The increased demand for secondary materials, particularly scrap metals, in cities due to development activities in both emerging economies and developing countries has increased the demand for recycling materials. It accelerated the growth of the circular economy and climate-smart development. This paper investigated the synergy between sustainable solid waste management and the circular economy in Tanzanian cities by examining the scrap business’s categories, quantity, market, and nature and the scrap business’s environmental benefits in Arusha. The study found that iron steel, cast iron, and aluminum were the most common scrap metal recovered and traded in Arusha. Offices and institutions, households, and garages were the primary sources of scraps. Over 314 tonnes of scrap metal were traded monthly in the city. The scrap business helped the steel industries save 300 tons of iron ore, 164 tons of coal, and 64 tons of bauxite while lowering their monthly energy consumption by 56%. Scrap metal trade contributes significantly to recycling, climate-smart, circular economy, and improving livelihoods. As a result, we call for a synchronized sustainable development and solid waste management system that connects product design, development manufacturing, and end-of-life products to improve the circular economy.

Waste pickers play essential socioeconomic and environmental scenes in cities of developing countries. This study explored waste pickers to understand their socioeconomic characteristics, challenges, and roles in Tanzania cities. A mixed-methods research design was utilized, including questionnaires, interviews, and observations, to gather data from waste pickers in the city. The findings revealed that Arusha generates 550 tons of waste per day, with male waste pickers dominating the industry at 60%. Many waste pickers were within the active working age of 18-49 (90%), and two third possessed primary education (66%). Many waste pickers were single (50%) and married (42.5%). A significant portion of them (69%) were native to the region, while less than a third had migrated. On average, waste pickers in Arusha earn up to 153,000 TZS (USD 66) monthly, hence looking for an alternative job. Waste pickers also play a significant role in the city's informal economy. They act as recovery hubs and central suppliers of recycling materials. Their work helps extend the lifespan of landfills, conserve resources, and protect the environment. However, they face challenges such as low earnings, scarcity of materials, and health issues such as injuries, harassment, and low prices for materials. Formalizing and integrating waste pickers into the city's solid waste management system can reduce GHG emissions, providing a sustainable and meaningful model for managing waste and mitigating climate change in Arusha. The study underscores the importance of acknowledging and supporting the role of waste pickers in achieving sustainable waste management and a climate-smart city.

The increased demand for secondary materials, particularly scrap metals, in cities due to development activities in both emerging economies and developing countries has increased the demand for recycling materials. It accelerated the growth of the circular economy and climate-smart development. This paper investigated the synergy between sustainable solid waste management and the circular economy in Tanzanian cities by examining the scrap business’s categories, quantity, market, and nature and the scrap business’s environmental benefits in Arusha. The study found that iron steel, cast iron, and aluminum were the most common scrap metal recovered and traded in Arusha. Offices and institutions, households, and garages were the primary sources of scraps. Over 314 tonnes of scrap metal were traded monthly in the city. The scrap business helped the steel industries save 300 tons of iron ore, 164 tons of coal, and 64 tons of bauxite while lowering their monthly energy consumption by 56%. Scrap metal trade contributes significantly to recycling, climate-smart, circular economy, and improving livelihoods. As a result, we call for a synchronized sustainable development and solid waste management system that connects product design, development manufacturing, and end-of-life products to improve the circular economy.

The adoption of compressed natural gas (CNG) vehicles has increased over the last decade, even in developing countries, in the pursuit of sustainable cities. This study examined the technological and environmental factors influencing CNG adoption as a vehicle fuel in Dar es Salaam, using a cross sectional approach. It integrates quantitative survey data from vehicle owners with qualitative insights from interviews with natural gas sector stakeholders, transport operators, and policymakers. The analysis employs inferential statistics, including multiple response analysis, linear regression, and thematic analysis. Findings show a strong awareness of CNG’s environmental benefits, including a 73% reduction in greenhouse gas (GHG) emissions and a 67% decrease in pollution. However, concerns about the availability of CNG refueling stations (73%), compatibility with vehicles (67%), and maintenance services (58%) hinder adoption. Government policies play a crucial role in promoting CNG adoption, with subsidies and stricter emissions regulations serving as key motivators. However, public awareness campaigns are limited in effectiveness, revealing an insufficient understanding of CNG’s benefits. Overall, this study emphasizes the need for collaboration between government and private sector stakeholders to enhance CNG adoption in Dar es Salaam and advance toward a sustainable transportation system that improves air quality and reduces greenhouse gas emissions.