Aquatic invasive weeds affect hydrological, ecological, and socio-economic activities on freshwater ecosystems. On the Lower Volta River (LVR) of Ghana, invasive aquatic weeds have been known to be nuisance to fishing, navigation, aquaculture, hydropower production and other agricultural practices in the area. While information on the spatial and temporal distribution of aquatic weeds would be beneficial in improving weed management and control measures on the river, such information is very scanty. Also, these aquatic weeds are also biomass resources, that can be transformed to bioenergy. Thus, this study evaluated the spatial and temporal variations of aquatic weeds on the Lower Volta River, and assessed their potential biomass for bioenergy production.Random Forest (RF) algorithm and Landsat images were used to map the distribution of the weeds in 1975, 2003, and 2020, respectively. Accuracy assessment results showed mean Overall Accuracy (OA) of 83.44% and mean User Accuracy (UA) of 79.24%. The results indicated that as of 1975, aquatic weeds covered only 1495 ha and appeared in some specific locations such as Kpong and Ada. However, by 2003, the weeds had spread to most parts of the river covering 5600 ha, which was an increase of approximately 4-fold within a period of 28 years. The area covered by the weeds, however declined by 1505 ha between 2003 and 2020. Thus, in 2020, water hyacinth covered about 36% of the aquatic weeds relative to 28% in 2003. The results showed that, the quantity of the water hyacinth biomass per unit area was 21.5 kg/m 2 . This result can also be used as the basis for resource assessment as well as determination of its viability for bioenergy production and strategies for its modern utilisation. The conversion of water hyacinth into bioenergy remains one of the best aquatic weed management strategies that must be adopted in LVR.
Cheap alumino-silicate materials such as clay materials and Y zeolite were selected for the catalytic pyrolysis of waste engine oil in a fixed bed reactor. A cheaper route of Y zeolite synthesis involving hydrothermal activation of the raw clay and hydrothermal synthesis was employed. X-ray diffraction technique, scanning electron microscopy, Fourier transform infra-red, and nitrogen desorption method were used to characterize the intermediate phases formed during the hydrothermal treatment of the clay and the synthesized Y zeolite during the hydrothermal processes. The chemical compositions of the liquid phase of catalytic pyrolysis were characterized by gas chromatography coupled with mass spectroscopy (GC-MS). The results revealed that the alkaline concentration strongly influenced the activation of the raw clay to obtain a useful phase for the subsequent synthesis of the Y zeolite. The synthesis improved the surface area from 29 m 2 /g for the clay to 745 m 2 /g for the zeolite. The catalytic pyrolysis resulted in diesel fractions of 64.8 and 54.7%, respectively for the Y zeolite and the clay. It was observed that the gasoline fractions increased to 20.5 and 19.1%, respectively for the zeolite and the clay. In the diesel fraction, the zeolite selectively improved the yield of the cyclo-alkanes which are key constituents in terms of the quality of diesel. Y zeolite was successfully derived from a natural clay and tested in the pyrolysis of waste engine oil. The synthesis route provides the opportunity to improve the catalytic property of the natural clay.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.