Use of Fenton oxidation to remove antibiotics from the pharmaceutical wastewaters

Zaradi velike količine uporabljenih antibiotikov je vse več le-teh prisotnih v odpadnih vodah. Na biološki čistilni napravi jih je nemogoče razgraditi z aktivnim blatom, saj so antibiotiki lahko strupeni ali pa so molekule enostavno preveč kompleksne za biorazgradnjo. Posledica tega je akumulacija, bioakumulacija v organizmih in s tem prenos po prehranjevalni verigi, hkrati pa tudi povečanje odpornosti vse več bakterij. V magistrskem delu smo želeli določiti učinkovitost predčiščenja modelne farmacevtske odpadne vode s Fentonovo oksidacijo za tri antibiotike, in sicer za tiamulin, amoksicilin in levofloksacin, ki se uporabljajo v veterini in humani medicini. Zanimalo nas je, če uporaba Fentonove oksidacije kot predčiščenje na biološki čistilni napravi vpliva na povečanje učinkovitosti celotnega čiščenja farmacevtske odpadne vode. Fentonova oksidacija je eden izmed naprednih oksidacijskih postopkov, ki lahko razgradi antibiotike na manjše oziroma manj kompleksne molekule. Zanimalo nas je optimalno razmerje med katalizatorjem (Fe2+) in oksidantom (H2O2), s predpostavko, da bo učinkovitost čiščenja premosorazmerna z dodatkom oksidanta. Z določanjem kemijske potrebe po kisiku (KPK) in celotnega (totalnega) organskega ogljika (TOC) smo sledili razgradnji antibiotikov in z oksidacijskim številom stopnji mineralizacije. Na koncu smo ovrednotili biorazgradljivost razgradnih produktov oksidacije in nazadnje določili še njihovo strupenost. Rezultati so pokazali, da predčiščenje s Fentonovo oksidacijo prispeva k povišanju učinkovitosti čiščenja na biološki čistilni napravi. Pri tiamulinu se je biorazgradnja povišala za 8 % pri najvišji dozi oksidanta v primerjavi z začetnim vzorcem, hkrati pa se je zvišala tudi strupenost. Pri amoksicilinu pa se je biorazgradnja povišala za 16 % in pri levofloksacinu za kar 62 % pri najvišji dozi oksidanta. Za razliko od tiamulina pa se je pri obeh ostalih antibiotikih strupenost zmanjšala. Razlika v učinkovitosti čiščenja modelnih odpadnih voda antibiotikov se pokaže pri različnih dozah oksidanta.Due to the huge amounts of antibiotics used, they are increasingly present in wastewaters. In a biological treatment plant antibiotics can not be degraded by activated sludge, because of possible toxicity or simply because the molecules are to complex for biodegradation. The result is accumulation, bioaccumulation in the environment and in living organisms, so therefore antibiotics circulate in the food chain, and at the same time the resistance of more and more bacteria is increasing. In the master\u27s thesis, we wanted to determine the efficacy of purification of model pharmaceutical wastewater with Fenton oxidation for three antibiotics (tiamulin, amoxicillin and levofloxacin) which are used in veterinary and human medicine. We were interested in whether the use of Fenton oxidation as a pre-treatment in a biological treatment plant affects the efficiency of the entire treatment of pharmaceutical wastewater. Fenton oxidation is one of the advanced oxidation processes that breaks antibiotics to smaller or less complex molecules. We were interested in the optimal ratio between the catalyst (Fe2+) and the oxidant (H2O2), with the assumption that the treatment efficiency will be related to the addition of an oxidant. By determining the COD and TOC, we demonstrated the degradation of antibiotics and the rate of mineralization by calculating the oxidation number. Finally, we evaluated biodegradability of degraded oxidation products and finally the toxicity was tested. The final results showed that pretreatment with Fenton oxidation contributes to increase efficiency of the treatment. In the case of tiamulin, biodegradability increased by 8% at the highest oxidant dose compared to the initial sampleat the same time, toxicity levels increased. While when testing amoxycillin and levofloxacin biodegradability increased for 16% and 62% respectively, at the highest dose of the oxidant. Unlike tiamulin, toxicity decreased with other antibiotics. The difference between treatment efficiency of antibiotics is shown at different doses of the oxidant