Abstract:Solid waste, which is a consequence of day-to-day activity of human kind, needs to be managed properly. Jigjiga City, like other cities in developing countries, faces problems associated with poorly managed solid waste operation. This study concerns about analysis of the city's current municipal solid waste management problems, opportunities and existing solid waste management practices and role of community participation. The survey was conducted in 03 and 05 kebeles. Different sampling methods were employed to select the study units including: stratified sampling, systematic random sampling, and purposive sampling. Though the bulk of the data collected were qualitative in nature, it was also supported by quantitative information collected through survey and secondary sources. The study discovered that there is low performance of SWM in the city mainly due to: lack of properly designed collection system and time schedule, inadequate and malfunctioning operation equipment, open burning of refuse, poor condition of the final dumpsite and less awareness creation among community which encouraged illegal dumping are the technical problem identified. Insufficient funds as well as lack of promotion on-waste reduction, recycling, absence of waste recovery, practice of energy option, waste separation and composting are among the management challenges facing the city. Social problems encountered include: lack of public awareness, unwillingness to pay, ill dumping manner (often around residence and any open spaces) and improper outlook for waste workers. Incompetence of organizations in terms of equipment required for operation and man power /staff qualifications, training and human resource developments and/or unreliable service are the institutional challenge that the city encountered in the sector. Finally, the study forwarded some important recommendations towards improving the waste management practices.

Nowadays, Cr-loaded wastewater released from industrial activities pose an increasing risk to human health and the environment. Adsorption processes have been widely used for the removal of chromium from the waste stream. In this regard, natural adsorbents are the most preferable and cost-effective methods. In this study, the efficiency of Odaracha adsorbent as a novel green technology in the removal of chromium from synthetic wastewater is analyzed. Batch adsorption experiments were conducted to evaluate the effect of contact time, pH, adsorbent dose, and initial concentration of adsorbate on Cr removal. The surface morphology of Odaracha adsorbent was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray powder diffraction. Experimental results showed that Odaracha adsorbent could perform effectively in a wide range of experimental conditions. However, in optimum experimental conditions, such as 180-min contact time, pH 3, and 15 g/L of adsorbent dose Odaracha adsorbent removes 94.68% of Cr from an aqueous solution having 110 mg/L of Cr concentration.

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Lead pollution is a severe health concern for humankind. Utilizing water contaminated with lead can cause musculoskeletal, renal, neurological, and fertility impairments. Therefore, to remove lead ions, proficient, and cost-effective methods are imperative. In this study, the Odaracha soil which is traditionally used by the local community of the Saketa District was used as a novel low-cost technology to adsorb lead ions. Odaracha adsorbent was characterized by scanning electron microscopy and Fourier transform infrared spectroscopy. The adsorption process followed the batch adsorption experiment. The response surface method was implemented to derive the operating variables’ binary interaction effect and optimize the process. According to the study’s experimental result, at optimum experimental conditions Odaracha adsorbent removes 98.17% of lead ions. Based on the result of the central composite design model, the Pb2+ ion removal efficiency of Odaracha was 97.193%, indicating an insignificant dissimilarity of the actual and predicted results. The coefficient of determination (R2) for Pb2+ was 0.9454. According to the factors’ influence indicated in the results of the central composite design model, all individual factors and the interaction effect between contact time and pH has a significant positive effect on lead adsorption. However, other interaction effects (contact time with dose and pH with dose) did not significantly influence the removal efficiency of lead ions. The adsorption kinetics were perfectly fitted with a pseudo-second-order model, and the adsorption isotherm was well fitted with the Freundlich isotherm model. In general, this study suggested that Odaracha adsorbent can be considered a potential adsorbent to remove Pb2+ ions and it is conceivable to raise its effectiveness by extracting its constituents at the industrial level.