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.
In Romania, over 40 % of the population lives in rural areas where wastewater infrastructures are poor or missing. Development of infrastructure in water supply and sewerage is essential for improving living conditions and human health. To solve the problem of domestic wastewater treatment in the areas where only decentralized sewage treatment systems can be implemented, compact installation that operating as a Sequencing Batch Reactor (SBR) process can be used. Unlike the conventional biological mechanical wastewater treatment systems, in which the process is divided into several basins, the treatment system that uses the SBR process segregates the treatment process by working times. Therefore, the compact installation that uses SBR process is among the most effective alternatives to the conventional wastewater treatment with low flow. To ensure a high degree of treatment in small treatment plants which operates by SBR process, it is essential to identify the correlations among some parameters, such as: qualitative and quantitative characteristics of the influent, construction characteristics of the treatment system and operating factors. The main direction of this research aims at identifying the mathematical model able to describe the heat balance for a SBR used in a small municipal wastewater treatment plant. Moreover, the theoretical model was correlated with the numerical values obtained during 30 days of measurements and monitoring of a small wastewater treatment plant used to treat real municipal wastewater. The installation used in this research was used in real condition to obtain the values as close to reality for the component of the heat balance.
The purpose of this research have been to determine the influence of soil main works systems (no tillage, fall tillage, spring tillage, discing in) on the physical properties (penetration hardness, air speed in soil) and chemical properties (humidity, humus, total nitrogen, calcium, chlorides) of the soil. The experiments have been carried out in the experimental field of National Agricultural Research and Development Institute - Fundulea, Romania, for a corn monoculture. The highest values of the soil penetration hardness have been recorded for the corn monoculture for which the spring tillage system had been applied (4.9 MPa, working depth 15-30 cm). The lowest values of total nitrogen and chlorides content have been recorded for the corn monoculture for which the fall tillage system had been applied (1.37 mg/kg d.s., working depth 15-30 cm) in the case of the total nitrogen and for the corn monoculture - discing in system (4.43 mg/100g sol, 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.
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