W ASTE AND POLLUTION FROM PALM OIL PRODUCTION AND MANAGEMENT

The two main wastes resulting from palm oil production in a mill are the solid and liquid wastes. Solid wastes typically consist of palm kernel shells (PKS), mesocarp fruit fibres (MF) and empty fruit bunches (EFB). The liquid waste generated from the extraction of palm oil of wet

process comes mainly from oil room after separator or decanter. This liquid waste combined with the wastes from steriliser condensate and cooling water is called palm oil mill effluent (POME) (ADB, 2006). Figure 5.1 shows the different point sources of waste in palm oil milling.

Air emission from the oil palm mills are from the boilers and incinerators and are mainly gases with particulates such as tar and soot droplets of 20-100 microns and a dust load of about 3000 to 4000 mg/nm. Incomplete combustion of the boiler and incinerator produce dark smoke resulting from burning a mixture of solid waste fuels such as shells, fibres and sometimes EFB.

These boiler fly ashes are also wastes and pose problems of disposal.

Figure 5.1 Sources of waste from palm oil milling (redrawn from ADB, 2006)

From the palm oil mills, according to the Asian Development Bank (ADB) study, the impacts of palm oil processing activities to the environment are in the following (ADB, 2006):

• Biogas generated from the anaerobic digestion escapes into the atmosphere and such biogas contains about 65% methane, which is one of the most potent greenhouse gases;

• The incineration of EFB emits particulates into the surrounding atmosphere; and

• Indiscriminate dumping of EFB causes additional methane emission into the atmosphere.

In terms of water pollution, illegal disposal of POME into waterways creates some problems related to killing of life-forms in the water (Ahmad et al., 2003; Shirkie and Ji, 1983).

However, because of the strict current regulation and stringent standard on effluent discharge imposed by the Malaysian Department of Environment, nowadays, it is difficult to find a case of direct POME disposal into water bodies in Malaysia. Even if such illegal practice exists, it is a

Waste from Palm

limitation of this paper not to find a report about illegal discharges of POME. Nevertheless, to illustrate the impact of illegal POME disposal and the pollution it causes, the article of Shirkie and Ji (1983) provides a good picture of such environmental crime. Shirkie and Ji (1983) reported that large amount of wastewater from palm oil mills were released during the 1970s that most of the major river basins along the west coast of Malaysia were affected. According to the report, the waterways received not only the suspended and dissolved wastes, but also acidic phenol compounds. The result was a stink that discouraged people from using the water to drink, wash clothes or utensils or bathe. Since such incidence, however, the Government of Malaysia enacted legislation in 1977 to regulate pollution form palm oil industry. Until then, few palm oil factories had any means of controlling their waste discharges. To date, water pollution due to POME is under the control and regulation set by the Malaysian Department of Environment.

In terms of waste management, the demand is generally driven by the government first and then by the private sector. The government is typically responsible for policies and regulations that establish standards for enforcement of waste management practices. The private sector is responsible for productive use of technologies (ADB, 2006). The Malaysian experience in effluent control in the palm oil industry demonstrates that a set of well designed environmental policies can be very effective in controlling industrial pollution. The Malaysian government’s efforts to reduce the effluent from palm oil industry have been implemented through a licensing system, which mainly consists of effluent standards and effluent charges. Progressively, stringent effluent standards were stated in the government’s environmental quality regulations (Igwe and Onyegbado, 2007).

Solid wastes, mainly PKS and MF are used for in-house energy generation. PKS are used as a source of fuel for the boilers. The fibres recovered from the nut/fibre separation stage are good combustible materials and can be used as fuel to the boiler. The fibres constitute the bulk of materials used to fire large boilers for generating superheated steam to drive turbines for electrical power generation.

Unfortunately, the shells contain silicates that form scales in the boilers. Also, when too much shells are fed into the furnace, it limits the amount of shells that can be utilised in the boilers.

Residual shell is disposed of as gravel for plantation roads maintenance. The application of shells for road hardening has no impact to environment.

EFB are partly dried in the sun and later used as fuel, if not incinerated or applied to the fields. An economic use of EFB is to return them to the plantation as a mulch to enhance moisture retention and organic matter in the soil. On the other hand, the ash recovered from the incinerated EFB can also be sold or used as fertiliser in the palm plantations (ADB, 2006).

Boiler ash is recycled as fertiliser and factory floor cleaning agent. The potash in the ashes reacts with the oil to form a weak potash soap that is washed away with water. In the bid to achieve a zero discharge of the palm oil mill, boiler fly ash have been used to reduce the biochemical oxygen demand (BOD), total suspended solid (TSS), colour and other contaminants from POME before discharge. According to Igwe and Onyegbado (2007), boiler fly ash has also been used in the removal of heavy metals from other industrial effluents.

Liquid waste treatment involves anaerobic fermentation followed by aerobic fermentation in large ponds until the effluent quality is suitable for discharge. As observed in some mills, the

treated effluent can be used in the farm as manure and source of water for irrigation. The sludge accumulating in the fermentation ponds is periodically removed and transferred to the land.