Palm Oil Mill Wastewater and Treatment

Palm Oil Mill Wastewater and Treatment

DOI: 10.4018/978-1-7998-2645-3.ch011
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Abstract

Palm oil is an essential agricultural commodity in Malaysia, as Malaysia is one of the largest producers and exporters globally. The processes of palm oil extraction and purification generate a large amount of wastewater known as palm oil mill effluent (POME). Currently, most treatment processes are carried out using a conventional ponding system which is outdated as it requires large land areas and long retention time. Discharge of poorly treated POME directly to the surroundings leads harms the environment, as it contains high contents of oil and BOD. Therefore, this chapter discusses the treatment method of POME from a newer perspective of membrane technology integrated with biological treatment. Various methods such as clarification system with nanofibre unit, cooling system, activated sludge system, and anaerobic membrane bioreactor, are reviewed on their principles of operation.
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Introduction

Overview of Palm Oil Mill Industry in Sabah

Sabah is one of the states formed Malaysia which is located in the north of Borneo Island. The land size of Sabah is 74,000 km2, most of which is covered by tropical forest and received high rainfall with an average of 3,000 mm annually. In the past, before the 1980s, the economy of Sabah relied on timber.

From the mid of the 1980s up to today, Sabah has transformed into the largest palm oil producer in Malaysia and the 3rd largest in the world. 2016 statistic shows that about 1.55 million hectares of land in Sabah has been planted with oil palm. The total oil plant planted in Malaysia was 5.74 million hectares. The reason for the fast-growing of Sabah's palm oil plantation compared to the other states in Malaysia is due to the abundant land space and fertile soil.

A total count of 126 palm oil mill is registered in Sabah alone as of 2015. The total production of crude palm oil produced is about 5.5 million metric tonnes per year. The production capacity usually ranged from 30 – 120 tonnes of fresh fruit bunch (FFB) per hour, where a conventional palm oil mill here runs at a capacity of 40 – 60 tonnes of fresh fruit bunch per hour.

However, the most significant factor is the slightly higher percentage of oil extract from the fruit bunch compared to that planted in West Malaysia. As a consequence of its large production scale, the palm oil industry has also been identified as the largest contributor to Malaysia's pollution load, by discharging a large volume POME into the environment. The large production of palm oil has exposed Sabah to high generation of wastewater which is produced during the extraction of crude palm oil from fruit bunches.

Due to its large generation and without proper treatment and management, wastewater produced from palm oil industry has been reflected as the most polluting industry in Sabah. This has led to many news reports and has increased public concern. Consequently, the government authority responsible to maintain environmental quality, the Department of Environment (DoE) has decided to make the standard discharge limit more stringent, changing it from Standard B to Standard A. Despite the change of discharge limit, minimal improvement has been seen in wastewater discharge from palm oil mills. One of the possible reason is the conventional wastewater treatment is unable to respond correctly due to the inconsistent weather condition in Sabah, especially during heavy rainfall season, a large volume of wastewater and very high BOD.

The conventional and currently utilized a ponding system to treat wastewater derived from palm oil mill can be considered as an outdated technology as other new technologies are readily available. However, most palm oil mill is reluctant in adopting new technologies mostly due to the high capital cost involved for the installation of new technology and low maintenance cost of the existing technology.

Recently, the palm oil industry has shown a positive development where some of the palm oil industries have started to venture into new technologies such as biofuel production from biomass and wastewater. This technology is attractive not only because it is able to reduce solid waste production and wastewater discharge, but it is also able to reduce operational cost and generate extra income for the company. The biofuel and biogas can be utilized in power generation, eliminating the need for diesel purchase.

If this positive trend proceeds, effluents from palm oil mill will no longer be categorized as wastewater, but rather a source of income for the mills. Therefore new technologies such as microalgae bioremediation and biofuel production as well as membrane utilization are beneficial to the palm oil industry. This will allow the industry to lower operational cost as it will be paid off through the production of by-products in the form of biofuel.

Key Terms in this Chapter

Palm Oil Mill Effluent (POME): Wastewater generated by palm oil processing mills which contain oil, grease, and suspended solids.

Membrane Filtration: System that is used to separate the biomass from treated POME using either microfiltration, ultrafiltration, or reverse osmosis membrane depending on the influent characteristics and quality of water desired.

Activated Sludge System: Aerobic treatment process that uses aerobic microbes to feed on the organic contaminants of palm oil mill wastewater.

Clarification System: System that separates oil residuals using mechanical means such as skimmer and removes solids present through sedimentation from the POME.

Anaerobic Membrane Bioreactor: Technology that combines the fundamental of anaerobic digestion and membrane filtration process, which works by breaking down the biodegradable matters by anaerobic microorganism and separating the biomass from treated water respectively.

Cooling System: System which cools down the hot POME to a certain temperature before subjected to the subsequent process that is affected by high-temperature fluid, i.e. activated sludge process.

Ponding System: Conventional POME treatment system which uses the natural biological treatments of anaerobic and aerobic systems.

Nanofibre: Films comprising of nanofibres overlap with each other in a completely random manner with pore size ranging from tens of nanometre to several micrometres which are used to adsorb the residual palm oil.

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