Evaluating Sewage Sludge Compost: Biofuels Production on Disused Open Pit Mines in Northern Spain Javier Menéndez HUNASER ENERGÍA Avda. Galicia, 44 33005 Oviedo (ASTURIAS) javiermenendezr@gmail.com Jorge Loredo Mining Exploitation Department University of Oviedo C/ Independencia, 13 33004 OVIEDO (ASTURIAS) jloredo@uniovi.es Abstract: - During the last decades the Asturian Carboniferous Central Basin (ACCB) has been exploited by means of open-pit and underground mining. Even though it is regarded as a crucial economic activity worldwide, mining has a significant negative impact on environment. Due to its nature, especially opencast mining inevitably leads to serious degradation on ecological and aesthetic values of the landscape. Topography and drainage, air, soil and water quality, vegetation including forest ecosystems, noise levels and ground vibrations, human health and habitation can be listed as the typical parameters that are mainly affected by opencast mining activities. When the extraction of reserve is over, the altered landscape has to be reclaimed in order to relieve the damaging effects of opencast mining and restore the landscape and its immediate surroundings. Although these are soils with very poor conditions, these lands can be used for the production of solid biofuels through short rotation energy crops. The main objective lies in the search for the species that best adapt to the conditions of the environment, since there is hardly any organic matter and the nitrogen content is scarce. The biofuels produced can help meet the 20-20-20 target, which is a commitment that aims to reduce 20% the consumption of primary energy and greenhouse gas emissions and increase renewable energy production by 20%. Key-Words: - Post-mining recultivation, energy crops, biofuels, mining land management, forestry biomass. 1 Introduction The forecast for the year 2020 is that 20% of the energy consumed in the European Union (EU) processes from renewable energy sources [1]. In order to comply with the EU's energy and climate objectives, it would be necessary for part of this energy to come from biomass as it is a sustainable option, as well as being considered as a promising alternative at present, since the confirmation of the negative effects on the environment of the use of fossil fuels, made the most developed countries, including Spain and the EU, adopt commitments to promote the use of clean and renewable energy sources [2] [3]. Therefore, it is predictable that the use of biomass as an energy source will increase by 45% from 2006 to 2020, which would represent 8% of the expected increase in renewable energy in the European Union [4]. Among the advantages it presents, we can highlight the diversity of its resources and conversion technologies which makes it an extremely versatile energy source, capable of replacing fossil fuels in a sustainable and environmentally friendly manner and contributes to the reduction of greenhouse gases [5]. In this context, the woody biomass, and within it the forest biomass, is considered as an attractive source of renewable energy, with thermal and electrical applications [6]. In addition to other possible advantages, as pointed out by [7] that indicate that the establishment of biomass plantations for the production of energy would serve as a recovery activity in rural areas, the neutral CO 2 balance or even the recovery of degraded areas. All these reasons mean that the installation of forest crops with bioenergy purposes can be considered a promising future option. Javier Menéndez, Jorge Loredo International Journal of Environmental Science http://www.iaras.org/iaras/journals/ijes ISSN: 2367-8941 82 Volume 3, 2018