The purpose of this research have been to determine the influence of soil fertilizations systems (fertilization with: nitrogen, phosphorous, nitrogen and phosphorous, farmyard manure) on the physical properties (penetration hardness) and chemical properties (humidity, metals) of the soil. The experiments have been carried out in the experimental field of National Agricultural Research and Development Institute -Fundulea, Romania, for a wheat monoculture. The lowest values of the metal content in soil (nickel, copper, zinc, arsenic, lead) have been recorded for wheat experimental variant -fertilized with N90P75 kg/ha (a1b4), and the highest content have been recorded for manganese (766 mg/kg dry matter), and for the wheat experimental variant a1b4, respectively (wheat-fertilized with N90P75 kg/ha active matter), working depth 0-15 cm.
Techniques for the treatment of polluted soils have as main objective the destruction, elimination or immobilization of pollutants. In situ soil flushing, which is based on the extraction of contaminants from the soil with water or other proper aqueous solutions is carried out by the permeation of the extraction fluid through soil layers. In this paper, an experimental setup was exploited for soil remediation based on the principle of in situ soil flushing for ensuring a high efficiency of treatment. Correlations were identified among soil properties that influence the treatment process, structural characteristics of the installation of remediation and operating parameters. The theoretical and experimental research of the soil depollution process presented in this paper constitutes an attempt to offer, by means of detailed analysis, constructive and functional dependences, which can set the basis for the design of new depollution technologies or modernization of the older systems.
This paper proposes to investigate in detail the behavior of polymeric membranes ultrafiltration process uses in the retention of humic acid from aqueous systems. Nowadays, the aqueous systems (contaminated water and/or wastewater) resulting from various domestic and industrial activities contain many contaminants, some of them increasingly dangerous to the environment. Laboratory testing of membranes in the ultrafiltration process as well as their experimentation with different chemical compounds is essential because it is important to know how they can be eliminated before they cause a negative impact. Testing of polymeric membranes consists in carrying out the process of ultrafiltration of aqueous systems containing humic acid over a set time, following the variation in time of the volume of permeate obtained as well as the influence of process parameters. Following the investigation of the ultrafiltration process of the water through the polymeric membrane, it was found that the formation of the humic acid layer on the surface of the membrane that favors fouling is delayed, after many hours of operation, due to both the internal fiber structure which offers advantages to this type of membranes as well as high efficiency of humic acid retention. Experimental results showed that the humic acid retention rate increased by up to 37% as a result of the double decrease of the conductivity value in the permeate samples from about 600 mS/cm to 373 mS/cm and the temperature being continuously increasing, from 22.5 at 25oC over 5 h influenced the entire ultrafiltration process. The full process approach as well as the expression and interpretation of the results will be detailed in this paper.
<p>Air quality depends on the type and size of industrial activities, traffic intensity, municipal and industrial waste management etc. In addition, air quality in urban areas depends by the green areas management, population density, climatic conditions and geographic. This paper study the correlations between the most important meteorological factors, humidity, temperature, wind and benzene accidental pollution, with influence on pollutant dispersion (related to 2008). The correlation were performed by taken in to considerations the accidental benzene pollution recorded in 2008 in Bacau City and meteorological factor recorded at the regional meteorological station.</p>
This paper proposes a tridimensional mathematical model for water migration time in a soil sample, as a prerequisite for the study of migration of various liquid pollutants in soil. The variables taken into consideration were measurement position, soil type, porosity and the height of soil column. The mathematical models were elaborated and tested based on experimental data, assisted by TableCurve 3D software for generating linear and non-linear equations. The proposed mathematical models offer a reliable method for determining water migration time in various soil samples, with future focus on other liquids migration ability.
This paper proposes a tridimensional mathematical model of the absorption capacity of heavy metals (cadmium and nickel) from the soil in the case of Phragmites Australis plant species (the soil and plant samples was taken from six locations/areas along the Bistri�a and Crac�u Rivers, belonging to the Siret hydrographic basin). The variable measures taken into consideration when carrying out the experiments and realizing the mathematical model are the distance from the water-soil interface from which the plant samples were taken and the concentration of the heavy metals in the soil. The mathematical model was elaborated and tested by means of the TableCurve 3D program used for generating linear and non-linear equations. A very high absorption capacity of cadmium from the soil was recorded A very high absorption capacity of cadmium from the soil was recorded, in the case of Phragmites Australis plant species (190�234 % higher than in the soil). The correlation coefficient of the mathematic model was between 0.90 and 0.98.
<p>The water deficit for consumption in various daily activities is more pronounced especially in countries where rainfall is low or in those areas where water demand is higher than available resources. This paper is a comparison between the airgap and water-gap distillation method. The results of the study have shown that the water-based distillation method can be more efficient, as the volume of permeate obtained is higher in relation to the increase in the flow temperature.The results obtained as well as the comparison of the advantages related to the two membrane distillation processes will be presented in the present paper.<strong></strong></p>
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