Monitoring of Surface Water Status in the Lower Danube Basin

Water pollution demands emergency actions for better water resource management to respect the concept of sustainable development. The aim of the Water Framework Directive, as long-term water policy of the European Union, is to assure the good quality of surface waters. Each state from Europe has to identify all the river basins lying within their national territory and to assign them to individual river basin districts. In this respect, an effective integrated system and monitoring technology, analysing, interpreting data and utilizing the results to make decisions related to the water resources protection, were developed. The main objectives are focused on the expansion of monitoring activities and obtaining more detailed information on the state of surface waters. Specific recommended equipment which enables to perform the analysis of recommended water quality parameters should be placed on the monitoring stations of the Lower Danube Basin. Respectively, this lack of equipment provides a challenge in the development of effective methodologies for collection and analysis of water quality data. The main priority was the development of an integrated water catchment area management strategy and to build up the online continuous monitoring system. Some of the technical goals for continuous water monitoring were reached in Hungary and Romania and are presented here

Synthesis of Zeolite from Fly Ash and their Use as Soil Amendment

The amendments may be natural or synthetic and by their origin organic or inorganic. Among amendments, the inorganic ones are recommended, such as gypsum, lime, zeolites and altered rocks, including sand, ceramic, perlite, ash, slag, zeolite, pyrites, dolomite, calcined clay, etc. Fly ash-based zeolites can be used as amendments to improve the use of the soil for agricultural purposes. Generally, there are different methods for the synthesis of new materials using solid waste – fly ashes. Methods are known to be composed of a single stage or two stages. The first method – the conventional – is direct hydrothermal conversion of the mixture of ash and alkaline solution (NaOH or KOH), but only 50% of ashes can be converted into zeolite. The second method consists in mixing the ash with KOH and fusion at elevated temperature. The method leads to an advanced conversion – the type of zeolite depending on treatment conditions. Other studies recommend the conversion of ash using microwave ovens or ultrasound bath; in this case, the conversion time is reduced to 1–2 hours. From these methods, the direct method was proposed to be used in synthesizing zeolites for agriculture, with a part in controlling release of fertilizers and as a soil amendment. The synthesized materials were characterized with respect to microstructure (electronic microscopy SEM) and chemical and mineralogical composition (EDAX, X-ray diffraction). By analyzing the obtained data, one may observe the destruction of the ash network and crystallization of the zeolitic phase, especially in the case of treatment by diffusion. The XRD analysis confirms the presence of zeolite in materials obtained. Good results were also obtained in the case of using ultrasound treatment for zeolite synthesis; also, the time of treatment significantly decreased in this case

Technical Efficiency of the Subsurface Drainage on Agricultural Lands in the Moldova River Meadow

This study aims to investigate the technical efficiency of different subsurface drainage variants, in terms of the depth of the tile drains, spacing between the drain lines, type and thickness of the drain + filter complex, and the improvement procedures. Within the four variants, the discharge rate of the soil moisture excess was studied. In variants A and D, the spacing between drains is 20 m, and in the variants B and E, the spacing is 15 m. The depth of the tile drains is 0.8 m in variants D and E and 1.0 m in variants A and B. In variant A, tile drainage was combined with land shaping in the bedding system with top of ridges and furrows. Soil moisture was determined on checkpoints placed on drain cross section, at 2 m from drain lines, and of the middle of the drain spacing. In the version with land shaping, the drain lines located under the furrows favor the excess moisture removal. A similar technical efficiency was recorded in unimproved variant but with spacing between drains of 15 m. Best efficiency at removing excess water was registered in variant of the filtering material from ballast associated with flax strains

Statistical Analysis of the Tensile Strength of Coal Fly Ash Concrete with Fibers Using Central Composite Design

The influence of coal fly ash and glass fiber waste on the tensile strength of cement concrete was studied using central composite design. Coal fly ash was used to replace 10% of the cement in the concrete mix. Glass fiber was added to improve the tensile properties of the concrete in different dosages and lengths. In total, 14 mixes were investigated, one only with 10% coal fly ash replacement of cement and the other thirteen were determined by the experimental design. Using analysis of variance, the order of importance of the variables was established for each property (flexural strength and split tensile strength). From the nonlinear response surfaces, it was found that higher values of flexural strength were obtained for fibers longer than 12 mm and at a dosage of 1-2%. For split tensile strength, higher values were obtained for fibers with a length of 19–28 mm and at a dosage of 1–1.5%

Physio-chemical properties of two cherry tomato varieties in relation to the greenhouse environmental factors

To prevail on the agricultural market, greenhouse grown cherry tomatoes need to meet certain quality standards. The quality can be assessed by determining several chemical and physical characteristics. The aim of the current study is to analyse such parameters of two cherry tomato varieties (Cheramy and Flaviola) in relation to their flowering stage and to the growing conditions within the greenhouse: air temperature, relative humidity and CO2 concentration. The soluble solids, titratable acidity and dry matter were determined. Furthermore, the β-carotene, lycopene and ascorbic acid contents were analysed. Tomato fruit size and firmness were also assessed. The current study illustrates a limited correlation between the environmental factors and the quality parameters. Thus, future research should be pursued for a better understanding of the effect of these climatic conditions on greenhouse grown tomatoes.publishedVersio