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The distribution of biomarker compounds and magnetic susceptibility observed in the sediment from a 20 m core drilled in the marshlands of the estuarine region of the Guadalquivir River (southwest coast of Spain) has allowed us to reconstruct the palaeoenvironmental evolution of this area during the Holocene. Several organic compounds (n-alkanes, n-ketones, n-alkanols, n-alkanoic acids and organic sulphur), as well as different biomarker ratios, have been used to show changing environmental conditions through time. These geochemical proxies suggest good preservation of the organic matter, although some diagenesis has occurred to particular organic compounds, especially the n-alkanoic acids. Our data indicate a major allochthonous supply of terrestrial plants, with less influence from aquatic plants or algae through the core. There are markedly different palaeoenvironmental conditions between the uppermost 5 m (last 6 ka cal. B.P.) and the rest of the core. From 5 m (ca 6 ka cal. B.P.) to 19 m (ca 8 ka cal. B.P.) depth the palaeoenvironmental conditions were almost constant. Based on organic sulphur content and n-alkane content logs, anoxic conditions prevailed from 8 to 6 ka cal. B.P., while oxic conditions with enhanced convection of water (prevalence of fluvial input), and consequently a greater organic matter supply, predominated in the upper 5 m of the core. Similarly, little variation in the magnetic susceptibility profile below 5 m indicates stable environmental conditions, while in the upper 5 m conditions shifted to one with elevated water input and clastic sediment supply. This is linked to palaeofloral alterations in the Guadiamar/Guadalquivir drainage basins and/or anthropogenic effects. We propose that from ca 8 to 6 ka cal. B.P. a stable landscape physiognomy in the surroundings of the estuarine area of the Guadalquivir River, with a predominance of pines and grassland. However, over the last 6 ka cal. B.P. a variation in the terrestrial plant biomarker compounds suggests an alternation of relatively dry and humid phases and/or the impact of human populations on altering the vegetation community have occurred.

The present study aims to extract the polluting material from a lagoon and use it as an alternative fuel in cement industries. To this end, in the methodology will analyze two alternatives for the waste: fuel generation and incineration. The polluting material from the Arganda lagoon has highly calorific value to be used as fuel. Thus, not only are these wastes used, but also an area with potentially hazardous waste is decontaminated. After the extraction, which due to the characteristics of the material is chosen for the novel pumping extraction, and subsequent generation of fuel, the process for using this waste is through the distribution of the created fuel to nine cement plants in Spain, leading to significant environmental benefits. The results of the process shows an energy efficiency of 97% for using the waste as fuel, and a consumed energy of approximately 6000 kWh/t·waste to the process that leads to the desired environmental benefit. The use of waste contributes to the reduction of CO2 emissions and a decrease in the use of fossil fuels.

The present investigation project aims to evaluate the extraction of contaminant material from two settling ponds to be used as alternative fuel in two cement plants. The extraction is carried out through mechanical means, and after that extraction, two options are compared: energy recovery and incineration. Through energy recovery, a potentially contaminated area is decontaminated and its waste is used; its high calorific value makes this option a viable one. The waste extraction is carried out through mechanical means due to the high density and viscosity of the waste. Because of these characteristics, the waste undergoes an on-site security adaptation to stabilize it, reduce declivity risk and make it suitable to be handled and moved. The second treatment is carried out in external installations where the final product is obtained (alternative fuel), which is to be used at industrial kilns. The entire described process shows a difference on the consumed energy of 6060.42 kWh/twaste between the two options under study: waste incineration and energy recovery. In addition, it also reduces CO2 emissions on 2.178 tCO2/twaste.