Composting has been proven to be an environmentally friendly process for urban organic waste, that can represent an opportunity for new uses under the circular economy framework. The binding of cadmium to fulvic-like and humic-like acids extracted from compost of algae and urban residues were evaluated, and the results show significant differences. The fulvic and humic acids from algae compost bind cadmium more efficiently than those from urban residues compost. Furthermore, data from humic acids from both composts display significantly higher ability to bind to cadmium than both their corresponding fulvic acids and the generic soil extracted humic matter.