Neiker-Tecnalia, the Basque Institute for Agricultural Research and Development, in collaboration with Sergal, Uaga and the Basque Board of ecological agriculture and food (ENEEK in its Basque initials), has launched a research programme the aim of which is to combine technologies and processes in order to transform animal husbandry excretions into a substrate that is guaranteed and reliable for use in ecological agriculture. Currently, the elements required for this sector, one of the most dynamic in Basque agriculture, are difficult to find and, on many occasions, come from areas distant from the farms – precisely against the philosophy of this type of production. Through this project, a solution is sought to the growing demand for a quality substrate that can be employed in ecological agriculture and, at the same time, achieve reuse as well as finding a solution to the manure and purines generated by large-scale farming operations, with suitable treatment, and thus fomenting sustainability throughout the sector To this end, the study compared various methodologies for composting, in order to evaluate the final quality of the compost obtained and its direct and indirect costs. In concrete, the use of turnover composting and biocomposting systems were evaluated from different perspectives: time of maturing, parameters of quality and the technical-economic management of both systems. In the case of compost turning, five farms were chosen to build the heaps of compost which are periodically turned over in a mechanical way and covered with a geotextile cloth. Temperature being the best indicator of how the process is progressing, each farmer was provided with a thermometer and a control card to record temperatures and humidity. To obtain a young compost (8 to 10 weeks) two turnovers are required and a third one to obtain a mature compost (4-6 months after the second). In order to undertake the study, Neiker-Tecnalia installed a biocomposter (closed composting system) made up of six modules of concrete to form a watertight silo that had an integrated forced ventilation system in order to accelerate the process of composting. During the decomposition stage, when the waste is in the biocomposter, no operation other than observing the correct working of installation should be carried out. Once this stage is finished, after between 40 or 50 days, the emptying process is initiated and a pile is formed outside the silo, in the maturing zone, for the stabilisation and humidification of the compost. This phase finishes once the temperature drops below 45º C. In both cases, after finalising the process of maturing, the heavy metal content, the C/N relation, the nutrient content and the percentage of organic material will be analysed, apart from undertaking a technical-economic evaluation of the consequences of employing turnover composting or biocomposting as composting systems. The idea is to generate a compost of quality at a lower cost than what is currently available on the market and to recycle nutrients in situ, on the farmland itself, as well as to ensure compliance with regulations, thanks to the proximity of the farms and their direct control of the whole process. In short, it is the creation of a business idea in which those directly affected and interested are involved, participating either as producers or consumers of compost, with the target of ensuring access to the product(s) and, at the same time, on preferential and competitive terms. The storage of manure involves the construction of an enclosed manure silo, separated from the farm animals – an additional economic burden for the farm. Another of the primordial objectives of the study being undertaken by Neiker-Tecnalia is the evaluation of systems of waterproofing the piles of manure as an alternative to a constructed receptacle. These alternatives involve placing the piles over previously compacted clay and on ground waterproofed with high-density polyethylene. In both cases, the piles are covered with geotextile mesh to avoid contamination by overflowing or by leaching.