Razvoj modela za integralno upravljanje organskim otpadom primenom principa cirkularne ekonomije srp info:eu-repo/semantics/bachelorThesis Organic waste is a biodegradable resource with high potential for nutrient andchemically bound energy recovey yet mostly landfilled. To enable itssustainable use, a model for integrated organic waste management wasdeveloped. Based on circular economy principles, the model allows foroptimized inclusion of locally available feedstocks into closed material andenergy loops. The mathematical model is based on a physical model that linksthe sources of organic waste with the locations of its transformation throughcomposting and anaerobic digestion, as well as with the points of nutrientrecovery in the form of compost and digestate and the production of energyrequired for plant operation and transport. The mathematical formulation ofthe closed loop is developed through sections describing the material andenergy flows of the system; the model itself is optimized in WolframMathematica. Model analysis is conducted through six simulations organizedinto three research phases: exploratory, evaluative and validation. In theexploratory phase the model’s ability to determine optimal feedstock mixingratios for anaerobic digestion and composting, and for assessing the potentialfor closing material and energy flows, is examined through multicriteriaoptimization. Within this phase, key system parameters are optimized: C/Nratio, minimum lignin content and minimum phosphorus content of 1% in thefeedstock mixture; establishing conditions for sustainable treatment. Theevaluative phase includes ten scenarios of organic waste managementdiffering in the number of feedstocks and the combination of treatments. Theefficiency of scenarios is assessed using a developed set of indicators: thedegree of feedstock inclusion in circular economy flows, material and energyleakage and the degree of material and energy circularity. The results showthat the scenario combining two treatment methods and two feedstocksachieve loop closure with low leakages and a high circularity rate, whileadding an additional feedstock increases the inclusion rate but also leads to ahigher material leakage in the form of compost. Increasing the number offeedstocks to four reduces the overall inclusion rate, indicating systemlimitations with introduction of larger number of feedstocks. A particularfocus is placed on tracking the change of C, N, P and K and the transformationof their forms from organic to inorganic, plant-available fractions in compost,with the aim of satisfying the nutrient requirements of a specific crop. Theresults confirm that the model can optimize a composting mixture whichcomposition meets the needs of barley. In the validation phase, modeledoptimal feedstock mixtures are compared with experimentally obtainedmixtures for defined C/N ratio in a biogas plant, confirming the applicabilityof the model under real operating conditions. Future research will focus onimproving the mathematical model by incorporating a larger set of criteria, aswell as on assessing the system’s circularity in relation to the number andtypes of included raw materials. Biografija autora: str.193.Bibliografija: str.142 -152. Datum odbrane: 24.03.2026. Waste management 2025 Momčilović Ristanović, Ana J., 1992- https://phaidrani.ni.ac.rs/o:3316 cobiss:196878601 thesis:8846 Stefanović, Gordana, 1959- Rajković, Predrag M., 1959- Živković, Predrag, 1975- Bajić, Bojana, 1986- http://creativecommons.org/licenses/by-nc-nd/3.0/at/legalcode [16], 184 str. 18406875 bytes