As a result of slaughtering processes, large volumes of effluents with high concentrations of organic, inorganic and microbiological pollutants are generated. The pollutants composition must be reduced by apply simultaneous processes in order, to obtain an proper effluent before discharge. In this paper, the efficiency of the physico-chemical treatment process was determined, in which a rotary sieve and the Dissolved Air Flotation (DAF) system were used. The efficiency of the DAF process was determined by comparing the quality indicators of effluents from a poultry slaughterhouse, analyzed both before and after treatment. To carry out the analysis, the samples were taken in October and November 2023, and they were determined by using certified laboratory procedures. After setting the DAF process to an optimal operating regime and chemicals dosages, the quality indicators were significantly reduced, reaching a maximum of 99%, 98%, 93%, 92%, 85%, 84%, for TSS, PO4, NO3, TKN, BOD5 and COD.

In recent years, more and more emphasis has been placed on the use of home filtration systems as a coarse pre-filtration step. The PP (polypropylene) filter cartridge is one of the most common of these systems, with the role of retaining solid suspensions from drinking water. However, few studies have focused on the fouling analysis of PP cartridges using EDS (Energy-Dispersive X-ray Spectroscopy) analysis methods. Through this study, a clear and in-depth view of the structures and morphology of PP filter cartridges as well as their impurity retention capacities and their impact is provided with the help of an SEM (Scanning Electron Microscope) analyzer. To achieve these goals, it was necessary to establish a specialized preparation methodology for this type of material in order to analyze it using the SEM and, at the same time, determine the optimal setting of the SEM parameters (improved resolution, reduced acceleration voltage, reduced data acquisition time, etc.) depending on the analysis performed for the visualization and detailed characterization of surfaces. Based on the SEM-EDS analysis and characterization, an uneven distribution of impurities on the surface of the PP fibers was identified. The number of impurities varied according to the depth of the cartridge due to the sieving effect that occurred owing to the varied sizes and shapes of the impurities, but also the structural differences and pore sizes of the filter material. So, the most common chemical elements identified were Al, Si, Na, Cl, Ca, Fe, and S, having a predominantly higher intensity from the inside to the outside of the PP filter cartridge due to pressure forces and the uneven flow of filtered water.

Virtual reality (VR) is increasingly used as an interactive instructional medium in engineering education, yet evidence on practical implementation and student-reported experience remains limited. This study examined students’ perceived experience and usability across VR and traditional instruction within a crossover design in a UV-C water disinfection lesson. Using a mixed 2 × 2 crossover design, 52 undergraduate engineering students completed both a VR lesson (Meta Quest 3; Unreal Engine 5.4) and a content-aligned traditional session delivered with slides and a physical UV disinfection stand. After each session, participants reported perceived flow (short Flow Index) and engagement (adapted User Engagement Scale); the System Usability Scale (SUS) was completed after the VR session only. A brief knowledge quiz and open-ended feedback were also collected and used descriptively. Students reported higher perceived flow and engagement in the VR condition than in the traditional condition, and VR usability was generally rated acceptable-to-excellent, with higher SUS scores observed in the VR-first sequence than in the traditional-first sequence. Qualitative feedback emphasized clarity and interactivity, and most participants expressed a preference for a blended approach. Overall, the results support the practical feasibility and positive user acceptance of the VR lesson in this instructional context. The findings also suggest that perceived usability may be associated with instructional sequence, although this pattern should be interpreted cautiously within the perception-based scope of the study.

The purpose of any electrode in die-sinking EDM is to transmit electrical impulses that facilitate workpiece erosion with minimum or no self-erosion. The performance of the electrode depends on the properties of the material that it is made of, application, and the workpiece material. This study focused on employing intensive machining regimes that increase productivity while maintaining electrode wear as low as possible to enhance cost-effectiveness. The experimental tests were organized using the response surface method and the analysis of the results is based on the ANOVA method. The findings revealed that the WCu 75/25 outperforms the other two in wear resistance and CuZn39Pb2 is the most wear prone. It was revealed that WCu 75/25 electrode at Ip ≈ 90 A and Ton between 360 and 390 µs represents the globally best solution for a minimum wear.

Poultry farming is important from a food point of view, as it provides products for the population. Waste resulting from poultry farming and processing is environmentally sensitive, which is why treatment technologies are crucial for sustainability. Conventional pre-treated wastewater originating from the poultry sector, combined with innovative methods of using substances with antimicrobial effects constitute another approach to eliminating health risks. This research aimed to evaluate the behavior of bacterial strains isolated from water samples treated by reverse osmosis (RO), ultrafiltration (UF), and ultraviolet disinfection (UV). To choose our antimicrobial substances, we surveyed the population using the Google Forms platform and the official questionnaire. Using a factorial design, the concentration of antibiotic or antiseptic, as well as the duration of their action on bacterial strains isolated in pure culture, was varied. The optical densities of bacterial cultures reflect the efficiency of treatments with antibacterial or antiseptic substances. Factorial design, corroborating the experimental results, led to the following: 4.84 mg·L⁻¹ antibiotic for 7.6 h and 4.23 mg·L⁻¹ chloramine for 16.23 h. The results obtained from mathematical modeling correspond to a decrease in the bacterial population. In perspective, combining purification technologies with antimicrobial substances, adapted to the volume of water through mathematical modeling, will reduce the risk of microbiological contamination, with bacterial recovery rate values ranging between 0.58 and 1.21 in the case of antiseptic using, and between 0.60 and 0.92 in the case of antibiotic using.

The aim of this study was to evaluate the s seasonal variability and climate-related associations of the main municipal waste fractions collected within the municipal waste management system of Bacau County, Romania, during the 2019–2024 period. The analysis integrated monthly municipal waste data with climatic variables obtained from the NASA POWER database, including air temperature, precipitation, wind speed, and solar radiation. Seasonal variability was investigated using one-way analysis of variance (One-way ANOVA), Tukey’s HSD post hoc test, and seasonal index analysis, while climate–waste relationships were assessed using Pearson correlation analysis and the cross-correlation function (CCF). The results revealed significant seasonal differences in residual waste and biowaste, whereas recyclable fractions (plastic, paper and cardboard, and glass) showed no statistically significant seasonal variation. Residual waste exhibited the strongest relationships with climatic factors, being positively correlated with air temperature (r = 0.794) and solar radiation (r = 0.649), and negatively correlated with wind speed (r = −0.670). Biowaste showed weak contemporaneous associations, while exploratory cross-correlation analysis did not provide robust evidence of delayed climatic effects. The study demonstrates that the relationships between climatic conditions and collected waste quantities are fraction-specific and cannot be adequately characterized by analyzing total municipal waste quantities alone. The proposed analytical framework can support the development of forecasting tools and adaptive planning strategies for municipal waste management in the context of climate change.