Sustainable alternative to manage the organic fraction of household solid waste: optimized composting in organomineral production

More than 50% of household solid waste is organic; thus, composting has emerged as alternative to extend landfills’ useful life and to reduce costs and minimize environmental impacts resulting from organic-fraction landfilling. The aims of the present study are to develop a domestic compost bin, optimize the main composting-process parameters set for household organic solid waste, generating an organomineral composite as final product from synthetic fertilizer application and featuring this matured biofertilizer. Rotatable central composite design was the method of choice to define the experimental matrix for variable optimization purpose. The following parameters were monitored throughout the experiments: moisture content, temperature, pH and C:N ratio. The mathematical model returned values close to 99% for optimum stabilization point and approximately 98% experimental data. This finding points out the efficiency of the generated optimization model. Temperature was not a compromising factor to achieve a proper composting process progress. According to the C:N ratio recorded throughout the experiments, the equipment mineralized the waste without reaching high temperatures, with small amounts of organic mass. The optimal conditions to maximize the stability of organic-mineral materials were reached when the process was carried out within 18 days, after 15-time compost revolving and the addition of 6.5% synthetic fertilizer (NPK). The equipment developed under the optimized composting parameters emerged as promising alternative to treat the organic fraction of urban solid waste, besides contributing to sustainable and environmental development, as well as to economic and social gains.