F. López-Rodríguez

Energy-environmental benefits and economic feasibility of anaerobic codigestion of Iberian pig slaughterhouse and tomato industry wastes in Extremadura (Spain).

Anaerobic digestion of Iberian pig slaughterhouse and tomato industry wastes, as well as codigestion operations from such residues, are reported to achieve 54-80% reduction in Chemical Oxygen Demand and 6-19 N m(3)/m(3) substrate methane production. Furthermore, 0.79-0.88 m(3)water/m(3) substrate is seen to be recovered after the above mentioned operations, which might be used as irrigation water, and 0.12-0.21 m(3)agricultural amendment/m(3) substrate with 91-98% moisture content. The present paper also reports on the economic feasibility of both an anaerobic codigestion plant operating with 60% slaughterhouse wastes/40% tomato industry wastes (optimal ratio obtained in previous laboratory-scaled experiments), and an anaerobic digestion plant for Iberian pig slaughterhouse waste. Payback times are reported as 14.86 and 3.73 years, respectively.

Development of a measure model for optimal planning of maintenance and improvement of roads

In recent years, the spectacular increase of traffic in the majority of the developed countries has led to heightened concerns about the state of the roads, particularly in regard to how to improve driving conditions and, consequently, lower accident rates. There are many facets that influence the quality of roads, such as design characteristics (width, ditches, etc.) or their maintenance (signs, marking, etc.). All of them must be considered with a series of indicators when analyzing different roads. This work develops a methodology, based on the formulation of the Rasch model, that allows us to obtain an objective measure of road conditions, and later to evaluate each of the indicators that describe the roads condition. As an example, data relating to the network of local and regional roads in the province of Badajoz, Spain, have been processed. Finally, results were implemented in a geographical information system (GIS) to visualize the distribution of all roads depending on their condition and, moreover, to make individual diagnoses of each road stretch possible, with the aim of optimizing resources allocation.

Determination of the infrastructure needs for municipalities using an objective method

Nowadays, in Spain, the state of the infrastructure and equipment at different municipalities is estimated using indices, which are based on surveys. Thus, the level of need at each municipality is established depending on 14 individual indices, which are related to three facets: health, services, and leisure. With the aim of obtaining only one need ranking, these indicators define a general index, which is a weighted average. However, the weights are incoherent when the individual indices are related to the three facets. In this work, the use of the Rasch model as a measurement instrument is proposed. This alternative to the general index allows municipalities to discriminate in terms of the indices and vice versa. Thus, in an objective manner, a ranking of the municipalities according to their infrastructure needs and, moreover, a ranking of the more (or less) frequent needs for all municipalities can be determined. With this method, it is not necessary to employ previous weights that distort the original data. As an example, data relating to the municipalities of the province of Badajoz, Spain, have been processed. The results are in accordance with the initial hypothesis that the priority ranking of the individual indices for all municipalities are: first, health; second, services; and finally, leisure. Moreover, with the Rasch model measure, we have observed a general propensity of the studied municipalities to enjoy a good quality of life because there are no important infrastructure needs. Finally, a Geographical Information System (GIS) was used to carry out different analyses. Thus, when population and quality of life were jointly mapped, a relationship between the two variables was not observed. Abnormal values of the indices for the municipalities were also visualized. The use of the Rasch model plus a GIS is fundamental to developing an objective allocation of resources to improve the infrastructures of the municipalities.

Optimal Locations of Biomass Logistics Centers for Energy Uses in the Province of Badajoz (Spain)

The forest biomass of the province of Badajoz (southwestern Spain) is around 274,335 tons, which is equivalent to 112,000 toe of energy. Consequently, the quantification, analysis, and mapping of the energy potential from the residual biomass, considering the most important forestry species of the studied province, were performed. Moreover, the optimum locations of biomass logistics centers were established. Results of this study are within the value chain of biomass, regarding to the production, transformation, commercialization, and use of the existing biomass to generate energy, heat, and electricity.

Environmental and energetic benefits derived from the anaerobic digestion of agroindustrial wastes

Agrifood industry plays a relevant role in the economic development of the autonomous community of Extremadura (Spain), and generates vast volumes of wastes featured by both high polluting potential and moisture content. The present work reports on a detailed analysis of biogas generation from the anaerobic digestion of industrial tomato residues and slaughterhouse wastes, in this way, yields achieved by treating the optimal flow has been 9.68 and 17.84 Nm 3 methane/m 3 substrate respectively. To determine the environmental and energetic benefits of anaerobic digestion, the annual waste generation rates in Extremadura were taken as input data; the methane and carbon dioxide volumes per ton waste were assumed as those of the hypothetical case of wastes being naturally decomposed; and the obtained biogas was regarded to serve as fuel for useful energy production (heat and/or electricity). Under these assumptions, the environmental benefit of the anaerobic digestion of the wastes was quantified and compared with the greenhouse emissions that might be observed if such wastes were directly dumped to the environment. If the analysed wastes were treated by anaerobic digestion, it would generate 50.9 GWh of electricity and prevent the emission of almost 204,000 equivalent tons of carbon dioxide annually.