Landfill gas generation and methane recovery at Naboro landfill, Fiji Islands: a case study from a developing Pacific Island country

The Naboro landfill in Suva, the capital city of Fiji Islands, is a sanitary engineered landfill, consisting of a compacted clay protective liner and leachate collection system. The waste is selectively placed, compacted and then covered with soil. The landfill was commisioned in 2005 and is currently receiving an average of 70,000 tonnes of waste annually. The municipal solid waste deposited in the landfill undergoes anaerobic decomposition and the methane gas generated escapes into the atmosphere, adding to the national greenhouse gas inventory. Currently there are no methane recovery and biogas utilisation technology in place or methane flaring at the Naboro landfill site. A feasibility study was carried out recently and based on the model output and field experiments, it was noted that methane recovery and utilisation could be a viable option although there could be some challenges associated with it. According to the waste chaacterization data supplied by the landfill operator it was noted that 83% is house hold waste, 11% is garden waste and 5% is food waste and 1% construction and demolition waste. Based on the type of waste deposited and the tropical weather condition it was calculated using the model that approximately 800 m3/h of methane is generated in 2016. Figure below shows the landfill gas generated at the Naboro landfill from stage 1 to stage 4. Due to tropical humid weather condition and waste rich is organic waste that decomposes rapidly results in the yearly average emission of 74% of total methane generated despite methane recovery via vertical wells installed at the end of each stage. The emission equates to 47,000 tons of CO2 equivalent per year despite methane recovery. The emission can be reduced if the methane generated could be extracted using vertical recovery wells half way through each stage rather than at the end of each stage and as a consequence a slight decrease in yearly average emissions of 41,000 tons of CO2 equivalent were noted. Another approach is to lay horizontal wells as the waste is compacted in the active cell and this could increase the efficiency of landfill gas extraction. The model result indicate that the use of horizontal wells reduces the yearly average emission to 55% of total methane generated. This highlights the fact that approximately 45 % of the methane generated could be harnessed and could be utilized to generate energy using gas engines. However a large fraction of the methane generated is still lost as emission to the atmopshere and this can be further reduced by enhancing the oxdising capacity of the soil cover. The methane oxidation in cover soil was measured to be 10.3% by measuring the CH4-CO2 ratios in the static chamber measurements. The experimental value is close to the IPCC default value of 10%. The paper will discuss other challenges associated with methane recovery at Naboro landfill particularly with landfill gas management

Study of the chemical composition of argan oil according to the shape of the fruit

The aim of this study was to investigate the effect of phenotypic diversity of argan fruit with different morphological characteristics (fusiform, oval, apiculate and spherical) on fat and protein content, inflexibility and fat chemical composition, oil acids and sterols. To investigate the links of argan fruit shape with the chemical composition of argan oil, with the help of native communities, 4 different fruit shapes (fusiform, apiculate, spherical and oval) were selected, which were harvested from the same place (Tamanar) in Essaouira province (South Plain region, Western Morocco). After harvesting the fruit of the argan tree, 100 samples were taken from each form. They were crushed to destroy the core. After extraction of hexane with Soxhlet, fat content, protein level, unsaponifiable content, composition of fatty acids and sterols in fat were determined. The results showed that the oval shape is the best shape of argan fruit because their kernels contain more than 50% fat and a higher percentage of unsaponifiables. The results on fatty acids and sterols showed that argan oil contained 80% of unsaturated fatty acids. The results also showed that the main products of the sterol composition in argan oil were schottenol (or Δ-7-stigmasterol) (42.8 and 46.4%) and spinasterol (39.8 and 45.6%). The study of the chemical composition showed that there was no correlation between the shape of the fruit of the argan tree and the composition of fatty acids. Depending on the shape of the argan fruit, fatty acids and sterols were not only related to the shape but also to the nature of the soil and its altitude, longitude and distance from the sea

Ozone in the Pacific tropical troposphere from ozonesonde observations

Ozone vertical profile measurements obtained from ozonesondes flown at Fiji, Samoa, Tahiti, and the Galapagos are used to characterize ozone in the troposphere over the tropical Pacific. There is a significant seasonal variation at each of these sites. At sites in both the eastern and western Pacific, ozone mixing ratios are greatest at almost all levels in the troposphere during the September‐November season and smallest during March‐May. The vertical profile has a relative maximum at all of the sites in the midtroposphere throughout the year (the largest amounts are usually found near the tropopause). This maximum is particularly pronounced during the September‐November season. On average, throughout the troposphere, the Galapagos has larger ozone amounts than the western Pacific sites. A trajectory climatology is used to identify the major flow regimes that are associated with the characteristic ozone behavior at various altitudes and seasons. The enhanced ozone seen in the midtroposphere during September‐November is associated with flow from the continents. In the western Pacific this flow is usually from southern Africa (although 10‐day trajectories do not always reach the continent) but also may come from Australia and Indonesia. In the Galapagos the ozone peak in the midtroposphere is seen in flow from the South American continent and particularly from northern Brazil. High ozone concentrations within potential source regions and flow characteristics associated with the ozone mixing ratio peaks seen in both the western and eastern Pacific suggest that these enhanced ozone mixing ratios result from biomass burning. In the upper troposphere, low ozone amounts are seen with flow that originates in the convective western Pacific

The Great Astrolabe Reef lagoon (Fiji) : results of the french-fijian ASTRO expedition

During the joint Fijian-French ASTRO cruise conducted in April 1994 in the Great Astrolabe lagoon and surrounding oceanic waters. Nutrient concentration and particulate organic matter stock and sedimentation rate was quantitatively investigated at 10 sampling stations. Dissolved inorganic nutrient concentrations were low in all the lagoon. Average POC and PON concentrations were respectively 144 and 20 mg/m3. The average sedimentation rate for these elements were 37 and 8 mg/m2/day. (Résumé d'auteur

Ossified haematomas and infectious bone changes on the anterior tibia: Histomorphological features as an aid for accurate diagnosis

Examination of the histological structure of bone not only helps investigators to estimate age at death, but can also aid in the diagnosis of palaeopathological lesions. The purpose of this paper is to assess whether histological features, as described in the literature, can confirm the macroscopic diagnoses of ossified subperiosteal haematomas, associated with healed scurvy, and syphilitic bone changes observed on the anterior tibiae of individuals from a 19th century mining community from Kimberley, South Africa. The frequent occurrence of these two diseases amongst the deceased was well established in related hospital documents and governmental documents. A section of bone was removed from lesions on the tibiae of 14 individuals. These bone changes were macroscopically diagnosed as being indicative of either treponematosis, ossified subperiosteal haematomas, or non-specific periostitis. Cross-sections were prepared for microscopic investigation, using a manual ground section technique. Ossified haematomas were histologically identified in seven individuals. These sections were characterised by normal cortical bone, an intact original periosteal surface, and newly formed, radiating trabecular bone apposing it. Three phases of ossified subperiosteal haematoma formation and remodelling could be distinguished. Infectious bone changes, most likely associated with treponematosis, were observed in one individual. These were characterised by lysis and numerous resorption holes/channels. No clear distinction could be made between the internal spongy, cortical or newly formed bone. Histological features described by some authors as characteristic of this condition could not be identified. In addition, three individuals presented with microscopic features indicative of both the aforemen-tioned bone affections, and three did not show any pathological changes on microscopic level. It was concluded that although specific pathological conditions can most likely not be diagnosed purely on the basis of histomorphological observations, broad distinctions could be made between lesions caused by the ossification of subperiosteal haematomas and bone changes due to infectious diseases

Intestinal parasitosis and use of untreated wastewater for agriculture in Settat, Morocco

Some text in ArabicAn evaluation was made of the risk of contamination by faecal parasites in the population from the use of wastewater in agriculture. The study was based in 3 rural clusters in the northern region of Settat city, Morocco: 2 rural clusters exposed to untreated wastewater in agriculture and 1 not exposed. The sample comprised 333 people aged 3–60+ years: 214 exposed and 119 non-exposed. Stool samples were collected and examined for intestinal parasites. The results showed that the prevalence of intestinal parasitosis (i.e. evidence of at least 1 type of parasite) in the exposed group was significantly higher that the non-exposed group (66.4% versus 31.9%; relative risk 2.1). The household crowding index was also higher in the exposed group.Parasitose intestinale et utilisation d’eaux usées non traitées dans l’agriculture à Settat (Maroc) RÉSUMÉ Une évaluation du risque de contamination de la population par des parasites fécaux du fait de l’utilisation d’eaux usées dans l’agriculture a été réalisée. L’étude portait sur trois grappes (douars) rurales de la région de Settat, au nord du Maroc : 2 exposées à des eaux usées non traitées dans l’agriculture et 1 non exposée. L’échantillon était composé de 333 sujets âgés de 3 à 60 ans et plus dont 214 exposés et 119 non exposés. Des échantillons de selles ont été prélevés et une recherche de parasites intestinaux a été effectuée. Les résultats montrent que la prévalence de la parasitose intestinale (établie par la présence d’au moins un type de parasite) dans le groupe exposé était significativement plus élevée que dans le groupe non exposé (66,4 % contre 31,9 % ; risque relatif : 2,1). L’indice de promiscuité était également plus élevé dans le groupe exposé

Reducing mortality risk by targeting specific air pollution sources: Suva, Fiji

Health implications of air pollution vary dependent upon pollutant sources. This work determines the value, in terms of reduced mortality, of reducing ambient particulate matter (PM2.5: effective aerodynamic diameter 2.5 μm or less) concentration due to different emission sources. Suva, a Pacific Island city with substantial input from combustion sources, is used as a case-study. Elemental concentration was determined, by ion beam analysis, for PM2.5 samples from Suva, spanning one year. Sources of PM2.5 have been quantified by positive matrix factorisation. A review of recent literature has been carried out to delineate the mortality risk associated with these sources. Risk factors have then been applied for Suva, to calculate the possible mortality reduction that may be achieved through reduction in pollutant levels. Higher risk ratios for black carbon and sulphur resulted in mortality predictions for PM2.5 from fossil fuel combustion, road vehicle emissions and waste burning that surpass predictions for these sources based on health risk of PM2.5 mass alone. Predicted mortality for Suva from fossil fuel smoke exceeds the national toll from road accidents in Fiji. The greatest benefit for Suva, in terms of reduced mortality, is likely to be accomplished by reducing emissions from fossil fuel combustion (diesel), vehicles and waste burning.© 2017 Published by Elsevier B.V

PM₂.₅ and aerosol black carbon in Suva, Fiji

Concentrations of particulate air pollution in Suva, Fiji, have been largely unknown and consequently, current strategies to reduce health risk from air pollution in Suva are not targeted effectively. This lack of air quality data is common across the Pacific Island Countries. A monitoring study, during 2014 and 2015, has characterised the fine particulate air quality in Suva, representing the most detailed study to date of fine aerosol air pollutants for the Pacific Islands; with sampling at City, Residential (Kinoya) and Background (Suva Point) sites. Meteorology for Suva, as it relates to pollutant dispersion for this period of time, has also been analysed. The study design enables the contribution of maritime air and the anthropogenic emissions to be carefully distinguished from each other and separately characterised. Back trajectory calculations show that a packet of air sampled at the Suva City site has typically travelled 724 km in the 24-h prior to sampling, mainly over open ocean waters; inferring that pollutants would also be rapidly transported away from Suva. For fine particulates, Suva City reported a mid-week PM₂.₅ of 8.6 ± 0.4 μg/m³, averaged over 13-months of gravimetric sampling. Continuous monitoring (Osiris laser photometer) suggests that some areas of Suva may experience levels exceeding the WHO PM₂.₅ guideline of 10 μg/m³, however, compared to other countries, Fiji's PM₂.₅ is low. Peak aerosol particulate levels, at all sites, were experienced at night-time, when atmospheric conditions were least favourable to dispersion of air pollutants. Suva's average ambient concentrations of black carbon in PM₂.₅ 2.2 ± 0.1 μg/m³, are, however, similar to those measured in much larger cities. With any given parcel of air spending only seven minutes, on average, over the land area of Suva Peninsula, these black carbon concentrations are indicative that significant combustion emissions occur within Suva. Many other communities in the Pacific Islands, as well as in Africa, Asia and South America share similar climate and similar burning practices and as such are likely to experience similar aerosol black carbon loadings. These black carbon levels indicate the need for combustion emissions, particularly those from open burning and diesel usage, to be addressed in air policy.12 page(s