Baseline study of methane emission from open digesting tanks of palm oil mill effluent treatment

Anthropogenic release of greenhouse gases, especially CO₂ and CH₄ has been recognized as one of the main causes of global warming. Several measures under the Kyoto Protocol 1997 have been drawn up to reduce the greenhouse gases emission. One of the measures is Clean Development Mechanisms (CDM) that was created to enable developed countries to cooperate with developing countries in emission reduction activities. In Malaysia, palm oil industry particularly from palm oil mill effluent (POME) anaerobic treatment has been identified as an important source of CH₄. However, there is no study to quantify the actual CH₄ emission from the commercial scale wastewater treatment facility. Hence, this paper shall address the CH₄ emission from the open digesting tanks in Felda Serting Hilir Palm Oil Mill. CH₄ emission pattern was recorded for 52 weeks from 3600 m³ open digesting tanks. The findings indicated that the CH₄ content was between 13.5% and 49.0% which was lower than the value of 65% reported earlier. The biogas flow rate ranged between 0.8 l min⁻¹ m⁻² and 9.8 l min⁻¹ m⁻². Total CH₄ emission per open digesting tank was 518.9 kg day⁻¹. Relationships between CH₄ emission and total carbon removal and POME discharged were also discussed. Fluctuation of biogas production was observed throughout the studies as a result of seasonal oil palm cropping, mill activities, variation of POME quality and quantity discharged from the mill. Thus only through long-term field measurement CH₄ emission can be accurately estimated.     

Understanding the role and influence of social norms: lessons for NRM

Much has been written about social norms in disciplines such as law and economics but they are less studied in the field of Natural Resource Management (NRM). Although norms are acknowledged to be an influence on decision–making, they are difficult to identify and measure in the field and their role is often implicit or not well understood or articulated. This paper addresses an important knowledge gap by combining social norms theory with the specifics of a particular case study. We examined the influence of social norms on landholder behaviour in a small rural community undergoing demographic change in Australia. Findings from interviews with landholders and government agency personnel indicate that established norms within the farming community are influencing incoming landholders; and that new norms and practices have also emerged as a result of government investment through the local Landcare group. We suggest that a better understanding of social norms in different contexts will give rise to strategies that make NRM interventions more effective.     

Reduction of Methane Released from Palm Oil Mill Lagoon in Malaysia and Its Countermeasures

Palm oil industry in Malaysia is one of the potential candidates for the CDM project because large amount of methane is emitted from the lagoons and open digesting tank of the wastewater treatment system. Therefore the first objective of the project is to investigate the actual GHG emission from the lagoons and open digesting tank in palm oil mills in order to establish the baseline for CDM project. Results indicated that methane contribution to biogas released from the open digesting tank and lagoon systems were 35% and 45%, respectively. These values are much lower than the reported value of 65% obtained by complete anaerobic condition of lab-scale experiments. Based on actual methane release measurement and information gathered from palm oil mill about wastewater treatment, significant amount of methane emission to the atmosphere can be reduced with the installation of new closed digesting tank system converted from the open digesting tank such as just by covering it with applying CDM. It is estimated that a total of RM2.6 million could be obtained from the selling of electricity generated from biogas generation and Certified Emission Reduction(CER). This revised version was published online in August 2006 with corrections to the Cover Date.     

Gamma-ray activity in the volcanic islands of the Southern Tyrrhenian Sea

Field gamma-ray spectrometry was used for the quantitative assessment of U, Th and K of rocks of Stromboli, Salina, Filicuidi and Panarea (Aeolian arc of the Southern Tyrrhenian, Italy). The air absorbed dose rate was calculated from radioelement concentrations. For some rocks the gamma-ray spectra were analysed with the three photo-peak methods and the response matrix method, which converts the pulse height distribution into the true incident gamma-ray energy spectrum. The higher values of U (8.2-9.8 ppm) coincide with higher Th (20.6-27.8 ppm) concentrations associated with rocks of shoshonitic composition. The spatial variation in radioelement concentration reflects the geochemical differences among the rocks. The air absorbed dose rate varies from 25 to 215 nGy h(-1). The highest values correspond to outcrops located in the eastern part of Stromboli, where the annual effective dose equivalent reaches a value of 264 microSv.