M. Zamorano

Evaluation of a municipal landfill site in Southern Spain with GIS-aided methodology

Landfill siting should take into account a wide range of territorial and legal factors in order to reduce negative impacts on the environment. This article describes a landfill siting method, which is based on EVIAVE, a landfill diagnosis method developed at the University of Granada. Geographical Information Systems (GIS) technology is also used to generate spatial data for site assessment. Landfill site suitability is assessed on a scale based on territorial indices that measure the risk of contamination for the following five environmental components: surface water, groundwater, atmosphere, soil, and human health. The method described in this article has been used to evaluate an area in Granada (Spain) where there is a currently operating landfill. The results obtained show that suitable locations for the disposal of municipal waste were successfully identified. The low environmental index values reflect the suitability of this landfill site as well as its minimal negative impacts on the environment.

Analysis of the relation between the cellulose, hemicellulose and lignin content and the thermal behavior of residual biomass from olive trees.

The heterogeneity of biomass makes it difficult if not impossible to make sweeping generalizations concerning thermochemical treatment systems and the optimal equipment to be used in them. Chemical differences in the structural components of the biomass (cellulose, hemicellulose, and lignin) have a direct impact on its chemical reactivity. The aim of this research was to study the influence of the organic components of the raw material from olive trees (leaves, pruning residues, and wood) in the combustion behavior of this biomass, as well as to find the component responsible for the higher ash content of olive leaves. Accordingly, the study used a thermogravimetric analyzer to monitor the different states and complex transitions that occurred in the biomass as the temperature varied. The decomposition rates of the different samples were analyzed in order to establish a link between each combustion phase and the composition of the raw materials. Two methods were used to determine the hemicellulose and cellulose contents of biomass from olive trees. Significant differences among the results obtained by the different methods were observed, as well as important variations regarding the chemical composition and consequently the thermal behavior of the raw materials tested.

A neural network based model for urban noise prediction.

Noise is a global problem. In 1972 the World Health Organization (WHO) classified noise as a pollutant. Since then, most industrialized countries have enacted laws and local regulations to prevent and reduce acoustic environmental pollution. A further aim is to alert people to the dangers of this type of pollution. In this context, urban planners need to have tools that allow them to evaluate the degree of acoustic pollution. Scientists in many countries have modeled urban noise, using a wide range of approaches, but their results have not been as good as expected. This paper describes a model developed for the prediction of environmental urban noise using Soft Computing techniques, namely Artificial Neural Networks (ANN). The model is based on the analysis of variables regarded as influential by experts in the field and was applied to data collected on different types of streets. The results were compared to those obtained with other models. The study found that the ANN system was able to predict urban noise with greater accuracy, and thus, was an improvement over those models. The principal component analysis (PCA) was also used to try to simplify the model. Although there was a slight decline in the accuracy of the results, the values obtained were also quite acceptable.

Effect of water washing on the thermal behavior of rice straw

Rice straw can be used as a renewable fuel for heat and power generation. It is a viable mean of replacing fossil fuels and preventing pollution caused by open burning, especially in the areas where this residual biomass is generated. Nevertheless, the thermal conversion of rice straw can cause some operating problems such as slag formation, which negatively affects thermal conversion systems. So, the main objective of this research is studying the combustion behavior of rice straw samples collected from various regions by applying thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). In addition, the thermal behavior of ashes from rice straw was also analyzed in order to detect their melting points, and ash sintering was detected at different temperatures within the range between 550 and 1000°C. Since washing rice straw with water could reduce the content of undesirable inorganic compounds related to the ash fusibility, samples of washed rice straw were analyzed under combustion conditions to investigate its differences regarding the thermal behavior of rice straw. The results showed that rice straw washing led to a significant improvement in its thermal behavior, since it reduced the ash contents and sintering formation.

Economic and environmental review of Waste-to-Energy systems for municipal solid waste management in medium and small municipalities.

The application of Directive 2008/98/CE on Municipal Solid Waste (MSW) implies the need to introduce technologies to generate energy from waste. Incineration, the most widely used method, is difficult to implement in low populated areas because it requires a large amount of waste to be viable (100,000 tons per year). This paper analyses the economic and environmental costs of different MSW-to-Energy technologies (WtE) in an area comprising of 13 municipalities in southern Spain. We analyse anaerobic digestion (Biomethanization), the production of solid recovered fuel (SRF) and gasification, and compare these approaches to the present Biological Mechanical Treatment (BMT) with elimination of the reject in landfill, and incineration with energy recovery. From an economic standpoint the implementation of WtE systems reduces the cost of running present BMT systems and incineration; gasification presents the lowest value. From the environmental standpoint, Life Cycle Assessment shows that any WtE alternatives, including incineration, present important advantages for the environment when compared to BMT. Finally, in order to select the best alternative, a multi-criteria method is applied, showing that anaerobic digestion is the optimal solution for the area studied.

Methodology of Environmental Diagnosis for Construction and Demolition Waste Landfills: a Tool for Planning and Making Decisions

Current legislation in the European Union regarding landfills provides measures, procedures and guidance to prevent or reduce, insofar as possible, negative effects on the environment. This means that Member States must take measures so that landfills cannot operate unless the operator first presents a plan for the site, which includes the implementation of improvements considered necessary by the engineer for compliance with regulations. Researchers at the University of Granada have developed a method to ascertain the degree of environmental impact that a construction and demolition waste landfill may produce on its immediate surroundings. This methodology is based on environmental indexes; its objective is to give crucial information concerning possible environmental problems produced by a landfill. The data thus obtained will permit the elaboration of guidelines for improvements in the location, design, and operation of landfills, or in extreme cases, their closing, sealing, and rehabilitation.

Modeling Environmental Noise Using Artificial Neural Networks

Since 1972, when the World Health Organization (WHO) classified noise as a pollutant, most industrialized countries have enacted laws or local regulations that regulate noise levels. Many scientists have tried to model urban noise, but the results have not been as good as expected because of the reduced number of variables. This paper describes artificial neural networks (ANN) to model urban noise. This model was applied to data collected at different street locations in Granada, Spain. The results were compared to those obtained with mathematical models. It was found that the ANN system was able to predict noise with greater accuracy, and therefore it was an improvement on these models. Furthermore, this paper reviews literature describing other research studies that also used soft computing techniques to model urban noise.

Treatment of Landfill Leachate with Aerated and Non-Aerated Submerged Biofilters

A submerged biological filter packed with clayey schists from brick industrial waste as support material was used to treat landfill leachate. The pilot-scale plant consisted of two separated reactors, running in aerated and non-aerated conditions respectively. The leachate was taken from a landfill in Granada (southeast Spain) and was considered as partially stabilized with average chemical oxygen demand (COD) concentrations of 18,683.3 mg COD/L. The efficiency of the system at reducing COD, biological oxygen demand (BOD(5)), total suspended solids (TSS), total volatile solids (TVS), total solids (TS), cations and anions concentrations was tested comparing aerating and non-aerating conditions under several volumic organic loadings (15.7, 25.1 and 31.1 kg COD/m(3)d), a hydraulic loading of 0.7 m(3)/m(2)d and an internal recirculation of 250%. Results obtained showed that the aerated reactor was more effective than the non-aerated reactor in the removal of COD, BOD5 and TS, with maximum efficiencies of 66.7%, 91.2% and 21.7%, respectively. The volumic organic loading of 25.1 COD/m(3)d obtained best results. However, for the removal of TSS and TVS the non-aerated reactor showed better results (42%). The behaviour of different cations (Na(+), K(+), and Mg(2+)) and anions (F(-), Cl(-), Br(-)) was also monitored and a reduction in their concentration in the effluent was detected, in the order of 61% for Ca(2+) and 100% for F(-).

Wastewater Treatment Using Fibrist and Saprist Peat: A Comparative Study

Two different peat types (fibrist and saprist) were compared to examine their respective wastewater treatment capacity in peat beds under different hydraulic loadings (1.8, 1.2, 0.9, and 0.6 m3/m2 d) and pollutant loadings (dependent on influent quality). The comparative study was carried out on a pilot scale using urban wastewater which had undergone preliminary treatment. The systems were observed to retain a higher quantity of suspended solids when the load was higher, regardless of the hydraulic loading and the type of peat employed. System performance with respect to BOD was similar to that observed for COD, and it was noted that the capacity to retain organic matter decreased when the hydraulic loading or pollutant loading was increased. This effect was observed in both peats but to different degrees, being lower in the case of saprist peat. The results indicate that it would be necessary to work with low hydraulic loadings in order to comply with legislative requirements on effluent. Peat beds are therefore suitable for implementation in small population centers, where the systems efficiency partly depends on the type of peat employed. In view of the systems performance with respect to suspended solids, this technology may be considered a good primary treatment, and could be usefully combined with other processes aimed at eliminating dissolved organic matter.

Coagulation–Flocculation Pretreatment of a Partially Stabilized Leachate From a Sanitary Landfill Site at Alhendín (Granada, Southern Spain)

Leachate recirculation, biological, and physicochemical treatment processes are used to treat leachate landfill, but all treatment technologies seem to need a combination of two or more methods to obtain an effluent with suitable properties to eliminate environmental problems. In spite of the considerable literature focused on the coagulation–flocculation applied to landfill leachate before biological treatments, most investigations are developed to study different operating variables as leachate characteristics, type, and concentrations of chemical products applied. Two ferric coagulants (ferric chloride and Ferriclar), two aluminum coagulants (PAX-18 and SAL-8.2), an organic coagulant and flocculant (Chemifloc PA-15), several anionic flocculant (Chemifloc A05.L, A10.L, A20L, and A30.L), and a non-ionic flocculant (Chemifloc N01) were used in jar-test experiments to determine the best conditions for the removal of chemical oxygen demand (COD) and total solids (TS) from a partially stabilized leachate collected at a sanitary landfill site at Alhendín (Granada, Southern Spain). The organic coagulant–flocculant PA-15 showed highest (17%) COD and TS removal efficiencies at a concentration of 2 mL/L. All combinations of coagulants and flocculants enhanced the COD removal efficiency. The best results (more than 25% COD removal) were obtained with a combination of ferric or aluminum-based salts in combination with high molecular weight flocculants.