The authors are grateful to the Foundation for Science and Technology (FCT,
Portugal) and FEDER under Programme PT2020 for financial support to CIMO
(UIDB/0690/2020).
To treat and reduce the heavy metals content in leachate byproducts from biological treatment in a waste treatment plant, adsorption is one of the most efficient techniques is the focus discussed in this work due the
composition of those liquids which contains nutrients but also hazards. The use of different adsorbents such as activated carbon, clays, and ion-exchange resins, is studied to adequate requirements for use as commercial fertiliser according to the regulations. This study concluded that the TOC presented in the leachate fulfil the EU requirements after a simple concentration process. The experimental design results obtained for heavy metals removal from the leachate show that a suitable combination of pH of 9 and ion exchange resins, especially Lewatit TP207 with a mass ratio of 0.4 g of resin per 20 mL of leachate, could reach the heavy metal content objectives. However, the leachate cannot be used as a commercial fertiliser using only this treatment because of the lack of Cr VI specific determination, which requires a crucial and deeper study, using as a starting point the optimal conditions obtained in this work.
