1. Zero-waste strategy of small wastewater treatment plants with integrated thermal treatment of generated solid wastesDanijela Urbancl, Christoph Hochenauer, Angelika Michaela Zachl, Nika Fekonja, Aleksandra Petrovič, Darko Goričanec, Marjana Simonič, 2025, original scientific article Abstract: The aim of the study was to analyse two small wastewater treatment plants (SWTPs) and compare their treatment performance with the aim of developing a zero-waste strategy. The analyses showed that the second wastewater treatment plant had a problem with an increased phosphorus concentration in the wastewater as well as fluctuations in nitrogen removal. One of the key aspects was the recovery of phosphorus in the form of struvite precipitated on zeolite, which can be used as a fertiliser due to its significant nutrient content. The main benefit of the same SWTP is the separate collection of cellulosic material (labelled as sample RS), which has the potential for reuse as biochar, while from the first SWTP the sludge sample (labelled as sample SS) was taken and torrefied for comparison with RS. Both samples were torrefied at 250 ◦C and 350 ◦C in nitrogen and carbon dioxide atmospheres. The RS products obtained in CO2 atmosphere at 350 ◦C showed the best biochar properties, as they had a higher heating value (HHV) and a higher C content. Elemental analysis showed that the carbon content in RS and SS increased from 43 to 65 % and from 35 to 39 %, respectively. Measurement of the HHV of the torrefied RS product showed an increase from 17 to 26 MJ/kg, while for SS it increased from 15 to 17 MJ/kg. The comprehensive combustion index and the EMCI index show higher values for the RS samples torrefied at 350 ◦C. The H/C and O/C ratios are favourable for these samples, as the high quality of torrefied biomass is associated with the highest prices on the market. According to the TGA and FTIR analysis, the type of torrefaction atmosphere, in contrast to the torrefaction temperature, has little influence on the subsequent use of the torrefied samples in combustion. The results show that the integration of torrefaction for biochar production with phosphorus recovery by struvite precipitation is an efficient solution for waste management in small wastewater treatment plants.
Keywords: wastewater treatment plant efficiency, torrefication, N2 atmosphere, CO2 atmosphere, solid biofuels, proximate and ultimate analyses, thermogravimetry
Published in DKUM: 29.10.2025; Views: 0; Downloads: 7
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2. Odstranjevanje nečistoč iz pralnih vod farmacevtske industrije s kemijskimi metodami in vakuumskim uparjanjem : magistrsko deloNika Fekonja, 2025, master's thesis Abstract: Odpadki v farmacevtski industriji so sestavljeni iz ostankov proizvodnje, ki jih je treba ustrezno obdelati in odstraniti, pri čemer metoda odstranjevanja temelji na sestavi odpadkov. V podporo krožnemu gospodarstvu je zaželeno, da se odpadni tokovi uporabijo za koristne namene, kot je proizvodnja izdelkov z dodano vrednostjo. Pri magistrski nalogi smo se omejili na tokove, ki v farmacevtski industriji predstavljajo največjo problematiko in predvsem tiste, ki dajejo največjo energetsko korist.
Dobljene tokove iz farmacevtske industrije smo preučili s fizikalno metodo – vakuumski uparjanjem in kemijskima metodama elektrokoagulacijo ter obarjanjem z apnom. Vakuumsko uparjanje smo izvedli pri različnih obratovalnih tlakih, kjer smo spremljali temperaturo uparjanja in koncentrata. Želeli smo doseči tlak, kjer pri procesu uparjanja ne bi presegli temperature 60 °C, saj ima obrat na voljo nizkotemperaturno toploto, katero smo želeli koristno uporabiti pri tem procesu. Dobljene produkte pri izbranem tlaku smo analizirali in izvedli meritve gostote, pH, prevodnosti, viskoznosti in nato še analize kemijske potrebe po kisiku (KPK), vsebnost dušika, fosforja, anionov, kationov ter vsebnost suhe snovi.
Namen raziskave je bil očistiti tokove, ki nastajajo v farmacevtski industriji s pomočjo vakuumskega uparjanja, pri čemer bi čisto vodo uporabili pri nadaljnjem procesu, medtem ko bi ostanek koristno uporabili za sežig, kar bi služilo kot pridobljena toplota. S tem bi zmanjšali emisije onesnaževal v odpadnih tokovih in tako pripomogli k okoljski trajnosti.
Keywords: odpadni tokovi v farmacevtski industriji, vakuumsko uparjanje, elektrokoagulacija, okoljska trajnost
Published in DKUM: 28.10.2025; Views: 0; Downloads: 11
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3. Sinteza in uporaba magnetnih nanodelcev, funkcionaliziranih s polisaharidom, za adsorpcijo strateških kovin : magistrsko deloLaura Furman, 2025, master's thesis Abstract: Strateške kovine, med katere spada tudi baker, predstavljajo ključne surovine v sodobni industriji, zlasti pri razvoju elektronskih in električnih naprav. Zaradi omejenih naravnih virov in naraščajočega povpraševanja postaja njihovo pridobivanje iz sekundarnih virov, kot so elektronski in električni odpadki (e-odpadki), vse pomembnejše. Ena izmed obetavnih metod na tem področju je magnetna nanohidrometalurgija (MNHM), ki združuje hidrometalurške postopke z nanotehnologijo in temelji na adsorpciji kovinskih ionov z uporabo funkcionaliziranih magnetnih nanodelcev.
V magistrskem delu smo sintetizirali magnetne nanodelce (MNPs), funkcionalizirane z λ-karagenanom (λ-CARR), naravnim polisaharidom, z namenom učinkovite adsorpcije strateških kovin iz vodnih raztopin, kjer adsorpcijska mesta predstavljajo sulfatne skupine. Kristalno strukturo nanoadsorbenta smo okarakterizirali z rentgensko praškovno difrakcijo (XRD), njegovo morfologijo in velikost pa določili s transmisijsko elektronsko mikroskopijo (TEM). Površinsko kemijo magnetnih nanodelcev, prevlečenih z λ-CARR, smo kvalitativno analizirali s Fourierjevo transformacijsko infrardečo spektroskopijo (ATR-FTIR), ter podrobneje z rentgensko fotoelektronsko spektroskopijo (XPS). Z dinamičnim sipanjem svetlobe (DLS) in meritvami ζ-potenciala smo ovrednotili velikost delcev in njihov površinski naboj. Količino vezanega polisaharida na površini nanodelcev smo določili s termogravimetrično analizo (TGA), magnetne lastnosti pa preverili z vibracijskim vzorčnim magnetometrom (VSM).
Razviti magnetni polisaharidni nanoadsorbent (MNPs@CARR) je pokazal potencial za odstranjevanje bakrovih ionov. Preučili smo vpliv različnih parametrov na adsorpcijsko učinkovitost, in sicer: maso adsorbenta, pH-vrednost raztopine, začetno koncentracijo Cu²⁺, kontaktni čas, temperaturo ter možnosti regeneracije in ponovne uporabe adsorbenta. Koncentracijo bakrovih ionov smo določali s kolorimetrično metodo s pomočjo fotometra. Kot optimalne pogoje za odstranjevanje Cu²⁺ z MNPs@CARR smo določili: γ (Cu2+) = 1,3 mg L−1, V= 20 mL, pH=6, T = 298 K, 20 mg adsorbenta, kontaktni čas=2 h, pri čemer smo dosegli 84,6 % učinkovitost odstranjevanja. Pri teh pogojih je MNPs@CARR po štirih ciklih regeneracije ohranil približno 60 % začetne adsorpcijske zmogljivosti. Rezultati nakazujejo, da je sintetiziran nanomaterial primeren za trajnostno obdelavo in predelavo strateških in kritičnih kovin (Al, Sr, B) iz sekundarnih virov, kot so tiskana vezja mobilnih telefonov.
Keywords: magnetni polisaharidni nanoadsorbent, strateške kovine, baker, predelava kovin, e-odpadki, magnetna nanohidrometalurgija, trajnostno ravnanje z viri
Published in DKUM: 02.10.2025; Views: 0; Downloads: 51
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4. Analiza prašnih delcev na površini maha : magistrsko deloRobert Baš, 2025, master's thesis Abstract: Namen raziskave je bil analizirati število trdnih delcev, akumuliranih na mahu. Preučevali smo delce treh velikostnih razredov: 10 μm, 2,5 μm in 1 μm. V odvisnosti od velikosti delcev smo ovrednotili korelacijo s koncentracijo težkih kovin ter preučili prostorsko odvisnost števila delcev glede na oddaljenost od cestnega omrežja.
Vzorčenje mahu smo izvedli po uveljavljenem protokolu iz literature. V laboratoriju smo vzorce najprej posušili, nato pa analizirali število delcev na 100 μm² površine lističev mahu z uporabo vrstičnega elektronskega mikroskopa (SEM). Analiza je temeljila na seriji posnetkov površine lističev, iz katerih smo na podlagi večkratnih meritev izračunali povprečne vrednosti ter ločeno obravnavali posamezne velikostne razrede delcev.
Poleg tega smo v okviru eksperimentalnega dela izvedli analizo vsebnosti težkih kovin z metodo induktivno sklopljene plazme z masno spektrometrijo (ICP-MS). Zaradi morfoloških značilnosti lokacije vzorčenja pričakovani rezultati niso bili doseženi. Kljub temu smo izvedli korelacijsko analizo med koncentracijami težkih kovin in številom trdnih delcev, ki je pokazala zelo šibko povezavo, ne glede na velikost delcev. Prav tako je bila šibka tudi korelacija med številom delcev in oddaljenostjo od ceste.
Keywords: težke kovine, PM delci, mikroplastika, ICP-MS, SEM
Published in DKUM: 29.09.2025; Views: 0; Downloads: 14
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5. Preliminary assessment of combination of membrane technologies for nutrient removals from domestic wastewater : bachelor's thesisMatevž Može Davidović, 2025, undergraduate thesis Abstract: The study focuses on wastewater treatment by investigating the use of microalgae in cooperation with bacteria, in combination with ultrafiltration and membrane photobioreactors. This approach also enables the extraction of nutrients retained by the organisms, referred to as biomass, which can subsequently be utilised. Three different water samples were tested and introduced into the same system. The first sample was the influent water, the second was the mixed liquor, in which microalgae function in a consortium with bacteria, and the third was the effluent water, referred to as permeate. Parameters such as pH, electrical conductivity, turbidity, suspended solids, chemical oxygen demand, inorganic and organic carbon, organic content, and ion concentration were analysed using standard procedures. Certain samples required filtration for specific analyses. The results indicated that measured values varied among the three samples, which is expected, as certain inorganic compounds are consumed as nutrients for microalgae growth. In addition, some nutrients are released through the progressive degradation of more complex compounds. This work demonstrates the effective application of these technologies and methods for municipal wastewater treatment, with a focus on the new rotating membrane (R-HFM), which has a positive impact on system performance. Overall, this represents a promising investment in the future of water treatment.
Keywords: Wastewater treatment, bioreactors, ions, microalgae, ultrafiltration, biomass, photobioreactors, nutrient recycling, bacteria, microbial activity, domestic wastewater.
Published in DKUM: 11.09.2025; Views: 0; Downloads: 1
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6. Določevanje indeksa kakovosti različnih vrst pitnih vod : diplomsko delo visokošolskega strokovnega študijskega programa I. stopnjeTjaša Slatinek, 2025, undergraduate thesis Abstract: V diplomskem delu je prikazana analiza različnih vrst pitne vode v Sloveniji, pri čemer smo primerjali vzorce iz javnih vodovodov ter dveh domačih vodnih virov. Do sedaj za izbrana zajetja še niso bile izvedene celovite raziskave, ki bi enotno ocenjevale kakovost vode z indeksom kakovosti vode. Cilj diplomskega dela je bil določiti kakovost pitne vode z uporabo fizikalno-kemijskih analiz, mikrobioloških preiskav ter določitvijo vsebnosti per- in polifluoroalkilnih snovi. Fizikalno-kemijske parametre smo določali v vseh vzorcih, med njimi pH, motnost, električno prevodnost, trdoto, celotne raztopljene snovi ter koncentracije kalcija, magnezija in železa. V sodelovanju z Nacionalnim laboratorijem za zdravje, okolje in hrano smo izvedli mikrobiološke analize za potrditev zdravstvene ustreznosti pitne vode. V izbranih vzorcih iz Ljubljane smo analizirali tudi per- in polifluoroalkilne snovi. Končni cilj je predstavljala izračunana vrednost indeksa kakovosti vode po Brownu. Rezultati kažejo, da so fizikalno-kemijski parametri v večini primerov ustrezali zahtevam Uredbe o pitni vodi, izjema je bil vzorec domačega vira po obilnih padavinah, kjer je bila motnost presežena. Mikrobiološke analize so pokazale, da sta bila oba vzorca domačih pitnih vod, Slovenj Gradec in Otiški Vrh, mikrobiološko oporečna, medtem ko so vzorci javnih vodovodov ustrezali zahtevam. Izračunani indeks kakovosti pitne vode je potrdil, da je kakovost vode iz javnih vodovodov izjemno visoka, medtem ko domači viri zahtevajo pogostejši nadzor.
Keywords: pitna voda, indeks kakovosti vode, mikrobiološke analize, trdota vode, parametri kakovosti vode
Published in DKUM: 04.09.2025; Views: 0; Downloads: 17
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7. New approach for adsorptive removal of the antibiotic ciprofloxacin: carboxymethyl-dextran-functionalised magnetic iron oxide nanomaterialsErik Mihelič, Lidija Fras Zemljič, Marjana Simonič, Sašo Gyergyek, Alenka Vesel, Silvo Hribernik, Matej Bračič, Ivan Anžel, Olivija Plohl, 2025, original scientific article Abstract: Antibiotic residues in environmental media pose a significant health, social and economic problem and require effective removal strategies. This study presents a novel approach for the removal of the antibiotic ciprofloxacin from water sources using magnetic iron oxide nanoparticles (MNPs) synthesised by co-precipitation, and subsequently functionalised with the polysaccharide carboxymethyl-dextran (CMD). The prepared nanoadsorbent was characterised extensively by various physicochemical analyses, to evaluate its morphology, crystal structure, surface chemistry, electrokinetic properties, thermogravimetric properties and magnetic features. These analyses confirmed the successful functionalisation of the MNPs with CMD highlighting its potential for effective adsorption applications. The stability of CMD coating on MNPs was evaluated in terms of total carbon content, an important, yet often overlooked factor. The adsorption performance of MNPs@CMD for ciprofloxacin was investigated systematically by studying the effects of adsorbent dosage, pH, initial ciprofloxacin concentration, ionic strength, adsorption time and kinetics, temperature, and reusability. Under optimal conditions, nanoadsorbent exhibited a satisfactory maximum adsorption capacity of 14.71 mg/g, and maintained a removal eff iciency of 79 % after four cycles, with minimal desorption of CMD layer on the MNPs. These findings demonstrate the potential of this magnetic polysaccharide nanoadsorbent for effective removal of ciprofloxacin from aqueous environments, enabling magnetic recovery and reuse.
Keywords: Carboxymethyl-dextran-MNPs, ciprofloxacin, adsorption
Published in DKUM: 26.05.2025; Views: 0; Downloads: 17
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8. The application of zeolites for fixation of Cr(VI) ions in sedimentsMarjana Simonič, 2025, original scientific article Abstract: The aim of the study was to investigate the fixation of Cr(VI) ions from contaminated sediments using synthetic zeolite 4A and natural zeolite clinoptilolite. Parameters such as pH, contact time, adsorption mass and temperature were investigated. If the ions of the heavy metals were mobile, they would become toxic to the environment. After sediment digestion, the initial and final concentrations of Cr(VI) were measured in sediment samples with or without zeolite. Inductively coupled plasma with optical emission spectroscopy (ICP-OES) and X-ray diffraction (XRD) were used to characterize the material. The adsorption kinetics were investigated using a pseudo-first order model, a pseudo-second order model, and an intra-particle diffusion model. The results showed that the zeolites enhanced the fixation of Cr(VI). Chemisorption was the main mechanism when using acid-modified zeolite.
Keywords: sediment, fixation, heavy metals
Published in DKUM: 19.05.2025; Views: 0; Downloads: 1
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9. Improving lignocellulosic and non-lignocellulosic biomass characteristics through torrefaction processMaja Ivanovski, Danijela Urbancl, Aleksandra Petrovič, Janja Stergar, Darko Goričanec, Marjana Simonič, 2022, original scientific article Abstract: In this study, three locally available biomasses, namely miscanthus, hops, sewage sludge,
and additionally, their mixtures, were subjected to the torrefaction process to improve their fuel
properties. The torrefaction process was conducted at 250–350 ◦C and 10–60 min in a nitrogen
(N2) environment. The torrefaction temperature and time were studied to evaluate the selected
biomass materials; furthermore, heating values, mass and energy yields, enhancement factors,
torrefaction severity indexes (TSI), and energy-mass co-benefit indexes (EMCI) were calculated. In
addition, thermogravimetric (TGA) and Fourier transform infrared analyses (FTIR) were performed
to characterize raw and torrefied biomass under the most stringent conditions (350 ◦C and 60 min).
The results showed that with increasing torrefaction temperature and duration, mass and energy
yields decreased, and heating values (HHVs) increased for all studied biomasses. The results of the
TSI and EMCI indexes showed that the optimum torrefaction conditions were as follows: 260 ◦C
and 10 min for pure miscanthus and hops, whilst this could not be confirmed for the sewage sludge.
Furthermore, the combination of sewage sludge and the above-mentioned types of lignocellulosic
biomass exhibited better fuel properties than sewage sludge alone.
Keywords: lignocellulosic biomass, sewage sludge, torrefication, thermogravimetry, TSI
Published in DKUM: 10.04.2025; Views: 0; Downloads: 16
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10. Cu(II) and Ni(II) adsorption on torrefied wood waste biomassMarjana Simonič, Darko Goričanec, Aleksandra Petrovič, Ilda Silić, Danijela Urbancl, 2025, original scientific article Abstract: The aim of the research was to study the torrefaction processes of wood biomass, compare the product characteristics at different torrefaction temperatures, and assess both moisture adsorption on raw and torrefied samples, as well as metal (Cu(II) and Ni(II)) adsorption on torrefied biomass. The novelty of the research was to investigate whether the presence of adsorbed metals in torrefied biomass significantly affects the energetic properties of the torrefied biomass, compared to torrefied biomass without metals. First, wood samples were torrefied at temperatures of 250 °C, 350 °C, and 400 °C. Following torrefaction, thermogravimetric analysis (TGA) was performed to evaluate mass loss and thermal stability. Next, changes in surface functional groups were examined, and higher heating values (HHV) were measured to assess the energy content. The results showed that torrefaction significantly increased the hydrophobicity of the biomass, leading to reduced moisture adsorption and enhanced material properties. Additionally, the adsorption of Cu(II) and Ni(II) ions on torrefied biomass was investigated. The results showed that the adsorption efficiency for Cu(II) was higher, reaching 62.4%, compared to Ni(II) at 21.2%. The adsorption process followed a pseudo-second-order kinetic model, which indicated that chemisorption was the dominant mechanism.
Keywords: adsorption, torrefication, nitrogen atmosphere, metals
Published in DKUM: 12.03.2025; Views: 0; Downloads: 6
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