Globally, the environment is the result of the interdependence between natural elements - water, air, soil, living things, and elements from human activity. Environmental pollution can be generally defined as the negative result of the domestic or industrial activity of any living thing that generates pollutants in the atmosphere or waste that reaches the ground or water. Numerous causes of pollution have made environmental protection one of the most important and essential problems in the world, pollution, and lack of protection measures affect people's quality of life. In this regard, the National Waste Management Strategy has been developed in Romania in 2019. This proposes a framework of measures to ensure the transition from the current development model based on production and consumption to a model based on the prevention of waste generation and the use of raw materials in industry, recovery, and recycling, thus ensuring the preservation of national natural resources. In this context, the current paper illustrates the achieved results from the experimental activities carried out using a closed composting system, that is a mobile one. The input materials in the composting process were sludge from a municipal wastewater treatment plant (26%), market waste (vegetables and fruits - 18%), and wood chips (56%). The results showed that, for the analyzed heavy metals, the concentrations in compost do not exceed the limit values for the second category of compost according to the Romanian regulation in force (Law 181/2020 - on the management of non-hazardous compostable waste). Consequently, the obtained compost from a mixture of sludge from the wastewater treatment plant, waste from the market (vegetables-fruits), and wood chips can be used on agricultural land.