Biological permeable reactive barriers coupled with electrokinetic soil flushing for the treatment of diesel-polluted clay soil.

Removal of diesel from spiked kaolin has been studied in the laboratory using coupled electrokinetic soil flushing (EKSF) and bioremediation through an innovative biological permeable reactive barriers (Bio-PRBs) positioned between electrode wells. The results show that this technology is efficient in the removal of pollutants and allows the soil to maintain the appropriate conditions for microorganism growth in terms of pH, temperature, and nutrients. At the same time, EKSF was demonstrated to be a very interesting technology for transporting pollutants, microorganisms and nutrients, although results indicate that careful management is necessary to avoid the depletion of nutrients, which are effectively transported by electro-migration. After two weeks of operation, 30% of pollutants are removed and energy consumption is under 70 kWh m(-3). Main fluxes (electroosmosis and evaporation) and changes in the most relevant parameters (nutrients, diesel, microorganisms, surfactants, moisture conductivity and pH) during treatment and in a complete post-study analysis are studied to give a comprehensive description of the most relevant processes occurring in the soil (pollutant transport and biodegradation).

Electrokinetic transport of diesel-degrading microorganisms through soils of different textures using electric fields.

The mobilisation of diesel-degrading microorganisms in soils of three different textures (sandy, clay and silty) using electrokinetic techniques was studied. The mobilisation tests were performed using a laboratory-scale electrokinetic cell in which a synthetic soil column was inserted between the cathode and anode compartments. Microorganisms were located at the anode compartment at the beginning of each assay. A constant cell voltage was applied, and samples were taken from the cathode and anode compartments. Microbial transport through the soil strongly depended on soil particle size. Small particle sizes (silty and clay soil) travelled at low velocities (microbial transport rates of approximately 0.06 and 0.17 cm/min, respectively), while large particle sizes (sandy soil) led to high numbers of microorganisms passing through the soil column. In sandy soil, an increase in the voltage gradient did not increase the quantity of mobilised microorganisms (approximately 10(7) CFU/mL for every voltage gradient applied). For clay and silty soils, a higher voltage gradient led to a higher quantity of microorganisms mobilised to the cathodic compartment and a lower delay time for detecting the presence of microorganisms in the same compartment.

Electro-osmotic fluxes in multi-well electro-remediation processes.

In recent years, electrokinetic techniques on a laboratory scale have been studied but few applications have been assessed at full-scale. In this work, a mock-up plant with two rows of three electrodes positioned in semipermeable electrolyte wells has been used to study the electro-osmotic flux distribution. Water accumulated in the cathodic wells when an electric voltage gradient was applied between the two electrode-well rows. Likewise, slight differences in the water flux were observed depending on the position and number of electrodes used and on the voltage gradient applied. Results show that the electro-osmotic flow did not increase proportionally with the number of electrodes used. During the start-up of the study, there was an abrupt change in the current density, pH and conductivity of the soil portions closest to electrodic wells due to electrokinetic processes. These differences can be explained in terms of the complex current distributions from anode and cathode rows.

Influence of soil texture on the electrokinetic transport of diesel-degrading microorganisms.

This work studied the mobilisation of diesel-degrading microorganisms in soils of different textures using electrokinetic techniques. The mobilisation tests were performed using a laboratory-scale electrokinetic cell in which a synthetic soil column was inserted between the cathode and anode compartments. Model soils of different textures were prepared by mixing silica and kaolin at different weight ratios. Microorganisms were obtained from an undefined diesel-degrading microbial culture and located at the anode compartment. In each four hours experiment, constant cell voltage was applied, and samples were taken from the cathode compartment. Changes in the pH due to water electrolysis were found to significantly influence the process performance, and the effect of the carbonate concentration (buffer) was studied to clarify this effect. With respect to soil texture, it was observed that large particle size led to high numbers of microorganisms passing through the soil column, and the presence of small particles, which give rise to small pores, was required to improve the retention of microorganisms. Finally, current-intensity measurements with different soil textures revealed that it was favourable to use only large or small particles, whereas a sandy clay soil (50% silica/50% clay) did not favour any of the fundamental electrokinetic processes.

[Impact of the spanish consensus on physical health of patients with schizophrenia]. / Impacto del Consenso Español sobre la Salud Física del Paciente con Esquizofrenia.

INTRODUCTION: This study evaluates the physical health of patients with schizophrenia and analyzes the change in the percentage of patients with evaluations in the known diabetes and cardiovascular risk predictors before and 6 months after the dissemination of the "Consensus on Physical Health in Schizophrenia Patients". MATERIAL AND METHODS: This is an epidemiological non-interventional and transversal study, in which 229 psychiatrists evaluated 1,193 clinical records of patients with a diagnose of schizophrenia according to ICD-10, attended in the psychiatry consultations planned in January and September of 2007. Study results were analyzed using descriptive statistics. RESULTS: 1,193 evaluable patients were included, with a mean age of 39.7±11.6 years, diagnosed of schizophrenia 15.0±10.3 years ago, and a 65.90% were men. The presence of concomitant diseases was 39.98%, being hypercholesterolemia (46.33%), hypertriglyceridaemia (33.54%) and arterial hypertension (26.00%) the most frequent. After the dissemination of the Consensus, the percentage of patients who had all the physical measurements taken increased by 13.75%. Forty eight per cent of the psychiatrists were considered as being aware of the Consensus. The percentage of measurements taken was higher within the psychiatrists who were aware of the Consensus (17.32%) than within those who were not aware of it (10.33%). CONCLUSIONS: The results of this study show an increase of the physical health control from patients with schizophrenia after the dissemination of the Consensus, which should improve an integral approach of these patients to ensure a similar life expectancy, quality of life and function to the general population.