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The implementation of three-dimensional (3D) printing for education in different fields brings numerous advantages that make learning easier for students. Also, it changes the model of students' participation in the teaching process so that they become active participants. This article considers the involvement of 3D printing in the teaching process in the field of hydraulic and pneumatic components by using the developed methodology. The goal was to find an approach that would help students to easier understand the design and operation principles of these components. The methodology was developed and applied in various forms of the teaching process during a 5-year period. The application of the methodology was evaluated based on the results of the online questionnaire. Traditional theoretical approaches enable a good transfer of basic engineering knowledge, but students are usually not ready to apply them in practice. The results show that the largest number of students (81%) stated that 3D printing should be included in the teaching process. The main reason was a better understanding of the considered components and the possibility of the application of acquired knowledge in the industry. 3D printing enables students to understand the considered component, its design, and operational principle. Further application of 3D printing enables the development of additional skills related to the developing, modeling, and manufacturing (printing) components. Also, students expressed increased motivation for learning.
RESUMO
Co-digestion implementation in wastewater treatment plants enhances biogas yield, so this research investigated the optimal ratio of biodegradable waste and sewage sludge. The increase in biogas production was investigated through batch tests using basic BMP equipment, while synergistic effects were evaluated by chemical oxygen demand (COD) balance. Analyses were performed in four volume basis ratios (3/1, 1/1, 1/3, 1/0) of primary sludge and food waste with added low food waste: 3.375%, 4.675%, and 5.35%, respectively. The best proportion was found to be 1/3 with the maximum biogas production (618.7 mL/g VS added) and the organic removal of 52.8% COD elimination. The highest enhancement rate was observed among co-digs 3/1 and 1/1 (105.72 mL/g VS). A positive correlation between biogas yield and COD removal is noticed while microbial flux required an optimal pH, value of 8 significantly decreased daily production rate. COD reductions further supported the synergistic impact; specifically, an additional 7.1%, 12.8%, and 17% of COD were converted into biogas during the co-digestions 1, 2, and 3, respectively. Three mathematical models were applied to estimate the kinetic parameters and check the accuracy of the experiment. The first-order model with a hydrolysis rate of 0.23-0.27 indicated rapidly biodegradable co-/substrates, modified Gompertz confirmed immediate commencement of co-digs through zero lag phase, while the Cone model had the best fit of over 99% for all trials. Finally, the study points out that the COD method based on linear dependence can be used for developing relatively accurate model for biogas potential estimation in anaerobic digestors. Supplementary Information: The online version contains supplementary material available at 10.1007/s12155-023-10620-8.