Biological water filtration is a process by which toxic compounds are removed from water using organisms. A well-sized biological filter is extremely important as part of a recirculating aquaculture system for fish farming. Biological water filtration equipment in aquaculture recycling systems is a technological set that restores the vital qualities of wastewater from fish ponds, thus allowing its reuse

Finite element analysis (FEA) is a computerized method for predicting how a product reacts to realworld forces, vibration, heat, fluid flow, and other physical effects. Finite element analysis shows whether a product resists under the working conditions, wears out, or works the way it was designed. Hemp fibre is a natural renewable material used in important areas of industry. The primary processing is performed on special equipment that ensures hemp fibre processing. In this study, the structural analysis module will be used for static analysis (resistance checking) and modal analysis (frequency analysis or calculation of a number of structure's own frequencies) for the important assemblies. The pressing and crushing rollers, their spindles and bearings and the frame (machine frame) of the hemp fibre processing equipment are analyzed and verified constructively and functionally. The results obtained are used in redesigning the equipment. Thus, it is expected that the new design of the hemp fibre processing equipment will have better performance in terms of metal consumption, energy efficiency and the quality of the obtained products. The equipment comprises a system with 8 pairs of processing rolls, and a vibrating system for separating the pieces from the remaining stems in fibre. The work is aimed at checking the dimensioning and the resistance to the efforts by the method of the finite element analysis (FEA) both for the construction of the rollers and the support frame.

The production and quality of any agricultural crop is determined both by the factors acting from the moment of sowing until harvesting, as well as by those that directly influence the seeds before sowing. In the organic cultivation of cereals, industrial plants, vegetables, medicinal plants, the seeds must be clean without any impurities because the maintenance of these crops does not allow using chemicals. There is a number of technologies and pieces of equipment for separating impurities. In case of separating impurities from the mass of small seeds, especially vegetable and flower seeds, the use of separation on sieves is very expensive because compared to other crops, vegetable seeds are produced in small quantities (except for beans, peas, lentils, etc.) and have a wide variety of characteristics. Vegetables belong to a large number of plant families. This is why their seeds have a very different structure, shape, size and chemical composition. To overcome these challenges, the experimental model Seed conditioning module for vegetable species – MCSL, which separates impurities by using the aerodynamic properties of the seeds was developed. Seed conditioning module for vegetable species is designed to improve the technologies of organic seed production for vegetable seeds, flowers, industrial plants, cereals and to solve practical problems regarding seed production in the case of vegetable crops. Starting from these considerations, the paper will present theoretical and experimental information on the influence of some factors on the aerodynamic properties of cereal seeds, vegetables and industrial plants. The quality of seed separation in this module depends on the degree of uniformity of the air velocity field in the working area, on the stability of this field and on its extent.

The present work is achieved based on the processing of the data accumulated over time, within the activity of research, technological engineering, and testing of machines for processing agricultural products in the last years, as well as studying the specialized literature with the latest achievements of some companies that make machinery for processing agricultural products. The compression of the hemp stalks for processing is analyzed, the main characteristics of the working rolls, the specific energy consumed are determined and an analysis of the obtained fiber length is performed. In order to develop a technical equipment for processing hemp stalks that ensures high performance, the following aspects were studied: the constructive and functional factors of a technical equipment that influence the working processes in order to choose a performance solution for processing hemp stalks. In the last part of the paper, the main technical and functional characteristics of a high-performance technical equipment for processing the hemp stalks harvested in green are established.

After the harvesting process, agricultural products (grains, fruits, vegetables, etc.) cannot be used directly for different purposes such as : preservation, consumption, industrialization, marketing, sowing, etc.) Prior to receiving a particular destination, it is necessary and obligatory for the harvested products to undergo preparatory operations on conditioning and quality control in order to meet different uses. In order to improve grain health and to avoid production decline and quality worsening due to the attack of diseases and pests transmitted through grains, treatment has long been used for some species and generalizes rapidly with better results of seed treatment by various means -physical, chemical or biological. Success in grain crops begins with efficient seed treatment, so one of the criteria for assessing the seed quality is its chemical treatment with major implications for the development of future crops. The development of an appropriate technology for the treatment of cereal seeds and technical plants requires a thorough analysis of all the factors involved in the chemical treatment of the seeds (seed quality, their destination, particularities of seed conditioning according to the variety, particularities of the equipment used). The paper presents experimental research results conducted on a machine with brush screw conveyor, which allowed the variation of operating parameters that are graphically represented. The testing methodology for treatment equipment has been developed according to the construction features and functional parameters. Therefore, we determine the interdependence between the coverage degree and the functional parameters that were tested and we formulate recommendations for the use of these types of machines.