REVIEWS

Composting of waste from palm oil mill: a sustainable wastemanagement practice

R. P. Singh • M. Hakimi Ibrahim • Norizan Esa •

M. S. Iliyana

Published online: 25 February 2010

� Springer Science+Business Media B.V. 2010

Abstract Malaysia is blessed with abundant natural

resources and bears a favorable climate for commercial

cultivation of crops such as oil palm. In Malaysia the

total plantation area of oil palm was 4,487,957 ha in

2008. It has been reported that in 2005 there was a total

of 423 palm oil mills having production capacity of

approximately 89 million tonnes of fresh fruit bunch

(FFB) per year. Waste from the oil palm mill process

include palm oil mill effluent (POME), generated

mainly from oil extraction, washing and cleaning up

processes. POME contains cellulosic material, fat, oil,

and grease. Discharging untreated effluent into water

streams may cause considerable environmental prob-

lems. The solid wastes generated are mainly decanter

cake, empty fruit bunches, seed shells and fibre from

the mesocarp. POME as well as the solid wastes may

rapidly deteriorate the surrounding environment if not

dealt with properly. Hence there is an urgent need for a

sustainable waste management system to tackle these

wastes. As these wastes are organic in origin, they are

rich in plant nutrients. Composting of waste generated

from palm oil mills can be good practice as it will be

helpful in recycling useful plant nutrients. This review

deals with various aspects of waste management

practices in palm oil mills and the possibility of

composting the wastes.

Keywords POME � Decanter cake �Empty fruit bunch � Fresh fruit bunch �Composting

1 Introduction

The manufacturing industries in Malaysia can be

divided into resource based industries and non-

resource based industries. Resource based industries

include rubber products, palm oil products, wood-

based products and petrochemicals. Non-resource

based industries include electronic and electrical

products, machinery and engineering products and

textiles. Malaysia is blessed with abundant natural

resources and a climate conducive for commercial

cultivation of crops such as rubber and palm oil.

Malaysia is the largest producer of palm oil, the third

largest for rubber and fourth largest for cocoa. There

were more than 3.79 million hectares of land,

occupying more than one-third of the total cultivated

area and 11% of the total land area, under palm oil

cultivation in Malaysia in the year 2003 (Yusoff and

Hansen 2007).

R. P. Singh � M. H. Ibrahim (&) � M. S. Iliyana

Environmental Technology Division, School of Industrial

Technology, Universiti Sains Malaysia, 11800 Pulau

Pinang, Malaysia

e-mail: mhakimi@usm.my

N. Esa

School of Educational Studies, Universiti Sains Malaysia,

11800 Pulau Pinang, Malaysia

123

Rev Environ Sci Biotechnol (2010) 9:331–344

DOI 10.1007/s11157-010-9199-2

Elaeis guineensis Jacq is the most productive oil

palm variety in the world, with one hectare of oil palm

producing 10–35 tonnes of fresh fruit bunch (FFB) per

year. Generally FFB can be harvested 3 years after

planting. The largest amount of FFB is harvested about

10 years after planting. The economic life of oil palm

plants is 20–25 years of its lifespan of 200 years. Out

of this, the plant spends its initial 11–15 months in the

nursery. The first harvest is 32–38 months from

planting and peak yield is 5–10 years after planting.

Normally, oil palm grows in the lowlands of the humid

tropics, 15�N–15�S where there is evenly distributed

rainfall (1,800–5,000 mm year-1).

The fleshy mesocarp of the fruit is used to obtain

oil and the yield is about 45–56% of fresh fruit bunch

(FFB). Oil yield from the kernel is about 40–50%

(Kittikun et al. 2000). Potential yield from both

mesocarp and kernel accounts for about 17 t ha-1

year-1 of oil (Corley 1983). About 1 tonne of crude

palm oil (CPO) is produced from 5.8 tonnes of FFB

(Pleanjai et al. 2004). Fibre, shell, decanter cake and

empty fruit bunch (EFB) accounts for 30, 6, 3 and

28.5% of the FFB respectively (Pleanjai et al. 2004).

It has been estimated that about 26.7 million tonnes

of solid biomass and an average of 30 million tonnes

of POME were generated from 381 palm oil mills in

Malaysia in 2004 (Yacob et al. 2005).

In view of the abundance of oil palm by-products in

the country, sustainable management of these by

products is necessary. If not properly dealt with they

may lead to environmental pollution. As waste from

oil palm is biological in origin, composting as well as

vermicomposting can be a good option for sustainable

management of this waste. There is a growing interest

in composting as well as vermicomposting. These two

processes can add value, and reduce the waste volume

to make its land application easier (Yusri et al. 1995;

Thambirajah et al. 1995; Danmanhuri 1998). Aisueni

and Omoti (1999) reported that the oil palm industry is

one of the best sources of agricultural wastes that

can be used as organic fertilizers. This review deals

with composting of various wastes generated from oil

palm mills.

2 Palm oil industry in Malaysia

Global demand for edible oils is increasing in the last

few decades, which resulted in a tremendous increase

in the area of oil crop cultivation, particularly of

soybean and oil palm (Yacob 2008). Global produc-

tion of palm oil, the most widely traded edible oil, has

also seen a significant leap in its production as well as

plantation areas. Malaysia and Indonesia together

contributes about 87 % of world palm oil production

(USDA 2007; Yacob 2008) (Fig. 1). Palm oil

production has almost doubled from 1990 to 2001,

with Malaysia and Indonesia contributing to most of

the increased production. In Malaysia, the area under

oil palm crop plantation has increased from 2.03 mil-

lion hectares to 4.49 million hectares from 1990 to

2009, an increase of 121.2%.

Frenchman Henri Fauconnier and his association

with Hallet, is attributed for the development of the

oil palm industry in Malaysia. Fauconnier visited

Hallet’s oil palm development in Sumatra in 1911

and purchased some oil palm seeds. These seeds were

planted at his Rantau Panjang Estate in Selangor. He

returned to Sumatra the following year to obtain

seeds which he had selected together with Hallet

from Tanjong Morawa Kiri Estate for further plant-

ing. With the seedlings obtained Fauconnier estab-

lished the first commercial oil palm planting at

Tennamaram Estate, to replace an unsuccessful

planting of coffee bushes (Tate 1996).

Elaeis guineensis Jacq, commonly known as oil

palm, is the most important species of the genus

Elaeis belonging to the family Palmae. The second

species Elaeis oleifera (H.B.K) Cortes, also known as

American oil palm, is found in South and Central

America. Although significantly lower in oil to bunch

content than its African counterpart, E. oleifera

contains higher level of unsaturated fatty acids and

has been used for production of interspecific hybrids

Fig. 1 World palm oil production 2006 (USDA 2007)

332 Rev Environ Sci Biotechnol (2010) 9:331–344

123

with E. guineensis. The oil palm is an erect monoe-

cious plant producing separate male and female

inflorescences. Oil palm is cross-pollinated and the

key pollinating agent is the weevil, Elaeidobius

kamerunicus Faust. Earlier oil palm was thought to

be wind pollinated and owing to the low level of

natural pollination, assisted pollination is a standard

management practice in plantations. However, this

practice was discontinued after the discovery that oil

palm was insect pollinated and the introduction of

E. kamerunicus from the Cameroons, West Africa in

1982 (Syed et al. 1982). Harvesting commences

about 24–30 months after planting and each palm

can produce between eight to 15 fresh fruit bunches

(FFB) per year. The FFB weigh about 15–25 kg

each, depending on the planting material and age of

the palm. Each FFB contains about 1,000–1,300

fruitlets, each fruitlet consists of a fibrous meoscarp

layer and the endocarp (shell) containing the kernel.

Present day planting materials of oil palm are

capable of producing 39 tonnes of FFB ha-1 and

8.6 tonnes of palm oil. Good commercial plantation

yields about 30 tonnes FFB ha-1 with 5.0–6.0 ton-

nes of oil (Henson 1990). The average FFB yield

was 19.14 tonnes while palm oil production was

11.80 million tonnes in year 2001 in Malaysia

(MPOB 2001). The total oil palm planted area in

the country increased by 4.3% to 4.48 million

hectares in 2008 (MPOB 2008a, b) (Fig. 2). Total

plantation area in Malaysia was 4,304,914 ha in

2007, which has reached 4,487,957 ha in 2008

(MPOB 2008a, b) (Fig. 2). Based on statistics

obtained from the Malaysian Palm Oil Board,

Malaysia controls about 45% of total palm oil

production in the world. In 2005 alone, there were

423 mills with a production capacity of approxi-

mately 89 million tonnes of fresh fruit bunch (FFB)

year-1 (Borowitzka et al. 2009).

Cultivars of E. guineensis can be differentiated

with the help of their fruit pigmentation and charac-

teristics. The most common cultivars are Dura,

Tenera and Pisifera, which are classified according

to the endocarp or shell thickness and mesocarp

content. Dura palms have between 2 and 8 mm thick

endocarp and medium mesocarp content (35–55% of

fruit weight). Tenera palms have 0.5 to 3 mm thick

endocarp and high mesocarp content of 60–95%

while the pisifera palms have no endocarp and about

95% mesocarp (Latiff 2000).

3 Palm oil production processes

Figure 3 shows the steps involved in oil palm mill

industry. The oil palm produces two types of oils,

palm oil from the fibrous mesocarp and lauric oil

from the palm kernel. Unit operations involved in oil

production after the fresh fruit bunches (FFB) are

transported to the palm oil mills consist of the

following steps:

1. Sterilization of the FFB is done batch wise in an

autoclave for about 2 h. The temperature inside

the autoclave is about 120–130�C. The objectives

of this process are to check further formation of

free fatty acids due to enzyme action, facilitate

stripping and prepare the mesocarp for subse-

quent processing. The steam condensate coming

out of the sterilizer constitutes one of the major

sources of wastewater (Thani et al. 1999).

2. Stripping (threshing): After sterilization, the FFB

are fed to a rotary drum-stripper where the fruits

are stripped from fruit bunches. This step gen-

erates the empty fruit bunches (EFB). The

detached fruits are passed through the bar screen

of the stripper and are collected below by a

bucket conveyor and discharged into a digester.

3. Digestion: Separated fresh fruits are put into a

digester, where they are mashed under steam-

heated conditions by the rotating arms. At this

stage, mashing of the fruits under heating breaks

the mesocarp oil-bearing cells. Twin screw

presses are generally used to press out the oil

from digested mash of fruit under high pressure.

Years1950 1960 1970 1980 1990 2000 2010 2020 2030

0

5

10

15

20Area (million ha) CPO (million ton)Oil Yield (tha-1 )

Par

amte

rs

Fig. 2 Area of oil palm and palm oil production. (MPOB

2008a, b)

Rev Environ Sci Biotechnol (2010) 9:331–344 333

123

Hot water is added to enhance the flow of the

oils. No residue occurs in this step.

4. Crude palm oil extraction: Homogenous oil mash

from the digester is passed through a screw press

followed by a vibrating screen, a hydrocyclone

and decanters to remove fine solids and water.

Centrifugal and vacuum driers are used to further

purify the oil before sending it to a storage tank.

The temperature of oil in the storage is main-

tained around 60�C with steam coil heating

before the crude palm oil (CPO) is sold. The

crude oil slurry is then fed to a clarification

system for oil separation and purification. The

fibre and nut (press cake) are conveyed to a

depericarper for separation (Thani et al. 1999).

The crude palm oil (CPO) from the screw presses

consists of a mixture of palm oil (35–45%), water

(45–55%) and fibrous materials in varying pro-

portions. It is then pumped to a horizontal or

vertical clarification tank for oil separation. In

this unit, the clarified oil is continuously

skimmed from the top of the clarification tank.

It is then passed through a high speed centrifuge

and a vacuum dryer before being sent to storage

tanks. Decanter wastewater and decanter cake are

the major wastes at this step.

5. Nut/fibre separation: The press cake discharged

from the screw press consists of moisture, oily

fibre and nuts, and the cakes are conveyed to a

depericarper for nuts and fiber separation. The

fibre and nuts are separated by strong air current

induced by a suction fan. The fibre is usually sent

to the boiler house and is used as boiler fuel.

Meanwhile, the nuts are sent to a rotating drum

where any remaining fibre is removed before

they are sent to a nut cracker.

6. Nut cracking: Nuts are cracked in a centrifugal

cracker or Hydrocyclone. After the cracking

process, the kernels and shells are separated by

clay suspension (Kaolin). The discharge from

this process constitutes the last source of waste-

water stream (Chow and Ho 2000). The sepa-

rated shells from the kernels are sold to other

mills as fuel. The kernels are sent to the kernel

drying process in a silo dryer to sell (for oil

extraction) to other mills.

4 Waste generation in palm oil mills

Effluents from palm oil mills and natural rubber

processing plants have been identified as the major

cause of the rapid deterioration of the aquatic

environment in the 1960s as well as 1970s. Both

were in fact the largest source of water pollution

during this period (DOE 1991). Palm oil mill effluent

Fig. 3 Processes involved

in oil palm industry.

(Source:

http://uwa-

pabriksawit.blogspot.com/

2009/10/schematic-process-

of-palm-oil-mill.html)

334 Rev Environ Sci Biotechnol (2010) 9:331–344

123

(POME) is generated mainly from oil extraction,

washing and cleaning processes in the mill. These

contain cellulosic material, fat, oil, and grease

(Agamuthu 1995). Discharging untreated effluent

into water streams may cause considerable environ-

mental problems (Davis and Reilly 1980) due to its

high biochemical oxygen demand (25,000 mg L-1),

chemical oxygen demand (53,630 mg L-1), oil and

grease (8,370 mg L-1), total solids (43,635 mg L-1)

and suspended solids (19,020 mg L-1) (Ma 1995,

2000). The palm oil mill industry in Malaysia has

thus been identified as the one discharging the largest

pollution load into rivers throughout the country

(Hwang et al. 1978).

The oil palm industry produces a wide variety of

wastes in large quantities (Fig. 4). Liquid wastes arise

from oil extraction and processing. The solid wastes

are the leaves, trunk, decanter cake, empty fruit

bunches, seed shells and fibre from the mesocarp.

4.1 Liquid effluent

The production of palm oil results in the generation of

large quantities of polluted wastewater commonly

referred to as palm oil mill effluent (POME). One tonne

of crude palm oil production requires 5–7.5 tonnes of

water, about 50% of which ends up as POME

(Ma 1999a, b). Based on palm oil production in 2005

(14.8 million tonnes), an average of about 53 mil-

lion m3 POME is being produced per year in Malaysia

(Lorestani 2006). The POME comprises a combination

of wastewater from three main sources i.e., clarifica-

tion (60%), sterilization (36%) and hydrocyclone

(4%) units (Ma 2000). It contains various suspended

Shell (6 %)

Fresh fruit bunch (100 %)

Evaporation (10 %)

Fruits (70 %)

Empty fruit bunch (20 %)

Nuts (13 %)

Bunch ash (0.5 %)

Crude oil (43 %)

Pericarp (14 %)

Water evaporation

(2 %)

Dry fibre fuel

(12 %)

Solids (Animal feed / fertilizer

(2 %)

Pure oil (21 %)

Water evaporation

(20%) Kernel (6 %)

Moisture (1 %)

Fig. 4 Products from oil mill process (Lorestani 2006)

Rev Environ Sci Biotechnol (2010) 9:331–344 335

123

components including cell walls, organelles, short

fibres, a variety of carbohydrates ranging from hemi-

cellulose to simple sugars, a range of nitrogenous

compounds from proteins to amino acids, free organic

acids and an assembly of minor organic and mineral

constituents (Ugoji 1997).

From the environmental perspective, fresh POME

is a hot and acidic brownish colloidal suspension,

characterized by high amounts of total solids

(40,500 mg L-1), oil and grease (4,000 mg L-1),

COD (50,000 mg L-1) and BOD (25,000 mg L-1)

(Ma 2000). POME has been identified as one of the

major sources of aquatic pollution in Malaysia. The

characteristic of a typical POME is given in Table 1.

In year 2005, 66.8 million tonnes of POME were

generated (Vairappan and Yen 2008). Current bio-

logical treatment technologies for treating POME

consists of conventional oxidation ponds (anaerobic

and aerobic), open and closed tank digesters with

biogas recovery and land application (Ma 1999a, b;

Kennedy and Hishamuddin 2001). Most of the palm

oil mills in Malaysia have adopted the ponding

system for the treatment of their effluents (Ma and

Ong 1985) consisting of a number of ponds where

initially anaerobic digestion can take place, followed

by facultative ponds where degradation of the effluent

occurs under aerobic conditions. The system is

capable of producing a final discharge with a BOD

of less than 100 mg L-1 (Chan and Chooi 1982;

Chooi 1984).

Ponding system is the most conventional method

for treating POME (Ma and Ong 1985; Khalid and

Wan Mustafa 1992), but other processes such as

aerobic and anaerobic digestions, physicochemical

treatments and membrane filtration may also provide

the palm oil industries with a possible insight into the

improvement of current POME treatment process.

However, the treatment that is based mainly on

biological treatments of anaerobic and aerobic sys-

tems is quite inefficient to treat POME, which

unfortunately leads to environmental pollution issues

(Ahmad et al. 2005). This is because the high BOD

loading and low pH of POME, together with the

colloidal nature of the suspended solids, renders

treatments by conventional methods difficult (Olie

and Tjeng 1972; Stanton 1974).

4.2 Solid wastes

The solid waste materials as well as by-products

generated in the palm oil extraction process are given

in Fig. 5. The most common among these by-

products is the empty fruit bunch, palm oil mill

sludge (POMS), palm kernel cake (PKC) and

decanter cake. Palm kernel oil (white palm oil) is

obtained from the seed known as kernel or endo-

sperm. When oil has been extracted from the kernel,

what remains is known as ‘palm kernel cake’ (PKC).

This is rich in carbohydrate (48%) and protein (19%)

and is used as cattle feed (Onwueme and Sinha 1991).

Palm kernel cake can be processed into animal feed

and chicken feed (Ismail 2004). According to Ismail

(2004) the protein content of PKC can be increased,

improving its marketable value.

As PKC is nitrogen deficient, additional nitrogen

addition is required if it has to be converted into

compost. Kolade et al. (2006) carried out composting

Table 1 Characteristics of palm oil mill effluent (POME) and

empty fruit bunch (EFB)

Parameter POMEa

(Averagec)

Empty fruit

bunchb

pH 4.7 6.7 ± 0.2

Oil and grease 4,000 –

Biochemical oxygen

demand (BOD5)

25,000 –

Chemical oxygen

demand (COD)

50,000 –

Total solids 40,500 –

Suspended solids 18,000 –

Total volatile solids 34,000 –

Ammonical nitrogen

(NH3–N)

35 –

Total nitrogen (T.N.) 750 58.9 (%)

Phosphorous (P) 180 0.6 ± 0.1 (%)

Potassium (K) 2,270 2.4 ± 0.4 (%)

Magnesium (Mg) 615 0.6 ± 0.2 (%)

Calcium (Ca) 439 0.6 ± 0.3 (%)

Boron (B) 7.6 –

Iron (Fe) 46.5 1.0 ± 0.2 (%)

Manganese (Mn) 2.0 230.3 ± 40.8 (mg kg-1)

Copper (Cu) 0.89 13.5 ± 1.6 (mg kg-1)

Zinc (Zn) 2.3 16.6 ± 2.6 (mg kg-1)

a Ma 2000b Baharuddin et al. (2009)c All values are in mg L-1 except pH

336 Rev Environ Sci Biotechnol (2010) 9:331–344

123

of PKC using poultry manure, with goat manure as

supplement. Composting was carried out using com-

binations of PKC and poultry manure (3:1 ratio) and

PKC and goat/sheep manure (3:1 ratio). In Thailand

about 60 crude palm oil mills produced approxi-

mately 1.24 million tonnes of crude palm oil from

6.4 million tonnes of fresh fruit bunches (FFB) in

2007 (Paepatung et al. 2006). Chavalparit et al.

(2006) reported that average values of waste gener-

ation rate per ton FFB from palm oil mills in Thailand

were 140 kg of fibre, 60 kg of shells, 240 kg of

empty fruit bunch (EFB) and 42 kg of decanter cake.

The productions of fibre, shells, EFB and decanter

cake were estimated to be 0.894, 0.13, 1.53, and 0.27

million tonnes per year, respectively (Chavalparit

et al. 2006). The fibre produced is mostly used as

solid fuel for boilers in the palm oil mills, while

shells are sold as solid fuel to other industries, e.g.,

cement factories (Paepatung et al. 2006). EFB, with a

high moisture content of 60–70%, are difficult to use

as fuel for power boilers. Partial EFB and decanter

cake are currently utilized as fertilizers and soil cover

materials in palm oil plantation areas, whilst the rest

of EFB is dumped in areas adjacent to the mill

Fig. 5 Oil extraction and waste generation process in palm oil mill (Prasertsan and Prasertsan 1996)

Rev Environ Sci Biotechnol (2010) 9:331–344 337

123

because of the high generation rate along with its

limitations for current utilization (Paepatung et al.

2009). Empty fruit bunch can also be incinerated to

produce potash, which is applied in the plantation as

fertilizer by mulching. The fibre and shell materials

are used as boiler fuel. The palm kernel is usually

sold to palm kernel oil producers for the extraction of

the palm kernel oil (Thani et al. 1999).

5 Oil palm industry and environment

The processing of oil palm fresh fruit bunches (FFB)

primarily for palm oil also results in concomitant

production of wastes in the form of palm oil mill

effluent (POME), empty fruit bunches, mesocarp

fibre and shell. POME is a colloidal suspension

containing 95–96% water, 0.6–0.7% oil and grease

and 4–5% total solids. It is a thick, brownish liquid

with discharge temperature of between 80 and 90�C

and is fairly acidic with a pH value in the range of

4.0–5.0. Typically POME contains a mean value of

6,000 mg L-1 of oil and grease (Industrial Processes

& The Environment 1999).

When the industry was at its early age in 1960s,

ignorance compelled people to dispose POME into

the waterways or by any other convenient methods.

The problem of pollution resulting from a mere

92,000 tonnes production by only 10 mills was not

apparent in the 1960s (MPOB 1999). The environ-

ment could somehow absorb these wastes. This

negligence did not last long. By the 1970s the

industrial growth was exponential, bringing along

with it pollution which the waterways could no longer

handle. The palm oil processing became synonymous

to POME pollution.

The oxygen depleting potential of POME is 100

times that of domestic sewage (Khalid and Wan

Mustafa 1992). The industries begin to face a major

problem of virtually completely lacking any proven

technology for treating POME. POME is discharged

from the milling process to wastewater treatment,

traditionally to anaerobic digestion in open ponds.

Palm oil mill effluent has been successfully

exploited as animal feed, fertilizer as well as a

source of energy (Khalid and Wan Mustafa 1992;

Igwe and Onyegbado 2007). In Malaysia, POME

sludge is usually dried up and then used as fertilizer.

Drying is done in open ponds, but during the rainy

season, the process creates problems such as sludge

flooding, insects, and bad odour. Some palm oil mills

extract a considerable amount of the solids from

POME with a decanter prior to treatment producing

decanter cakes. Decanter cakes from palm oil mills

can be used in several different ways (Chavalparit

et al. 2006). The decanter cake can be mixed with

inorganic fertilizers. Dry decanter product can be

converted into commercial grade pellet animal feed.

In order to be able to sell the wet decanter cake to a

feed mill, this by-product has to be dried (Chavalparit

et al. 2006). This can be done through the use of low

pressure steam from the boiler with a temperature of

210�C as a heating medium to dry the decanter sludge

into a cake with moisture content below 10%

(Chavalparit et al. 2006). An indirect, horizontal

dryer can also be used to dry the decanter solids to

low moisture content (90% TS). The temperature of

the dryer exhaust gases is about 100�C (Chavalparit

et al. 2006). The dry decanter product can be

converted into commercial grade animal feed pellets

(Chavalparit et al. 2006; Schmidt 2007). However,

the use of this technology is not a common practice

(Schmidt 2007).

6 Environmental regulations of effluent

discharge in the palm oil industry

The environmental restrictions in palm oil industry

were decided to be a necessary licensed approach that

would permit close control of individual factories. On

the basis of prevailing environmental circumstances,

environmental restrictions also provide a mechanism

for permitting variable effluent standards. The envi-

ronmental quality regulations for the crude palm oil

industry were the first set of regulations promulgated

under the Environmental Quality Act (EQA), 1977

for control of industrial pollution source (Thani et al.

1999). The Environmental Quality (prescribed Pre-

mises) (Crude Palm Oil) Regulations 1977, promul-

gated under the enabling powers of Section 51 of the

EQA, are the governing regulations and contain the

effluent discharge standards. Other regulatory

requirements are to be imposed on individual palm

oil mills through conditions of license under Envi-

ronmental Quality Act 1974 (Act of 127). The

effluent discharge standards ordinarily applicable to

crude palm oil mills are given in Table 2.

338 Rev Environ Sci Biotechnol (2010) 9:331–344

123

7 Composting of waste generated

from palm oil mills

The improper disposal of large quantities of agro-

based industrial waste causes energy, economic, and

environmental problems. Since these wastes have a

high content of organic matter and mineral elements,

they can potentially be used to restore soil fertility

(Khan et al. 2009). The recycling of organic residues

in soil can mitigate environmental hazards resulting

from intensive agriculture (Ordonez et al. 2006).

Composting is a microbial technology that is fre-

quently used to stabilize various types of industrial

wastes such as sludge from pulp and paper mill,

sugar, oleochemical, pig rearing, olive milling etc.

Composting is attractive since it can reduce the

volume/weight of sludge (Abd-Rahman et al. 2003).

Composting can reduce the mixture volume by 40–

50%, effectively destroying the pathogens by the

metabolic heat generated in the thermophilic phase,

degrade a big number of hazardous organic pollutants

and provide a final product that can be used as a soil

amendment or fertilizer (Epstein 1997). Moreover the

composted waste is easy to handle and can be used as

soil conditioner, thus providing additional income

(Abd-Rahman et al. 2003). Composting is useful for

waste recycling and produces a chemically stable

material that can be used as a source of nutrients and

for improving soil structure (Castaldi et al. 2005).

The composting process involves the conversion

of organic residues of plant and animal origin into

manure. It is principally a microbiological process

based on the activities of several bacteria, actinomy-

cetes, and fungi (Bharadwaj 1995). The end product

is rich in humus and plant nutrients and the by-

products of composting process are carbon dioxide,

water and heat (Abbasi and Ramasamy 1999).

In the composting process, aerobic microorgan-

isms use organic matter as a substrate. The microor-

ganisms decompose the substrate, breaking it down

from complex to intermediate and then to simpler

products (Epstein 1997; Ipek et al. 2002). During

composting, compounds containing carbon and nitro-

gen are transformed through successive activities of

different microbes to more stable organic matter,

which chemically and biologically resembles humic

substances (Pare et al. 1999). The rate and extent of

these transformations depend on available substrates

and the process variables used to control composting

(Marche et al. 2003).

Naturally, composting takes place when fallen

leaves pile up and starts decaying. Eventually the

decayed leaves are returned to the soil, where living

roots reclaim the nutrients from the remains of the

leaves. Ancient people dumped foodstuff in piles near

their camps, and found the wastes rotted and formed

habitat for the seeds of many food plants that sprouted

there. Possibly this may have led to the realization that

dump heaps were good places for food crops to grow,

and humans began to put seeds there intentionally.

Apparently, recycling of organic residues through

composting seems to be an ancient practice. It has

acquired ever greater significance, and in the present

times the use of composting to turn organic wastes

into resource should be practiced with a sense of

urgency as landfill space becomes increasingly more

scarce and expensive (He et al. 1995). During

composting, most of the biodegradable organic

Table 2 Effluent discharge

standards for crude palm oil

mills (Environmental

Quality Act 1974, 2005)

* No discharge standard

after 1984

Parameter Unit Parameter limits

(second schedule)

Remarks

pH – 5–9 –

Oil and grease mg L-1 50 –

Biochemical oxygen demand

(BOD; 3 days, 30�C)

mg L-1 1,000 –

Chemical oxygen demand (COD) mg L-1 * –

Total solids mg L-1 * –

Suspended solids mg L-1 400 –

Total volatile solids mg L-1 –

Ammonical nitrogen (NH3–N) mg L-1 150 Value of filtered sample

Total nitrogen (T.N.) 200 Value of filtered sample

Rev Environ Sci Biotechnol (2010) 9:331–344 339

123

compounds are broken down and a portion of the

remaining organic material is converted into humic

acid like substances, with the production of chemi-

cally stabilized composted materials. Agricultural

application of partially decomposed or unstable

compost results in nitrogen immobilization and

decreases the oxygen concentration around root

systems due to the rapid activation of microbes.

Additionally, chemically unstable compost is phyto-

toxic due to the production of ammonia, ethylene

oxide, and organic acids (Mathur et al. 1993; Tam

and Tiquia 1994). Therefore, evaluation of compost

stability prior to its use is essential for the recycling

of organic waste in agricultural soils (Khan et al.

2009).

With the aim to boost the composting process,

increasing the degradation rate and quality of the final

compost, several modifications have been made in the

process, such as the addition of biodegradable wastes

to reach the optimum C/N ratio of about 30 (Costa

et al. 1992; Haug 1993), that is co-composting, and

the addition of chemicals to increase the reaction

rates and the composition of the compost (Bangar

et al. 1988; Brown et al. 1998). In order to reach the

optimum C/N in the composting piles, co-composting

is widely used.

Composting is widely used to produce organic

fertilizer from empty fruit bunches. Composting this

by-product resulted in 50% reduction in both the

volume as well as the transportation cost of empty fruit

bunches (Chavalparit et al. 2006). Unapumnuk (1999)

carried out the composting process for a mixture of

EFB, decanter sludge and urea (as N source). Batch

process composting was carried out in heaps, which

were piled up into a size of 2 m 9 2 m 9 1 m and

covered with plastic. The composting piles were turned

regularly to maintain aerobic condition. Spraying of

water was also done on piles to maintain the moisture

content around 50–60% in the composting process. The

composting piles having initial C:N ratio of 39:1

showed a rapid degradation rate and maturated in

80 days (Unapumnuk 1999). The mature compost

contained N, P2O5 and K2O equal to 2.26, 3.3 and

2.25% of the total matter, respectively. Compost finally

obtained would replace chemical fertilizers equivalent

to about 13.5 Baht ton-1 (Unapumnuk 1999). Average

nutrient content of EFB has been reported as 0.8% N,

0.1% P, 2.5% K and 0.2% Mg approximately on a dry

weight basis (Gurmit et al. 1981).

Baharuddin et al. (2009) carried out a study with

the objective of investigating the physicochemical

changes during co-composting Empty Fruit Bunch

(EFB) with partially treated palm oil mill effluent

(POME) on a pilot scale. The partially treated POME

from anaerobic pond was sprayed onto the shredded

EFB throughout the treatment. For proper aeration

the composting piles were turned over 1–3 times per

week. Temperature as well as oxygen content was

monitored at different depths of the composting piles.

The temperature was reported to increase and reached

up to 58.5�C on the third day of treatment. After that

the temperature fluctuated between 50 and 62�C and

then it decreased in the latter stage of the process

(Baharuddin et al. 2009). The pH of the system

(7.75–8.10) did not vary significantly throughout the

treatment period while moisture content reduced

from 65–75% to about 60% at the end of the

treatment. The initial C/N ratio of 45 was signifi-

cantly reduced upto 12 after 60 days of composting.

The final compost contained a considerable amount

of nutrients (carbon, nitrogen, phosphorus, potassium,

calcium, magnesium, sulfur and iron) and trace

amounts of manganese, zinc, copper (Baharuddin

et al. 2009). Additionally very low levels of heavy

metals were also detected in the compost. The

bacterial count involved in the composting process

was found to decrease at the end of the composting

period. Baharuddin et al. (2009) also reported that

pilot scale co-composting EFB with partially treated

POME gave acceptable quality of compost and ease

in operation. The compost product finally obtained

can be used in palm oil plantations as fertilizer and

for soil amendment (Baharuddin et al. 2009).

Zahrim et al. (2007) carried out in-vessel compost-

ing study of palm oil mill sludge (POMS) with sawdust

as an alternative waste management option. Sludge

was collected from Sri Ulu Langat Palm Oil Mill,

Dengkil, Selangor, Malaysia, and sawdust was col-

lected from various furniture factories around Bangi,

Selangor. A mixture of POMS–sawdust (52 kg sludge

and 28 kg sawdust) which was mixed manually was

put in a 0.3 m3 bioreactor. Temperature is one of

the important indicators for a composting process

(Nogueira et al. 1999). Zahrim et al. (2007) reported

that maximum temperature for the reactor was about

40�C. Composting of most substrates is characterized

by an initial period of rapid degradation followed by a

longer period of slow degradation (Diaz et al. 2002).

340 Rev Environ Sci Biotechnol (2010) 9:331–344

123

The organic matter (OM) degradation profile

during composting process, determined by the OM

loss, followed a first order kinetic equation with a

degradation rate (k) of 0.014 day-1 and 51% max-

imum OM loss (Zahrim et al. 2007). Nutrient content

in POMS compost is comparable with other industrial

sludge compost. Compost of palm oil mill–sawdust

mixed with sand was found to improve the growth of

C. citrates (Zahrim et al. 2007). Therefore compost-

ing can be a suitable method for converting palm oil

mill sludge into compost that can be used as a pot or

container growing medium.

Empty fruit bunch is a suitable raw material for

recycling as it is produced in large quantities as waste

product from palm oil mill. It is often used as fuel to

generate steam in the mills (Ma et al. 1993). The

bunch ash produced as a result of burning (about

6.5% by weight of the EFB) contains about 30–40%

K2O. The ash is used as a fertilizer for the potassium,

K (Lim 2000) and has been found to improve the

yield of oil palm grown on acid coastal soils in

Malaysia (Hew and Poon 1973; Toh et al. 1981).

To prevent air pollution, the process of incinera-

tion was restricted by the Department of Environment

(DOE) through the Environmental Quality Clean Air

Regulation Act, 1978. The EFB is now used mainly

as mulch (Hamdan et al. 1998). The EFB helps in

controlling weeds, prevent erosion and maintain soil

moisture, when placed around young palms. The

transportation and distribution of EFB in the field is

getting more expensive due to the labor cost. Now

there is a growing interest in composting EFB, in

order to add value, and also to reduce the volume to

make its application easier (Yusri et al. 1995;

Thambirajah et al. 1995; Damanhuri 1998).

An average oil palm mill can handle about

100 metric tonnes of fresh fruit bunches daily. At

the mills where oil extraction takes place, solid

residues and liquid wastes are generated. The solid

residues, mainly EFB, are more than 20% of the fresh

fruit weight (Ma et al. 1993; Kamarudin et al. 1997).

EFB is a common raw material used in composting.

Other materials are often added, particularly chicken

manure and POME. POME contains very high

nutrient content (Zakaria et al. 1994), and direct

utilization of POME as fertilizer has been preferred

by large oil palm plantations. The sediments left after

POME treatment, which is also known as palm oil

mill sludge (POMS) have a higher nutrient value than

the slurry (Zakaria et al. 1994) and are either recycled

to the field or sold to the public.

Hamdan et al. (1998) carried out the decomposi-

tion study of EFB in oil palm plantations. The EFB

was spread in the field as mulch on top of nylon net at

a rate of 30, 60 and 90 mt/ha/year. Spots were

selected for N supplementation to meet a required

C/N ratio of 15, 30 and 60 (control) at each EFB

application rate. Decomposition was estimated by the

weight of EFB remaining in the nylon net (Hamdan

et al. 1998). After 10 months of application the EFB

was found to be completely decomposed (Hamdan

et al. 1998).

Different organic N rich sources, such as goats,

cattle and chickens manure, have also been evaluated

as N additives for the composting of EFB (Thambi-

rajah et al. 1995). EFB compost with goat manure,

cattle manure and chicken manure had a C/N ratio of

14:1, 18:1 and 12:1, respectively, after 60 days of

composting, while the control without manure had a

C/N ratio of 24:1.

8 Conclusion

Crude palm oil mills generate various by-products

and large quantities of wastewater, which may have a

significant impact on the environment if not managed

properly. As waste produced from palm oil mills are

biological in nature and have high organic content,

composting as well as co-composting can be a good

option. These wastes may create environmental

problems with time due to high organic content.

Improper disposal in open area may result in

contamination of ground water via leaching or nearby

waterbody through runoff water. The improper waste

management practice may also result in aesthetic

problem, air borne diseases and also may be causal of

several vector borne diseases. Therefore, environ-

mental management should place the greatest empha-

sis in waste minimization at source or recycling.

Composting provides a viable alternative method for

managing organic wastes.

Acknowledgments The study was funded through Universiti

Sains Malaysia (USM) short-term grant number 304/

PTEKIND/ 6310003. The authors acknowledge USM for

providing research facilities.

Rev Environ Sci Biotechnol (2010) 9:331–344 341

123

References

Abbasi SA, Ramasamy EV (1999) Biotechnological methods

of pollution control. Orient Longman (Univesities Press

India Ltd.), Hyderabad

Abd-Rahman R, Kalil Mohd S, Abu Zahrim Y (2003) Com-

posting palm oil mill sludge—sawdust: effect of different

amount of sawdust. In: Proceedings of national workshop

in conjunction with ARRPET workshop on wastewater

treatment and recycling 2: removal chloroorganics and

heavy metals. ISBN 983-2982-04-9

Agamuthu P (1995) Palm oil mill effluent treatment and uti-

lization. In: Sastry CA, Hashim MA, Agamuthu P (eds)

Waste treatment plant. Narosa Publishing House, New

Delhi, pp 338–360

Ahmad AL, Ismail S, Bhatia S (2005) Optimization of coa-

guration—flocculation process for palm oil mill effluent

using response surface methodology. Environ Sci Technol

39:2828–2834

Aisueni NO, Omoti U (1999) The making of compost from empty

oil palm bunch refuse. Books of abstracts. Soil science society

of Nigeria conference, Benin, vol 21–25, pp 48–49

Baharuddin AS, Wakisaka M, Shirai Y, Abd Aziz S, Abdul

Rahman NA, Hassan MA (2009) Co-composting of empty

fruit bunches and partially treated palm oil mill effluents

in pilot scale. Int J Agric Res 4(2):69–78

Bangar KC, Kapoor KK, Mishra MM (1988) Effect of pyrite

on conservation of nitrogen during composting. Biol

Waste 25:227–231

Bharadwaj KKR (1995) Improvements in microbial compost

technology: a special reference to microbiology of com-

posting. In: Khanna S, Mohan K (eds) Wealth from waste.

Tata Energy Research Institute, New Delhi, pp 115–135

Borowitzka MA, Critchley AT, Kraan S, Peters A, Sjøtun K,

Notoya M (2009) Nineteenth international seaweed sym-

posium, Vairappan CS, Yen AM, Palm oil mill effluent

(POME) cultured marine microalgae as supplementary

diet for rotifer culture. Springer, Netherlands. Dev Appl

Phycol. doi: 10.1007/978-1-4020-9619-8_20

Brown MJ, Robbins CW, Freeborn LL (1998) Combining

cottage cheese whey and straw reduces erosion while

increasing infiltration in furrow irrigation. J Soil Water

Conserv 53:152–156

Castaldi P, Alberti G, Merella R, Melis P (2005) Study of the

organic matter evolution during municipal waste solid

composting aimed at identifying suitable parameters for

the evaluation of compost maturity. Waste Manag

25:209–213

Chan KS, Chooi CF (1982) Ponding system for palm oil mill

effluent treatment. In: Proceedings of regional workshop

on palm oil mill technology and effluent treatment. PO-

RIM, Malaysia, pp 185–192

Chavalparit O, Rulkens WH, Mol APJ, Khaodhair S (2006)

Options for environmental sustainability of the crude palm

oil industry in Thailand through enhancement of industrial

ecosystems. Environ Dev Sustain 8:271–287

Chooi C F (1984) Ponding system for palm oil mill effluent

treatment. In: Proceeding on workshop of palm oil mill

effluent technology, July 31, 1984, PORIM, Kuala Lum-

pur, pp 53–63

Chow MC, Ho CC (2000) Surface active properties of palm oil

with respect to the processing of palm oil. J Oil Palm Res

12(1):107–116

Corley RHV (1983) Potential productivity of tropical perennial

crops. Exp Agric 19:217

Costa F, Garcıa C, Hernandez T (1992) Residuos organicos

urbanos. Manejo y utilizacio n. CSIC, Madrid

Danmanhuri MA (1998) Hands-on experience in the production

of empty fruit bunches (EFB) compost. Paper presented at

the CETDEM malaysian organic farming seminar, Petal-

ing, Jaya, Selangor, Malaysia, pp. 50–61. Dateline: 25/10/

2002 09:45:09r

Davis JB, dan Reilly PJA (1980) Palm oil mill effluent—a

summary of treatment methods. Oleagineux 35:323–330

Diaz MJ, Madejon E, Lopez F, Lopez R, Cabrera F (2002)

Optimisation of the rate vinasse/grape marc for co-com-

posting process. Proc Biochem 37:1143–1150

DOE (1991) Progress in Malaysia towards environmentally

sound and sustainable development 1976–1990. Depart-

ment of Environment, Ministry of Science, Technology

and the Environment, Malaysia, p 4

Epstein E (1997) The science of composting. Technomic

Publishing Co. Inc., Lancaster

Gurmit S, Manoharan S, Kanapathy K (1981) Commercial

scale bunch mulching of oil palm. In: Proceedings 1981

international conference on the oil palm in agriculture in

the eighties, Kuala Lumpur, pp 367–377

Hamdan AB, Tarmizi AM, Tayeb Mohd D (1998) Empty fruit

bunch mulching and nitrogen fertilizer amendment: the

resultant effect on oil palm performance and soil proper-

ties. PORIM Bull Palm Oil Res Inst Malaysia 37:105–111

Haug RT (1993) The practical handbook of compost engi-

neering. Lewis Publishers, London

He XT, Logan TJ, Traina SJ (1995) Physical and chemical

characteristics of selected US municipal solid waste

composts. J Environ Qual 24(3):543–552

Henson IE (1990). Estimating potential productivity of oil palm.

In: Proceedings of 1990 ISOPB international workshop on

yield potential of oil palm, PORIM, pp 98–102

Hew CK, Poon YC (1973) The effects of muriate of potash and

bunch ash on yield and uptake of potassium and chlorine

in oil palms on coastal soils. In: Wastie RL, Earp DA

(eds) Advances in oil palm cultivation. Incorporated

Society of Planters, Kuala Lumpur, pp 239–244

Hwang TK, Ong SM, Seow CC, Tan HK (1978) Chemical

composition of palm oil mill effluents. Planter 54:749–756

Igwe JC, Onyegbado CC (2007) A review of palm oil mill

effluent (Pome) water treatment. Global J Environ Res

1(2):54–62

Industrial Processes and the Environment (1999) Department

of Environmental Malaysia, Handbook, vol 3, pp 1–90

Ipek U, Obek E, Akca L, Arslan EI, Hasar H, Dogru M, Baykara

O (2002) Determination of degradation of radioactivity

and its kinetics in aerobic composting. Bioresour Technol

84:283–286

Ismail ZI (2004) New machine set to boost palm kernel cake

industry. New Straits Times, Malaysia

Kamarudin HH, Mohamad DA, Johari S (1997) An estimated

availability of oil palm biomass in Malaysia. PORIM Occ

Paper Palm Oil Res Inst Malaysia, p 37

342 Rev Environ Sci Biotechnol (2010) 9:331–344

123

Kennedy AG, Hishamuddin O (2001) Bioremediation of treated

and raw POME (Palm Oil Mill Effluent) using Spirulina

plantensis. In: Japar Sidik B, Arshad A, Tan SG, Dacud SK,

Jambari HA, Sugiyama S (eds) Aquatic resources and

environment studies of the straits of Malacca: current

research and reviews, Kuala Lumpur, pp 203–210

Khalid R, Wan Mustafa WA (1992) External benefits of

environmental regulation: resource recovery and the util-

isation of effluents. The Environmentalist 12:277–285

Khan MAI, Ueno K, Horimoto S, Komai F, Tanaka K,

Yoshitaka O (2009) Physicochemical, including spectro-

scopic and biological analyses during composting of green

tea waste and rice bran. Biol Fertil Soils 45:305–313

Kittikun AH, Prasertsan P, Srisuwan G, Krause A (2000)

Environmental management of palm oil mill. Internet

conference on material flow analysis of integrated bio-

systems. March–October 2000. http://www.ias.unu.edu/

proceedings/icibs/ic-mfa/kittikun/paper.html

Kolade OO, Coker AO, Sridhar MKC, Adeoye GO (2006)

Palm kernel waste management through composting and

crop production. J Environ Health Res UK 5(2):81–85

Latiff A (2000) The biology of the genus Elaeis. In: Yusof B,

Jalani BS, Chan KW (eds) Advances in oil research, vol I.

Malaysian Palm Oil Board (MPOB), pp 19–38

Lim B (2000) The new straits times, 28 Dec 2000

Lorestani AA Zinatizadeh (2006) Biological treatment of palm

oil mill effluent (POME) using an up-flow anaerobic sludge

fixed film (UASFF) bioreactor. Ph.D. thesis, School of

Chemical Engineering, Universiti Sains Malaysia

Ma AN (1995) A novel treatment for palm oil mill effluent.

Palm Oil Res Inst Malaysia (PORIM) 29:201–212

Ma AN (1999a) Treatment of palm oil mill effluent. In: Singh

G, Lim KH, Leng T, David LK (eds) Oil palm and the

environment: a Malaysian perspective. Malaysia Oil Palm

Growers’ Council, Kuala Lumpur, pp 113–126

Ma AN (1999b) Treatment of palm oil mill effluent. In: Singh G,

Huan LK, Teo L, Lee DK (eds) Oil palm and the environ-

ment. A Malaysian perspective. Malaysian Oil Palm

Grower’ Council, Malaysia, pp 113–123

Ma AN (2000) Environmental management for the palm oil

industry. Palm Oil Dev 30:1–10

Ma AN, Ong ASH (1985) Pollution control in palm oil mills in

Malaysia. J Am Oil Chem Soc 62:261–266

Ma AN, Cheah SA, Chow MC (1993) Current status of palm

oil processing waste management. In: Yeoh BG et al (eds)

Waste management in Malaysia: current status and pros-

pects for bioremediation, pp 111–136

Marche T, Schnitzer M, Dinel H, Pare T, Champagne P,

Schulten HR, Facey G (2003) chemical changes during

composting of a paper mill sludge—hardwood sawdust

mixture. Geoderma 116:345–356

Mathur SP, Owen G, Dinel H, Schnitzer M (1993) Determi-

nation of compost biomaturity. I. Literature review. Biol

Agric Hortic 10:65–85

MPOB (1999) Malaysian oil palm statistics, 19th edn.

Malaysian Palm Oil Board, Kuala Lumpur

MPOB (2001) Oil palm statistics, 21st edn. MPOB, Bangi, p 131

MPOB (2008a) A summary on the performance of the

Malaysian oil palm industry—2008. http://econ.mpob.

gov.my/economy/Performance-130109.htm

MPOB (2008b) Palm oil: demand and controversy, a summary

of the performance of the Malaysian Oil Palm Industry

2008. Available at http://www.climateavenue.com/en.

biod.palm.exp.demand.htm

Nogueira WA, Nogueira FN, Devens DC (1999) Temperature

and pH control in composting coffee and agricultural

wastes. Water Sci Tech 41(1):113–119

Olie JJ, Tjeng TD (1972) Traitment et evacuation des eaux

residuaires d’une huilerie de palm. Oleagineux 27:215–218

Onwueme IC, Sinha TD (1991) Field crop production in tropical

Africa. CTA (The Technical Centre for Agricultural and

Rural Co-operation), Ede, The Netherlands, pp 1–480

Ordonez C, Tejada M, Benitez C, Gonzalez JL (2006) Charac-

terization of a phosphorus—potassium solution obtained

during a protein concentrate process from sunflower flour.

Application on rye-grass. Bioresour Technol 97:522–528

Paepatung N, Kullavanijaya P, Loapitinan O, Songkasiri W,

Noppharatana A. Chaiprasert P (2006) Assessment of

biomass potential for biogas production in Thailand. Final

report submitted to The Joint Graduate School of Energy

and Environment, Bangkok, Thailand (in Thai)

Paepatung N, Noppharatana A, Songkasiri W (2009) Bio-

methane potential of biological solid materials and agri-

cultural wastes. As J Energy Environ 10(01):19–27

Pare T, Dinel H, Schnitzer M (1999) Extractability of trace

metals during co-composting of biosolids and municipal

solid wastes. Biol Fertil Soils 29:31–37

Pleanjai S, Gheewala SH, Garivait S (2004) Environmental

evaluation of biodiesel production from palm oil in a life

cycle perspective. The joint international conference on

‘‘Sustainable Energy and Environment (SEE)’’, Hua Hin,

Thailand, 1–3 Dec 2004

Prasertsan S, Prasertsan P (1996) Biomass residues from palm

oil mills in Thailand: an overview on quantity and

potential usage. Biomass Bioenergy 11(5):87–395

Schmidt J (2007) Life cycle assessment of rapeseed oil and

palm oil. Ph.D. thesis, Part 3, Alborg University, Denmark

Stanton WR (1974) Treatment of effluent from palm oil fac-

tories. Planter 50:382–387

Syed RA, Law IH, Corley RHV (1982) Insect pollination of oil

palm: introduction, establishment and pollinating effi-

ciency of Elaeidobius kamerunicus in Malaysia. The

Planter, Kuala Lumpur, vol 58, pp 547

Tam NFY, Tiquia SM (1994) Assessing toxicity of spent pig

litter using a seed germination technique. Resour Conserv

Recycl 11:261–274

Tate DJM (1996) The RGA history of the plantation industry in

the Malay Peninsula. Oxford University Press, New York,

p 688

Thambirajah JJ, Zulkifli MD, Hashim MA (1995) Microbio-

logical and biochemical changes during the composting

of oil palm empty fruit bunches; effect of nitrogen sup-

plementation on the substrate. Bioresour Technol 52:

133–144

Thani MI, Hussin R, Ibrahim WWR, Sulaiman MS (1999)

Industrial processes & the environment: crude palm oil

industry, Handbook No. 3. Department of Environment,

Kuala Lumpur, pp 7–54

Toh PY, Poon YC, Yeow KH (1981) Bunch ash as a nutrient

source in oil palms. In: Proceedings national workshop

Rev Environ Sci Biotechnol (2010) 9:331–344 343

123

on oil palm by-product utilization, Kuala Lumpur,

pp 135–139

Ugoji EO (1997) Anaerobic digestion of palm oil mill effuene

and its utilization as fertilizer for environmental/roteltion.

Renew Energy 10(2):20

Unapumnuk K (1999) Solid waste management in palm oil

mills: a case study in Thailand. Master’s Thesis, Asian

Institute of Technology, Thailand

United States Department of Agriculture (USDA) (2007)

Indonesia: palm oil production prospects continue to

grow. Available at http://www.pecad.fas.usda.gov/high

lights/2007/12/Indonesia_palmoil/

Vairappan CS, Yen AM (2008) Palm oil mill effluent (POME)

cultured marine microalgae as supplementary diet for

rotifer culture. J Appl Phycol 20(5):153–158

Yacob S (2008) Progress and challenges in utilization of palm

biomass, Advanced Agriecological Research Sdn. Bhd. http://

www.jst.go.jp/asts/asts_j/files/ppt/15_ppt.pdf. Accessed 27

Nov 2008

Yacob S, Hassan MA, Shirai Y, Wakisaka M, Subash S (2005)

Baseline study of methane emission from open digesting

tanks of palm oil mill effluent treatment. Chemosphere 59:

1575–1581

Yusoff S, Hansen SB (2007) Feasibility study of performing an

life cycle assessment on crude palm oil production in

Malaysia. Int J Life Cycle Assess 12:50–58

Yusri A, Mat Rasol A, Mohammed O, Azizah H, Kume T,

Hashimoto S (1995) Biodegradation of oil palm empty

fruit bunch into compost by composite micro-organisms.

Paper presented at the EU-ASEAN conference on com-

bustion of solids and treated product

Zahrim Y, Rakmi AR, Kalil MS (2007) Sludge composting: a

case study on palm oil mill sludge (POMS). AJChE 7(2):

102–107

Zakaria ZZ, Khalid H, Hamdan AB (1994) Guidelines on land

application of palm oil mill effluent (POME). PORIM

Bull Palm Oil Res Inst Malaysia, p 28

344 Rev Environ Sci Biotechnol (2010) 9:331–344

123