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Most solid waste management schemes minimally consider low concentration biodegradable agricultural waste management, though the environmental impact of this waste category is significant over a time frame. The column-mode study seeks to address the issue by suggesting potential utilisation of post-harvest waste for heavy metal sequestering. Locust beans husk char of 100 and 200 g was employed to inspect removal efficiency, isotherm and kinetic models of some heavy metals at 30, 60, 90, 120 and 150 min contact time. Elemental composition of the biosorbent was investigated using the SEM-EDX machine. The results obtained depict that over 85% aluminium and nickel removal was achieved at 150 min detention time. The Freundlich isotherm well described most of the sorbates sorption (R 2 ≥ 0.91). The sorption rate equally fitted into the second-order pseudo kinetic model (R 2 ≥ 0.88). Ion exchange took place during the sorption. Locust beans husk has promising adsorption potential in heavy metal ions removal from fouled surface water.

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Wadi El-Rayan wetland is an inland Egyptian Ramsar site of international importance, due to its rich biodiversity. The wetland constitutes two man-made lakes. The lakes size, particularly the Lower Lake, is in continuous reduction, and the vegetation productivity pattern is changing as result of deteriorating water and soil quality, domestic and industrial activities. This research was carried out to map the spatial and seasonal distribution of certain physico-chemical parameters of geo-referenced soil samples covering the two lakes parts using ordinary kriging GIS technique. The study utilized ArcGIS ver.10.7 software, and 76 soil samples collected from representative sites; 38 samples during winter and 38 samples during summer seasons. Soil data were analyzed statistically and geo-statistically based on best fitted semivariogram model. The results indicated high concentrations of some soil physical and chemical parameters, especially in summer and in the Lower Lake of Wadi El-Rayan. The summary statistics for soil parameters had shown that the median of some soil parameters is higher than the mean which indicated the presence of abnormal data. This finding has been approved through the spatial distribution mapping which clearly showed the differences in spatial and temporal distribution between the upper and lower lakes of Wadi El-Rayan. The study concluded that the generated spatial distribution maps using ordinary kriging method can be used as an effective tool in Wadi El-Rayan wetlands’ soil management.

This article is the result of a systematic review of published life cycle assessment (LCA) studies on water and wastewater treatment in Africa. After applying the search and selection criteria, 32 observations for energy use were included and 20 for the global warming potential (GWP) and the eutrophication potential (EP). The dependent variables were categorized by technical, method, and typology factors. The meta‐regression model aligned with the descriptive statistics on the variation of the dependent variables due to water source but not location. Regarding energy use, GWP, and EP, the water source and the study location had the most significant influence in contrast to the life cycle impact assessment method. There is a need for more such LCA studies in Central and Western parts of Africa.

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