Background Wastewater generated in an urban landfill (i.e. 'leachate') can present high contaminant levels. This is mainly due to the high organic matter (with a very low biodegradable fraction), nitrogen and salt content. One of the most complex problems is the removal of nitrogen. The difficulties of eliminating nitrogen, which is almost entirely composed of ammonium, are caused by: - A high nitrogen concentration, which increases over time. - A low carbon-nitrogen (C:N) ratio. The available organic matter for denitrification purposes using a classical activated sludge process is not enough to ensure high denitrification efficiencies. - The use of physical-chemical treatments (i.e. ammonia stripping plus ammonium sulphate recovery) present high technical and manipulation complications because of control, stability and hazard aspects. In addition, the removal the high salt content mainly relies on the use of filtration processes. Management and treatment of this effluent is therefore a costly exercise. For these reasons, the application of innovative techniques to reduce the economical and environmental impact of treating landfill leachates has to be considered. The leachate treatment must be applied in order to solve the different aspects of the problem: i) the high nitrogen contents, ii) the non-biodegradable organic matter increasing over time, iii) the high contents of inorganic salts (i.e. chloride). Where it is not possible to solve the problem holistically by applying a unique technology, a combination of different physical, biological and chemical technologies could be a suitable option to reduce the contamination levels of leachates. Objectives The objective of the CLONIC project was to demonstrate the effectiveness and environmental benefits of an innovative process (PANI/SBR/ANOMMOX and thermal dry) for the treatment of leachate. Treatments based on a partial biological autotrophic oxidation of ammonium to nitrite (PANI-SBR process), followed by an autotrophic anaerobic ammonium oxidation via nitrite (Anammox process), were to be studied as a more sustainable and cheaper alternative for the nitrogen removal from urban landfill leachates. Following this, thermal drying treatment using biogas as an energy source was to be carried out in order to retain the salt in the dry powder produced. Results The CLONIC project has successfully demonstrated the feasibility and the environmental benefits of leachate treatment with the PANI-SBR-ANAMMOX and thermal drying process. During the operational phase, the feasibility of PANI-SBR applied to leachates directly, followed by the ANAMMOX process was demonstrated; nitrogen removal of 98% was achieved. The Thermal Drying technology has shown to be an effective process for salinity influents, as all the salts were withheld in the solid phase, and the gaseous emissions had a pollutant concentration much lower than the legal limits (details of the atmospheric emissions produced by the thermal drying plant during the operational phase are presented in a table on page 9 of the Layman's report). In comparison to current leachate treatments, the new combination of these two technologies present numerous advantages. The environmental benefits are as follows: - In comparison with physico-chemical treatments, the overall operation is reduced due to the fact that reagents are not used and by-products of difficult elimination/treatment, such as ammonia sulphate, are not produced. - In comparison with biological treatments, the new process needs 35% less aeration than a conventional biological nitrification. - The production of biomass is lower than in converntional biological treatments. - The combination of the technologies PANI-SBR-ANAMMOX + thermal drying allows for the closing of the nitrogen cycle, releasing nitrogen into the atmosphere. An environmental analysis (using FLEXRIS methodology) was carried out in order to evaluate and compare environmental and economical costs of a conventional leachate treatment, consisting of OHP plus NH4 Stripping, versus CLONIC treatment (PANI-SBR-ANAMMOX+ Thermal Drying). The results showed an environmental cost of 0,02566 €/L for the conventional treatment and 0,013315 €/L for the CLONIC treatment, which implies that the CLONIC process achieves an improvement of 48%. The application of the biological process PANI-SBR-ANAMMOX for the treatment of leachate is what makes the CLONIC project particularly innovative. The Anammox method had already been tested in some previous experiments, but not coupled to a PANI-SBR process and not for leachate treatment. Although the project focused on leachate treatment, the biological process developed has a wide range of applications because it can be adjusted to any effluent with high contents of ammonia and salts, such as waste water, anaerobic digestion effluents, pig slurry or industrial processes. The stakeholders of this technology are waste management companies, WWTP, certain industries and the agricultural sector (especially for pig slurry). Furthermore, although it has been widely used in other sectors such as ceramics and food, this was the first time that the thermal drying technology was used for leachate treatment. Although the CLONIC project has successfully demonstrated the processes at semi-industrial scale, the continuous connection of the combined processes has not been fully achieved at full scale. For this reason, and in view of the very successful results obtained in the CLONIC project, the beneficiary, CESPA, and partner, LEQUIA-UdG, will continue the study of the PANI-SBR-ANAMMOX process with the aim of exploring the technology at industrial scale. In this second CLONIC project stage, it is foreseen to scale-up the 500 L pilot plant to a full scale plant. This new project, called PANAMMOX (Partial nitritation and anaerobic ammonium oxidation for landfill leachate treatment by means of PANI-SBR and ANAMMOX processes), has been funded by the Spanish government through the PROFIT programme of the Ministerio de Educación y Ciencia.