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Electric and electronic equipment (EEE) consumption has grown to worrisome proportions in developing countries (DC S ), resulting in massive amounts of electrical and electronic waste (e-waste) being produced. A diagnosis of e-waste proliferation is required for its sustainable management plan in Rwanda. This review is based on open-access papers with e-waste as a keyword, the present situation of EEE, and e-waste in Rwanda. The need for various information communication and technology (ICT) tools, such as end-user devices, cooling-system devices, network equipment, and telecommunication devices, is strongly encouraged by Rwandan national plans, which deem ICT as a vital enabler of knowledge-based economy and development. In 2014, EEE was 33,449 tonnes (t), which is expected to be 267,741 t in 2050, with a yearly increase rate of 5.95%. In this regard, out-of-date EEE is being dumped as e-waste in large quantities and at an increasing rate across Rwanda. E-waste is often disposed of in uncontrolled landfills together with other types of household waste. To address this rising threat, as well as to preserve the environment and human health, proper e-waste management involving e-waste sorting/separation from other waste streams, repairs, reuse, recycling, remanufacturing, and disposal has been proposed.

Plastic products are now essential commodities, yet their widespread disposal leads to environmental and human health effects, particularly in developing nations. Therefore, developing nations require comprehensive studies to assess the current state of plastic and plastic waste production to enhance plastic waste management practices. This review analyzes the import and export of plastic and the production of plastic waste in Rwanda, aiming to improve waste management practices. This review used open-access papers, reports, and websites dealing with plastic waste management. In this review, 58 articles from the Web of Science and 86 from other search engines were consulted to write this review. The findings revealed that the daily estimated plastic waste produced per person ranges between 0.012 and 0.056 kg. The estimated amount of plastic waste generated per person per year in Rwanda could be between 4.38 and 20.44 kg. Plastic waste accounts for between 1 and 8% of the total municipal solid waste produced per person per day in the country, which ranges from 219 to 255.5 kg. The average annual amount of imported plastics could reach 568.2881 tons, whereas the average quantity of exported plastics could reach 103.7414 tons. This shows that plastic management practices have not yet adopted technically advanced or improved practices, which should concern efforts to protect our environment. This study suggests approaches that can vastly improve plastic waste management and potentially open massive opportunities for the people of Rwanda.

Economic development, urbanization and population growth are three parameters that are influencing the quality of water nowadays. Textile wastewater is a typical industrial wastewater generated by human activities. This alkaline wastewater contains many pollutants and has high BOD and COD loads. Pollutants in textile effluents include suspended solids, mineral oils (e.g. antifoaming agents, grease, spinning lubricants, non-biodegradable or low biodegradable surfactants) and other organic compounds, including phenols from wet finishing processes (e.g. dyeing), and halogenated organics from solvent use in bleaching. Effluent from dyeing processes is colored and may contain significant concentrations of heavy metals (e.g. chromium, copper, zinc, lead, or nickel). The present study is focusing on heavy metal pollution found in textile wastewater because of their toxic effect in the environment and most studies on textile wastewater focus on the removal of organic pollutants.In Rwanda, textile wastewater contributes to heavy metal pollution in the swamps receiving that water. Chapter 3 presents the assessment of metal pollution in a swamp receiving textile wastewater from UTEXRWA in Kigali (Rwanda). The Nyabugogo swamp is a natural wetland located in Kigali City (Rwanda). This wetland receives all kinds of untreated wastewaters from the city. The assessment of heavy metal pollution (Cd, Cr, Cu, Pb and Zn) included all environmental compartments of the swamp: water and sediment, the dominant plant species Cyperus papyrus, fish (Clarias sp. and Oreochromis sp.) and Oligochaetes. Cr, Cu and Zn concentrations in the water were generally below the WHO (2008) drinking water quality guidelines, whereas Cd and Pb were consistently above these limits. Except Cd, all metal concentrations were below the threshold levels for irrigation. The highest metal accumulation occurred in the sediment with up to 4.2 mg/kg for Cd, 68 mg/kg for Cu, 58.3 mg/kg for Pb and 188.0 mg/kg for Zn, followed by accumulation in the roots of Cyperus papyrus with up to 4.2 mg/kg for Cd, 45.8 mg/kg for Cr, 29.7 mg/kg for Cu and 56.1 mg/kg for Pb. Except Cu and Zn, other heavy metal (Cd, Cr and Pb) concentrations were high in Clarias sp., the Oreochromissp. and the Oligochaetes. Therefore, there is a human health concern for people using water and products from the swamp.From the results of chapter 3, there is a need for the development of a cheap, reliable technology applicable in developing countries for heavy metal removal from polluted water bodies. This research aimed at improving the heavy metal removal from textile wastewater using an integrated system for wastewater treatment. The integrated system consists in a combination of an anaerobic reactor as the main treatment step, followed by a polishing step composed by a macrophyte stabilization pond. The main treatment step will remove a large quantity of heavy metals, mainly by adsorption combined to metal sulfide precipitation. The polishing step will be achieved by phytoremediation where removal will be conducted by algae and plants (duckweed and water hyacinth). The integrated system will show the complementary action of both systems in metal removal.

Complexation of CrIII was studied using the ligand 2, 2’ Bipyridyl (Bpy). Potentiometric titration was used in the modelling of CrIII-Bpy complexes and establishment of complex stability constants by use of ESTA software package. Investigation of the mechanism involved in the voltammetric determination of chromium by adsorptive cathodic stripping voltammetry (AdCSV) showed different behavior of chromium in 0.1 M ammonium buffer when compared to a neutral electrolyte (0.1 M sodium nitrate). Alternating current voltammetry (ACV) showed evidence of Bpy adsorption on the electrode surface (HMDE) whereas CrIII did not show any adsorption evidence but complexes of CrIII-Bpy were also adsorbed onto the electrode. Cyclic voltammogram (CV) of Bpy exhibits a reversible process and CrIIIwas characterized by a quasireversible process.CrIII-Bpy is investigated here as a model metal-ligand system used in analytical procedure. A set of generalized requirements for the determination of CrIII by AdCSV is proposed and discussed. It is anticipated that the generalized requirements will be applicable to any metal-ligand system used by that analytical technique. It is assumed that it should lead to an “educated” choice of a suitable ligand in order to increase selectivity and improve the detection limit in ultra trace analysis (ppb-ppt levels) by AdCSV.