1. Določitev optimalnega markerja homogenosti krmnih mešanic : magistrsko deloKristina Gluhak, 2019, master's thesis Abstract: Krmne mešanice so sestavljene iz organskih in anorganskih materialov. Zakonodaja zahteva, da so zmesi krmnih mešanic po sestavi homogene in da posamezne komponente med zmesmi ne povzročajo kontaminacije krmnih mešanic med sabo, zato je potrebno izvesti testa homogenosti in navzkrižne kontaminacije. Kot markerji se lahko uporabljajo posamezna barvila (na primer metilvijolično), antibiotiki, kovine, magnetni delci itd.
Osnovni namen raziskav v okviru magistarskega dela je razvoj analizne metode, ki bo po statistični obdelavi rezultatov omogočala kvantitativno določanje markerja v različnih krmnih mešanicah. Proučevali smo manganov(II) oksid (MnO) kot možni marker. V vzorcih koruze in krmne mešanice smo analizirali vsebnost petih kovin: bakra, kalija, mangana, fosforja in cinka. Vsebnost kovin smo določili z induktivno sklopljeno plazmo z optično emisijsko spektrometrijo (ICP-OES). Pridobljene rezultate kemijske analize smo komometrično obdelali. Izbrane kovine smo analizirali na vzorcih podjetja Perutnina Ptuj d.d.
Izvedli smo validacijo analizne metode in ovrednotili merilno negotovost. Ugotovili smo, da je metoda določanja izbranih kovin v koruzi in krmni mešanici z ICP-OES linearna, natančna, točna in primerna za ovrednotenje vsebnosti izbranih kovin v navedenih vzorcih.
Keywords: ICP-OES, homogenost, koruza, krma, marker, validacija, merilna negotovost
Published in DKUM: 10.10.2019; Views: 1407; Downloads: 108
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2. Effect of low-density static magnetic field on the oxidation of ammonium by Nitrosomonas europaea and by activated sludge in municipal wastewaterJasmina Filipič, Barbara Kraigher, Brigita Tepuš, Vanja Kokol, Ines Mandić-Mulec, 2015, original scientific article Abstract: Ammonium removal is a key step in biological wastewater treatment and novel approaches that improve this process are in great demand. The aim of this study is to test the hypothesis that ammonium removal from wastewater can be stimulated by static magnetic fields. This was achieved by analysis of the effects of static magnetic field (SMF) on the growth and activity of Nitrosomonas europaea, a key ammonia-oxidising bacterium, where increased growth and increased ammonia oxidation rate were detected when bacteria were exposed to SMF at 17 mT. Additionally, the effect of SMF on mixed cultures of ammonia oxidisers in activated sludge, incubated in sequencing batch bioreactors simulating wastewater treatment process, was assessed. SMFs of 30 and 50 mT, but not of 10 mT, increased ammonium oxidation rate in municipal wastewater by up to 77 % and stimulated ammonia oxidiser growth. The results demonstrate the potential for use of static magnetic fields in increasing ammonium removal rates in biological wastewater treatment plants.
Keywords: odpadne vode, bakterije, Nitrosomonas europaea, statično magnetno polje, biološke čistilne naprave, nitrifikacija
Published in DKUM: 24.07.2017; Views: 1171; Downloads: 361
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3. Kinetic studies of catalytic ozonation of atrazineBrigita Tepuš, Marjana Simonič, 2008, original scientific article Abstract: The aim of our work was to degrade atrazine by the ozone treatment of both a model and the original drinking water samples, using Pt-catalyst, and to evaluate the performance of this catalyst. The rate constant for the reaction of atrazine with ozone was determined in the model water sample. The activation energies and the reaction orders of ozone decomposition were determined in both the model and the drinking water samples. Ozone treatment using Pt-catalyst has some influence on the loss of atrazine in the sources of drinking water. The concentration of some metabolites in the model and drinking water was observed during ozone treatment. The toxicity of atrazine to crustacean Daphnia magna in the original drinking water and in the ozone treated water samples was also assessed.
Keywords: ozone, Pt-catalyst, atrazine, water treatment, waste water, kinetics
Published in DKUM: 05.07.2017; Views: 1352; Downloads: 86
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4. Denitrification of spent regenerated brine using molassesBrigita Tepuš, Marjana Simonič, Aleksandra Petrovič, Jasmina Filipič, 2014, original scientific article Abstract: Spent BRINE from the regeneration of exhausted resins has to be properly treated before its disposal. The heterotrophic denitrification of regenerated brine was studied in present work. Molasses which served as a carbon source has until now not been applied during brine denitrification. The nitrate and nitrite consumptions were observed according to different ratios between total organic carbon and nitrate (TOC / NO3 ratios) and the influence of NaCl was studied during batch experiments. This work ascertained that molasses is a very good source of carbon, and no addition of other nutrients is necessary. The complete nitrate removal from regenerated brine could be achieved using molasses.
Keywords: nitrate, denitrification, regeneration brine, molasses, kinetics
Published in DKUM: 05.07.2017; Views: 1326; Downloads: 414
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5. VPLIV POLIELEKTROLITOV NA VSEBNOST SUHE SNOVI V ODPADNEM AKTIVNEM BLATUNika Zrilić, 2015, master's thesis Abstract: Magistrsko delo obravnava problematiko s področja čiščenja odpadnih voda, pri katerih uporabljamo konvencionalni postopek čiščenja z aktivnim blatom. Zajema opis odpadne vode, virov in njenih lastnosti ter predstavlja postopek čiščenja z aktivnim blatom, proces flokulacije in uporabo različnih polielektrolitov pri procesu dehidracije blata. V preliminarnih poskusih, ki smo jih izvedli na ČN Ptuj, smo s spreminjanjem pretoka na centrifugi preverili, kako omenjena sprememba vpliva na vsebnost suhe snovi v odpadnem aktivnem blatu. Izvedli smo tudi primerjavo med JAR-testom in ročnim mešanjem pri doziranju polielektrolitov.
Namen magistrske naloge je bil preveriti vpliv dodatka različnih polielektrolitov, s katerimi smo želeli zvišati vsebnost suhe snovi v odpadnem blatu. ČN Ptuj uporablja polielektrolit Acefloc 80902+. S preverjanjem učinkovitih polielektrolitov smo preverili, ali lahko povečamo vsebnost suhe snovi v odpadnem aktivnem blatu z uporabo različnih polielektrolitov. Pri tem smo uporabili različne polielektrolite, ki smo jih dobili s strani različnih proizvajalcev. Preizkusili smo tekoče in prašnate polielektrolite, ki smo jih dozirali odpadnemu aktivnemu blatu v različnih količinah. Določili smo optimalne koncentracije polielektrolitov, ki bi bili primerni za dosego čim večjega deleža suhe snovi v dehidriranem blatu. Po filtraciji blata (supernatanta) smo določili naslednje parametre: TOC, pH, prevodnost, alkaliteto in motnost. Na podlagi analiz smo ugotovili, kateri izmed polielektrolitov daje najbolj zadovoljive rezultate. Za najučinkovitejše polielektrolite smo naredili ekonomsko analizo in predlagali, kateri polielektrolit bi bilo smiselno uvesti na ČN Ptuj.
Keywords: odpadna voda, čiščenje odpadnih voda, aktivno blato, flokulacija, polielektrolit
Published in DKUM: 04.03.2015; Views: 2334; Downloads: 326
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6. Uncertainty of nitrate and sulphate measured by ion chromatography in wastewater samplesBrigita Tepuš, Marjana Simonič, 2007, original scientific article Abstract: This paper presents an evaluation of measurement uncertainty regarding the results of anion (nitrate and sulphate) concentrations in wastewater. Anions were determined by ion chromatography (EN ISO 10304-2, 1996). The major sources of uncertainty regarding the measurement results were identified as contributions to linear least-square or weighted regression lines, precision, trueness, storage conditions, and sampling. Determination of anions in wastewater is very important for the purification procedure, especially the amount of nitrate in waste and potable waters. The determined expanded uncertainty was 6% for nitrate anions and 8.3% for sulphate anions. The difference between measurement uncertainties determined by the two methods, the weighted and linear least-square methods is negligible.
Keywords: wastewater, nitrates, sulphates, measurements, measuring uncertainty
Published in DKUM: 01.06.2012; Views: 1902; Downloads: 364
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