Sulphide Gas. These gases are responsible for the distinctive pungent odor at the composting area.

Once every two weeks the windrow is turned with a help of an excavator (Figure 3); this is to allow Oxygen into the pile and ensure aerobic conditions for the microbial functions. It takes over 6 months for a pile to turn into compost. Once ready the pile is transferred to the processing area.

Figure 3 Excavator used to turn the windrow

In the processing area, the compost pile will be sieved into different size and additional microbes such as nitrogen fixing bacteria (Azotobacter) are added as value addition. One ton of this compost material currently is worth RM 600.

Vermi-compost process: Organic piles are made up as in the open system under a roofed facility (provide shade). The windrow is then added with 7 species of worms, with different preferences (i.e. in terms of their preference on the location within the windrow, the type of organic food they consume, reproduction etc.). This mixture of worms will consume organic material and excrete material, which is fertile. This material is referred to as vermicast.

Cardboard is sometimes added to the windrow as food to the worms to enhance their growth. In addition the decanted cakes from the oil mill is placed on top as food for worms and fungi. Unlike the normal composting method, micro-sprinkling is done with water on these windrows, and the water that is sprinkled on the windrows are collected down a sump and recycled until concentrated which produces “Worm Tea”; which is worth approximately RM 4000 per ton.

 The compost produced using this method is richer in nutrients, and is sold at RM 1600 per ton, which is almost 40% expensive than the compost produced using the normal method.

Conclusion: Composting allows the use of agro-waste from the oil mill which otherwise would be either incinerated, or sent to landfill.  This not only helps reduce waste produced, but also helps generate revenue for the company, with minimal work and equipment.

The POME treatment at this facility uses anaerobic treatment in the first stage, which eventually releases large amounts of Methane. As methane gas has a very high Global Warming Potential, it is important to find alternative method that reduces the organic content in the first stage of treatment. It is equally important to find a way to use this organic material in the composting process. 

It takes over 6 months to complete the preparation of one batch of compost, and each compost pile takes up considerable space. With limited land it is important to explore ways to catalyze the composting process without incurring much cost or additional equipments.

Figure 4 Vermi-compost piles