Biological nitrogen removal from urban landfill leachates by the conventional nitrification-denitrification process is expensive due to the need for external carbon source dosage, the high energy demand for aeration and the sludge production. Alternative processes based on the autotrophic nitrogen removal carried out by anammox are cost effective alternatives for the treatment of high ammonium content wastewater with low C:N ratio. A combined partial nitritation-anammox process is a feasible alternative to treat leachates.
The main goal of this PhD thesis is to study the feasibility of applying the anammox process to the treatment of mature urban landfill leachates previously conditioned in a partial nitritation process. This work is a part of the development of the PANAMMOX® process as an alternative to conventional nitrification-denitrification to perform biological nitrogen removal from leachates. The objectives of the work started at lab-scale level with an anammox enrichment focused on the study of the long term dynamics and key parameters for the control and operation of anammox SBR. Moreover, the characteristics of the anammox biomass were also investigated. Then, the treatment of landfill leachate by anammox was firstly studied at lab-scale for the acquisition of the basic knowledge for the scale-up of the process. Finally, the start-up of a pilot-scale anammox reactor was carried out in order to definitively test the feasibility of treating leachates in an anammox SBR.