Indoor biowaste treatment using small-scale composters has proven effective for processing organic waste and recovering valuable resources. This study evaluated the performance of the handmade C-EcoForHome composter, supplemented with an inoculant, in processing biowaste generated at five educational institutions in Split. During the biowaste treatment, key parameters were monitored, including temperature, compost heap height, moisture content, dry and volatile matter, carbon and nitrogen content, pH, and electrical conductivity. The collected leachates were analysed for volume, pH, electrical conductivity, and turbidity. Pre-composts were subsequently matured in two soil types, where the same physicochemical parameters were assessed to evaluate further stabilisation. Fourier-transform infrared (FTIR) spectroscopy was used to evaluate compositional changes in the biowaste resulting from composting conditions, and to analyse the produced water-dominated leachates. The results showed that the C-EcoForHome composter effectively processed biowaste in institutional settings, producing stable pre-composts with only minor variations compared to the initial substrate composition. Anaerobic fermentation caused acidification, ion release, and partial stabilisation of organic matter, while soil maturation further contributed to drying and consolidation. Indoor small-scale biowaste treatment represents a sustainable, low-maintenance solution for biowaste management, producing nutrient-rich pre-compost suitable for soil amendment.
U ovom radu provedeno je mehaničko recikliranje niti za košnju u laboratorijskom dvopužnom ekstruderu. Procijenjen je utjecaj mehaničkog recikliranja na strukturu, toplinska svojstva i toplinsku postojanost materijala od kojeg su izrađene niti za košnju. Primjenom infracrvene spektroskopije s Fourierovom transformacijom (FT-IR) utvrđeno je da su niti izrađene odpoli(ε-kaprolaktama), odnosno poliamida 6 (PA6). Ekstrudiranje nije utjecalo na strukturu PA6. Toplinska svojstva niti za košnju određena su primjenom diferencijalne pretražne kalorimetrije (DSC). Rezultati su ukazali na to da je ekstrudiranje imalo utjecaj na pakiranje i slaganje lanaca, odnosno uzrokovalo početak kristalizacije PA6 iz taljevine pri višoj temperaturi. Utjecaj mehaničkog recikliranja na toplinsku postojanost niti za košnju istraživan je primjenom termogravimetrijske analize (TG). Temeljem vrijednosti karakterističnih parametara ( T onset i T max) može se zaključiti da mehaničko recikliranje ne narušava toplinsku postojanost PA6. Mehaničko recikliranje može biti potencijalno rješenje zbrinjavanja rabljenih niti za košnju.
Engineering education is increasingly focused on developing both digital skills and sustainability awareness. To meet modern workforce demands, engineers must be proficient in using digital tools while designing environmentally responsible processes. The “Process Design” course at the Faculty of Chemistry and Technology integrates COCO ( Cape-Open to Cape-Open ) and ChemSep simulation software to enhance students’ digital competencies and deepen their understanding of sustainable chemical engineering. These free tools allow simulation of chemical processes, thermodynamic calculations, and optimisation of energy-efficient designs, enabling environmentally conscious decision-making. COCO, built on the CAPE-OPEN standard, includes modules for flowsheeting, unit operations, and reaction modelling, while ChemSep is used for simulating distillation columns. Together, they enable students to assess environmental impacts and design more sustainable processes. For this purpose, a survey was conducted among students to assess the software’s usability and its role in developing technical and soft skills such as creativity, critical thinking, and teamwork. The results showed that students recognised the value of the opportunity to simulate real-world processes, particularly in the context of sustainability. They found the tools accessible and effective in bridging theoretical knowledge with practical application. Students also emphasised the need for increased practical exercises and the incorporation of more complex simulation tasks. The integration of COCO and ChemSep proved beneficial in preparing students to address sustainability challenges through practical and digital competencies in process design, offering a free and accessible alternative to commercial simulation software, which is often limited by high costs and licensing constraints.
Efficient wastewater treatment is essential for environmental protection and sustainable water resource management, particularly when dealing with complex wastewater streams. Hybrid processes that combine electrochemical and physicochemical methods are increasingly explored due to their potential to enhance pollutant removal efficiency and reduce operating costs. This study evaluates the performance of hybrid treatment methods for complex compost wastewater by integrating electrocoagulation (EC), zeolite and magnetic assistance using aluminium (Al) and iron (Fe) electrodes. The influence of different electrode materials on magnetically assisted hybrid treatment process was assessed with respect to key treatment indicators, including chemical oxygen demand (COD) and turbidity reduction, as well as electrode mass loss, surface morphology, suspension settling, and EC sludge amount. Energy consumption and electrode usage were also considered to evaluate process economics. The results show that the application of a magnetic field in Al electrode systems slightly improves COD and turbidity removal, enhances anodic dissolution, and contributes to a more homogeneous surface morphology. In contrast, Fe electrodes exhibit a partially opposite response – the magnetic field accelerates floc settling and increases EC sludge production but reduces pollutant removal efficiency due to decreased dissolution intensity. Ferromagnetic Fe electrodes respond more strongly to the magnetic field, promoting aggregation and compaction of Fe-hydroxide flocs and partial surface stabilisation, which leads to lower anode mass loss. Weakly paramagnetic Al electrodes, on the other hand, are not directly affected by the magnetic field, but experience an indirect influence through magnetohydrodynamic (MHD)-induced micro-mixing and improved mass transfer. This leads to more uniform and intensive dissolution and a slightly higher pollutant removal efficiency. These findings provide a deeper understanding of the interactions between electrochemical and magnetic effects in hybrid electrocoagulation and offer guidance for optimising electrode material selection and magnetic field parameters to achieve more efficient and sustainable treatment of complex wastewater.
Hrvatski geolog i mineralog Fran Tućan (1878. – 1954.) i Mijo Kišpatić (1851. – 1926.), njegov bivši profesor na Zagrebačkom sveučilištu, postavili su 1912. godine teoriju prema kojoj je crvenica nastala trošenjem vapnenaca i dolomita, dok je boksit nastao od nje. To su temeljili na Tućanovim mineraloškim i kemijskim analizama dalmatinskih i bosansko-hercegovačkih boksita, koje su pokazale da su kemijski slični u kiselini netopljivom ostatku krških karbonatnih stijena. Teoriju su većinom prihvatili hrvatski, a poslije i jugoslavenski znanstvenici, ali je danas dovedena u sumnju zbog najmanje tri konkurentne teorije. U radu se razmatra sadržaj i povijest Tućanove teorije, a usto se govori o povijesti iskorištavanja boksita i industrije aluminija u Hrvatskoj i Jugoslaviji.
